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Technical => Engine Tech => Topic started by: Driverguy on August 02, 2020, 12:41:05 PM

Title: Proper injectors for stock Speed Density 5.0
Post by: Driverguy on August 02, 2020, 12:41:05 PM
My car has been diagnosed as having a bad set of injectors, and it runs poorly. SOME of the injectors, at some pont in the cars life, have been replaced with ones that have a different housing.  I look at the parts store/rockauto, and there are numerous part #'s and slight variations in injector styles.  How am I to figure out what part # is correct for my motor?  From what I understand, injectors are very specific and it is crucial to the vehicle's performance that they be matched to the computer.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: Vintage on August 02, 2020, 06:08:40 PM
Assuming the diagnosis of bad injectors is correct, and the car you are referring to is the 1988 Cougar 5.0 in your sig, the stock injector is the old Bosch style EV1 14 lb/hr injector, usually gray in color at the top where it plugs in. I don't have the original part #, but its probably obsolete/discontinued anyhow. This link to equivalent replacements for sale at Amazon may have some additional part # info or reference:

https://www.amazon.com/MOSTPLUS-14LB-Injectors-F47E-A2E-0280150710/dp/B07PMVV9JM/ref=sr_1_2?dchild=1&keywords=14+lb+injectors+ford&qid=1596404733&s=automotive&sr=1-2

Not to undermine whoever diagnosed the bad injectors, but I'd also have them check all engine vacuum lines, especially ones under the upper intake plenum going to the fuel vapor charcoal cannister, the map sensor, the pcv valve, etc. The speed density system is sensitive to vacuum leaks, and the rubber lines under the upper plenum are highly pr0ne to aging cracks/leaks, which will cause extremely poor driveability/idle.

An HO conversion might be an option too, Cool Cats website has a write up on whats involved with that if you are interested.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: Driverguy on August 03, 2020, 12:37:37 PM
Yes, I plan to do an entire GT-40 intake swap in the near future, and talk to BBK about a setup for uprated injectors, MAF, fuel rails, etc, and a mass air conversion.  But since, with my current list of projects, that may be a little while longer than antited, i just want to get it to run properly as is for the time being.  I'll check the vacuum lines as well for damages.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: Driverguy on August 03, 2020, 12:46:19 PM
https://www.rockauto.com/en/catalog/mercury,1988,cougar,5.0l+302cid+v8,1198605,fuel+&+air,fuel+injector,6224

so all these injectors, with a whole list of compatable part numbers on some, all seem to have the same body style.  I would be inclined to believe that they are all the same, just from different manufacturers, but i notice that several are from the same company, but with different part numbers themselves.  Also, the ones listed on the site seem to be from an 'E' series of part numbers, while the one you showed me covers an 'F' series.  Am I overthinking this?  or are there valid small differences?
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: thunderjet302 on August 03, 2020, 01:45:30 PM
14lb EV1 style injectors are stock on a 86-88 5.0 Thunderbird/Cougar. Don't even worry about larger injectors till you have a HO cam and MAF.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: Vintage on August 03, 2020, 05:05:36 PM
https://www.rockauto.com/en/catalog/mercury,1988,cougar,5.0l+302cid+v8,1198605,fuel+&+air,fuel+injector,6224

so all these injectors, with a whole list of compatable part numbers on some, all seem to have the same body style.  I would be inclined to believe that they are all the same, just from different manufacturers, but i notice that several are from the same company, but with different part numbers themselves.  Also, the ones listed on the site seem to be from an 'E' series of part numbers, while the one you showed me covers an 'F' series.  Am I overthinking this?  or are there valid small differences?

Not really, the differences in part # or application probably stems from the fact that Ford used your 5.0 fuel injected standard output, or SO, engine in multiple vehicles over the years throughout the 80's and 90's.  Everything from Lincoln Town Cars to lowly E150 work vans. Same fuel injector, same basic fuel system in operation, just packaged slightly differently since a van has a different engine bay than a Crown Vic.

The important thing would be to ensure that you get ones rated at the 14 lb/hr rating because your engine computer is using that assumed fuel flow rating across the injector. Make sure any injectors you get have new  O-rings and lube them while installing, engine fires are no bueno.

 
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: Driverguy on May 23, 2021, 09:16:11 PM
I replaced the injectors over the winter, just started really driving it now that the weather is better.  The bucking and hesitation is GONE, and I have great throttle response.  BUT, now I have a serious idle surge problem.  I checked the EGR and EGR solenoid for issues, they were both fine.  I replaced the TPS and followed the idle reset procedure to properly calibrate it, no change.  I made sure the timing was still set at factory recommendation.  I checked for vacuum leaks/breaks.  Engine light is NOT on. 

