Ecm

[z24 drag]

What wires grounds the ecm , check engine light not working, 2nd wiring harness in 2 weeks ,what's causing the harness issues please help

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[neophile_17]

Sorry to hear you're having problems. What ECM are you using?

[z24 drag]

Factory ecm, just pulled engine out to replace bearings, noticed performance was bad ,car is running rich ,so I changed oxygen s,and coil pack,no change,noticed no check engine light ,I know if I change the harness it fix car but for how long problem keeps comin back had same issue with previous z24 after swap

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[Guest]

Considering there's about 2 dozen "stock ECMs" that can run a 60 degree V6, and many more that can be swapped in to run a 60 degree V6 with some tuning, it would help to know the service number, application, and any other details.

Also studying a service manual where the ECM wiring is concerned will help you determine which wires do what and may help you figure out what is going wrong. In my experience the harness don't fail, so I think you're barking up the wrong tree here with the harness being a failure point.

[z24 drag]

Ok I'll get the severe number for the ecm, ( tried a different ecm from an 89 z24 and 92 corsica

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[z24 drag]

Ecm 16198262 and 1227730

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[neophile_17]

http://www.gmtuners.com/files/Fiero_2.8_to_7730_$A1_DIS.pdf

Ignore the first two columns. This table is for converting a Fiero harness to run a 7730 computer (yours). As you can see there are several grounds.

The (fuel) injector ground MUST go to the block or heads and must be separate as several have found out the hard way.

[Guest]

http://www.gmtuners.com/files/Fiero_2.8_to_7730_$A1_DIS.pdf

Ignore the first two columns. This table is for converting a Fiero harness to run a 7730 computer (yours). As you can see there are several grounds.

The (fuel) injector ground MUST go to the block or heads and must be separate as several have found out the hard way.

I've never separated the injector grounds and have never had an issue. I ran all of the grounds independently to the engine block where they shared a single lug. I've used similar grounding with other ECMs as well.

[neophile_17]

I've never separated the injector grounds and have never had an issue. I ran all of the grounds independently to the engine block where they shared a single lug. I've used similar grounding with other ECMs as well.

That's true I wasn't 100% clear. My intention was to convey separate wire not necessarily separate ground lugs. Just don't try to run a single wire from the engine to the ECM and then tie them all together close to the ECM. I never had a problem but I saw posts about other guys chasing their tail because they did exactly that and it stuck with me.

[Guest]

That's true I wasn't 100% clear. My intention was to convey separate wire not necessarily separate ground lugs. Just don't try to run a single wire from the engine to the ECM and then tie them all together close to the ECM. I never had a problem but I saw posts about other guys chasing their tail because they did exactly that and it stuck with me.

Yeah, for some reason, which I still have to figure out at some point tiing the grounds together close to the ECM, even to a large wire seems to cause issues.