PontiacBonnevilleClub.com

Ok, my car has 40,500 miles. Its a 2004 Northstar. I got the code for the catalytic converter, so rather than replacing that, I replaced the rear O2 sensor. Went to the parts store and they reset it. No problems.
So the car has been running like a dream. I've put over 6,000 miles on it in a month. Not one single problem except the O2 and the occasional "Service stability system" code.
Well, I was sitting having lunch in my car. Was running fine.
I go to drive off, make it around the corner, and the car just dies. No warning, no running rough, etc. Just dies!! Well, I coast into a parking space. I tried starting it and you can hear the starter engage the flywheel, but nothing. I checked fuses, I let it sit there for 2 hours to cool, and even after that, I tried jumping it off. Nothing. Just the starter engaging the flywheel with no results. I have full power to lights, windows, everything electrical. Temp reading has been sitting right on the same place its always sat. No oil in the coolant, no water in the oil. I don't even smell anything burning. I'm completely stumped. Could the engine have locked up without warning?
What could be my problem?

Does it even spin the engine? Unfortunately if it doesn't, you can't use the ancient chinese secret of tapping the starter case to break the brushes in the starter off the wall since the starter is under the intake plenum.

There is way to many possibilities as to why it died in the first place, but first things first, get it started again.

Nope, It won't spin the engine. You can hear everything engaging as if to start, but nothing. Like trying to start an old riding lawnmower. Just click on it until it turns over, but unfortunately, it won't turn over. Its sitting right where I left it until I find a towing company and mechanic. I was hoping to find something on here that could be the cause.

I dunno man, I have a few things, but anything is a crapshoot right now. And I hate being wrong, so...

Could be as simple as the starter is hung up like I previously mentioned, but that doesn't answer why it shut down like it did, which is where I have a whole Christmas tree of mental flowcharts in my head running.

I was thinking maybe a locked up ac compressor, but it was working fine before it shut off. Then maybe a locked up alternator? But again, it was working fine. I just can't think of anything. I was hoping someone with a similar experience could lead me verses going into this blind. I've never had to have a mechanic before, so I don't even know where to begin. If I can get this b*tch running again, I'm going right to the Toyota dealer and trading it in!

I'll tell you. I just went through the same thing, My ac compressor was making noise. I knew it was going. I had gone to the store. Came back. Cut it off. Went to go somewhere else shortly after and it wouldn't start.

Took battery out. had battery tested. it was bad. Replaced it. No joy. Still wouldn't turn. Was doing same thing. Starter was engaging the flywheel but not turning it.

I wouldn't have thought the ac compressor would have seized while sitting there off, either.

The way I diagnosed it is I took the serpentine belt off and started the car, (letting it run for only about 15 seconds because without the belt you have no water circulating). That let me know it was an accessory stopping it. Then I turned the alternator with my hand. It turned. The ac compressor was frozen.

I've seen that happen once in a blue moon, but that was on some anemic little sh*tbox 4 banger. Typically an engine, such as a torquey V8, even with a compressor frozen, has enough grunt, especially if at a higher than idle speed, to either jump or destroy/sheer the belt in the process of continuing to rotate. And when it did that, you'd hear the shriek of the belt as well as probably smell burnt rubber.

Now it's quite possible if run long enough like that (no main accessory belt), with no water pump being turned, that no coolant would be circulating and the car would over heat. But I would think you would notice the little temp gauage on the dash as it started to get warmer, and probably some major overheat error message in the D.I.C. once the epic climax was achieved.

The difference is, Northstars water pumps aren't driven off the main accessory drive, they're driven off the camshaft on the front bank of the engine. So no overheat situation would be at hand as long as the engine was still running, the water pump is still running.

My guess is if no mechanical failure was heard, detected, smelled, etc, that it is most likely electronic. A short. A lack of class 2 communications between modules, which included vehicle security info not being shared amongst those modules, which CAN shut things down and/or render the car as nothing more than a paperweight until said communications and VIN# verifications are performed, etc...

I wouldn't have expected it to be the ac compressor either till it happened to me last Thursday. My brother who is a top notch mechanic even said to me that the ac compressor doesn't have enough arse to stop an engine from turning.

But when it happened, it got me to wondering if there could be some sort of torque sensor that would stop the starter from turning in the event something seized.

But of course my compressor was already howling so it wasn't hard to guess.

One question... Something that stands out. You mention that the temperature is pinned right where it was where it died. When you turn the key, and the engine is cold, the gauge should go to cold. Is that not what is happening? Do you still get a gauge sweep at startup? Do the lights dim when you hit the start, as if the the starter is trying and drawing a heavy load?

Like it's hung up.

BOOOOOOOOOO!!!!!! I found my problem, and sad to say, none of the things mentioned above was it. The motor locked up. What luck! UGH! I haven't had the *dang* thing but a little over a month. Mechanic took the starter off and the serpentine belt, and said he couldn't turn the motor over at all. He's checking on a new motor and I'm scared to even know what that's gonna cost. :(
Thanks for the advice though. I went out and worked on it with your suggestions this morning and nothing worked. I had to call a tow and this is where I stand now. The most effed up part is that it gave absolutely no indication of going bad. No smoke, maybe a little rough idle at times, but nothing serious. I mean it was so quiet while I was driving. Sad day.

Ouch!

Well, got the price today. For a new motor, labor, and a 1 year nationwide warranty is going to be $2,300 bucks.
I'm clueless, but that sounds like a good deal.

Any thoughts?

Is that just a short block? I.E. heads would come from the original motor, which would include a bit of labor I would think, and I might question that he is competent in replacing those heads and all that is associated with thm...

Engine was on my list too, but one of the last things... I would like to think you'd have noticed prior to that that something was wrong.

Did he remove the spark plugs and see if he could turn it over? I'd almost think it would be hydrolocked or something...

I was gonna ask the same.

Thanks for the info. I can check. But I thought there'd be a warning too, but nothing. Last code reading was low oil pressure, but there was never a light and the gauge hand stayed between 30-60 psi.

Hate to be a naysayer, but $2300.00 installed with warranty for a Northstar, I think something is wrong, I doubt you could get a 3800 replaced for that price.

Agreed. That's why I asked if it were just a short block. But then there would be labor to swap heads.

Or is it a used motor?

Places I called when I had my GXP wanted $4000-$5000 to swap a Northstar, some places said they wouldn't even touch it.

But used engines can be had for $500-$1000 with reasonable mileage.