88tbird Maf, A9P 306, 21lb inj, GT40 heads, Professional products Upper & lower.
car has hi/low beam mod where when the hi beams are seleted the low beams remain on.
Car runs a lot of led conversion lighting in either bulbs or led lighting strips along the bottoms of the doors... which are off when the doors are closed.
Issue--
while at speed, the engine will shut down for a time frame of less than a second to a max of a couple seconds then recover.
This situation is more re-occurring or "more pr0nounced" during cooler days and / or during the time frame of the first t-stat cooling exchange.
Visual / feel symptoms--
The tachometer drops to zero rpm, all other gauges remain online and within normal visual expectations.
The symptom can be "forced to happen" if extra heavy loads are added to the alternator such as hi-beams.
This may be misleading because the key is still on so if the EEC shuts down, the coil will loose its ref ground yet other cluster items will still be powered "on" since the Alt is getting input signal and producing voltage because the belt is spinning.
the overall misleading affect is that the Tach is the only thing that reacts during the event.
We are into researching what the issue is for nearly all of 2019.
the car is a daily driver and is my son's car which with work and little time off, it limits progress but slowly we eliminate probable faults.................
Troubleshooting---
pulled codes,,,, we had ....
18 - gone now that tfi harness is fixed
91 & 95 - still remains
after codes are dumped, we proceed with cylinder balance test and passed.
We found that if with the most lightest of touch, if you moved the TFI harness, the symptom occurs.............
>> purchased from LMR a TFI harness repair kit and retested.
replacement of the above did not cure the issue.
Replaced Dizzy as a whole kit from one of the box stores...... did not fix the issue.
-did fuel pres test while driving and gauge taped to windshield.. pres was low"ish" during low RPM's and around high"ish" during high rpm's like 40 or so.
-kept fuel pres tester connected while the car was off and parked, several hours later the pressure finally arrived at zero... like 7 hours or more.
we began to shotgun troubleshoot,, cause really we dont know here else to go other than REPLACE THE FUEL PUMP which has not been done yet.
we replaced the dizzy, dizzy harness, coil, plugs, wires, ECT, ACT, Alternator, Battery, Ign sw, i ign sw harness from LMR, O2 sensors, replaced EEC capacitors, EEC relay, added grounds to the engine bay, cleaned the MAF,
we are looking at replacing the EEC and the fuel pump next up.
I have recommended to Mason (my son the owner whom is out of state), to do the following .....
Pull every friggin fuse not required to make the car run and retest. Even if this means he has to drive with emergency flashers on as a safety step on public roads.
If we are lucky enough to find the symptom is gone, this lets us insert fuses back into the car until the issue comes back which then tells us which ckt is a probable fault.
if the symptom remains, it tells us what remaining ckts to focus on.
Help anyone??????????????????
Scott
304 772 3411
Stock or Aftermarket distributor?
Wow. You have done a lot.
If shaking and moving the TFI harness is still doing it, it makes me think that area.
Is the ignition switch the original one? They can cause some strange things when failing. Good luck man.
Replace the ign switch. Pulling all the fuses is halfassed and a waste of time to boot.. ;)
He said he had already replaced the ignition switch, and ign switch harness.
I would closely inspect the fusible link/pwr wire for the EEC . It's by the battery on the hot side of the starter solenoid. I've seen symptoms exactly as you are describing that stemmed from a damaged wire that was hard to see because its in that rat's nest of wiring that connects at the starter solenoid. It had what looked like a split or knife nick immediately below the fusible link itself, causing intermittent contact/loss of power to EEC and the car to do split second shut offs sporadically . Soldered in a new wire/fusible link and problem was gone.
Also, with car idling, a wiggle test of the salt and pepper shaker connectors for the EFI harness at the back side of the intake might be a good idea.
Make sure the coil HV or a plug wire is not too close to the TFI cable harness. It may cause "cross talk" on the TFI wires.
Didn't see where he'd mentioned replacing the ign switch..my bad.
Vintage is spot on with the EFI connectors, I'd also borrow a known good EEC and try in it for a day or so.
Where are you going with the fuel pump? That doesn't sound to me like it's a cause. :dunno:
thanks everyone for the replies,,,
i will answer at random to all....
ign sw changed,, dizzy is stock replacement.
Good info on cross talk softtouch, i had heard about such a oddity but over the years forgot all about it till you mentioned it.
purpose for the fuel pump i spoke to is because the computer has reason to dump a code pertaining to the fuel pump.
ok.................................... more details on "how we troubleshot.... which someone may need to try this themselves one day.
We will check the fuse link mentioned... that something i have not tried yet.
=================
I went out on a limb and early on told mason , lets avoid dumping money at the issue and use a temp test light while driving to "catch" the intermittent in the act.
Initially we were focused on the Tachometer signal since it was going dead during the event. I told mason to temp tie in a rigged up test lamp to the EEC relay by tapping the coil +12v side. bring the fused wire over to the steering wheel area and add a tiny bulb then ground the other side of the bulb.
With koeo or koer,, the lamp should be on.
when the shut down happens, we should see the lamp momentarily blink off. For some reason this never happened telling us the EEC relay remained energized during the event.
we are attempting over time to wash / tense and repeat this process on other individual circuits we want to monitor.
