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grounds for ecm

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Old 06-20-2011, 06:40 PM
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Car: 87 iroc
Engine: 305 tpi
Transmission: auto
Axle/Gears: 3.23 limited slip
grounds for ecm

when i pulled my ecm out of my dash i found a blue wire not attached to either the ecm or a ground point or anything, the blue wire is coming out of the main wire harness and has a metal loop crimped on the end like the ones found on a ground wire attachment point. has anyone ever seen this before or know whee it goes or if it is supposed to be disconnected. i looked around and nothing jumps out as an obvious attachment point.

i just replaced my ecm and the car still does not read codes like it is supposed to and others have thought it might be a bad ground for the ecm....could i add a new ground wire from one of the sheet metal screws holding the metal box of the ecm together to the metal post behind the kick panel?
Old 06-20-2011, 08:21 PM
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Re: grounds for ecm

Don't ground the ECM case locally. The ECM case is grounded via the wires that runt ot he engine block. By adding a local ground, ground loops are created. IOW, other devices will be using the ECM ground wires for their use, not the ECMs use.

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Old 06-20-2011, 08:25 PM
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Re: grounds for ecm

ok, have you ever seen the blue wire i described?
Old 06-20-2011, 09:03 PM
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Re: grounds for ecm

Originally Posted by grasshoppertym
ok, have you ever seen the blue wire i described?
No, and not knowing the vehicle year, engine, transmission and whether it is a CCC or EFI...

RBob.
Old 06-21-2011, 07:00 AM
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Re: grounds for ecm

it is an 87 iroc 305 tpi auto trans and all stock
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