AaronE

Howdy folks, I'm hoping someone knows what might be going on, and some searches didn't help. This morning, I started my car up and it was running fine. I got out to go turn a light off in the house, and when I came back, my car sounded terrible, like it was running on half the cylinders. My landlord happened to be standing next to it when it happened - he said it just started idling really low.

I figured it would come back to normal, so I drove down the driveway but had nearly no power. I turned around and could barely get up the hill. When I got back, there was smoke coming from the back of the engine. I turned it off and jacked it up. Seems like the copious white smoke was coming from where the cats meet the headers.

The specs: 1992 SC400 w/ 150k that was running fine. I looked around under the hood but couldn't find anything obvious.

Anybody had this happen or have an idea what's happening?

Thanks a million,
-Aaron

sightdev

white/grayish is an indication of moisture in the exhaust system. It shouldn’t leak out of the exhaust system but you may have a worse problem than that now. Exhaust should be fixed after addressing the idling problem.

- Blown head gasket. Check oil mixture in your radiator reservoir or/and oil dip stick.
- One of the coil may have failed. Remove one of the connector to see if it makes any different. If it is same with one of the coil disconnected, that coil is no longer in operation. If it won’t start, the other coil may be at fault.
- Your plugs may be wet. If this is the case, you should let the engine warm up and the engine should start idling normal as it reaches higher operating temperature. This should be addressed afterwards.

I am sure many of the forum members will provide more constructive recommendation but you should start with the simple try-and-error approach. If you have access to the tools to read the error output, this would be better.

AaronE

Sorry, should have been more specific. The smoke continued to billow for a good minute after the car was turned off. As far as I know, I don't have an exhaust leak. While the car was on, exhaust was coming from the tailpipes, but not white smoke.

AaronE

- I had checked the oil and it seemed fine. Also, it happened suddenly and at idle, which makes me doubt head gasket failure. I think the smoke is coming from outside the cats.
- I'll check the coils. It does seem like about half the engine isn't working. There was very little abnormal vibration to the engine, just a different, rough-running sound. Are they visible from the top of the engine or are they buried somewhere?
- The engine was running fine when I started it, and it hasn't rained in months, so I'm skeptical of the wet plugs. Good suggestion though.
- And, as far as error codes, the check engine light is not on, so I wouldn't get any, right?

If it were the coil(s), what would cause the smoke? The smoke's definitely something new.

Thanks for the help!

AaronE

So, disconnecting either coil causes the engine to not start. I disconnected the two prong connector, not the main lead (since it didn't seem to want to come off, and I broke one of the plastic tab guards).

It seems like it is the coils, however, since the symptoms seem exactly like this thread.

What's next? Rotors and cap?

mkorsu

Check your plugs too. Make sure they aren't fouled. During this whole issue it is possible that an/all O2sensor/s went, fouling the plugs.

AaronE

Wait! Nevermind! It is the driver's side coil. Turns out that if you disconnect the input to the coil, the engine must detect that and not run. If I disconnected the output of that coil, the engine runs just the same. If I instead disconnect the output of the other coil (top of engine) the engine won't start. (actually, I unplugged it and it still worked at first, but only because I didn't move the lead far enough away! even arcing 2" from the coil to the plug, it still ran! go denso coils!)

Anyway, I'll be ordering a coil today...

Thanks again!

mkorsu

Way to go!!!

You just saved $400-$500 by not going to the dealer!

AaronE

SCORE!

Plugged the new coil in and voila! Runs perfectly.

I love clublexus.

Thanks to all who helped, directly and indirectly,
-Aaron