Originally Posted by WARP TEN (Post 319439)

Question: Does your car have catalytic converters or have they been removed for headers? It looks like your exhaust is stock from the video but I also had a stock system from headers back on my '95 but removed cats to go with headers. I also regularly had a bad smell on startup but that was the old smell of the '50s and '60s--before cats, when we tuned cars by smell and the look of the smoke out the exhaust. If your car does have cats, is it possible they have become non-functional? If your cats are fine and you think you have an exhaust leak it would have to be ahead of the cats to produce the smell you describe, I would think, which would mean headers. Certainly an exhaust leak should be corrected. Also, my take on the "smoke" and moisture from the mufflers is that it is simply condensation and entirely normal. I also had it. The pipes are lower than the muffler outlets for much of their length and a lot of moisture can accumulate in them. Drive for an hour or so then see if you get much on a cold start afterwards. As to a clunk in the suspension somewhere, I also had such a clunk especially when I backed out of my slightly inclined driveway, afterwards normally I wouldn't notice it. While everything looked fine, Marc changed the sway bar bushings and that solved it--no more clunk. My car had only 30k miles on it but the bushings just got old and hard. You indicated you felt it in the steering wheel so maybe front bushings need a look. --Bob

Originally Posted by secondchance (Post 319441)

Issue #2:

If clunking noise is when you go over left to right uneven road (car swaying left to right), I would suspect worn out rear sway bar bushing. I recommend urethane bushing since OEM rubber bushing will fail quite fast.

If clunking noise is from directional change as in forward, stop, reverse, most likely driver side rear bearing hub being torqued to 160 lb-ft. This was revised to 190 lb-ft by Chevrolet.

Originally Posted by A26B (Post 319437)

The black, sooty condensation from the exhaust at first startup of the day is symptomatic with leaking injector housing gaskets at the cylinder head interface. Coolant seeps into adjacent intake port, accumulates & blows out on first cold start of the day.

Originally Posted by DRM500RUBYZR-1 (Post 319452)

1- pull the plugs
2- look at the plugs
3- one or more will be black
4- replace the plugs
5- ONLY AFTER you replace the Injectors

With as much carbon and soot you are showing, it looks like your injectors are dumping fuel. Likely failed due to alcohol as they are pre 93.

Your ZR-1 requires basic maintenance including plugs and injectors. It is 28 years old.

I would also agree with an earlier poster that you also likely have leaks at the injector housings, but start with the simple stuff, if injector replacement resolves the issue, stop there. If not; then have a round two.
:cheers:
Marty

Originally Posted by wfot (Post 319455)

I have a set of injectors up for sale currently, they are accel 21 lb injectors that already have the secondary nub filed done, so they are ready to install with all O-rings -
the injectors are a number one issue with the 90 - 92s.

https://www.zr1.net/forum/showthread.php?t=32652

Just an FYI
John