Black Smoke, How Serious is it?

[ber55ber55]

I think i have already asked this before, but I would rather repost and ask again.

Since ive owned the car (about and year and 25k miles ago) the car has smoked at high rpms when I give it full throttle. At low rpms and normal driving no smoke. idle no smoke. In first gear its just a quick cloud of black smoke, then in second, from about 4k to red line it smokes and after that its done.

Ive done a compression test only dry though. From when i bought the car till now. I have gottin the same figures. They seem normal. Slightly lower then spec. What else could it be?

I havint adjusted th valves since ive had the car, and i dont know when the last time actually was. Could that make a difference?

Basically how serious is black smoke?

I have always heard black smoke means head gasket.

I dont have oil in the coolent yet or anything serious like that. I am losing a fair amount of oil around the bell housing seal, when i will get fixed in the up coming weeks when i have the extra cash.

Any and all input/advice/knowledge will be greatly appreciated since i am still an amateur or better yet a rookie at this.

Thanks in advance

[stilljester]

Well lots of white smoke is the most common display of a failing/failed head gasket. I'd avoid high RPMS, check your valve adjustment and timing.

[Barney Paull-Edwards]

Black smoke, excess fuel.sounds like high vacuum/ load time,checked the air filter? If not that then something is fooling the ECU into giving it a rich mix,sensor. It is a 525 Petrol isnt it? rich mix will not kill it but will wear rings /bore prematurely, clog up a cat and generally ruin your car eventually.Re-reading your original thread I would definately get all your sensors checked as they are the only common point,could be a resistance loading on temp,do you have emission checks, if it passed then look at throttle pot for bad spring.

[ber55ber55]

Black smoke, excess fuel.sounds like high vacuum/ load time,checked the air filter? If not that then something is fooling the ECU into giving it a rich mix,sensor. It is a 525 Petrol isnt it? rich mix will not kill it but will wear rings /bore prematurely, clog up a cat and generally ruin your car eventually.Re-reading your original thread I would definately get all your sensors checked as they are the only common point,could be a resistance loading on temp,do you have emission checks, if it passed then look at throttle pot for bad spring.

Hmmm...i replaced the cat and o2 sensor about 10k miles ago. When i firs bought the car it barely passed smoke. Was on the limits. I dont have the sheet in front of me to give you the exact number. Yes i have checked the air filter. Clean. i doubt that its the o2 since it is replaced, but who knows. what other "sensors" could it be. Also what is the throttle pot? Thanks for your input. You have already put me slightly at ease

[Jon K]

can be coolant temperature sensor indicated wrong coolant temp and consequently wrong fueling. same with intake temperature sensor. could be AFM poorly adjusted. can be spark misfire resulting from bad plug wires or plugs, coil, or distributor. lots of stuff.

[ber55ber55]

can be coolant temperature sensor indicated wrong coolant temp and consequently wrong fueling. same with intake temperature sensor. could be AFM poorly adjusted. can be spark misfire resulting from bad plug wires or plugs, coil, or distributor. lots of stuff.

Ha! VERY NICE! A list huh? Where would you suggest i start. I had the distributor out before and the brushes and everything looked godo. I alos have to other coils from a 525 and 325.

The AFM adjustment thing.....

I one time...a long long long time ago had a very rough idle. In the end it turned out to be a slightly loose battery cable. Can you believe that?!?! I checked everything else before that. Coil, dist, cables, plugs, normal stuff. I even bought to other AFM. (as you can see i am trying to sell them now on this site) I did though screw around with the adjustment screw. No matter where or how i turned it, nothing changed. Could you explain how to properly adjust the AFM? After i do that, and its not fixed, i guess i will start with the temp sensors, since they seems the cheapest and easiest to change. Thanks for your advice.

-A

[Jon K]

Ha! VERY NICE! A list huh? Where would you suggest i start. I had the distributor out before and the brushes and everything looked godo. I alos have to other coils from a 525 and 325.

The AFM adjustment thing.....

I one time...a long long long time ago had a very rough idle. In the end it turned out to be a slightly loose battery cable. Can you believe that?!?! I checked everything else before that. Coil, dist, cables, plugs, normal stuff. I even bought to other AFM. (as you can see i am trying to sell them now on this site) I did though screw around with the adjustment screw. No matter where or how i turned it, nothing changed. Could you explain how to properly adjust the AFM? After i do that, and its not fixed, i guess i will start with the temp sensors, since they seems the cheapest and easiest to change. Thanks for your advice.

I would do a stomp test and see what codes come up. You might also consider your throttle position sensor. As for the AFM adjustment, I am a MAF guy, and even then, I am now a MAP guy haha, no AFM's for me. I know how they work and why they work but when they don't I just kick them. The guys on this forum can more than help you adjust the AFM ideally - I would do the stomp test and see what comes back.

[ber55ber55]

I already tried the stomp test. Clean. I even inserted my code/reset tool (would tell me the same deal) Clean as well. I already fixed the TPS. Well didnt fix. Readjusted, since it had slipped from its orginial position. Alright i will search the forum for AFM adjustment. Thanks again

[ber55ber55]

Well i guess to properly adject the AFM i need an exhaust analyzer. Where the F*** am i gonna get one of those. Doesnt the smog guy have one of those. Would appreciate it if someone had one i could borrow or knew a smog guy in my area that could help me out. Im in Agoura Hills California

[Paul in NZ]

any decent workshop will have an exhaust analyser.If its running rich generally because of a faulty temp sensor you would have poor mileage..what are you getting?check ou the mileage thread to see what other guys are getting.although mpg is altered by many different things.