I should add, while I had the intake off to change the injectors, I also deleted the smog pump, but NOT the egr.  I don't know if this would cause idle issues.  I DID leave the smog solenoids connected to the harness to avoid an engine light.

Also, I made sure I bought 14LB injectors, under your advisp00get.  I bought F47E-A2E replacements, 'Check fit' menu said it was correct for 1988 cougar, and description said it fits ford 5.0.  BUT, the injectors I removed, 6 of them were stamped E67E-B4B, and the other 2 were a different style/housing, part number suggested they were for a Jaguar...

Did I put the wrong injectors in?  Did I ruin the Idle fuel/air ratio removing the smog tube?  Or is there something else I need to look into?  I'm very happy i have driveability back; the car does perform better, but it is bothersome having to rev it up at stop lights, and sometimes it takes 2 tries to start it up now.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: mcb82gt on May 25, 2021, 11:21:07 AM
2 times to start.

I would check the fuel pressure.  May have a pump going out.

If you bought all 8 injectors of the 14lbs, you did correct. Dont worry about what you pulled out.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: Aerocoupe on May 27, 2021, 08:48:58 AM
Fuel pump is a great place to start and frankly you will need more pump when you do the HO swap (minimum 19 lb/hr injectors and most run 24's or 30's) with a calibrated MAF or a chip so if you replace it I would go with a minimum of a 190 lph unit now and put an adjustable FPR on as well to get the pressure dialed in.

When is the last time you checked the distributor cap and rotor, plug wires, and plugs?  May just need a simple tune up but you can inspect these things and it should be pretty obvious if they need to be replaced.  Check the gap on the plugs and I only say this due to the mix and match on the injectors leads me to believe that other things on the car may have been haphazardly changed or poorly executed.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: Driverguy on June 19, 2021, 09:13:18 PM
Ran test, delayed because the fuel pressure gauge I was using malfunctioned, had to wait for a new one to be ordered.  19.5 psi on ignition, 32psi at idle, spikes to 34psi at 2000rpm, then returns immediately to 30, and idling with the regulator vacuum line unplugged, its at 40PSI.  Mustang forums seem to idicate that this is okay, but my haynes manual says i should be looking at 40 PSI, even though it does not state under what cirspoogestances that PSI should be had.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: Aerocoupe on June 22, 2021, 03:17:02 PM
What is your base timing set at?  Have you replaced the cap rotors and plugs?  One way to check the plug wires it to start the car at night in a dark dark place.  Look under the hood for sparking from the plug wires.  Have you check the EGR for it being plugged up?  Mine used to get plugged with carbon and cause issues.

One last thing is if you are unsure of the balancer I would find TDC on the motor using a piston stop device and see if the pointer is really at 0 deg.  My dad taught me how to make one out of an old spark plug.  Its in this thread on Post #34:

https://www.foxtbirdcougarforums.com/index.php?topic=34313.msg405533#msg405533
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: softtouch on June 22, 2021, 03:39:40 PM
Ran test, delayed because the fuel pressure gauge I was using malfunctioned, had to wait for a new one to be ordered.  19.5 psi on ignition, 32psi at idle, spikes to 34psi at 2000rpm, then returns immediately to 30, and idling with the regulator vacuum line unplugged, its at 40PSI.  Mustang forums seem to idicate that this is okay, but my haynes manual says i should be looking at 40 PSI, even though it does not state under what cirspoogestances that PSI should be had.
Vacuum hose disconnected is how you check the pressure. 40 psi is good.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: Driverguy on June 22, 2021, 10:13:39 PM
What is your base timing set at?  Have you replaced the cap rotors and plugs?  One way to check the plug wires it to start the car at night in a dark dark place.  Look under the hood for sparking from the plug wires.  Have you check the EGR for it being plugged up?  Mine used to get plugged with carbon and cause issues.

