One cylinder started missing, excessive smoke...

[RM12577]

Hey guys, had the CA in my 240 for a couple of years and, well I kind of neglect it because my chassis keeps having things go bad... I think it might have caught up to me. Driving home yesterday I downshifted to pass a slow moving school bus, shifted down one gear too many and revved a little high, shifted up right away but I looked behind me and there was a decent sized cloud coming from my car that I saw in the headlights of the bus, I pulled over and one cylinder was missing when I stopped and let it idle. I shut it off for a bit checked out everything on the motor to make sure nothing fell off or came disconnected that was apparent, looked normal. So I started it and drove home on three cylinders, about 2 miles from home the cylinder that I had lost started running again and it sounded okay, I didn't rev it but it got me home, today I checked the plugs and they are all black because my car is always running rich, and it idled fine until I revved it then it started missing on one cylinder again, I plan on doing some work to it this weekend, basic stuff first like plugs, and my thermostat stopped working so I need to replace that, anything else you guys can think of that I should check, I will probably check the compression while I am doing plugs because I am worried I messed a piston up. Is there anything else you guys think I should check? it has a turbo that is only a year old on it, I would hope that it isnt blown turbo seals but I dont think that would make one cylinder go out, and it smokes more from mid to high rpm's. When my last turbo went out it smoked at idle most... this is my daily and my only car that is tagged currently so I am out of cars until I get something running...

Carl

[Ca_Silvia]

Compression test that b**** for sure. Doesn't sound good though...

[float_6969]

If it runs rich and fouls the plugs, it's hard on the coils. The cylinder that failed probably has a weak coil and the extra load caused it to fail.

I would replace the thermostat, warm up the motor, and do a compression check. Depending on how it comes out, I'd replace the plugs, and clean all of the grounds. Also make sure your ignitor is properly grounded and the back has good contact with metal to sink heat away.

[RM12577]

Well I have the ignitor grounded well, I made sure all of the coils are grounded, I will pick up a new set of plugs this weekend and try it with them, I also will be getting the thermostat for it and see what the compression is. I thought it was odd that after low rpm cruising it seems to mellow out then after just revving it up it caused that cylinder to drop out on me again, it will be nice and warm this weekend so it should warm up faster after i get the thermostat replaced as well, I will let you guys know what I find....

[boost_boy]

Me thinks you mashed-up pistons #3 or #4 or possibly split the fire ring for one of those cylinders causing oil and/or water to enter. Pull the plugs and check them for oil. Whichever one is oil-soaked, it will require you to pull the head for further inspection. Too many variables can cause this issue as over-revving isn't such a hard thing on this motor. Timing, engine health, components such as injectors or other things could cause you issues. Good luck with this as it sounds like you are in for a treat.

Dee

[RM12577]

Well I had pulled them and checked to see if any were oily but they were all identical, just rich black no liquid, I bought a new set of cheap plugs because it is a 3 day wait for the ngk's... and i got the thermostat in before dark, I will be testing compression tomorrow to see if it is compression, I really hope it is just plugs or something but knowing my luck I will have to switch to one of my other cars for a while to tear this one down...

[RM12577]

Alright, ran the compression test, got 100 on cylinder 1, and cylinder 2, got 82 on cylinder 3 and 92 on cylinder 4, all of these sound extremely low to me but what is funny is that after letting it warm up the spark plug in cylinder 1 was the wet plug, so I put the new plugs in and it idles alright but still smokes quite a bit when I gas it so I am going to have to figure out if its cylinder 3 that is making it smoke or what...

[boost_boy]

Alright, ran the compression test, got 100 on cylinder 1, and cylinder 2, got 82 on cylinder 3 and 92 on cylinder 4, all of these sound extremely low to me but what is funny is that after letting it warm up the spark plug in cylinder 1 was the wet plug, so I put the new plugs in and it idles alright but still smokes quite a bit when I gas it so I am going to have to figure out if its cylinder 3 that is making it smoke or what...

Please don't run the engine in that condition or risk a chance at messing-up something else. My professional recommendation: pull the engine, disassemble it, pay close attention to the ring lands of the pistons. Your headgasket is history, so don't stare at it too much and get into the "what if" thought process.

Dee