96 monte Z34 3.4 DOHC, car is showing no symptoms other then blowing the ECM BAT fuse once the key is turned to the on position so i cant even put my scanner on it to see what the problem is, it did this at hwy speed with no syptoms just cut out and now blows the ECM BAT fuse.

i did a visual for a burnt wire or short to ground somewhere and nothing, the only other thing i can think of is to pull the ECM harness and start testing for a short to ground

anyone else have this problem or maybe herd of it that can give some helpful advice

 

I have not heard of anyone else having this problem. Probably like you said, a bad wire in the harness somewhere.

 

well i just followed the wiring scematic and the same wire for the ECM BAT also powers the fuel pump which i just had to install my 3rd airtex fuel pump in 6 months so ima pull the FP relay and see if it still does it if not then im following the FP harness, i pulled the FP connector by the tank and it still did it so if it stops when the relay is pulled im thinking itll be between the relay and that connector.....

 

ok so disconnected the fuel pump harness at the tank, tryed and it poped, so while leaving it disconnected i also removed the fuel pump relay and tryed with no pop this time

well did an ohm check on the fuel pump main feed wire at the tank end of the harness and at the relay with my DVOM and boy is she beeping away, keeping the negative on a good ground and the positive on the feed wire there is deffinetly a solid short to ground

i know the harness goes up into the car from the tank then must head toward the engine under the carpet but where does this fuel pump wire go from there, where does it go threw the firewall, if its just a stand alone wire from the underhood fuse panel to the pump i could just run a whole new wire, the haynes wiring diagram doesnt show the theft deterant system interfering at all just shows the wire coming from the fuse then spliting to the computer and to the pump

help? before i tare this poor old monte into peices trying to trace this wire

no GM techs here?

 

problem solved!!!!

i noticed while holding my DVOM on the wire the condition changed when i wiggled the harness that goes from the tank up into the floor, so i pulled the carpet up and what do i see........the harness had been yanked so hard at one point the casing on the wires peeled off and was grounding on the body so a quick cut, solder, heat shrink an all is better

fuse no longer blows, im getting more fuel pressure(probly the correct PSI now), the car runs(better then its ever had) and what i thought was a weak alternator was just that short to ground, now im getting the full 14v at idle and 13 with all loads on,

so a little shorting wire was causing all this crazy stuff....but its fixed now and if anyones showing any of these symptoms it only takes a minute to lift the trunk carpet and take a look, but look closley

 

Glad to hear you got your problem solved. Happy driving.

 

thanks kinda happy to have killed 3 birds with one stone, i hear the alts on these are a PITA to change, i do have to do a timing belt soon

 

well instead of starting a new thread ill keep posting here, the car has ran great until just now when i started it and it wouldnt start, but by holding the starter on for a few seconds(maybe 10) it fired up, ran rough and i shut it down, hooked up the scanner and im getting a P0305 cylinder 5 missfire and a P0441 Evap system incorrect purge flow

the evap is probly a hose somewhere, the hoses are in bad shape...

also does anyone have the vacuum hose routing diagram or something going from the smog pump to were ever its supposed to go, hose is just hanging at the pump

help on the #5 missfire?

what is also confusing me is i restarted it and it started fine and is running fine now gonna take it for a run and see what it does

 

been running the car for like 5 days now with no problems, the cylinder 5 misfire code is still there even after clearing it 2 days ago

i want to take a look at the plugs but i have a bad habbit or am just cursed but normaly when i remove plug wires i end up breaking 1 or 2, any suggestions on seccessfully removing the wires so i can look at the plugs and possibly ohm test the wires? or is it simply just twist & pull and hope for the best

it really sucks that the upper intake has to come off, i guess while its off i could also change the lower intake gaskets since ive read they are known to blow/leak.


i was also wondering if this engine can be removed from the top or if im gonna have to find someone with a lift to remove the cradle and everything else from underneith? the rear main and the oil pan are leaking about 2qts a week and buying oil that often gets expensive