Full boost, no power, valve tap!

[Crazy91GSX]

Hey guys... one more problem with my 90 laser fwd turbo. I got on it a few times last night, and after one of them, the car started acting very odd. When I punch it, the boost spools very fast, too fast even. Almost instantly after i hit the gas, it spools. Then, the car stumbles a bit, like the loss of fuel. After a couple seconds, it smooths out and runs fine, except there is no power and there is loud clatter from the valve cover. So, i did a compression test, all 4 cylinders show ~ 120. Next thought was boost leak. Checked all ic pipes - no holes, and all clamps were nice and tight. any ideas on what my problem could be?

 

[yoshimitsuspeed]

Check the timing.

 

[blue92laser]

timing jumped....line up the marks and see what yah come up with.

 

[XxrusianxX]

sounds liek a turbo problem, check for shaft play. Do you have an after market boost gauge or is it the stock one?

 

[Crazy91GSX]

Well, I haven't Checked the timing yet, but I did find out one thing. The #4 piston hit the spark plug. I changed the plugs, and #4 had no gap. It was closed up. So, after I put the new plugs in, I went for a drive. after awhile of driving, i pulled the plugs out again, and same problem. Gapped the plug, compression tested again (130), put the plug back in and ran my errands, afterwards, I went to check the plug again, and it was loose. However, It will not come out, just spins freely.

 

[ninety7gst]

sounds like u stripped the threading in your cylinder

dunno about your inital problem though...

 

[ArticNemesis]

If your #4 piston hit the sparkplug, you have bigger problems then it stumbling... I seriously doubt that it hit the actual plug. and as previously posted, it sounds like you stripped the threads in the head. Also, I wouldn't exactly go driving your car around until you check your timing.

 

[Crazy91GSX]

Im almost certian that the piston hit the spark plug. Because when i pulled it out, it was flat, no gad at all. All other plugs were fine. And, after i put in the new set and ran it for awhile, same thing. The way i see it, if the piston does hit the plug, it's gonna crack or something, but that cylinder, like the rest has great compression. Any other reason why the plugs will mysteriously flatten at the tip?

 

[scotthidley]

Pressurize the intake from the turbo inlet on to make sure there are no leaks. I had a giant hole in my l i/c pipe that I couldn't see as it was under the foam padding. I was hitting 20 psi on the evoiii around 2500 rpm, while the gauge read full boost, the was slower than stock.

If your plug just keeps spinning, it sounds like you stripped the threads in the head.

 

[yoshimitsuspeed]

http://www.dsmtuners.com/forums/showthread.php?t=151621&highlight=compression
120 is not exactly good compression.
I think you can helicoil that spark plug but you will have to search around for details.