Looking for some input here on an issue that popped up last week on my wife’* 01 SSEI. Car had a cold starting problem that was do to a bad crank sensor, replaced it and made it worse "like a cold diesel", bought a GM one and now it starts fine. Around this same time it picked up boost related problem. When the engine is up to temp in WOT and above 4k on the tach the boost goes over 10psi and it misfires or detonates. The power falls off hard at this same spot before you can hear anything inside the car. If you back out it and keep the boost under 10psi it clears.

I checked a few things today like the sc oil level "a little low" and the bypass actuator which I can see moving when you snap the throttle. It had set a couple codes P1274 and P0300 when the bad crank sensor was in there, and we noticed cylinders 2&5 misfires on the scan tool just before it set a random misfire code. We swapped out a coil off my other 3800 and it made no difference. After I replaced the second crank sensor Friday it started up and runs fine but this same high rpm problem remains.

Other things we checked were the PCM plugs in the air box, all the vac lines on the engine and ran a couple tanks of injector cleaner through it. Can't find anything out of the ordinary and no other codes are showing up. It set another code today but I have not pulled it yet. I don't recall the boost ever going above 10psi before this started. Was thinking of changing plugs and wires but my experience tells me its computer related by the way it acts. The car is bone stock and runs fine the rest of the time.

Any ideas

well it could be your MAP sensor, or your BCS there is no way that you should bury the boost gague stock

Check the plug wires with an ohm meter, and inspect the plugs.
The hesitation is the pcm pulling timing due to the misfire.
There is a chance it could be the icm (ignition control module) but I would check the plug wires first.

Thanks for the input everyone.

I call a friend at the local GM dealer today who said it the timing may need to be calibrated in the PCM since the crank sensor was changed. He said this could cause the random misfires and set the codes if it is off. Was thinking it might be a timing issue due to the detonation, yes I am running 93 octane in it. I am going to have the wife take it in on Wednesday and let him check it out, will report back what he finds.

Mark, I hope your wrong but that is my second thought. When the defective crank sensor was in there it lit off the raw fuel in the pipes a few times and experienced a couple hard kickbacks when starting. It was harsh enough that it could have damaged a cat. But then again after a cold start while in open loop it does not act up like when it'* warm.

Is the boost gauge reading produced from the MAP data only? If so that might explain the high boost readings.

Yep, any time you change the cam sensor you should have a CASE learn done.

Ok here is what I found out from the dealer. NOTHING GOOD !
They could not diagnose the high-end misfire and over boost issues. While test-driving they could only see 4 and 6 cylinder misfires above 4 grand. They changed the oil, plugs and wires and no change. It set a catalytic converter inefficiency code once, then nothing else. I told them thanks and would pick it up later.

When my son picked it up he said there was a light tick coming from the top end it sounded like, I told him to just drive it home easy and park it. By the time he drove15 miles to the house the tick became a knock and is full time now. I had him pull the belt of the SC, there was no change. I have only listened to it over the phone, but it sounds like valve piston contact and not crank related. Anyways not sounding good.

Unless someone here has a better idea, I think I will probably just pull the engine and try to find a replacement. So now my question, is there a difference between a SC engine and non SC engine besides the blower?


Very Sad
:(

Sounds like either they didn't do the CASE learn and might want to soak you for unneccesary expenses or they did a CASE Learn, but it needs a coil pack or ignition module.

Just read the last part of your last post.
Check Ebay -I just saw a 2002 Bonneville SSE-SSEi engine (doesn't say if it is supercharged or not) with less than 72 miles on it for $999 BUY IT NOW. I believe the shipping might be a tad bit expensive though unless you are near enough to pick it up.
Also, if that'* too much and you need a engine try www.car-part.com -should have no problem finding a Supercharged 3800 for cheap -note you can search for pre-Y2K SC'ed 3800'* too as all that is different are the motor mounts which can be swapped off of your old engine.

Best of luck.

They did the CASE lean before the first test drive. I trust the tech who worked on it enough to know he did what he said. He also told me "I wouldn't drive it without pulling the valve covers to check the tick and the valve springs" which I ignored....

I find it very strange it progressed from a cold start problem to a hard knock in under 100 miles. No smoke or blow by so I don't think it smoked a piston. But I'm sure I'll find out when I pull the heads.

So consensus is there is no difference in the long block portion of the 3800 SC or not? Just want to make sure before I put down the cash for a replacement.