One last thing is if you are unsure of the balancer I would find TDC on the motor using a piston stop device and see if the pointer is really at 0 deg.  My dad taught me how to make one out of an old spark plug.  Its in this thread on Post #34:

https://www.foxtbirdcougarforums.com/index.php?topic=34313.msg405533#msg405533
Plugs, wires and cap look to be in good shape upon inspection, i suspect they were recently changed before I purchased the car 2 years ago.  I set the timing as per the timing instructions on the fan shroud decal, 10 degrees I believe.  I checked the EGR for function, as well as the egr solenoid.  I could verify TDC, im just not really sure that would be a problem since the car runs just fine save for idle.  I could check for arcing from the plug wires next time im out at night...I was thinking of replacing the wires anyway for vanity, perhaps now theres another reason to change them, i dont know
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: thunderjet302 on June 22, 2021, 11:31:06 PM
Vacuum leak? Did you damage the upper to lower intake gasket when removing the injectors? Are all the injector o-rings sealing correctly? Any vacuum hoses cracked? Stick a vacuum gauge on it. Should read around 20 inches with a stock engine.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: Aerocoupe on June 25, 2021, 01:56:31 PM
And the 10 degrees of initial timing was set with the spout connector removed, correct?
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: Driverguy on June 25, 2021, 06:13:04 PM
yes, it was removed.  New gaskets and o rings were used in the intake/injector re-installation.  I'll check vacuum...
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: Driverguy on July 01, 2021, 10:54:43 PM
Vacuum is at 19-20 at idle
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: softtouch on July 02, 2021, 04:36:07 PM
Have you checked for codes?
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: Driverguy on July 07, 2021, 10:38:06 PM
checked codes, none stored, CEL isn't on.  Noticed that the exhaust odor is more pungent than usual, and quite a lot of water/carbon came out of the tailpipes yesterday when i had it running/revved it up in the driveway.  Wondering if maybe the converter is getting clogged up, and my removal of the smog system didnt help things
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: softtouch on July 08, 2021, 02:13:58 AM
You should get a code 11 if there are no fault codes.
If you got no codes of any kind, it could mean the EEC software is not running.
Put the key in run without cranking and the fuel pump should run for a couple of seconds and shut off.
If it runs continuously, that's another indication the software is not running.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: softtouch on July 15, 2021, 01:49:01 PM
No codes can also be a blown signal return circuit in the EEC.
The one wire (pigtail) at the test connector is the signal return.
There are 5 sensors that will not be working if the signal return is blown:
MAP, TPS, ACT, ECT & EGR position.

With the key on, check for 5v between the O/W wire (ref v) and the BK/W wire (sig rtn) at the TPS.
People have fixed this problem by opening up the EEC and tracing pin 46 circuit to find the blown spot and soldering a wire across the open circuit.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: Driverguy on August 14, 2021, 10:18:52 PM
Sorry for the delay, I just checked my codes, as the light came on briefly the other night while driving.  Unlike OBD2 codes, it seems that OBD1 codes are stored after the key is shut off, so the CEL does not come back on again?  I ran the codes, both with key on engine off, and key on engine running, and got several stored codes;

11
91 - No oxygen sensor switching detected
41 - Oxygen sensor circuit indicates system always lean
21 - Engine coolant temperature (ECT) out of self-test range
42 - Oxygen sensor circuit indicates system always rich
92 - Shift solenoid circuit failure
18 - Ignition diagnostic monitor (IDM) circuit failure

code 92 i can attribute to the time i accidentally knocked off my kickdown cable a few weeks back.  Also, I can say the car is running SUPER rich; the exhaust smells like shiznit, and it's been getting worse, it's embarrassing now.  I'm pretty sure the bad mixture is causing the idle surge, rather than the IAC or TPS, I just dont know whats attributing the bad mixture.  Could it be bad O2 sensors, since 3 codes have to do with oxygen sensing?

A nagging guy at my shop says my smog pump delete is causing all this problem, but I really don't understand how it could be, since I left no vacuum leaks, and did not remove any electrical connectors or sensors.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: softtouch on August 15, 2021, 04:04:02 PM
I would check the ECT first.
It will have a 2 wire connecter. BK/W and LG/Y wires.
If the one of the wires is broke, this will indicate to the EEC that the engine is super cold.

The ECT resistance range needed to pass the KOEO test  : 50°F = 58.75 K ohms,  220° F = 1.84 K ohms.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: softtouch on August 16, 2021, 02:02:59 PM
I was too quick to jump on the ECT as your cause of running rich.
First we have to sort out when you got the codes.
The codes can have different meanings depending on when you got them.
For example, if you only got the 21 code from KOER, it means you didn't warm up the engine before running the test.

