intake manifold on 2000 grand prix 3800 engine exploding

Girlfriends car. Would not start after running great for two weeks following a replacement of the Mass Air Flow sensor and the crank sensor. Car did start for just a few seconds then nothing. Dealership took car in and the next morning they went to start it, it blew the plastic intake manifold into 4 or 5 parts and caught on fire. Just wondering if anyone has ever heard of this or has experiece with this happening. My fathers 2001 Buick Park avenue had an explosion under the hood a while back and the car burned to the ground.

Its backfiring and blowing the plastic UIM to pieces. You need to figure out why its backfiring then replace the UIM.

Its backfiring and blowing the plastic UIM to pieces. You need to figure out why its backfiring then replace the UIM.

Well yeah! I was wondering if any others here on this board have ever experienced it before. Dont want the car back if they dont find out what caused it. As my fathers car proved that if you dont get to it quick it will go up in flames fast.

I dont know. Overfueling maybe? When was the last full tune up done?

Run a search on the forum. Another member had this issue a while back, I cant remember how it was resolved.

I saw a thread a few days back in the new posts section where the title said 3800 engines recalled, I read the thread and it said it was because of fire risks, I have the same engine in my regal.

Found it. http://www.automotiveforums.com/vbulletin/showthread.php?t=949817

Yes, read the link in that thread, you may be able to get it fixed for free since that happened, I doubt that it had anything to do with your problem though. But 97 to 03 Grand Prix with that engine are in the recall.

He should defenatly bring the car in for the repair work unless he has replaced the valve cover gaskets already (most of us have), but his problem is with backfiring and blowing up the upper intake manifold.

Jim, I think you should replace the UIM, get the car running, and then check out the fuel system. Make sure that the fuel pressure regulator isnt leaking gas into the UIM.

Was the SES light on? Any codes?

I wonder if there is some way the ignition timing is off....

The car is in the shop right now. In fact it was the dealership that tried to start it when it blew. I am just wondering if anyone here has seen or heard of this before because they claim at the dealership that they have never seen this before but our Mechanic who came from there said he has seen it a few times. They are having a hard time diagnosing it as has been a week since it happend and the $ is piling up!

I've never heard of one of these plastic UIM's exploding unless someone was spraying starting fluid or other flammable liquid into the UIM in an attempt to get the car to start. It's not uncommon for overzealous DIY people to do this, but a dealership should know better. There's an outside chance as Tblake mentioned that a leaky FPR allowed fuel to get in there, but highly unlikely. IMO, the dealership owes you a UIM as I believe their tech screwed up.

The problem I am having with this is my fathers car burned to the ground and his car sat for a month and when he hit the key he heard what sounded like a shotgun going off under the hood, then flames. The mechanic trying to start the pontiac was not using starting fluid as the day before when they picked it up the car had no spark. I have read several other forums that have said that GM was investigated on this and over 600 incidents and over 45 fires from this so I wanted to see on here. Really surprises me that no one has had this happen. Mechanic as lucky as if he would have been standing in front of the car he would have been badly hurt or killed!

http://www.carcomplaints.com/Buick/Regal/2001/fuel_delivery_system/intake_manifold_exploded.shtml

http://www.carcomplaints.com/Chevrolet/Monte_Carlo/2001/fuel_delivery_system/intake_manifold_exploded.shtml

http://www.carsurvey.org/viewcomments_review_44502.html

http://www.allworldauto.com/comments/1998_buick_lesabre_comments_and_complaints_c42-255-1998-72-1.html

http://www.canadiandriver.com/forum/index.php?ftopic=55704.0

I'm trying to find a specific recall for yours but I seen several vehicles I think the problem was the fuel pressure regulator which was recalled and was the cause of the problems with backfiring and the intake manifolds exploding.

Jim, are you sure the fire on your dad's car wasn't an effect of a leaky valve cover gasket? Was it the same 3800na motor as yours?

This reminds me of a cadillac (northstar) that came into the shop one day. I know, different motor, but attempting to start the car, it kept backfiring, and oh man, just a quick crank and BOOM! In the shop it sounded like a bomb went off. No one could figure out why untill someone noticed that one of the plug wires had been routed to the wrong plug.... Once on the right plug, car ran good.

Jim, are you sure the fire on your dad's car wasn't an effect of a leaky valve cover gasket? Was it the same 3800na motor as yours?

The car that burned down had sat for a month in a garage. When he turned the key he heard the sound of a shotgun blast then black smoke out the hood and by the time he got to the front of the car to open the hood, fire was shooting out by the windshield. Lucky to get it out of the garage. 20 degree temps that day and first time to start it so cold motor.

Girlfriend got the car back. Dealer claims it was a defective Mass Air Flow Sensor that caused this. I dont know if I buy that but they covered everything under warranty so will see how it acts. 35 miles and it is still in one piece so that is a start. Thanks to all here. Appriciate it very much!