Help me save a chevy lumina

Neighbor has seriously messed up his 98 (I think 98) lumina, 3.1 ltr. Grounded out the small lead coming out of the alternator and now electrical gremlins galore.

When the battery is connected, the power locks go constantly, ditto electric trunk release. Turn car to the run position and the starter engages and wont disengage. Perhaps fried the power train control module?

Classic SAABs and vintage vws are my regular world... And don't have a shop manual for it.

He is going to scrap the car if we can't solve this one, would be a shame

If i'm not mistaken, GM's of that era (96 and up OBDII) have 2 computers, one for the powertrain (PCM) and one for the body (BCM). You may have success by merely de-powering the computers (extended time disconnected from the battery) so they reset.

My son owned a 1995 and we put a new battery in and then the clock glowed super bright and wore the battery down at night.

Blammo - fuse pulled to clock and radio memory. Problem fixed.

I hate Lumina's. Another GM car I was happy to see leave. (the other was a 1986 Pontiac Grand Am)

Frigidaire wrote: He is going to scrap the car if we can't solve this one, would be a shame

No, that would not be a shame. Not at all.

My first question was.... Why? However it sounds like bad relays. Try a reset, and if that doesn't work, start digging at the relays under the hood.

disable the power locks and trunk -you don't need them, anyways- and wire up a push button to the starter solenoid- you know, like the race cars have.

Sounds like the BCM is fried. Might want to find out the cost of a new BCM and go from there.

For only $1600 you could drive the police version, maybe.

http://baltimore.craigslist.org/cto/4413030802.html

Donebrokeit wrote: Sounds like the BCM is fried. Might want to find out the cost of a new BCM and go from there. For only $1600 you could drive the police version, maybe. http://baltimore.craigslist.org/cto/4413030802.html

sure looks like a cop car..

gutted interior.. notch in the door where the spotlight used to be.. 3800 engine in boring looking stripped down looking gramma's car..

the want is strong with me..

Have you tired dead heading it yet? Pull the battery out, short the cables together, step on the brakes and cycle the key a few times. If that doesn't fix it things have fried.

novaderrik wrote:

Donebrokeit wrote: Sounds like the BCM is fried. Might want to find out the cost of a new BCM and go from there. For only $1600 you could drive the police version, maybe. http://baltimore.craigslist.org/cto/4413030802.html

sure looks like a cop car.. gutted interior.. notch in the door where the spotlight used to be.. 3800 engine in boring looking stripped down looking gramma's car.. the want is strong with me..

Mmmmmm, Recaros.

Kenny_McCormic wrote: Have you tired dead heading it yet? Pull the battery out, short the cables together, step on the brakes and cycle the key a few times. If that doesn't fix it things have fried.

This, pretty much. Although I can't imagine that shorting a low-current wire to ground would adversely affect anything. Especially since, with very rare exceptions, the computer controls everything via ground side.

For certain, the BCM is damned unhappy.

Oh if only I had a repair manual for it. Presently with the wires disconnected from the alternator completely and the main positive to the starter off, the gremlins are still there. Now the starter solenoid only kicks in when the car is actually turned to the start position. Found what i believe is the PCM/ ecu in the front passenger side of the engine bay. This is going to be a to be continued, as I can only get to the picknpull next weekend. Anyone have a guess where the bcm might be? Possibly the same unit as what I think the PCM is? Would love to send this beauty off a cliff but need to get it running to do that

Oh and it has sat for weeks with no battery connected. So think it has a serious fault that isn't a short term scrambling. Sure did float along smoothly on the highway before all this. Hope that he'll give it to me some day, if I can get it fixed, so that I can drive it out of the rust belt on a one way trip to go pick up a more interesting car. A modification of the arrive and drive. Take a few minutes to scrap this thing while picking up the new wheels.

The PCM controls the engine and transmission. Powertrain Control Module. GM likes to put these under the hood.

The BCM controls the lights, power locks, trunk release, anti-theft, and a bajillion other things. Body Control Module. I've never seen one that wasn't buried in the dash somewhere.

The weird thing is, the PCM generally controls the alternator.

Try this: Unplug the PCM (should have two looong connectors with a 7mm headed bolt in each one) and reconnect the battery and see if the car still goes all possessed. There is a slim chance that, somehow, the PCM is sending strange data over the network and the BCM is interpreting that as commands to go haywire.

What was he doing when he "grounded out" the wire? Did he ground it by replacing the alternator and pinched it, or did he accidentally connect it to a different ground wire, or ?

It should be noted that, if you're working on what I think you're working on, the underhood fusebox is right in that vicinity, and it also serves as the junction between the drivetrain harness and the chassis harness. Weird wild stuff can happen if you get the Pepsi Syndrome in there.

My curiosity still would like to know what he was doing when he grounded that wire, and why he was doing it. It's possible that the grounded wire is a red herring. (IE - "You replaced my transmission and now the parking lights don't work." "The parking lights don't work because whoever installed your stereo connected the illumination wires to each other, blowing the fuse." "Oh, yeah we had the radio installed the day after we picked it up from you...")

In reply to Knurled: took a while to find time to return to the repair. Previous guy had been replacing a power steering line when he ripped out the small lead to the alternator, then couldn't figure out where it went, assumed (wrongly!) that it was a ground so grounded it out.

Anyways, car fixed! Got another neighbour involved, and as we pondered replacing the PCM we checked the keys to see if the car had an anti theft coded key. Neighbour spotted the remote on the keys for the aftermarket remote starter. Which controls the power door locks AND the starter. Start car. Won't shut off. Buzzing under dash from said autostarter module. Pulled many wires. Now all good. At least as good as a Chevy Lumina can be

In my modest defense I've never owned a car with an auto starter!

This is why I won't own a car with such add-ons.