CDN3g

I have a Check Engine fault code 51 which, according to the code reader manual as an ECM problem on my '82. The car does start and run, although it does have a slight miss when cold. Drivability improves as it warms up.

Do I need to replace the ECM ? I noticed that Eckler's sells a rebuilt ECM but they instruct to reuse the PROM from the original ECM. Does anyone have any experience with this particular fault code and what remedy do you recommend? Thanks

Chuck

jdp6000

Make sure the plugs at the ECM are in secure. Clear the code and see if it comes back.

You may have some corrosion inside the ECM in the area of the prom. If its not seated right or one of the pins is bent you will get that code. Look for evidence of corrosion.

New ECM's don't come with the prom. You need to swap out yours.

7T1vette

Also make sure any grounding wires/connections are clean and solid. If the Check Engine Light (CEL) is lit when the key is turned to ON position, and it goes out after the engine is started, then the ECM is "working". But, bad electrical/ground connections can cause errors in its data, which could be the reason for the Code 51.

Removing cables, cleaning contacts, and reinstalling with dielectric grease on those connections is the first step in analyzing your problem, since the trouble codes pointed to the ECM. There is no clear indicator of an ECM problem, as a defective ECM would not be reliable/accurate enough to diagnose itself as a problem. An exchange of the ECM is the last item on the list when everything else has been ruled out. Start with clean connections.

CDN3g

Thanks for this very practical advice. I have other things to spend my Corvette fund money on besides a new ECM.

Chuck

1yy07

chuck, if you need a new ecm old gm#1225550, new gm#19143616.acdelco#218-12250