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93 Notch Wiring Issue? Need Help !!!

  • Thread starter Thread starter Jerryj
  • Start date Start date Dec 19, 2017
J

Jerryj

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Dec 19, 2017
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#1
  • Dec 19, 2017
  • #1
I'm having a 93 notch built for someone for a Christmas present. Everything is almost complete, however there's something going on electrically that keeps rearing its ugly head.

I drove the car to the builders, ran fine. Upon tear down, numerous wire splices were found, wires cut and dangling, etc. The builder rewired things the correct way...he said, and I trust his word. However, when firing up for the first time after complete rebuild or motor and trans, the car ran rough for a short period of time and the died. At this point it would noit crank back up. Builder said the ecm was bad original (A9L), put another known good a9l in and wouldn't work. For giggles he put in a A9P that he had a the car ran fine. This is a five speed car, all the research I've done says in a straight drive car either ecm's will work. So I figured for what ever reason my original ecm went bad, and the ones the builder had a9l's were bad to start with. So I bought another good a9l and installed, still ran like ....put the a9p back in, runs good.

Why aren't the a9l's working ?
 

jrichker

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Dec 19, 2017
#2
  • Dec 19, 2017
  • #2
Probably a wrong O2 sensor harness. Use an auto trans O2 sensor harness with a 5 speed transmission and it burns a trace off the computer printed circuit board. The computer is repairable, but it takes some soldering skills and some patience.

The clue is the computer will not dump codes
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/
 
J

Jerryj

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Dec 19, 2017
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Ok I'll check it out. But the car ran fine before all the work with the a9l that was in it. However, there were signs that , that a9l had been modified at some point.
 

Mustang5L5

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#4
  • Dec 19, 2017
  • #4
What work was actually done? Usually if something works before, but doesn't now, the first question to ask is "what changed?"

Pin 46 on the ECU is what you want to check. Pull the ECU off, probe pin 46 and crank. You should get zero volts here. Usually if you do, ecus fry.
 
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