1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

blue smoke on deceleration......

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Old 02-09-03, 12:52 PM
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blue smoke on deceleration......

,,,did the atf after rebuilding the gsl carb,,,took MAX out for a run,,ran her pretty hard a few miles but then i noticed a cloud of blue smoke when switching gears after wot,,,,,also, when decelerating in 2nd or 3rd and then punching it i get a cloud of blue,,,,hasnt done this b4,,,hope it cures itself,,,anyway, started snowing so i had to back off the throttle and go home,,,,,,,,,,,,,,

Last edited by DONNA; 02-09-03 at 12:56 PM.
Old 02-09-03, 01:06 PM
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does your engine normally burn a noticeable quantity of oil, blue smoke or not?

There's a solenoid on the top/back of the engine designed to limit throttle return speed when you let off the throttle, and another gizmo designed to shut off fuel to the rear rotor on deceleration. Both are emmissions controls, as older cars would puke unburned gas out the tailpipe the moment you let off the throttle after hard acceleration or downshifted to engine brake.

It COULD be (just a theory, mind) that your car is suddenly burning a greater ratio of oil to fuel on decelleration due to one of these emissions devices not working properly, possibly in conjunction with above average oil sent to the combustion chamber.
Old 02-09-03, 01:14 PM
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It could be a sign that your alternator is operating inefficiently.
Old 02-09-03, 01:29 PM
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is your shutter valve inactive? if so, that could possibly cause what your describing. if thats it, then its not a problem.
Old 02-09-03, 01:31 PM
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Originally posted by Manntis
does your engine normally burn a noticeable quantity of oil, blue smoke or not?

..1..no problem with oil consumption at all..

There's a solenoid on the top/back of the engine designed to limit throttle return speed when you let off the throttle, and another gizmo designed to shut off fuel to the rear rotor on deceleration. Both are emmissions controls, as older cars would puke unburned gas out the tailpipe the moment you let off the throttle after hard acceleration or downshifted to engine brake.

..2. is one of the gizmos the dashpot and the other the shutter valve..??,i checked the dash pot per haynes, should disengage at like 3k or so and the shutter hose is plugged off,,,,oh well at least i am sure im getting oil,,so no biggie,,,just strange that it started happening.

It COULD be (just a theory, mind) that your car is suddenly burning a greater ratio of oil to fuel on decelleration due to one of these emissions devices not working properly, possibly in conjunction with above average oil sent to the combustion chamber.

Last edited by DONNA; 02-09-03 at 01:34 PM.
Old 02-09-03, 01:33 PM
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Does your car backfire when you deaccelerate?
Old 02-09-03, 01:37 PM
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backfires on occasion if i let it decelerate for over a couple of seconds.after wot...why....
Old 02-09-03, 01:39 PM
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Originally posted by Oostreetracerrx7
Does your car backfire when you deaccelerate?
...it will backfire if i dont shift withing a few seconds,,why??
oopps,,for the dubble post,,,,comp sys slo....

Last edited by DONNA; 02-09-03 at 01:42 PM.
Old 02-09-03, 02:12 PM
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Ok...

It's not your shutter valve nor is it your dashpot. It's definitely not your alternator lol!

Did you say you just ATF'd the motor? If so, there's your likely explanation right there. My bet is it's burning off residual ATF left over from the procedure. In the spring, after metering some oil into my engine for the first start of the season, it will smoke initially but *also* a little bit for a while, it takes some driving for it to all go away.

Give it a few days and see if it goes away.

Your alternative explanations are, first and most commonly, what you're describing is a characteristic symptom of the oil control rings in the engine starting to fail. This will cause an ever-worsening smokescreen and requires a rebuild. On the upside, it can last a while before it gets really bad. Alternatively, maybe your OMP is stuck open - you know how to check that right? Stick your hand down there and see if the OMP is sliding up and down properly, or alternatively pull the lines and test the amount injected according to the Haynes manual.
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