High rpm pop, now smoking like crazy...

[delta448]

The other day I got a little urge and took off out of work with a little more aggression than usual. I redlined and shifted from 1st into 2nd and was climbing up the tach in 2nd when I heard a muffled but very distinct "pop" sound. I immediately jumped off the throttle, shifted to 3rd and felt the engine misfiring and starting to limp. I pulled into my driveway, which is only about a mile from my work, and the engine stalled and died. It started back up without any problem but the idle was surging all over the place (300-1200rpm) and it didn't want to stay running, it kept stalling. I also noticed that my usually low coolant overflow bottle was nearly full.

After sitting overnight, I noticed no oil leaks this morning before my wife took me to work for my 14hr shift. I've visually checked all intercooler piping and everything so far seems okay. The car will start and idle fine for a little while, but once it idles for a few minutes it starts dropping rpms slowly and wants to choke. Also, if you touch the throttle it wants to choke, but it will run as long as you keep softly revving the gas. There is a rather large amount of black smoke coming out the tailpipe, and it smokes a little even after the engine is shut off. I can smell unburnt fuel really bad, even under the hood but especially bad -enough to make my eyes water- out the tailpipe. The exhaust at idle is very raspy and sounds like a cylinder is down.

I have very limited free time to fix the car or perform tests on it, so I'm hoping that with everyone's help I can pinpoint the problem and get my daily driver back on the road ASAP.

What I am currently thinking:
-possible detonated piston
-possible fouled or melted plug
-possible blown injector
-possible oil pressure issue

Opinions are appreciated.

 

[Meh987]

First off, try a boost leak test. This is most likely your problem. You may have had an intercooler pipe blow off and not had it be immediately visible. When you've done the boost leak test, then we can start looking to see if there's a deeper problem.

 

[Talesin]

Boost leak test, then compression test. If it detonated, you may have a cracked piston... happened to me, but I never heard the pop. Didn't idle surge either, just smoked like crazy and was really weak. Might also have nailed/bent a valve if you had skipped timing. Compression test will point out which cylinder, then a leakdown test to find out what's boned.

Given the smoking and circumstances, my first guess would be a detonated cylinder though. Sucks if that's it, here's hoping it's something not as bad.

 

[delta448]

Thanks for the help guys.
Problem solved.

Blew apart one of those worthless worm gear style clamps on the UICP above the intercooler.

I feel pretty stupid now.

 

[ypnas777]

Get T-bolt clamps, I've never had a coupler blow off since switching to T-Bolt clamps. Blowing apart an intercooler pipe is scary

 

[Talesin]

Get your intercooler piping beaded. Screw t-bolt clamps until you're blowing worm gear clamps off with proper beads... NOT easy to do, and a crapload cheaper than t-bolt clamping everything.