ZR-1 Down =(

[Okiedoke]

I was starting the Z to go on a drive when it replied with a pretty resounding NO. The car started pretty rough doing a slow shaking and lurching all over. I gave it a little gas and the RPM came up. I then noticed some white smoke come out of the exhaust. The check engine light came on. I opened the hood and think I heard a small hissing sound like air coming out of a tire. I shut it down. When I walked to the back, I saw the exhaust had sprayed some black dots. I've included the photos below.

I last drove the car a week ago. It started rough like this, but I thought maybe it was because I hadn't driven the car in 4 weeks. When I stepped on the gas a little, the engine smoothed out. After a couple of minutes, it was back to normal. I'm thinking whether it may be something I might have accidentally touched when wiping down the engine 5 weeks ago. I was extremely careful though and the cloth was a bit damp, not enough to drip. So how badly screwed am I?

Here's the spray out of the exhaust:


Here's a closeup:

[Paul Workman]

White "smoke" from one of the tail pipes is a sign of coolant getting in the combustion chamber. That may or may not be a "biggie", depending.

A more common cause is the plenum gasket or IH gasket. There is a narrow gap between the intake runner and the coolant port on both the #2 or #3 cylinder in both sides of the IH. Those not withstanding, and we're possibly talking about a head gasket...and that means the head(s) need to come off: a big job.

Let's hope it is only the plenum gasket, or IH gasket (not so likely). Before I installed gaskets from Jerry's Gaskets I went through two others in short order before striking upon Jerry's.

See what you find. Good luck!

[gbrtng]

It probably backfired and blew the MAP hose off at the back of the plenum. Check at the rear of the round thingy for a loose hose. Reconnect and the CEL will go away by itself.

[Paul Workman]

Originally Posted by gbrtng

It probably backfired and blew the MAP hose off at the back of the plenum. Check at the rear of the round thingy for a loose hose. Reconnect and the CEL will go away by itself.

Yeah, good point, Glenn. Coolant leaks, in my experience, didn't set off the SES light, and looking again I DO see "stuff" from both tail his pipes, more indicative of a problem common to the entire engine - not to mention doing the simple checks first!

[Z06scentair]

Charcoal canister come apart?

[Billy Mild]

My car occasionally has that black soot come out of the exhaust as well. My car runs fine, put down 330 WHP on a dyno. My old 944 turbo did it as well. I think it is the mixture of condensation and soot breaking apart in your exhaust.

[Dime]

Originally Posted by Billy Mild

My car occasionally has that black soot come out of the exhaust as well. My car runs fine, put down 330 WHP on a dyno. My old 944 turbo did it as well. I think it is the mixture of condensation and soot breaking apart in your exhaust.

Mine does as well, and runs fine too. Pretty sure Billy's right; just exhaust soot.

[A26B]

I am in agreement with Paul's assessment. Condensation in the exhaust won't cause poor engine operation.

I just finished assembling mine after removing secondaries and re-porting. I always had a chronic problem with wet soot from the exhaust. The source turned out to be the injector housing to cylinder head gasket had failed around the coolant passage. New gaskets with hi-tack sealant around the port on both sides of the gasket has so far cured the problem.

The possibility also exists that the coolant port from the injector housing to plenum for T-Body heat, may be leaking into an adjacent intake port. Not as likely but still worth checking. I eliminated the coolant to the T-Body while doing this remedial work.

[Okiedoke]

Originally Posted by gbrtng

It probably backfired and blew the MAP hose off at the back of the plenum. Check at the rear of the round thingy for a loose hose. Reconnect and the CEL will go away by itself.

Not that I know where this hose is, but I looked in back and didn't see anything obvious that was disconnected. I've included a picture from both sides:

[Dmod81]

It would be that black plastic line just to the lower right of the green connector in your first picture. It can be kind of hard to reach and reconnect sometimes.