305 tbi smoking
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Junior Member
Joined: Jun 2006
Posts: 77
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From: Scranton, Pa
Engine: 383 stoker in progress
Transmission: Soon to be a TH400
305 tbi smoking
okay to start, 2 summers ago i changed the intake gasket on my 92 firebird formula. soon after i did that, it began to smoke pretty bad. no unusual noises to go with the smoke. It starts right up, even after sitting all last summer and winter. Im just curious to what you guys think could be wrong. I've replaced the intake gasket several more times, thinking that it didnt seat right, and its sucking oil into the combustion chamber. but it still does the same thing.
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Joined: Sep 2008
Posts: 238
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From: Anchorage, Ak
Car: 1988 Pontiac Firebird
Engine: 5.0 TBI
Transmission: W/C T5
Axle/Gears: 3.08 Posi
Re: 305 tbi smoking
First off what color smoke is it? Does it smoke all the time? Have you done any mods to your motor? How many miles are on the motor? What motor is it? All these questions should be answered. You willl get more responses if you provide ALL the details of the problem you are having. -Russ
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From: Lowell, Michigan
Car: 1988 Trans Am, 2005 Sierra 2500
Engine: Vortec 357
Transmission: Built TH700R4 with 26-2800 Stall
Axle/Gears: GM 10 bolt 3.73 Posi
Re: 305 tbi smoking
if its blue smoke, its time to change out your valve cover gaskets most likely. otheriwise if its anything like my 305 tbi that has been sitting all winter, the rear main seal may be leaking and burning off on the exhaust like mine now is... oh well time for my "new" motor lol.
Thread Starter
Junior Member
Joined: Jun 2006
Posts: 77
Likes: 0
From: Scranton, Pa
Engine: 383 stoker in progress
Transmission: Soon to be a TH400
Re: 305 tbi smoking
okay the smoke has a very light blue tint to it, its a 5.0 tbi , no mods, and theres about 145,000 miles on it. i just cant understand why it would start doing this within a day after changing the intake gasket. it has been sitting for awhile but when i started it up yesterday it was doing the same exact thing. it didnt smoke anymore then it did before i parked it.which leads me to think its NOT the valve seals. if it were, i would get a huge puff upon startup. not it this case. it starts up with no smoke, then after running for 10 seconds or so, you can see it start to come out of the tail pipes. when the engine is revved a bit, a huge cloud will come out.when i let it go back to idle it returns to a very faint cloud (barely noticable.)
Senior Member
iTrader: (8)
Joined: Feb 2008
Posts: 550
Likes: 0
From: Lowell, Michigan
Car: 1988 Trans Am, 2005 Sierra 2500
Engine: Vortec 357
Transmission: Built TH700R4 with 26-2800 Stall
Axle/Gears: GM 10 bolt 3.73 Posi
Re: 305 tbi smoking
you may have either bad piston rings or you do have valve seals going to crap.
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