I was running through some diagrams and apparently the eec provides the coil primary with a ref ground to fire off spark but not before this ref ground is sent through a resistor.
we did do a wiggle test on fuse links and salt // pepper conn's to try to "cause" the issue with no luck.
we are going to attempt to refocus on the fuse link area.
The wire with the resistor from the Tach side (ground side) of the coil to pin 4 of the EEC is how the EEC monitors the circuit.
It is supposed to give a code 18 if it malfunctions. I am surprised you don't still have a memory code 18.
There are three ways you can loose spark and tachometer reading:
!. Loosing voltage on the Batt side of the coil. A good place for your test light.
2. Tach side of coil not being switched between ground and no ground by the TFI. The PIP pulse from the TFI to the EEC should cause the EEC to send the Spark Out pulse to the TFI. Try running with the SPOUT jumper pulled out. This will take the EEC and associated wiring out of the picture.
3. Something holding the Tach side of the coil to ground. Try disconnecting the tachometer. Probable easier said than done if this is a factory tachometer.
About the fuel pump code 95. You may want to review the MASS air upgrade instructions. I believe there is a wire you have to add to pin 8 of the EEC. The speed density EEC's did not monitor the fuel pump circuit.
its so refreshing to have some help.
I will call mason now and tell him to check this thread.
I think i can isolate the tac by the second lead on the coil if i recall correctly.
Also, i believe we did actually run the car without the spout... i will check with mason. he will be home this weekend for a couple days along with my other boy chance.
we did add wires per eric's posted instructions,,
also,, mason is going to test hit without the spout,, i dont think we've tried that yet.
I told him to get on here and take control of this thread.
with spout unhooked,
car started fine
when we added rpm no issues...
when we turned on headlamps during high rpms sitting still, the car sputters and misses.
I never asked, can we drive with spout out?
This intermittent issue happens "sometimes" when we turn on headlamps,, and yet it happens sometimes without headlamps on,,,
the intermittent happens more often during the first coolant cycle exchange time frame **OR** if its colder. outside.
when the car is warm,, the issue happens less and less BUT*** we can make the issue happen with a hot motor if we simply add headlamps.
the important note about headlamps is................. we are only "USING" headlamps as a sure fire way to verify if the problem is still present or not.
the engine shut down happens regardless of picking headlamps or not.
Just out of curiosity, what brand of ign switch did you replace the stocker with?
i replaced with another stock unit,, i believe mason got the ign sw & pigtail from LMR
can we test drive the car without a spout installed>?
Check the voltage at the Batt side of the coil:
1. With the key on.
2. With the engine running.
3. With engine running and the head lights on.
4. With the engine running and the headlights and any other electrical load you can think of. HVAC blower, rear window defogger, etc.
5. Next, turn the key off and unplug the TFI connector.
6. Turn the key on and check the voltage between the Batt and the Tach (one wire on the Batt, the other on the Tach) at the coil. Should be close to zero. A voltage here shows a current draw through the coil without the TFI involved.
will do today..... thank you,,,, i know where you are going with this softtouch
answer below to voltage reading request but i took it a step further
1st is from batt neg to coil battery, 2nd is from coil battery to chassis
i figured since we are at it, why not get this info as well.
1. With the key on.
12
12
2. With the engine running
13.8
13.9
3. With engine running and the head lights on.
low beam
13.8
13.8
hi-beam
13..8
13.8
4. With the engine running and the headlights and any other electrical load you can think of. HVAC blower, rear window defogger, etc.
all on
12.95
12.65
#5 & 6... sorry,, will get that later today or tomorrow morning, mason has to get on the road....
mason just broke down in south western va
called for a tow,, he's about an hour from his house.... so maybe later i can update.
the car started to go into on of its random fits after an hour of back road hilly driving.
it just went dead and stayed dead, he coasted to a safe area and got off the road.
he got out and check the shrader valve for fuel,, got a pretty good spray.
he pulled the coil wire off the dizzy and pull all the slack towards the driver door and with the other hand turned the key,,, he seems to think there is no spark.
while waiting on a tow... the car cooled down a bit and he tried to start again and it started for about a couple seconds.
waited a little bit more and the car ran again just a smidge longer.
update,, mason is home
when the tow truck got there he actually drove the the car upon the flatbed!!!!!!!!!!!!!
he got home,, all is well,, the car is running fine so he went off to see food at food lion and drove home.
first thing we notice is THE CLOCK lost power because its reset.
the area he was driving gave a temp reading of around 205,, lots of hills and such.
this computer came from Vinnietbird... and is a reman.
normally this issue happens more often with the air is colder outside.... but thats not the case today.
i wonder if this reman eec has a safety shut down ckt thats wearing out,,,,,, isnt there one on the eec for shutting down the car if excessive temps are reached? this is a eec from an application of mass air. not sure if those eec have such a safety shut down ckt.
softtouch-- here is results to your remaining 2 questions
5. Next, turn the key off and unplug the TFI connector.
6. Turn the key on and check the voltage between the Batt and the Tach (one wire on the Batt, the other on the Tach) at the coil. Should be close to zero. A voltage here shows a current draw through the coil without the TFI involved.
results
0 volts measuring on the TFI from pin 4 to 5 with key on engine off
these two pins are tac and battery directly on the connector itself
We moved on and pulled codes
on demand codes are qty of one = 95
memory codes are qty two = 18 & 95 (this code 18 shown does play into your earlier curiosity).
we are currently setting up to focus on the fuel pump ground ckt which is an ORANGE WIRE under the passanger seat.
