Electrical Help. I’ve about had it with this car....

amurray50

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Jul 5, 2020
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Hi. I have a 347 Stroker and it was running fine until recently. I had a tune out on there for driveability because it was bucking and surging at low RPM.

Anyway, after the chip went in the car started stalling randomly. It drives perfectly normally until you go to stick it at like 3500 in any gear. Like a race pull. You let it sit at 3500 for like 15 seconds and then when you slam the gas, the car just shuts off. Electrical is all still on and the Tach starts bouncing all around.

I had him take the chip out and the fuel smell came back and I thought I had the problem solved and now it’s doing it again.

My mechanic is putting a new distributor in a we tried his test unit and the car died right away. Only restarted when we unplugged the TFI.

I feel like they are never going to find this problem. It’s driving me crazy. I never know if my car is going to shut off on a hot or not. Plus, it’s dangerous shutting off in the middle of the road. The car will not restart until you cycle the key off.

The MAF is inside the fender well. The guy who did that had to lengthen the wires from the original location. Is it possible something is lose?

I’m in South Florida and I just can’t seem to get to the bottom of this. New distributor going in tomorrow, but I do t think that’s going to do it.

Anybody have any ideas so I can actually have some fun with this car?
 
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7991LXnSHO

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I would run codes and the diagnostics and see what all the computer thinks is wrong.
(The surging idle checklist will still be a great help in the initial diagnosis of this serious problem.)
 

Cheapskate207

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Jan 12, 2020
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I would probably get a new mechanic. Possibly find someone that specializes in mustangs or older cars. If you’re not doing the work you probably shouldn’t have to research what it is that needs to be done. I don’t tell my Dr. how to do his job...
 
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silverlx50

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Apr 4, 2007
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I'd agree, run codes.

Check all grounds, nice good places with metal to metal contact and check the wires to ensure no damage to the wires.

Maybe check the ignition switch for loose connections.

Search like crazy here and on Corall. You will find so much info to help you.

Looks like you are in Fl, I'm sure there has to be a Mustang guy somewhere close.
 

2000xp8

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I'd list the rest of the parts, heads, cam, intake, TB, injector size and meter brand and calibration.
 
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7991LXnSHO

Now I want a 10 year badge
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I am not specifically finding the ECU test procedure, but if you can get as far as a 90 response in running the tests, it is not very likely the direct problem. The system needing restarted hints to me at a ground or power interruption, and checking the grounds is a good idea before running diagnostics anyways. Also, I would check the coil connections and wires and the ones at the TFI module.
Then I’d start on the surging idle checklist. This list is akin to what your doctor should do for a routine checkup.

he just went ahead and did it. I don’t want it done. The. He offered it to me and I kept it on there. Tha ya when all this started. I think he friend mybEEC
he just went ahead and did it. I don’t want it done. The. He offered it to me and I kept it on there. Tha ya when all this started. I think he friend mybEEC
 

jrichker

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@amurray50

The phrase My mechanic tells me that you bought the wrong car. After 27 to 34 years, things wear out, break down, may be abused by the efforts of some previous owner's shoddy work. When you buy a 5.0 Foxbody Mustang, with it comes the necessity of having some mechanical talent, tools, knowledge and a place to work on the car without harassment by the people who live around you. The ability to fix the car is part of the requirements of ownership; it's not just make the payments for the normal cost of owning and operating a motor vehicle. These cars are a great hobby, but just like any hobby. if someone else does the work, it gets very expensive and difficult to get quality workmanship and not wreck your finances.

If you aren't into digging in, learning what the car needs to keep running properly, and doing the DIY mechanic thing, then sell the car and buy a Honda or some other import.

Resources:

EFI (Electronic Fuel Injection) Computer - every stang after 85 has or had one: don't let it intimidate you. The computer based EFI systems are not hard to fix and most of the time they tell you what's wrong with the engine. Here's a book that will get you started with how the Ford electronic engine control or "computer" works.

Ford Fuel Injection & Electronic Engine Control 1988-1993 by James Probst: ISBN 0-8376-0301-3.

It's about $35-$45 from Borders.com see http://www.amazon.com/ . Select books and then select search. Use the ISBN number (without dashes or spaces) to do a search

Use the ISBN number and your local library can get you a loaner copy for free. Only thing is you are limited to keeping the book for two weeks. It is very good, and I found it to be very helpful.

For lots of great ideas and tech notes on upgrades and repairs, be sure to check
out http://forums.stangnet.com/showthread.php?t=643651 “Useful Technical Thread Index” sticky at the top of the 5.0 Tech forum.

Places to check out here on Stangnet:
http://www.stangnet.com/mustang-forums/threads/technical-thread-how-to-index.808661/ How to do it tips for some of the most common problems and upgrades for 5.0 Fox body Mustangs.
http://www.stangnet.com/mustang-forums/threads/the-official-progress-threads-thread.761371/ the collection of build/progress threads from Stangnet members. You get to find ideas and clues to what works well and what doesn’t.
http://www.stangnet.com/mustang-forums/resources/ Has tech tips for common problems on Mustangs.


Help for your current problem:

First step for any engine problem:

Dump codes sticky


Look at the top of the 5.0 Tech forum where the sticky threads are posted. One of them is how to dump the computer codes. Codes may be present even if the CEL (Check Engine Light) isn’t on. You don’t need a code reader or scanner – all you need is a paper clip, or if your lady friend has a hair pin, that will do the job.
I highly suggest that you read it and follow the instructions to dump the codes. http://www.stangnet.com/mustang-forums/threads/how-to-pull-codes-from-eec4.889006/


High speed miss on a warm engine
Revised 24 June 2019 to add new source & part number for TFI removal tool .

The TFI module mounted on the distributor is one of the culprits for a high speed miss on a warm engine. The other suspect is the PIP sensor inside the distributor. If the problem does not occur when the engine is cold, the TFI module or PIP is definitely suspect. Dumping the codes may help determine which one it is. You may need a special socket to remove the TFI module, but most auto parts stores will have one for $5-$7.

It is not uncommon that the replacement parts may be defective; TFI modules made by non Ford manufactures seem to have a high failure rate.

Be sure to use plenty of the heat sink grease on the new TFI and clean the old grease off the distributor.

Lisle P/N 64650
See https://shop.advanceautoparts.com/p...0kH8DTh2LmTcgnmc_E4aAuCIEALw_wcB&gclsrc=aw.ds



diagram courtesy of Tmoss & Stang&2Birds
TFI_5.0_comparison.gif
 
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