Grand National problems

[74gto]

I have no clue how this works but I have a 87 Buick Grand National I rebuilt and put a stage 2 turbo and very mild internals in the motor. I replaced all sensors and injectors with stock ones and put an adjustable fuel pressure regulator and hot wire kit on the fuel pump. The car drove great like a bat out of hell for about 500 miles and then I went to take it for a drive and the tranny wouldn't shift properly, it hesitated at 2500 rmp and it had a lack of vacuum. Not to mention it blew black smoke out the exhaust (fuel right) no it wasnt fuel, I check compression and it was 85 psi to 90 (way low) so I put oil in the cylinders and checked it again and it still had the same compression. I think it might be a head problem, but any help I could get would be awesome.

[Syndicated]

How much boost are you running?

[1988GTU]

Whats the fuel pressure set at? Did you do anything with the tune for the stage 2? Was it putting out some kr before it dropped on its performance? Are you getting smoke out the valve cover port? Need more info.

BTW this is a 60* site not 90*, so you might catch some flack posting for help about a 3.8L

[bszopi]

BTW this is a 60* site not 90*, so you might catch some flack posting for help about a 3.8L

This is a 90* engine I think most of us take exception to...

Brad via Tapatalk

[Syndicated]

Hell of a motor though!

[1988GTU]

Selective racism to the 90* lol

This is a 90* engine I think most of us take exception to...

Brad via Tapatalk

[Purple pit]

So there is no one on the GN/T-type site? I just find it odd, but sure like to see a GN owner here. Almost bought one once. On av gas it ran 10.30's, bit too fast dad said.

[robertisaar]

Selective racism to the 90* lol

well, i hate the 3.8 a lot less than the 3800.... i also like the 4.3 above the 3800s.... even the shortstar ranks above them IMO.

So there is no one on the GN/T-type site? I just find it odd, but sure like to see a GN owner here. Almost bought one once. On av gas it ran 10.30's, bit too fast dad said.

turbobuicks.com (i think) was still a fairly active forum last time i looked.

[RedZMonte]

Id start by pulling the heads and inspecting. if all cyl are low compression i would expect comp should be much higher then that... What pistons are you running (compression ratio's?) its odd that all cyls are that low... you would expect one or 2 cyl if it was rings or valves. so either that is just what your setup runs or something is way off... also try your comp gauge on another engine... something maybe wrong with your gauge.

S

[TGP37]

Check the play on the compressor of the turbo. Do you have a blow off valve installed? If not, you probably trashed the compressor bearing seal and pumping oil into the intake. That or the exhaust seal is shot.......which probably explains the smoking. Which can also push exhaust pressure into the oil system, which can ruin the rings in short time by neutralizing the pressure difference across the rings.

At that point, the car will run like dog crap too.


Check the play on your turbo shaft.