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k5ahudson
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SEP 18, 02:40 AM
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Hi guys! I'm about 99% my ECM is toast after accidentally getting the positive and negative reversed while jumping the car. The car turns over and has spark, so I've narrowed it down to the ECM or less likely the fuel pump. The pump runs if I bypass the ECM and the check engine light does not come on while cranking.
My question is what all do I have to do to swap the ECM? I know there is a ECM specific to my year and transmission, but do I have to do anything else in addition to transferring the PROM? Any programming needed? Thanks for your help.[This message has been edited by k5ahudson (edited 09-18-2024).]
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82-T/A [At Work]
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SEP 18, 06:06 AM
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| quote | Originally posted by k5ahudson:
Hi guys! I'm about 99% my ECM is toast after accidentally getting the positive and negative reversed while jumping the car. The car turns over and has spark, so I've narrowed it down to the ECM or less likely the fuel pump. The pump runs if I bypass the ECM and the check engine light does not come on while cranking.
My question is what all do I have to do to swap the ECM? I know there is a ECM specific to my year and transmission, but do I have to do anything else in addition to transferring the PROM? Any programming needed? Thanks for your help. |
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This is the PROM / ECM chart that shows what ECMs came with what proms, and which are right for your car / configuration.
But first thing I would ask... have you checked your ECM codes? If you check the codes, you should get a "code 12." If you are not getting this, then the ECM is likely bad, but it's a good way to diagnose first before you spend the money / effort on swapping out the ECM.
Go here to figure out how to check the codes:
https://www.pontiacperforma...icles/OSG/codes.html
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k5ahudson
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SEP 18, 09:32 AM
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| quote | Originally posted by 82-T/A [At Work]:
But first thing I would ask... have you checked your ECM codes? If you check the codes, you should get a "code 12." If you are not getting this, then the ECM is likely bad, but it's a good way to diagnose first before you spend the money / effort on swapping out the ECM.
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Thanks for the reply. As I said, the check engine light is not coming on. Not at all. I doubt it is the bulb because I was checking for a code a couple of codes for an unrelated problem about a month ago. It worked fine.
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82-T/A [At Work]
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SEP 18, 11:20 AM
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| quote | Originally posted by k5ahudson:
Thanks for the reply. As I said, the check engine light is not coming on. Not at all. I doubt it is the bulb because I was checking for a code a couple of codes for an unrelated problem about a month ago. It worked fine.
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I apologize, I seem to be skimming posts too quickly lately and missing things. Yeah, my goal was just to see if you had in fact tried to check for computer codes. If you're doing that and get literally nothing... and you've verified positive power to the ECM (e.g., not blown fuses... fusable link?), then the ECM is definitely more than likely dead.
There's enough used ECMs on eBay that I wouldn't bother trying to swap out PROMs just yet. See if you can find the exact one for your car on eBay first. I just bought, for $27 shipped, a 1986 ECM for a 4cyl 5-Speed... which I needed for my daughter's 85 4cyl 5-speed so we could take advantage of the updated programming of the PROM that uses the V5 compressor instead of the DA6. So, most of them are pretty cheap!
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Vintage-Nut
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SEP 18, 02:13 PM
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Testing the ECM
https://www.vehicleservicep...-order-a-replacement
I had 'weird problems' with an ECM in a different vehicle, so I sent my computer to ECU Exchange for testing.
They found a bad power supply which created distortion on the reference and system voltages.
They repaired it; I got it back; installed the computer and the vehicle runs great now......
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Original Owner of a Silver '88 GT
Under 'Production Refurbishment' @ 136k Miles[This message has been edited by Vintage-Nut (edited 09-18-2024).]
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k5ahudson
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SEP 18, 02:14 PM
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| quote | Originally posted by Vintage-Nut:
Testing the ECM
https://www.vehicleservicep...-order-a-replacement
I had 'weird problems' with an ECM in a different vehicle, so I sent my computer to ECU Exchange for testing.
Their found a bad power supply which created distortion on the reference and system voltages.
I got it back; installed the computer and the vehicle runs great now......
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Roughly how much did it cost you?
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Vintage-Nut
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SEP 18, 02:31 PM
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k5ahudson
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SEP 19, 03:11 AM
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| quote | Originally posted by 82-T/A [At Work]:
... and you've verified positive power to the ECM (e.g., not blown fuses... fusable link?) |
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Fusible link!!! I totally forgot about that being a possibility. I'll check on that tomorrow. Thanks!!
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