KOEO (Key On Engine Off)
Memory
KOER (Key On Engine Running)

KOEO runs self tests then presents on-demand codes (O). After a single separator pulse. presents memory codes(M).
KOER presents an engine code, 4 for 8 cylinder. Then runs tests and presents running codes(R).
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: softtouch on August 16, 2021, 08:07:24 PM
Code 18 R SPOUT c°ircuit open during self test (Check the jumper plug)
Code 18 M Loss of signal from coil negative, Ignition diagnostic monitor. Or spout grounded.

code 21 O&R ECT out of test range.
   To pass test, coolant temp must be:
   KOEO- 50° F to 240° F
   KOER- 180° F to 240° F
Code 41 R  Right O2 sensor shows lean
Code 41 M  Right O2 sensor not switching (stays lean for 15 seconds or more)
Code 42  R  Right O2 sensor shows rich
Code 42  M  Right O2 sensor not switching (stays rich for 15 seconds or more)
Code 91  R   Left O2 sensor shows lean
Code 91  M  Left O2 sensor not switching (Stays lean for 15 seconds or more)
Code 92  R   Left O2 sensor shows rich
Code 92  M  Left O2 sensor not switching (Stays rich for 15 seconds or longer)
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: thunderjet302 on August 19, 2021, 03:27:43 PM
ECT out of range can happen if the test is run on a cold motor. If that's the case ignore it.

41, 42, 91, 92 narrows it down. Check the oxygen sensor harness. Make sure that the harness is intact and plugged in on the correct sides. If the right side oxygen senor is plugged into the left side oxygen senor connector (for example) then there will be all sorts of screwy problems.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: TheFoeYouKnow on August 19, 2021, 10:07:19 PM
Vacuum leak.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: thunderjet302 on August 19, 2021, 11:40:19 PM

OP said car has 20" of vacuum at idle. It could be a vacuum leak but that reading is on point for a stock engine.

But I wouldn't be surprised by a vacuum leak somewhere either.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: TheFoeYouKnow on August 19, 2021, 11:56:05 PM
I want OP to spray brake cleaner around the intake side of those injectors at idle, as well as the general space under the plenum. Maybe try a known good MAP sensor.  Is OP measuring vac at the booster, the PCV or the MAP?  That upper intake has been off and the injectors out, 9 of 10 times, it's a vacuum leak someplace that's getting overlooked in the previous work area.  Is MAP (as the primary load sensor) connected to the upper, and is it connected in the right place?  Were the injector o-rings lubed before installation into the manifold?  A torn injector o-ring that was installed dry will vacuum leak and you'll never hear it.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: Driverguy on August 20, 2021, 12:49:46 PM
measured vacuum at the vacuum distribution block.  the injector o rings were lubed, yes.  if the vacuum leak is small enough that I am still getting a 20lb reading, could that really be attributing to such harsh idle consequences, and overfueling?  I'm leaning toward o2 sensor/failure as Thunderjet suggested...
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: softtouch on August 20, 2021, 01:55:46 PM
You will be "over fueling" if the vacuum is not getting to the fuel pressure regulator.
As the vacuum goes up, the fuel pressure is supposed to go down.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: softtouch on August 20, 2021, 02:04:41 PM
Can indicate which category the codes are in?  KOEO, Memory or KOER
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: Driverguy on August 22, 2021, 11:45:47 AM
Yes, i will recheck the codes and categorize them, sorry for the delay
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: Driverguy on August 31, 2021, 11:20:03 AM
Did the test again...

KOEOFF - 11

MEMORY - 91
                  - 41

KOER - 4

Not sure why last time i got so many engine running codes...also some of the old memory codes must have been forced out, because the 91 and 41 codes were stored 3 times each.

Title: Re: Proper injectors for stock Speed Density 5.0
Post by: softtouch on August 31, 2021, 07:58:49 PM
Did you stop the KOER before it finished?
It post the engine code, 4 for 8cyl engine, then runs the tests.
If the tests found no problems it should have posted  code 11.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: Driverguy on September 02, 2021, 11:57:30 AM
waited quite a while after the '4', nothing followed.  Also it seems that the engine was running super high idle when i had the test jumper hooked up, because when i unplugged it, the idle dove.

Probably related, not only is the exhaust reeking of fuel and black, but it's also now spewing out black condensation that's staining my garage and driveway.  I have it on good authority that my cat is clogged up, and now its fouled my O2 sensors and dumping even more fuel in.  The fact that I removed the smog system probably accented the problem. 
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: TheFoeYouKnow on September 02, 2021, 01:37:32 PM
Known good MAP sensor, 12v disconnect, repeat KOER
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: softtouch on September 03, 2021, 12:20:35 PM
The smog pump (thermactor) system not working will not cause your problem.
Is it possible your smog delete procedure screwed up some other systems? Give us the details of your smog delete and maybe we can spot something.

