Blew another head gasket

L

lost2a6

Member
Joined
Nov 5, 2002
I just wanted to share a problem that I've been having lately. My car has devolved a miss fire under high boost. This results in it popping back through the intake. The last time that it did this, it popped a couple of times and then had a very loud violent boom! This in turn blew both head gaskets on #3 & #4 cylinders. My wide band looks good and it's not getting any knock at the time that it starts miss firing. What I believe is happening is the ignition system isn't up to par and Isn't firing the plugs every time under pressure. This results in unburned fuel/alcohol in the combustion chamber. When it pops back in the intake, this gives it boost spikes which in turn makes it spray more alcohol which makes the miss fired combustion chambers even richer. The plug finally fired and all of the unburned gas/alcohol went boom. I'll also add that every now and then, at light throttle cruising , the car will miss fire very briefly then resume back to normal. When the light throttle miss fire occurs, it drops all cylinders, like briefly shutting the car off and back on again. Has anyone ever experienced these problems?
 
Had that similar ordeal blew a gasket still banged out finally found the problem the cam sensor shaft play
Ended up shearing the rotor right off, high hp really puts a beating on them, replaced mine then through on a RJC steal rotor and bolt so that shouldn't happen again.
 
I would pull the sensor cap check to see if it's loose maybe moving in and out of the window
 
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When mine sheared it I thought I blew the motor super loud back fire lol then I was able to rig up a paper clip to just get it to fire then unplugged it to batch fire mode that was a crappy day
 
Try starting it up unplug the sensor may idle a bit funny but got hammer on it see if it goes away if it does that's the problem
 
Hello My name is Dave. I very new to this web site. But i an the proud owner of a 87 GN. With 8300 miles on it. The car set for years. Most of them out side. But the car is in very good shape. It just got a new paint job. Looks very good. It has a few problems. But i am getting to them one at a time. The bigest problem is a miss like yours. At high boost and WOT. It almost sounds like a back fire. But the car runs great. Just as long as i dont hold it at WOT. Car starts well and idle faily smooth. And has very good drivability. This miss is only under full load. At higher RPM. I have driven it enought and ran all the gas out and working on a tank full tanl of 90 + in it. No service engine light. This is the only problem that has me somewhat stumped. It will pull hard enoght to turn the tires over with out the miss. But if you go all out with it .... That is when the problem starts. The miss that is. So i am hoping that one
 
Old Guy Dave said:
Hello My name is Dave. I very new to this web site. But i an the proud owner of a 87 GN. With 8300 miles on it. The car set for years. Most of them out side. But the car is in very good shape. It just got a new paint job. Looks very good. It has a few problems. But i am getting to them one at a time. The bigest problem is a miss like yours. At high boost and WOT. It almost sounds like a back fire. But the car runs great. Just as long as i dont hold it at WOT. Car starts well and idle faily smooth. And has very good drivability. This miss is only under full load. At higher RPM. I have driven it enought and ran all the gas out and working on a tank full tanl of 90 + in it. No service engine light. This is the only problem that has me somewhat stumped. It will pull hard enoght to turn the tires over with out the miss. But if you go all out with it .... That is when the problem starts. The miss that is. So i am hoping that one
Click to expand...


make sure its not over-boosting. check all the wastegate hoses.

Bob
 
TurboBob said:
make sure its not over-boosting. check all the wastegate hoses.

Bob
Click to expand...
I had the same problem but it wouldn't go over 18/20 lbs. of boost.

I sure would like to know what causes this to happen. My cam sensor looked good last time I checked it but will check it again tomorrow.
 
Mine the bushings were gone basically hard throttle pulling sucking the cam sensor down bashin the crap out the rotor and cracking the cap
 

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Thanks, I did replace the cam sensor a long time ago and haven't had it out since and or checked it. I will add that when I fool with the coil pack harness, it appears to get better but that could be my imagination. I'm going to check voltage to the module or possibly go ahead and hot wire it.
 
I totally understand I was fortunate to get dealer cost on a lot of stuff freaking cam sensor is insane high now like 300 ish got one for 240 at my cost can count on my hand how many crap modules and coil packs I burnt through:mad:
 
Rick I think at the time I was more impatient then anything lol hAppend past spring hard to keep it off the rd
 
Tony serio said:
Rick I think at the time I was more impatient then anything lol hAppend past spring hard to keep it off the rd
Click to expand...
Yeah I know the feeling....but always pays to shop around. Now you can buy a spare. I picked up a couple spares a few years ago when they were $55 at Autozone.
 
I think I saw that as well a few years back they were super cheap people were buyin multiples , lol I think in way if it breaks ill right it off as a parts replacement through the dealer lol
 
Dave you might need to start your own thread but I had similar problems with cal packs and ignition moduels .. especially on low mile cars
 
This is Dave again. Just wanted to thank everyone. Just finished up. Its almost midnight here. I think the problem is solved. Hat off to Turbo Bob. This is what I found. After me my youngest son and his family had dinner. Came back to my house and started in on it. Waste gate hose was rotted off 7/32 vacuum line. Also pulled the spark plugs. #5 really bad. Insulator on the electrode was broken off. Did not look like it was hit with anything. Check compression on that cylinder 150 psi. Installed all new plugs. New vacuum lines to the turbo daspot. And line to fitting on boost side of turbo. Took out and ran it. All good now. The plugs had been changed once because thay where not factory plugs. Installed some AC Delco CR43TS. Had Bosch Platinum HR8BP plugs in it. Wish i knew how to post a photo of the plug from #5. I am surprised it ran as well as it did. Also removed the C clip from the wastgate valve and checked for free movement. It moved freely. Instlled new E clip. Like i said earlier. It only has 8278 miles on it. So going to bed now. Tired.
Again thanks to you all.

P.S. Forgive me if I have committed any improprieties here. I am new at this.
 
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