What i want to do is jumper around the fuel pump relay with the KOEO, jumping the yellow to pink//black.
I will then have mason bang on the tank & wiggle test wring with the end game to discover if there is an intermittent somewhere.
once that is done, we will ground the tan/light green wire at the self test conn, then turn to KOEO and listen for continuous fuel pump running. we will then bang around on wiring, tank and wherever else to try to create an intermittent.
we will back pedal over to the earlier comment about the Clock lost power during masons roadside breakdown. i notice on the fuse panel, fuse 8 is apart of a separate dc busswork on the fuse panel..... lets call it dc buss #8 which consists of fuse 4,8,16 & 12. this DC buss bypasses the ign switch and is a home run to fuse link E (bk/or).
The EEC shouldn't shut the car off it if gets too hot. It has no way to so. Plus 205* is in the normal operating temperature range.
We are now getting closer to the issue but its still vague....
We started the car and it idles , we have no way to know how long it will idle if we let it do or even if it will eventually die.
What we do know is that with a cold motor if we add RPM at or over 3k,, the engine will cut out,, yet the pedal is still pushed in.
"think rev limiter!!!
we tested this again,, holding the pedal to around 3k,, and the rpm came up but then the engine tries to die but then recovers.
all this with our foot still holding the gas pedal in the same 3k rpm spot.
since we know the car is now stalling out if you hold the pedal to around 3k,, we move to spark visual. we check on spark and its bluish white.. so spark seems ok.
we grounded the tan/light green at the self test conn then went to koeo.
the fuel pump did not actually sound steady ,, you know the mechanical noises things can make if there is wear and tear. the pump is older though,, like *a lot* older, at least 80k miles older.
With the FP running we wiggle tested & lightly banged on things in the trunk, on the bottom of the fuel tank, the EEC area, the starter relay area and under the pass seat. fuel pump did not cut off.
we connected a test light to the fuel pump power wire Pink / Black.
we stated and it idles fine.
we push and hold the pedal and he engine responds but as we hold the pedal, the engine itself falls on its face.
the rpms go down on thier own and the engine tries to recover.
The test light remains on during the entire event of the engine falling on its face... so the EEC is referencing a good ground to the FP relay,, and the relay itself is staying energized.
this is starting to sound like a fuel pump ............... mason is going to run up to autohole to buy a presure tester.. its about time he owned one anyway.
tested fuel pres sitting still.
lol.. like we can drive it!!
ok
FPR vac line disconnected and cap on end
start car= 40psi
rev to around 3k and engine cuts out and begins to stall but recovers ,, but.. Fuel tester remained at 40psi the whole time.
well now this really sucks.....
removed belt
started car on battery only...................
Problem narrowed down.... Car runs as it should!!!!!!!!!!!!!!!!!!!
Issue number 1- we need to have a belt!!!
so... now we begin troubleshooting.
now we are examining all things about this attachment.
a doc we all contributed to over a few years,, this version includes specifics to the 2.3L as a result of lessons learned the hard way by one of our members
it appears that all these years the 3G upgrade this car has was never completed.
we have a 3g alt installed.
our yellow reg wire ends up landing on the starter relay (not really such a big deal,, voltage drop is my only issue... but it is still getting battery on this "A" terminal.
our red wire is taking the long way around by following the upper rad core support,, i would have sent that large output wire in wire loop across the motor and groom it to the starter relay to eliminate about 9feet of wire.
here is where it gets interesting.
in our current config..... on the output stud of the alt, we have a large power wire that leads to the batt side of the starter relay. in parallel with that we have what appears to be an OEM brown/org wire that follows the long way around also but enters into the fire wall within the factory wire harness.
we are taking the battery out now to examine wires in the loom under the battery tray.
ok,, we are at a point of no more things to check.
right now with no belt installed, the car runs as it should.
our 3g alt wiring may not actually "look " correct but electrically it is not a problem.,,, and has not been a problem since it was done by the previous owner Privateer who is member.
we did the following...
undid the entire wire harness loom from the alternator , all the way across the upper rad core support and all the way around under the battery to visually inspect.
continuity checked the alternator regulator yellow / white wire all the way up to the starter relay ring terminal with both ends disconnected.=pass
continuity checked the alternator regulator gray wire on either end and isolated, = pass
continuity checked both starter relay studs to chassis= open-pass
we put the belt back on the car and monitored alt output voltage to be around 14.6vdc and gently increased RPM to see if the voltage followed throttle, it did not, it held right at 14.6 "ish" no matter the RPM so the alternator is regulating.
at one point we had ran on battery for a while and when we put the belt back on , our alt voltage was around 15.2... too high to me,, - thoughts on this?????????
what could be the problem..???????
any reasonable troubleshooting would say either the alt or the wiring for the alt is faulty somehow.
one thing i did not think of till now is i need to check the 3 pin connector at the alt from Pin to pin to see if the connector itself is failing. granted i need to isolate / disconnect both ends.
