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?

 

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.

RBob.

 

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.

 

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