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Topic: 88 Bird intermittent engine shut down***SOLVED (Read 9586 times) previous topic - next topic

88 Bird intermittent engine shut down***SOLVED

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


Re: 88 Bird intermittent engine shut down

Reply #1
Stock or Aftermarket distributor?
1988 Thunderbird TC, 5spd
Stinger 3" single exhaust, Cone Filter, Adjustable Cam Pulley, Schneider roller cam, Walbro 255 lph, AEM Wideband O2
'93 Mustang Cobra replica wheels on 235/50R17

'21 F150 Powerboost
'17 Husqvarna TX300

Re: 88 Bird intermittent engine shut down

Reply #2
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.
Mike

Re: 88 Bird intermittent engine shut down

Reply #3
Replace the ign switch. Pulling all the fuses is halfassed and a waste of time to boot.. ;)
'84 Mustang
'98 Explorer 5.0
'03 Focus, dropped a valve seat. yay. freakin' split port engines...
'06 Explorer EB 4.6

Re: 88 Bird intermittent engine shut down

Reply #4
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.

Re: 88 Bird intermittent engine shut down

Reply #5
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.

Re: 88 Bird intermittent engine shut down

Reply #6
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:  
'84 Mustang
'98 Explorer 5.0
'03 Focus, dropped a valve seat. yay. freakin' split port engines...
'06 Explorer EB 4.6

Re: 88 Bird intermittent engine shut down

Reply #7
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.




Re: 88 Bird intermittent engine shut down

Reply #8
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.

Re: 88 Bird intermittent engine shut down

Reply #9
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.

Re: 88 Bird intermittent engine shut down

Reply #10
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.

Re: 88 Bird intermittent engine shut down

Reply #11

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.

Re: 88 Bird intermittent engine shut down

Reply #12
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.

Re: 88 Bird intermittent engine shut down

Reply #13
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.


Re: 88 Bird intermittent engine shut down

Reply #14
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.