Are you sure the TFI and TFI harness are no longer wiggle or vibration sensitive.
The belt driven stuff and the belt itself can vibrate. The air from the belt driven fan may wiggle the wires.
i guess we are sure.... i dont really know how to answer... because
without a belt the car runs as it should without any cutting out at 3 or more K.
we are troubleshooting again so i will check on what your asking and report back
response to your question,,, after tfi harness repair,, the harness was secured to a diagonal AC compressor brace,, then when the car was running the harness was handled aggressively to confirm it would no longer cut out the car.
with belt installed and ***NO alternator connections made,, CAR RUNS AS IT SHOULD.
with the sense lead plugged in and with a belt & flipping headlamps on/off--- CAR RUNS fine
With sense lead and 3 pin connector plugged in and flipping headlamps on / off --- CAR RUNS FINE.
this means that without an alternator dumping angry pixies onto the starter relay,, all is well.
moving on to isolating which fuse link ring terminal re-introduces the problem by way of the alt output.
ok,, we just dd an isolated load bank test of the alternator.
we have a belt on
we have the 3 terminal connector connected
we have the 3g single wire terminal connected.
we have the alt output cable disconnected and safely secured back.
We connect the ground side of a 100watt load bank to the alt chassis. (a random spare headlamp bulb for some u/k vehicle)
we have our positive side of our load bank ready but not connected.
we start up the car and all is well, car runs as it should
we connect the positive side of our load bank to the alt output stud.
the 100watt load bank blows!!!
we measure the voltage on the output stud of the alt with no load attached since its now free spooling and it reads 35vdc.
so all this points to the alternator.
yet the alt seemed ok while in the car.
will report back......
mason is running a lot of LED converted bulbs in his car... including headlamps.
I am starting to think that LED's and the power supply they have ,, that within those conversion circuits, if there is even a minor failure,,, the alt may end up under stress and this may cause the alt regulator to not be stable.
this alt right not is prob only 3months old.
all i know to this point is that the alt itself and its readings while the car was running hit 15.2vd one time and thats when our batter had been significantly used as the stand alone power supply. within a few seconds the alt regulated the voltage to around 14.7vdc .... still to me that feels a tad high.
mason took the alt back to advance ,,, they say its good.
apparently box stores use automated testers now that depend on software and such to test an alternator.
I did ask a total of three advance auto parts stores about their tester,,,
i asked,, does your tester offer a step that tests with "NO" load. no one knows.
the point i am making here is that mason came back from advance after being told the alt was good,, he tested the alt with no load and now he is getting around 45vdc.
he is heading to autozone now, to have it tested there.
With the alt output disconnected, the A input to the regulator is at the 12volt battery level. It increases the field current to try to raise the voltage to 14.2 volts. It has maxed the alt out with full field current trying to get it up to 14.2 volts.
what are your thoughts on our voltage readings with no load?
That's what I was trying to explain.
The regulator is trying to raise the voltage to 14.2v but the voltage it sees at the A input stays at 12v.
It has nothing to do with load. The regulator is not seeing the alt output, it only sees the battery output.
with no load, do you know if its normal to have 35 or 45vdc?
What you are seeing has nothing to do with load.
The regulator is maxing out the field current because you have disconnected the alt output.
In other words, it can't see what voltage the alt is putting out.
The regulator is only seeing the battery voltage. It is trying to raise the voltage to 14.2 volts.
It keeps trying until it maxes out the alternator field current resulting the max voltage the alt is capable of.
ok... that value is not really "known". i would think that it would be though ,, at least a range not to exceed X volts.
so what do you suggest we test next?
we even made sure the A I and S terminals did not have continuity with each other and we even extracted them and manuallly slipped these onto the regulator. eliminating the connector itself.
i think i know how to remedy this issue,,
i need to sweep our yellow white wire temp down to the output stud so that the battery can be seen on the output stud....
currently the yellow white is home run up to the starter relay per stock config
I don't understand which end of the yellow wire you are planning to move.
Do you have another alternator you can try?
sorry ,
i had to run and get food for the dear ol' wife
ok,,
i plan to keep the yellow white terminated to the starter relay,, and also jump it down to the alt output post,, only when we do a load bank test to load down the alt.
I want to put load on it externally to verify the car still works fine when the alt is under load.
no we do not have another alt to try
That will work.
oddly convienet,, the previous owner put a 30A fuse near the alt in series with the yellow white,, so we are going to temp a jumper off this fuse blade and to the back of the alt.
We will restart the car and then see if the voltage output simmers.
we did pull codes earlier today in the middle of all this...
on demand KOEO=95, 18, 66
memory koeo=21, 94
setting up A terminal jumper now,, then will set up a load,, then start car, then add load.
