1990 Mustang GT FP/ECU Problems/Questions, Plz Help.....

[mjay2020]

I am having engine problems with my 1990 GT 5.0. I took it to a electrical shop where the mechanic diagnosed the problem as being the ECU/Computer. He advised me that I can go to junk yard and get another one as long as the numbers matched. I went to pick-a-part and they told me to get a computer out of a car of the same year with the same characteristics. They printed me out a paper with similar ID #'s that I can pick from (I attached a copy of that paper to this post). I bought one and the mechanic told me that he needed to program coding to computer in order for it to work with my car. Please take a look at the video and tell me if any of you think the problem would be my ECU. My question is does the computer need programming? Can I program it myself since the mechanic wants to charge me $145? Or could the problem be a relay or the fuel pump? Take a look at the video and any advice would be greatly appreciated.
Thank You


1990 5.0 Engine Stall video by mjay2020 - Photobucket

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[jcb]

engine stall

is any codes being set and have u checked for avacuum leak

 

[jrichker]

Run away from the mechanic as fast as you can. Stock computers from 86-95 5.0 MUstangs cannot be "re-programmed" in the field without modification & some extra hardware to make it work.

The $145 figure exceeds the cost of a remain unit from the auto parts store. Computers seldom fail, it usually is a sensor or wiring problem.

For starters, get rid of the cone air filter in the engine compartment. The hot air from the engine and the turbulence from the fan cause airflow problems through the MAF. This causes an uneven air/fuel mixture that creates many hard to diagnose engine problems. The original stock airbox is a 100% improvement over what you have now.


See the "Surging Idle Checklist for help with all your idle/stall problems.

The quick and easy way to dump the codes is in there too, and all you need to do it is a paper clip! The first two posts contain all the fixes & updates. At last count there were 24 possible causes and fixes for surging idle/stall problems. I continue to update it as more people post fixes or ask questions.

 

[Mustang5L5]

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[Mustang5L5]

I agree. No "programming" needed.* You simply get the computer, and plug it in and that's that.
Cost of used computer is usually $75-100 on the market, with J/Y computers usually being cheaper.* Install is a simple 3 minute remove and replace of the original computer in the passenger side kick panel. $145 for install is total rip.

However, i don't think your issue is computer related.* The engine runs.* It just surges and stalls. Actually, it looked like it wanted to surge but stalled before it could. I'd probably look at the IAC first and diagnose from there.

Let me ask you this.* The idle Air controller is the small 6" long cylinder on the front side of the throttle body.* There's a single 2-wire connector at the bottom.* Get the engine idling and unplug this.* Does the engine stall out almost immediately?

 

[mjay2020]

Since I swapped them, I am having a cranking issue. Its not doing what it was originally doing in the video. I charged the battery but havent had a chance to start it yet. I also have the stock air cleaner. the serial code from j/y comp is:
EEC-IV SFI-MA12A A9P
E9ZF-12A650-CA G
61SM12AF03 22302-209 0L01

I will post code for the original comput in a couple hours. I had autozone charge the batt yesterday. So you guys think nothing is wrong with org. comp? I will post video of exactly how the car is cranking in a couple of hours.
Thank you

Ok here is the serial code for the original comp in my mustang:
EEC-IV SFI-MA12 A9L
E9ZF-12A650-A2A G
60SM12AF01 19600 - 1679

THIS MORNING I tried to start and I am gonna post video on the symptoms. Its acting different but it sounds a little better. watch the video you guys please and any advice will be greatly appreciated....


PB010018.mp4 video by mjay2020 - Photobucket

 

[Mustang5L5]

Thats an automatic computer (A9P). Your computer is a 5-spd computer. (A9L). Ypu can use an AOD computer in a 5-spd of your car is an original 5-spd car.

So is the video above with original computer, or the new one?

Did ypu have any check engine codes stored before? A CEL doesn't need to be on tp store a code.

 

[mjay2020]

I did put the original EEC back in the car and the problem is cranking, but if u watched the video,

PB010018.mp4 video by mjay2020 - Photobucket

underneath the air filter is a relay that is making noise, either the fuel rail or the injectors are making some kind of vacuum/air noise, and some times when u put key in and turn to "Run" the fuel pump will either prime or it will stay on until I turn off ignition. I am gonna run codes early this morning and I will post my results. Car is 5-speed.

Why do u think it is doing this?

 

[mjay2020]

Ok this is the latest

I did most of the stuff on the "Surging Idle CheckList". and take a look at the video and this is whats going on.



PB020019.mp4 video by mjay2020 - Photobucket



I tried to run codes but when the ignition is set to run, my OBD1 wont go into test mode. Its just got one long beep sound.

 

[jrichker]

Dump the codes with a paper clip, the "Surging Idle Checklist tells you how to do it. You must get an 11 or codes, because if you don't, you have other problems.

 

[mjay2020]

here is the latest videos on my car. Please view them and I would appreciate any advice or help. Thank you.


PB100082.mp4 video by mjay2020 - Photobucket


PB100083.mp4 video by mjay2020 - Photobucket

 

[mjay2020]

my code reader wont work cuz the car doesn't stay on long enough for the code reader to get codes

 

[jrichker]

The engine does not have to be running to get the codes to dump. Connect the jumper or paper clip, put the trans in neutral, push the clutch (if it has one) to the flooor. Turn the ignition to run and watch the check engine light flash. Count the groups of flashes, write the down and post them. You must get some codes or an 11. No 11 and no codes is a computer or wiring problem. I will give you 5.0 Mustang specific code definitions and fixes for the codes you post.