Resolved Is this something to worry about - things I saw when I removed my upper intake?

[vferrizz]

Hi. I have a 91 lx 5.0 and had the same problem. I fixed vacuum leaks, replaced purge valve, replaced coil, tune up, checked timing, ran codes and fixed items referred to by codes. My car ran great except under wot. Got to about 3500 rpm and would break up real bad. If I eased off on throttle would run better. I bought and built car for hpde and having this problem not acceptable. Turns out problem was TFI (thick film ignitor) unit on side of distributor. I got MSD replacement unit from American Muscle because it comes with the insulating film required. I usually prefer motorcraft but they have bad reviews. Put this on and car runs great and problem is gone. You need to turn distributor to get access to the screws but very easy to fix. Need special tool so order that when order tfi. Will also need to reset timing since you moved dist. Not as rewarding as drinking heavily but car might run better. It was very frustrating for me because every time I would fix something car ran great until next road trip and problem was still there. After replacing tfi I have done 6 different events and problem is gone! Hope it works for you.

I did go that route as well. Relaced the original TFI module with a Motorcraft replacement but no changes in how the car ran. I thought maybe it could be a PIP sensor issue so I put a replacement MSD pro billet distributor and used the TFI module that came with it and still not changes in how the car runs. This does not mean I should not probe into this more. I assumed since the parts were all new the act or replacing the parts would rule out this as a potential problem but folks on this site have stated they have installed new parts that were bad. Appreciate the input.

 

[AeroCoupe]

So an aftermarket chip that supports a custom tune installs here:

Based on the ones I have personally seen and pictures on the internet I would say it was part of the repair by ECU Exchange. The 4332 "chip" is not stock as far as I know but some other more knowledgeable folks should chime in on this.

 

[vferrizz]

So an aftermarket chip that supports a custom tune installs here:

Based on the ones I have personally seen and pictures on the internet I would say it was part of the repair by ECU Exchange. The 4332 "chip" is not stock as far as I know but some other more knowledgeable folks should chime in on this.

That chip was there before I sent my ECU to ECU Exchange. As far as I can tell from looking at my ECU after it came back from ECU exchange all that was done was replace the caps. I don't think they do much more than that anyway. I just know from looking at other pictures of ECUs, that chip is definitely not original. I am looking for a local tuner that may possibly know???

 

[AeroCoupe]

I’ve seen a few threads on here where ECU exchange has replaced more than the caps so that’s why I assumed that.

Tuner may or may not know would just depend on experience.

 

[vferrizz]

Hopefully, I found something today that I hope means something useful. I put the code reader aside and decided to wipe the engine running codes and do the test by counting the CELs. This should eliminate any possible issues with the code reader. After the car was warmed up, I installed the jumper and started the car. I initially got 4 CELs (meaning the computer counted 8 cylinders - the code reader either showed blank at this point or "0"). It ran though the initial tests and for the first time I got a code 11 (never got one of those with the code reader). I did a goose test as soon as the intial computer testing was done and got no additinal codes (according to a Ford EEC-IV book I have that is what is supposed to happen - if you don't do the goose test, which means put the pedal to the floor and get RPMs above 2000) you would get a code 77. The first time I did the test I forgot the goose test and got a code 77 so on the seond try looks like I did things correctly. Of course when I put the pedal to the floor it sputtered like crazy like it has been. I decided to put the pedal to the floor again but this time I pushed in the clutch and the RPMs went right up to 5000 with no sputtering at all. I did it a few more times with the same results. I let out the clutch and put the pedal to the floor again and it sputtered like crazy. This is starting to tell me it has something to do with having an auto computer in a manual car unless it is a strange coincidence.

 

[AeroCoupe]

Lots of threads on this topic but this one is recent.

Drivetrain - Can I Use A9p Ecu With A T5 Manual Trans

Doing a t5 swap in a 93 notch. Did a 5.0 swap on this car and used a AOD. Now I am collecting parts to do a t5 swap and I thought I read a while back you can use a a9p ecu on a 5 speed. I can pick up a a9l local for $75.00. Would it make sense to just change out the a9p to the a9l, what all is...

stangnet.com

Long winded one over on the Corral (what else is new) but there is a really good picture of the trace that can fry on the ECU in it.

https://www.corral.net/threads/will-a9p-computer-work-with-5-sp-car.1271225/

 

[CAMTWO1070]

Yeah I already found two broken / cracked vacuum lines. The line to the fuel pressure regulator was cracked and the line underneath the upper intake that goes to the smog stuff fell apart as I was trying to remove it. I am buying a bunch of vacuum hose now. I am hoping that is another symptom of how crappy the car is running.

cracked vacuum lines can be an issue especially at the FP regulator...

when an engine is running and vacuum is applied the fuel pressure goes down below the preset 39psi and running an engine in the low ranges with full fuel pressure to the injectors coupled to the possibility you may need to replace the fuel injectors from damage from doing so would be causing the issues...

When you drive around with too much FP it increases the fuel injectors duty cycle past 80% which causes them to run hot/overheat also causes it to run pretty rich and not correct..............

The overheated injectors in turn dont react to the computer as theyre expected to and the whole thing goes awry...

 

[AeroCoupe]

Above 80% they will tend to overheat however that is not that big of a concern on a street car as they do not see high duty cycle for anything but brief periods of time. Road race cars will heat them up as they tend to run up in the rpm's for the entire session on the track. I ran my 24's at almost 100% duty and the car drove and ran well but the ability to tune the idle and leaving power on the table drove a change. It idled better and made more power when the 42's went in but it took another session on the dyno.

Anyhow, not saying you are wrong but application wise not that huge of a concern except in WOT conditions for prolonged periods of time.

 

[vferrizz]

Finally got it figured out and fixed. Thanks to all that posted replies and things to look at and address. I did find a handful of minor issues that were corrected but finally found the root cause. Thanks AeroCoupe for planting the seed and thread links for the things to do when swapping from AOD to manual trans, especially the part about the O2 harness connector pinning. I found mine still pinned for an AOD. I drove the car like this for 8K miles before it finally reared its ugly head. I re-pinned it for a manual trans and car now runs perfectly. Time for a long deserved cruise with the top down and some Iron Maiden on the stereo!