Mason is saying oddly ,, the car seems to idle rough now. im thinking i would be to if i was messed with this much.
scott 304 772 3411
hummm..
with a short jumper from the A terminal to the alt out stud...and with the alt output cable disconnected... we start the car (which will now have the car running on battery) we find 200mv DC output.
we shut down car
we ohm from the alt output stud (red meter lead) to case (Black meter lead) we get a quick up ramp to 30mgOhm then open.
reverse our leads..
output stud (black meter lead) to the case (red meter lead) , we get 2.6mg ohms.
i thought you should have an open ohm value condition from the output stud to the alt case then reverse your leads and be reading through the diodes.
sorry about the output of the alt where i said it had only 200mv,, mason made a mistake understanding what i needed ... retesting
well ,,, i just discovered i cant isolate the alt output to a load bank,,,, due to how the original yellow white is still in place.. so i will move on.
hooking everything up to normal.
starter relay fully populated.. and alt fully populated with all normal wiring.
ok
we made our yellow "A" terminal loop down to the alt stud.. it is no longer terminated to the B+ of the starter relay.
we also re connected our main alt output wire back
start car... stepping and holding the pedal at around 3k,,, the car acts like it has a rev limiter,,, and recovers , falls on its face and recovers.
alt reads 38A @14.3vdc
Batt reads 24A @ 14.2vdc
we disconnected the alt output and CAR RUNS AS IT SHOULD,, accelerates way past 3k rpm
so we have come full circle
so over the course of today,,
we have been running the car without a filter and thats prob why we had a minor idle issue.
The engine has gotten a lot warmer over these different tests and i think we are close to simulating the situation where mason had to get a tow.
we throw the filter back in of course,, it came out because mason was taking apart wiring harness and such.. so he moved the air box cover and filter out of his way,,, and forgot to get the filter back in.
now that the engine is warmer,,, it is dying after it runs for a little bit. it dies earlier with a filter and lasts a tad longer without.
so now that we have a dying motor,, maybe the problem will be more revealing....??????
codes right now
koeo
on demand
95
memory
66
14
94
we are focusing on the fuel pump code for a lack of not knowing where to go.
while the engine had just died we tested again from the TFI pin 4&5 (tac and coil batt) and got less than .2 (two tenths) of a volts
we currently have the fuel pres tester hooked up and are comparing the point of when the motor dies and if the fuel pump falls off before the motor...
result=
engine dies first,, then only after the motor shuts down the fuel pres drops to about 35 and then around 30psi.
as the engine begins its death,, the rpms slowly start to sag.. then the motor recovers but then the motor starts to sag again and the motor dies.
so,, it appears the fuel pump remains on line throughout the engine problem from start up to its death.
I know i have a code for fuel pump ground but it seems ok.
codes now trying to rememdy moving code 95 to memory...
we added a jumper wire to the fuel tank to batt neg.
ran car till it died.
ran car again until it died.
codes now
on demand codes KOEO
95
Memory
14
66
95
87
ok,,
screw it..
we are doing a fuel pump.... and we are going in through the trunk.
we checked vac at idle,, steady 17psi
put vac tester on the fuel pres reg and it held 20psi rock solid for a long while. (engine off of course).
The MAF upgrade should have run a wire from the PK/BK wire that goes to the fuel pump to pin 19 of the EEC.
The 88 EVTM page 61 shows the wire already in there at C455. Shown as N/C (not connected)
This C455 is near the EEC and has the red , yellow and tan wires that go to the pump relay.
The EVTM shows you should have the pink/black wire there also.
This is the fuel pump monitor circuit.
This should have nothing to do with how the car runs.
thank you,,
update..
fuel pump changed,, problem remains.
we are moving over to test light the Coil and continuity check the eec pin 4 eec resistor and check that no TFI conductors are touching each other.
with battery unhooked,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
unplugged the ign sw
unplugged EEC
unplugged TFI
measured resistance of the Tach wire dg/y wire from the TFI conn all the way out to the eec conn = 22.6k ohms= pass
with eec hooked up,
we continuity checked all 6 conductors to each other up at the TFI
we have continuity from pins 3, 4, 5.
the 1988 evtm shows pin 3 lands on the eec eventually
the 1987 evtm does not show pin 3 goes to the evtem.
I went out to my 20th coug and found with my tfi unhooked, i to have continuity from pin 4 & 5 but not 3.
with eec unhooked
with tfi unhooked
we continuity checked all 6 conductors to each other up at the TFI
Pin 3, 4 , 5 have continuity to each other.
i do not know what to make of this.
moving on to coil "test light" test.
Coil test with test light
test light from red/lt gn to chassis
koeo= pass
koer= pass, add rpm light still holds strong ,, engine dies and light remains strong
test light across the primary
KOEO= no light pass
KOER= light comes on and pulses as expected,, add RPM and engine starts to die tach signal reacts accordingly in an irractic manner as the engine tries to recover until the engine dies and the light goes out.
so
what stands out in this post is that with the ign sw , eec & tfi unhooked along with battery unhooked, the TFI pins 3,4,5 have continiuity and i do not know why
next up,, we are going into the instrument cluster to see out our tac signal
it appears from our test light that the engine falling on its face around 3krpm is coordinating with the loss of tac signal on the gauge. our test light blink pattern tells us we have a spark related issue,,,
that will be tomorrow
this conductor has a splice point that offers 4 paths.
at the coil it offers two paths.
My EVTMs don't show the TFI connector pin numbers..
Can you reference the pin numbers to circuit numbers?
