drpixel

Greetings all.. I have a '94 RX-7 that's smoking more than the Marlboro man, James Dean and Groucho Marx together in the same room. It's definitely oil in the smoke, I can tell by smell. It's also a faint bluish color. The car also idles rough.. sounds like a piston engine with a cylinder out. Not knowing what else to try, I pulled the plugs out to replace them (it was about time to do so anyways) and found the front topmost plug (is this called T1?) was blackend, wet and smelled strongly of gas. I had just run the car prior to this and allowed it to cool down. All other plugs look normal for the most part.

What would this one plug looking so much different that the others indicate?

drpixel

I hate to bump my own thread, but does anyone have an answer for this? At this point I'm not sure what to do with this car. If the answer is obvious can someone at least tell me so? If you need more information, I'd be glad to get more. What should my next steps be to determine what is causing the fouled plug and tons of smoke?

amp

iTrader: (50)

check for leaky turbos...

hanman

Check to make sure the map sensor is connected. Sometimes the vacuum hose comes loose and will give you all kinds of trouble.
Check for oil in the intercooler lines (leaking turbos).
Do a compression test.

drpixel

When I changed the plugs, I removed the intake piping from the manifold and did notice a fine oily residue on the walls of the piping. Is any amount considered normal, or is this pretty much a sign that the turbos are leaking oil? Should I consider removing the turbos to inspect, or what do you recommend at this point?

hanman

a fine coating should not be an issue. If it is "pooling" oil, then you have an issue.

drpixel

Thanks for the advice! I was wondering about having the compression checked, so I'll try to get that done and report back. I've seen the procedure for the compression check out on fd3s.net.

In your experience would I be better served performing this myself or taking it to a dealer to have the test performed? I've also run across this site: http://www.aaroncake.net/rx-7/blown.htm but it's suggesting removing the leading plug to diagnose a blown engine. Which method is correct?

dgeesaman

iTrader: (7)

The idea of removing a plug and listening to the sound is a basic but useful step that will tell you if an engine is blown badly.

A compression tester DIY style is a step above that since you get numbers to look at. But they're not perfectly accurate numbers.

The best compression test is done with a rotary specific tester that also compensates for cranking RPM. The dealer can do this. If you're buying an FD and trying to gauge just how strong the engine is, this is worthwhile.

By the sound of your description, I would try the DIY compression tester. Your numbers won't be identical to a "proper" compression test, but you'll get enough of a picture of what to do next.

If it were your turbos I would expect the engine wouldn't run rough and you wouldn't have a misfire on one of the rotors.

Dave