Yes, running rich can cause the cats to overheat and eventually ruin them.

Your idea that the O2's getting carboned-up and causing the EEC to dump in more fuel, I'm having trouble with that theory.
The O2 measures the difference in oxygen content between the exhaust and the ambient air.
A big difference means rich and a small difference means lean. If the sensor is carboned over so it can't sense anything, this would be a big difference and the EEC would cut back on the fuel.

KOER does change the idle speed as part of it's tests.

Check your fuel pressure. The no vacuum pressure is 39 psi.
 
Let KOER complete it's tests.

Title: Re: Proper injectors for stock Speed Density 5.0
Post by: Beau on September 04, 2021, 05:21:44 PM
How's the fuel pressure regulator?

When those go bad, it will make it run shiznit-rich and do what you are describing. Also no/low vac to the FPR will pretty much do the same.

Like softtouch says, the cats being (potentially) plugged up has NO bearing on the eec "telling" the injectors to pulse in more fuel..that will NOT happen on this eec system...

As mentioned, I'd test fuel pressure, then vac at the FPR if it's suspect (and in my opinion it sure as hell is), and Foe's point is valid too about spraying carb cleaner around the intake and such.

Possible you have a torn or cracked hose on the bottom of the upper? When I did the Cobra intake on mine, one of those hoses was cracked from being on the shelf for a time before I got it and with the engine running, it would open up and make it act plumb silly.

Vac gauges are worth their weight in gold coin, though you still have to the leg work to find where the leak(s) hang out...

But my $ is on that FPR...
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: Haystack on September 05, 2021, 01:48:20 AM
I'm also leaning towards the map sensor or a vacuum leak. Having 19-20 at idle should be in spec. An easy way to test it,, as well as a base idle reset.

With the car running, unplug the iac. The idle should barely change. How I adjust it, I turn down the idle screw until it starts to buck or have a hard time idling, then I plug it back in. Thats it.

If you have a bunch if vacuum leaks, then you will not be able to lower the idle enough the car might die.

The reason I bring this up, if the iac is unable to control the idle, the car will try to compensate by messing with timing and fuel. This causes all kinds of issues.

If you can get the car to almost die, then the iac is able to perform it's job, and you really don't have to worry about vacuum.

However, I would check the plastic vacuum manifold. These 5.0's like to eat motor mounts. I've had a few where they started surging and gas mileage went way down. Either that plastic manifold was broken/cracked it the hose had a hole. This is the main vacuum distribution for the whole engine.

You need to verify that the mao sensor is indeed getting the same 19-20ish vacuum at idle. If that's all good and you are able to do the iac reset like I said, I would feel pretty good about saying that the map sensor is probably bad.

As far as the cats go, they usually only last 7-10 years and about 100-150k miles. Almost every one of these cars I've seen, the cat is either completely hollow, it blowing honeycomb out the exhaust. I even passed emissions with 291k miles on a car that had a very annoying rattle. The rattle ended up being a round chunk of cat material that bugged me for years. It was about the size of a golf ball, just bug enough to not go through the exhaust opening in the cat.

One day I replaced the rusted out tail pipe, when I dropped it, a little ball came rolling out and my rattle was gone.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: TheFoeYouKnow on September 05, 2021, 07:38:20 AM
The MAP sensor performs the same function as a MAF would if you had one, but it bases it off of VACUUM MEASUREMENT.  I hate that you can't monitor a datastream before 92, because we could just compare actual to measured.  Failure mode example:  idle vac actual is 20.5 inhg, but MAP is bad, so MAP is saying it's 13.9 inhg.  Is this scenario, you have good vac, but since the MAP data to EEC is bad, EEC's load calc is also bad. (garbage in, garbage out) EEC advances timing and adds fuel for power enrichment, meanwhile, TP has not changed, and HEGO is pegging rich.  Rich HEGOs in power enrich mode is not unexpected, but 1.0v ish from TP may or may not flag a fault.
On-board sensor diagnostics is hard for EEC4, especially when you're talking about close-range or in-range failures. MAP, doubly so, because MAP is one of the sensors that most on-board sensor diag relies on for known value assumptions. 
Most MAP diags i've done in the past 10 years have been GM, because they use it in conjunction with MAF while Ford dumped it completely for MAF, and I just don't see those cars vary much.  If we had access to an appropriate year PC/ED manual, we could test using reference values (sensor output voltage relative to vacuum measurement).  A known good sensor from the parts store is cheaper that a PC/ED or access to one, so Before you chase those balloons any further, try a known good MAP.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: TheFoeYouKnow on September 05, 2021, 07:40:51 AM
Part of the reason vac leak issues are so problematic on SD cars is that if vacuum is leaking, not only do you have the issues that come along with a vacuum leak, but you also now have a skewed MAP value.  On GM cars, we'd use that fact as a preliminary confirmation of any suspected vacuum leakage.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: softtouch on September 05, 2021, 06:09:21 PM
Did you remove the vacuum to the thermactor solenoids?
If so, maybe you inadvertently also removed the vacuum to other stuff. MAP sensor, fuel pressure regulator etc.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: softtouch on September 07, 2021, 04:57:21 PM
After re-reading the whole thread, your fuel pressure checks in post #9 indicate the regulator has vacuum and is working  fine.
Sorry, I'm an old coot and can't remember what I read back in June.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: Driverguy on January 22, 2022, 06:00:56 PM
Sorry I've been absent from this thread for the last few months, been caught up in another project.