Did the test light blink pattern change before the engine completely stopped?
My research of the TFI connector tells me:
pin 3--Circuit 16 hot in start or run
pin 4--Circuit 32 hot in start.
pin 5--Circuit 324 SPOUT yellow/light green wire.
With the TFI & EEC connectors disconnected:
Pins 3 & 4 having continuity is OK. They both got to components that connect to ground.
Pin 5 SPOUT having continuity to any other pin NOT GOOD
here you go,,
pin 5 is not the spout,, pin 5 is the tach signal dg/y.
the 87 & 88 evtm diagrams do not match for 5.0L.
physically the colors are the same for all six pins in colors so the 5.0L diagrams are likely wrong.
Pin 3 of the tfi within the 87 evtm shows no termination to the eec
Pin 3 of the tfi within the 88 evtm shows a termination to the eec
softtouch,,
"if" its true that on the 87 cars,, pins 4&5 have terminations to the eec ,,, and if the 88 evtm is true to have pins 3, 4 & 5 wired to the eec,,, then perhaps what we are seeing is correct.
either way if we disconnect the eec, we should loose continuity yet you have identified a way for pins 4 & 5 to remain and tone out to each other.
if what you have found is true,, i am thinking it may be possible for pin 3 to also do the same thing,, pin 3 being the red/lt blu
Sorry for the long delay..Had to run over to Delaware this morning.
I googled the TFI pinout and came up with them numbered in the opposite direction.
Anyhoo the tach wire will have continuity to 3&4 because it goes to the Tachometer.
All three of those pins go to components that are referenced to ground.
The 88 EVTM doesn't show the Sport model cluster wiring. You have to look at page 47 Turbo wiring to see the Tach hook-up.
On page 149 cluster connectors, there is only one wire difference between turbo and sport lx and xr-7
ok,, then we may want to use wire colors,, i may be backwards on my numbering convention.
the physical connector i thought was labeled Top down 1-6. i recall and confirm what you are saying though.
here is the 88evtm showing pin3 (red / light blue also leading to the eec
earlier i said the RED/LB wire for the 88evtm terminates to the eec. which is what i refer to above as pin 3 .
this wire i speak to red/lb lands on the ign sw as another tap / color brn/wh ckt 376.
my point is i should stop using pin numbers and use wire colors.
so to edit my earlier post................
with the ign sw , eec & tfi unhooked along with battery unhooked, the TFI wires below have continuity with each other.
rd/lg
r/lb
dg/y
unhooked inst cluster= problem remains
moving on to isolating the tach signal dg/y
we will disc the batt then ..............
tone to chassis
then....
tone to the load side of each fuse to see if this wire is touching another load circuit.
tach signal wire has no continuity to chassis
tach signal wire has no continuity to any fused load
thinking on what to check next.
for the record...
when the event happens each and every time we demand rpm,, the engine cuts out and tries to recover.
the problem is more and more pr0nounced if the engine is hot.
when the engine is at driving temps,, it will fail to start at all.
Could this be a MAF problem....
i have spark
i have fuel
i have alternator
i have start up conditions easy if engine is not really super hot
car idles good
it falls on its face when we add pedal,, so i am thinking one thing that remains is airflow and the parts associated to that.
r/lg Hot in start & Run to EEC power relay coil..bottom of coil to ground (Chassis metal)
r/lb Hot in start to starter relay coil...bottom of coil to ground (Chassis metal)
dg/y Tach wire to tach electronic circuit in cluster. electronic circuit has a ground (Chassis metal)
They are all tied together through the chassis metal. That's why you have continuity between them.
ok,,
we are using a heat gun on the mass air sensor with a bone cold motor to simulate the car is hotter.
we are trying to see if we can make the car fail early by heating the maff housing .
we do know that when the car gets hot, the problem is more pr0nounced.
we might be on to something.
we heated the mass air and the problem remained.
we unplugged the mass air sensor and the engine should have died but it did not
we even added gas and the car tried to fit it a bit but it took the rpm we gave it and held.
we even turned on the headlamps.
normally when we give it rpm, to say 3k,, the engine sorta feels like it ramps up then rolls down to a dead stall.
we also get the same symptoms by simply picking headlamps. and some minor rpm.
so....
what say you all?
is there a possible condition that the maf could fail yet not throw a code?
i never knew how to,, but this guy did a decent job of dialing in the details.
https://www.youtube.com/watch?v=p0ocaDmcAIM
we will test our maf tomorrow
we followed some various ways to monitor the mass air flow sensor....
one way was to side tap a wire the computer is using to monitor the voltage.
maf unplugged on wire harness end , KOEO unless otherwise noted below,, here are the results
pin A = 12v
pin b = continuity to chassis
pin c = no continuity to chassis ( with engine running,, at idle, volts= .9v,, smoothly increased to 2vdc at wot),, somehow we were able to get some higher rpms to get this test.
Pin D= no continiuity to chassis,
It appears our maf is good.
engine and EEC grounded properly?
************** we gained info...................
we got the engine hot and now even without a belt we can make the car fail.
so.........the idea of taking the belt off has no relevance.
