Computer identification..

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There is a 1" x 1.5" plastic sticker on the end of the computer opposite the wiring connector.

Computer & interchange information for 5.0 Mustang

Revised 16-Oct-2011 to add O2 sensor harness warnings

The Mass Air computers from 89-93 are interchangeable with a few exceptions. Just be sure you use the MAF & MAF sensor from the same series computer. The auto transmission computers use a different start circuit than the manual computers. You can use an auto trans computer in a 5 speed car with no problems or changes. I have done it in my original 89 Mustang GT, and I know it works OK. I would recommend avoiding using a 5 speed computer in an auto trans car due to the possibility of damaging the computer’ internal signal ground circuitry.

The odd duck is the 93 Cobra computer, labeled X3Z which is internally calibrated for 24 lb injectors. Use the MAF & MAF sensor from the X3Z computer to avoid problems with the computer's internal calibration. Try and avoid the 93 Cobra computer if you can.

Some cautions about O2 Sensor harnesses need to be observed to avoid damage to the computer.
Only run a 5 speed trans O2 harness with an A9L. Do not run an Auto O2 sensor harness with an A9L. Doing so will damage the computer’s internal signal ground.
Only run an Auto trans O2 sensor harness with an A9P in a car that has an Auto trans. Using a 5 speed trans O2 sensor harness with an Auto trans will cause no crank problems.
See http://forums.corral.net/forums/general-mustang-tech/1094179-oxygen-sensor- harnesses-manual-auto-differences-year-differences.html for more O2 sensor wiring harness info
If you have a damaged computer with signal ground problems, See http://www.stangnet.com/mustang-forums/749974-computer-issue.html#post7490537 for Joel5.0’s fix to the computer internal signal ground.

All the following are mass air unless they say Speed Density
8LD - MANUAL 88 5.0L Mustang Speed Density
8LF - Auto 88 5.0L Mustang Speed Density
A9L - 89-93 5.0L Mustang 5-spd Mass Air
A3M - 93 5.0L Mustang 5-spd Mass Air
A3M1 - 93 5.0L Mustang 5-spd Mass Air
X3Z - 93 5.0L Cobra 5-spd Mass Air internally calibrated for 24 lb injector
A9P - 89-93 5.0L Mustang Auto Mass Air
A9S - 88-93 5.0L Mustang California Mass Air
C3W - 89-93 5.0L Mustang Auto
DA1 - 87 5.0L Mustang 5-spd Speed Density
J4J1 - 94-95 5.0L SVT Cobra 5-spd
T4M0 - 94-95 5.0L GT Vert 5-spd
U4P0 - 94-95 5.0L GT Auto
W4H0 - 94-95 5.0L GT
ZA0 - 95 Cobra R
D9S - Lincoln LSC
ZXA3
LLX3
CCA1
CCA0
AOL2
AOL3
 
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I kinda have a Frankenstein. My mustang is an 85 with what is supposed to be an 88 motor. The EEC is the VM1 which is correct for the car year. The VM1 is a speed density EEC but if I'm not mistaken it should be for a carbureted engine. Will the EEC work correctly with the 88 SD FI engine? I'm trying to chase down some gremlins.

Thank you.
 
It should work OK. If you aren't having other problems your current computer should do the job.

To find any other problems that he computer has detected, dump the codes.
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. I highly suggest that you read it and follow the instructions to dump the codes.
 
It should work OK. If you aren't having other problems your current computer should do the job.

To find any other problems that he computer has detected, dump the codes.
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. I highly suggest that you read it and follow the instructions to dump the codes.


Thank you. I've gotten a KOEO code of 67, had to bypass it as you stated for the KOER by grounding pin 30 and then have gotten codes 21, 44, and 94. I know what those codes are and will be trying to remedy them. The biggest gremlin I've got is the car failed an emissions test with very high HC, but NOx and CO were within tolerance. A friend thought that it might be a vacuum leak but if it is it's small as the car has 15" vacuum at idle.
 
Can anyone tell me what this is out of? It's in my 88 mustang gt 5.0 manual transmission, speed density. Can that be Why its running rich
 

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Can anyone tell me what this is out of? It's in my 88 mustang gt 5.0 manual transmission, speed density. Can that be Why its running rich
Dump the codes to find out why the car isn't running right.

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/
 
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That computer is programmed to run an engine with the 1-5-4-2-6-3-7-8 firing order. Running that computer on an HO firing order engine will cause all sorts of problems.
 
There is a 1" x 1.5" plastic sticker on the end of the computer opposite the wiring connector.

Computer & interchange information for 5.0 Mustang

Revised 16-Oct-2011 to add O2 sensor harness warnings

The Mass Air computers from 89-93 are interchangeable with a few exceptions. Just be sure you use the MAF & MAF sensor from the same series computer. The auto transmission computers use a different start circuit than the manual computers. You can use an auto trans computer in a 5 speed car with no problems or changes. I have done it in my original 89 Mustang GT, and I know it works OK. I would recommend avoiding using a 5 speed computer in an auto trans car due to the possibility of damaging the computer’ internal signal ground circuitry.

The odd duck is the 93 Cobra computer, labeled X3Z which is internally calibrated for 24 lb injectors. Use the MAF & MAF sensor from the X3Z computer to avoid problems with the computer's internal calibration. Try and avoid the 93 Cobra computer if you can.

Some cautions about O2 Sensor harnesses need to be observed to avoid damage to the computer.
Only run a 5 speed trans O2 harness with an A9L. Do not run an Auto O2 sensor harness with an A9L. Doing so will damage the computer’s internal signal ground.
Only run an Auto trans O2 sensor harness with an A9P in a car that has an Auto trans. Using a 5 speed trans O2 sensor harness with an Auto trans will cause no crank problems.
See http://forums.corral.net/forums/general-mustang-tech/1094179-oxygen-sensor- harnesses-manual-auto-differences-year-differences.html for more O2 sensor wiring harness info
If you have a damaged computer with signal ground problems, See http://www.stangnet.com/mustang-forums/749974-computer-issue.html#post7490537 for Joel5.0’s fix to the computer internal signal ground.

All the following are mass air unless they say Speed Density
8LD - MANUAL 88 5.0L Mustang Speed Density
8LF - Auto 88 5.0L Mustang Speed Density
A9L - 89-93 5.0L Mustang 5-spd Mass Air
A3M - 93 5.0L Mustang 5-spd Mass Air
A3M1 - 93 5.0L Mustang 5-spd Mass Air
X3Z - 93 5.0L Cobra 5-spd Mass Air internally calibrated for 24 lb injector
A9P - 89-93 5.0L Mustang Auto Mass Air
A9S - 88-93 5.0L Mustang California Mass Air
C3W - 89-93 5.0L Mustang Auto
DA1 - 87 5.0L Mustang 5-spd Speed Density
J4J1 - 94-95 5.0L SVT Cobra 5-spd
T4M0 - 94-95 5.0L GT Vert 5-spd
U4P0 - 94-95 5.0L GT Auto
W4H0 - 94-95 5.0L GT
ZA0 - 95 Cobra R
D9S - Lincoln LSC
ZXA3
LLX3
CCA1
CCA0
AOL2
AOL3
I have 88 mustang gt 5.0 manual and speed density no MAF. I been running a 9K17 ecm,have a running rich problem. I got a DA1 which is supposed to be in my car and it won't start and run . Can you help?