Wrong Computer???

[Carlitoboy]

Good day all!
I've been recently inquiring about not being able to start my car; I'm a GA GT1 2001. The starter will crank but the engine won't fire up.

Possible issues I've read about:
1)Passlock system "Security Light" --> Possible
2)Ingnition cylinder. --> Dunno what this is
3)Fuel Pump/Filter --> Not the problem

Anyway, my mechanic checked out the car yesterday. Spent the WHOLE day testing all kinds of stuff; tried a new ignition module, camshaft module, this and that. He could not find the cause. He did find that sometimes there is spark, and then no spark...??? Regardless, he never got the car to fire up at all. He could only concude that it was a computer problem. We were thinking of getting it tested so he removed the computer and called the dealer to ask some questions before we sent it in for testing. He gave the GM service guy the serial number of the computer and my VIN... Guess what he told us. That serial number of the computer belongs to 1990 Buick Cutlas! We called another dealer service center who told us the computer belongs to a 2000 Oldmobile!

Is that not dekcuf up or WHAT!!

Another dealer mentioned that the computer is covered by warrantly up to 150,000 KM. I qualify for coverage so I may have some luck. But what I want to know is, what the heck is this computer doing in my car? Does this computer track mileage history? Is this why my gas mileage has always been questionabley low? Is this why my check engine light goes on 4 or 5 times a year and the code is missfire? I'm going to sue some ass man! :mad:

Is there something I should know? Is this normal for these cars to have these computers? What should I do???

Regards,

[rixGAphx]

Don't know who told you what or why.

There were major computer changes for GA's in '94, '96, and '99.
NONE of these will work for any other group of years.
I *think* there may also have been a major change around '00 or '01, but I'm not sure.

GM made the same 'essential' vehicle as the GA for Pontiac, Buick, and Oldsmobile.
So within any given group of years, a PCM (Powertrain Control Module, the engine/tranny 'puter) could well be the same for any of the three models (Achieva, Alero, etc.).

I think people are just screwing-up when the research the serial number.
No WAY was your '01 able to run with a 1990 Buick engine 'puter; the connectors, software, sensors, etc. are just too different.
2000 Olds? Prolly right on. And the 2000 Olds will prolly run fine with the PCM from an '01 GA. There's half-a-bazillion parts that interchange between various GM model lines, including sensors and PCM's.
* * * * *

Your PCM may indeed be the problem, especially if a GM mechanic has fully analyzed all other possibilities.
Whether the PCM has been the source of previous problems (misfire codes) is doubtful.
More likely the other way around: some glitch in your system may have fatally damaged the PCM.

Do you have an aftermarket alarm, with iginition disable and/or remote strt? This has incredible potential to foul-up a GA's already-tempermental electrical system.
* * * *

When your SES light comes on and the problem is P0300 (multiple random misfire) or a cousin (P0301, 0302,..), the PCM will generally stop reading the O2 sensor and revert to a very rich, gas-guzzling 'default' setting for the injection and ignition.

The actual cause of the misfire could be lean injection (bad fuel pressure or bad injector(s) or faulty signal to the injectors(s) (from the PCM), rich injection (one or more injectors stuck partially-open by a build-up of crud), or fualty ignition.
Faulty ignition could be caused by one or more of the coils failing (they don't just fail, sometimes they continue working intermitently), the ignition module, the plug wires, the plugs, or the signal from the PCM.

If it were me, I would really concentrate on the ignition system at this point.

Have you checked the ignition coils?
I've heard stories that some work well when hot but not when cold, and vice versa.
Also, where they plug into the ignition module, the pins and sockets can become corroded or coated with oil, prevent strong dependable connection.

Also, check that the PCM is properly-grounded, maybe even run an auxilliary ground from the PCM to the body/chassis.

Finally, as in everything electrical with a GA, make sure the battery, alternator, and cables are in tip-top shape.
Cutt off the molded rubber boots from the cable ends and inspect/clean/repair the corrosion that develops invisibly in there.
Replace the boots with slip-on aftermarket rubber boots that can be inspected.
I've installed an auxilliary ground cable from the batt connection to the body just to be sure.
Lack of strong voltage/amperage to a GA will cause mysterious things to happen.
And trust me, they DO HAPPEN :banghead:
* * * *

Ignition Switch is located in the dash. It goes bad ocassionally, and can be replaced.

The ignition 'cylinder' is the device into which the key inserts, like the cylinder in your front door knob at home.
The cylinder can also fail, and is replaceable.

When mine failed, it just grabbed the key and wouldn't let me do ANYTHING: not turn it in any direction, not remove it, nothing.
Had to have a mobile locksmith come repair it at home.

Others have experienced different types of failures, but I don't recall anything like your symptoms being associated with a faulty ignition switch or cylinder.
* * * * *

I know you say it isn't the fuel pump or filter.
Have you checked the fuel pressure regulator, and the fuel pressure at the rail?
If the regulator is bad, it could have caused your former P0300 misfire, as well as your current won't-even-start condition.

Whew!! :wipebrow:

Hope this helps,
-Rick

[HeyDace]

Is this a V6? Have they checked the signal from the crank sensor. This can be read with a scanner. The crank sensor refrances the spark for each cylinder. It sounds like that to me. Those are very hard to diagnose and most GM techs will pull one off the shelf to try it out.

[Carlitoboy]

Thanks rixGAphx! That's alot to take in and I appreciate that. I'll let you all know what the dealer tells me.

Heydace it is a V6. My mechanic (before taking it to the dealer) check all that good stuff.

Thanks again guys!
Carlitoboy

[Carlitoboy]

Folks,

It turns out that the computer is fine and it belongs to the car. Also, they didn't have a problem starting it to drive it into the garage... Go figure... When I tried to relearn / reset the security, it didn't work. The reading the dealership got was about the Passlock.

Off the work order:

Complaint: Check Cause engine cranks over but wont start

Cause: Unable to duplicate concern, battery was drain and security code P1626 and B2960 was stored in history. Possible cause could be ignition lock cylinder failure

Correction: Perform system diagnostics and charge and check battery

So we drove the car home and changed the battery and she fires up no problem now... $400 dollars later (including new battery).

That's a nice kick in the sack ain't it? I'm gonna have to end my golf season early this year it seems... :mad:

Oh well. You make your own bed, you have to sleep in it right? If you don't want these problems then don't own these cars.

Anyway, thanks all for your input and advice! This is a cool forum.

Carlito

[rixGAphx]

Glad yer on the road again, thanks for reporting back.

Sorry about the bite to the wallet. :(

-Rick