Also,,,
we gained another piece of info...
after the car did get warm,,, we lost all tack signal to the coil...
which means we lost spark.
the computer controls the ground ref to the coil,,, and apparently after the engine gets warm enough,, the computer will shut down spark.
beau,
we willl check that next
beau,,
yes good ground
we gained another piece of info...
after the car did get warm,,, we lost all tack signal to the coil (ground to the coil)...
which means we lost spark.
when the car fails,, while hot,, we try to restart and it wont,, and the reason why is there is no spark.
the computer controls the ground ref to the coil,,, and apparently after the engine gets warm enough,, the computer will shut down spark.
so,,,
its either the TFI or the computer..........
the web is saying that its getting hard to get a new TFI that is good out of the box.....
a few weeks ago when this issue was more tolerable and manageable, we decided to swap the dizzy for new from advance. the issue was getting worse and worse. we took the new dizzy from advance a few weeks later and traded it in for new...
so this car is on 3 dizzy's since feb.
so,, im confused..
im watching a vid on testing a tfi in a ford 5.0...
they is testing each side of the coil.. he is saying a few things that contradict what i thought.
he shows a test light to the batter side of the coil to chassis then he cranks,, light stays fairly solid,, no blinking etc...normal.
he show the other side of the primary with test light to gnd... like sorta blinks.... normal.
yet he says ***********the reason why my car is not actually starting is because there is no computer plugged in.!!!!!!!!!!!!!!!!
I was under the impression the eec supplied the pulsed reference ground to the coil.. he implies that the TFI does that job.
on this wire ,, in our cars , it ties to pin 4 on the eec and consists of a 22kohm resistor in series with it.
I am basing my not having spark after the engine is really warmed up and hot to the computer failing to provide a ground.
??????????????
OK,,
tomorrow i will make sure everything is connected up like normal.
if i disconnect the spout connector and the car runs fine,,, then that tells me something....
it means that ....
A- the computer is a probable fault when the spout is in
B- the reasons for the computer may be the computer itself or a low voltage input to the eec.
~~~ apparently if the input voltage from the eec power relay is sort of low,, and if the spout is plugged in you will have conditions of intermttant or no or low spark.
This also meants it misguides troubleshooting and wastes time.
C-wiring to or out of the eec power relay load side contacts is either experiencing high resistances or high resistances as a result of either load or heat.
to answer my own earlier question----- NO the computer does not manage the ground to the coil to deliver spark. that is done primarily by the TFI. the computer takes in a pip signal and sends it back to the tfi.
ran engine at idle till it got hot,,, got the motor to the point that stepping on the gas makes it cut out.
disconnected the spout connect and the car still did not start.
if the car started then that would mean a bad eec or power feed to the eec
it seems to be a TFI
replaced TFI,,, with no codes pointing to anything spark, lean , rich , pip etc,,,,, the TFI gave us continuous good running performance at idle for over an hour.
Step on the gas and all is well.
turn on the headlamps and step on the gas...... car starts to kick back and buck.
turn of headlamps
undo spout conn
restart car
all is well
add headlamps and car begins to buck and kick back on us.
turn off car and think
...................................................................
remove headlamp sw
start car with spout plugged in
paperclip jumper the headlamps to "ON"
car buck and kicks back on us... so............
I conclude thus far that the action of adding headlamps may perhaps be the cause of what i believe is the idea that this car is "EATING" TFI's. We are on our 3rd dizzy since march... meaning we either A- thought the box store dizzy was a out of the box failure or b- the car ate the ign module fairly quickly.
I believe we have rolled the clock back to about two weeks ago when the symptom was "car cuts out and dies randomly" although in my post 1 i implied early on that the addition of headlamps and the visual of loss of Tach seemed to be the only common denominators.
so... we are doing a test drive today with no headlamps to confirm that if no lamps are picked, we will find out if the car runs as it should. IF YES- we move over to looking at the possibility of the headlamps and the factory equipped auto-lamp ckts are not conflicting each other.
I do have some one piece f interesting news............
while the car was running during its 1 1/2 hour time frame,, mason took amp clamp readings on either side of the battery.
on the hot cable input he had 3amps, on the ground side he had 8 amps.
i find this odd personally. its as though there could be another active circuit that is back feeding chassis ground.
i told mason to install a blocking diode between battery neg post and battery negative ground cable in the correct direction so that the battery can see chassis but anything on chassis cant see battery neg.,,, that might not be a good idea but i am trying to see if we can find out whats up with 8amps on the ground side.
the alt total amps during the above i describe was about 14amps.
we discover that if we disconnect the battery negative, the car dies........... so.. bad alternator also.
its odd how all these things are running us in circles.
will have alt tested again by advance.... if they say its a good alt,, it proves their tester is not testing for everything.
Put a new or known good alt in there and let us know.
Is this car a V8 swapped TC or was it a V8 from the factory? I ought to remember, but can't.
If it IS a swapped TC, maybe the headlight harness is shaged. The TC used a different headlight harness than the V8 cars....if it was modified.....perhaps something is amiss.
Maybe I'm barking up the wrong tree here, too. I don't know.
But if the car acts up when the headlights are on, then something with that is way the hell out of place.
car is factory 5.0L,,
new alt installed.
no change.
the issue is this.....
