Based on the info you have provided, I think rings and valve guides are not the problem ... so think about this:
When we decelerate the fuel flow goes to ZERO on a WARM engine (you can check this by unlocking the console ... not sure which test, however).
If it is not shutting off all of the gas when you decelerate, then when you accelerate you are burning some unburned gas and that causes a short burst of smoke. Not sure if this is even possible, but I seem to remember similar problems back in the ole' days ... high float levels causing this phenomena on carbureted cars.
You say it is not as bad now ... how do you drive your car? Hard, moderately, or like an old lady? If you don't drive it like it was stolen, you should go out and DRIVE, and DRIVE IT HARD without actually thrashing it for a couple of hours. Then see if it improves.
There are problems that can happen with fuel injection and injectors that I am not informed enough to discuss, and you could STILL have an oil leak problem ... installation error with the replaced oil separators, for example.
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"The greatest obstacle to discovery is not ignorance; it is the illusion of knowledge."
I think what you are describing would actually cause a backfire, not a cloud of smoke. If he actually was getting extra fuel dumped into the cylinder on deceleration (which is certainly possible), then I agree some unburned fuel might get flushed out the exhaust on acceleration, but I'm pretty sure that when it hit the hot exhaust it would ignite and cause a backfire (just like turbo'd cars when you dump off the gas quickly).
I agree with your advice to give the car a good driving for a couple hours, and would be interested in the color of the smoke: blue = oil, white/clear = water/gas...
I think what you are describing would actually cause a backfire, not a cloud of smoke. If he actually was getting extra fuel dumped into the cylinder on deceleration (which is certainly possible), then I agree some unburned fuel might get flushed out the exhaust on acceleration, but I'm pretty sure that when it hit the hot exhaust it would ignite and cause a backfire (just like turbo'd cars when you dump off the gas quickly).
I agree with your advice to give the car a good driving for a couple hours, and would be interested in the color of the smoke: blue = oil, white/clear = water/gas...
d-
Actually, it was somewhat dependent on the car (engine, if you will). Often it did backfire, but not always (degree of valve overlap and all). And, of course, cats (they run HOT) hadn't been invented, then.
Black smoke would also indicate unburned fuel or more likely, an overly rich mixture. (There must be a feature on fuel injected engines that produces a richer mixture on acceleration, as the accelerator pumps do in carburated cars.)
I ruled out the valve guide idea, because the FIRST sign of valve guide seal failure was smoke on startup. And, I ruled out rings, because they would cause smoke under more conditions than he describes.
John.
Last edited by jclyman; 4th November 2007 at 19:45.
Pull the two inlet tubes and see if there is still alot of oil in the plenum.
Also please get with the shop and ask about how they tested the engine.
Those numbers are just wrong, you should be getting a negative 5 atmosphere in a compression test.
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I don't baby it that much and it does see the orange line quite often. I lifed plenum and found a line layer of oil all over, it had dark patches infront of the seporators, so I got them changed. No pooling of oil though. I don't think it is unburnt petrol because of the colour of the smoke and the little black spot on my rear bumper. BMW have said that my MAFS need changing because they are not working too well, you wouldn't now though, there is so much pull in 2nd gear it almost hurts.
I don't baby it that much and it does see the orange line quite often. I lifed plenum and found a line layer of oil all over, it had dark patches infront of the seporators, so I got them changed. No pooling of oil though. I don't think it is unburnt petrol because of the colour of the smoke and the little black spot on my rear bumper. BMW have said that my MAFS need changing because they are not working too well, you wouldn't now though, there is so much pull in 2nd gear it almost hurts.
If you already drive the way you said above, there is nothing that can go wrong doing a MAF test - you simply drive like that while watching a readout on your display...
If you already drive the way you said above, there is nothing that can go wrong doing a MAF test - you simply drive like that while watching a readout on your display...
d-
Right, Doug. Even if Andy777 doesn't touch redline, he will get some usefull information ...
Figures that are way low, like under 100, will tell him to suspect the MAFs.
"Just do it." We're NOT puttin' you on (well, other than hitting a slower car in front of you ... just pick a safe spot).
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