I decided to test my exhaust/cats/O2 sensor theory a few weeks ago, mostly because I wanted to upgrade anyway.  I put headers on, 2 high-flow cats, 2 new O2 sensors, and an X-pipe, and took out each of my plugs, cleaned off the fouling, and re-installed.  Also disconnected the battery for a few days so the computer could reset itself. 

Ran the car for about 20 minutes today; for the first 10 minutes it ran fine, then it started spitting, which I could hear easily because I don't have lers on yet.  Then, a few minutes later, it started surging again.  No CEL, and it didn't stall, but still surging nearly as bad as before. 

My theory now is that it was still running rich, and took 10 minutes to foul up the plugs again and start really running poorly again.

My next ideas are to use brake clean/carb cleaner to test for vacuum leaks (although I checked the vacuum pressure, why not try anyways), and change plug wires (I put a high-end MSD coil on it last year to try to solve the problem, but i still have stock motorcraft 7mm wires, perhaps they are old and/or can't handle the hot spark from the uprated coil)

I'm hearing the MAP sensor come up often in your recent replies, is it something I should consider testing/replacing?
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: Driverguy on January 22, 2022, 06:07:29 PM
Also, further to the question about how I deleted the smog system, I removed the steel pipe to the back of the cylinder heads, cleaned out the threads the best i could with a 5/8 tap and brake clean, and plugged the holes with bolts and high heat thread sealant.  I removed the pump/bracketry, and shortened the serpentine belt.  I removed the hoses and air diverter solenoids, but I did NOT disconnect the 2 vacuum solenoids on the cowl behind the strut tower; I left them plugged into their harnesses, left the vacuum lines connected, and simply capped off the lines that used to go to the air diverter solenoids.  I assumed it would be better to leave them plugged in and connected to vacuum, so the computer didn't register them as missing/defective, was I wrong?
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: TheFoeYouKnow on January 22, 2022, 06:13:01 PM
That you clear keep alive memory, then get 10 good minutes says that your fuel trim adaptive is biasing rich. Super rich. Since your load sensor is the map, and probably the primary sensor for establishing fuel adaptation, I'd start there. You have no way of monitoring the output of this sensor, and if you had the live data value, I'm not sure reference data is available. The hard fact is that you have no way to test the output vs actual vacuum. If live data were available in parameter form, you'd compare it to an actual vacuum gauge. You need a known good sensor and a another 12v reset. You can also check for vacuum leaks, but based on the magnitude of your error, it would have to be a big one.
I believe it's likely that your MAP is reporting less vacuum than actual. Keep in mind that the MAP itself can be leaking vacuum internally.
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: Driverguy on January 22, 2022, 06:26:17 PM
https://troubleshootmyvehicle.com/ford/4.9L-5.0L-5.8L/how-to-test-the-map-sensor-1

Found this guide to testing MAP sensor function...Suppose I'll try testing and possibly replacing that, as well as spray the brake clean around the intake
Title: Re: Proper injectors for stock Speed Density 5.0
Post by: TheFoeYouKnow on January 25, 2022, 05:50:06 AM
That's a really good article.  If you do the bench test, be certain the output not only scales down, but does so with accuracy vs the table in the article.  It's a good idea to put vacuum to the sensor, and just check to make sure it HOLDS that vacuum for several minutes, because if it's leaking, it will give an inaccurate output.