smg944

iTrader: (34)

went to go start my 2nd gen today. brand new battery and the cranking was a bit slow. i kept it cranking and it started smoking from the pass side. i traced it down to the ecu grounds. they were cut and put directly to ground. so i seperated them all and the 3g ground wire from the ecu is giving off 3.7v. im guessing this is not normal could my ecu be blown??

smg944

iTrader: (34)

ttt anyone...?

SureShot

The ECU energizes solenoids by providing the ground, so it's normal to see voltage from the solenoids on a bad ground wire.
You did good by fixing the ECU grounds.

If the engine will start, I'd run a quick general voltage check:
Engine running, headlights & heater fan on high:
Alternator post to alternator frame = 14-14.5 volts (verifies the alternator output)
alternator post to battery (+) = 0 volts (verifies the primary + wire)

alternator frame to battery (-) = 0 volts (verifies the primary ground)

Turn off the motor, but leave the lights on.
Battery (+) to battery (-) = ~12.5 volts and holds steady. (verifies battery)

smg944

iTrader: (34)

the voltage was coming from the ecu side. i had cut the ground wire, then hooked up a meter to get a reading. so basicly direct from the ecu ground wire 3g i am getting 3.6v. if that is normal thats fine, my issue is that if i crank the engine for more then 10-15sec the wire starts to smoke.

p.s the reason i am cranking for so long is because its a fresh rebuild that has not been started yet.

smg944

iTrader: (34)

ttt..

theonlygreat

Measuring voltage into an ECU with a high impedence DVOM can be tricky. You are more than likely feeding through other circuits. The readings are not reliable. This is probably a normal reading. For the source of the smoke I'd look at what the ECU is turning on with that ground. Like maybe some gigantic injectors or any other output of the ECU or corresponding wiring that might be shorted or pinched from the engine installation.

HAILERS

Frankly it sounds like MAYBE the ground wire from the battery negative post is not connected up good to the chassis (just below the left hand front strut) and that same wire is not grounded good on the long starter bolt where it was originally connected by the factory. You can use any of the other transmission/engine bolts and it'll be fine. But it seems your batt to chassis to engine grounding is not good at all. And like all the grounding action is happening thru small gauge wiring. Like on the ECU.

On the other hand it could be something totally different.

If I were you I'd also pull the plugs off the ECU and check the grounds for OHMS at the PLUG, not the jack on the ECU. The gnds should all read below one ohm with the KEY TO OFF. Like 3A, 3G, 2R and that other one out there. Pure black wires.