-if the car is started, and gas is applied to around 2 to 3 k rpm,, the engine will cut out and sputter.
-if we add headlamps,,, this will increase "amplify",, not "cause" the issue. I say this because after several senerios of testing, this has become a fact.
******as a result of failing, the cause is spark becomes absent.
******we see this by having a test light on the coil green wire to chassis or across the coil to observe a strobe.
******the strobe is broken up or blinks some or not at all at around 2 or 3 k rpm.
it fails with or without headlamps.
we lose spark and as a result lose tach signal.
yesterday after new alt (BRAND NEW), was installed and we failed again, we moved on to this.....
-kept headlamp sw disconnected,
-disconnected multifunction sw
-retested and car still fails.
today we will.....
disconnect every single item in the car that we can to get to by fuse or connector till the situation is the car has only what it needs to start and run.
if problem is the same,, we may just make an assumption that ..............
-the EEC is failing to "manage the engine"
-the maf is bad ~although when we test it with our meter it seems to be doing fine.
focusing on why the car turns off when the battery negative is disconnected while engine running........................
disconnected EEC
-pin 20,40,60 all tone good to chassis
-pin 49 ad pin 6 also pass
we are retesting old spots.
start car...............
we hook a test light up from chassis to the red input of the coil primary.
strong constant light
while running , we hook a test light up from the chassis to the green of the coil primary
this causes the car to stall out and die.
we unhook the spout connector and get the same results.
Just checked back in, I havent read the whole thread yet, and I know you said in your orignal post that you replaced the coil. But symptoms sound a bit like you might have a bad secondary coil winding that is aggravated by either heat(expansion causing a gap or break in coil's internl winding) or strain of additional rpm above idle and/or additional vehicle electrical loads (headlights,etc) robbing enough of coil's input voltage to make it act up due to faulty internal winding.
Depending on how intermitent the problem is you can try to ohm it out with engine/coil cold and then again when warmed up or try a known good coil off similar car if you have one. The foxbody coils are all interchangeable.
I would not remove batt cables with engine running, it can hit the alt's voktage regulator pretty hard and if the regulator doesnt dig it, it can send a nasty voltage spike through vehicles electrcal system that will smoke your ecu, radio, or any other thing it feels like eating.
yeah,,
if the battery is in a load state, that is very true. we are troubleshooting now using the coil as a visual reference for the reference ground.
we may have this solved.
4 distributors and 5 TFI modules later..
the root cause seems to be the suppliers for Advance Auto.
one trip to Autozone today for a dizzy and all is well.
no issues at all.
we will button up all the mess we have caused chasing our tails and test hit tomorrow evening.
stay tuned.
confirmed,,,
root cause was the supplier "advance auto parts".
Problem solved using Autozone as the supplier.
car up and running great now.
thank you all for the help
Glad to hear it. Advance might need to tighten up a good bit on their suppliers.
Wow! all that because of py new parts!!! I usually don't go to Advance, now I will definitely stay away.
I went through 4 MSD pro billet distributors from Orielly all cutting out above 2000 rpm before I finally bought one from american muscle and its been in the car for 2 years now with no problems, since then I've always carried a spare "known good" distributor in the trunk just in case.
Had same problem as Dog with MSD billet distributor and had their 6AL box fail after only 3 years use. The old joke was the MSD acronym stood for May Suddenly Die. Got rid of all MSD stuff except for window switch for nitrous.
I find the content of your message compelling...
your exact description is the very symptom we had.
Couple that symptom with the visual indication of our tach dropping to zero during the cutting out event.
We stumbled on a stang thread stating a similar situation but the gent doing the thread mentioned he got fixed only after "4 dist's later and finally" he got his up and running which he later pointed to the box store as the source of all his headaches.
we all should be building a contingency plan for future TFI failures.
I just went back and read the post, this exact story happened to me a few years back when I converted my car to HO and replaced the distributor for some reason I can't remember. I still have 4 or 5 tfi modules laying around somewhere taken apart before I started replacing the distributors. At one point I also had a cap leaking and would drop my tachometer out at higher rpms and misfire/cutout, that's a fun one when you find it by adjusting the timing and get bit multiple times by 40kv. I wish I would have read your post sooner! I would have mentioned all that.
Motorcraft, spare. Make a remote mount with a heatsink...
checked all those boxes by newer birds and cougs with the TFI module/heat sync mounted up inside the cowl wiper arm area.
found several for easy pickings but the the tfi's on these heat syncs are not push start tfi's so ....
http://fatfoxx.com/products.php
I was minutes away from ordering from this place when I decided to try a distributor from american muscle which fixed my concern.
I completely agree with motorcraft only tfi modules. Unless you enjoy replacing them. I still have my special tfi socket somewhere around here.
My '88 3.8L had the TFI module mounted to a heat sink on the rad core support, up in the cool air flow, from the factory. Since I did the 5.0L swap, it's now mounted on the distributor. I might eventually extend the TFI harness and mount it back on the rad support.
if you disconnect your tfi plug in and swing out the slack all the way to fire wall, you will find out that whole cable will dress in with slack to way forward of the pass strut tower.
no wiring work needed.
alll you need now is a 3 wire extender to go from the tfi to the pip in the dizzy