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1986 Pontiac Parisienne doesn't shut off
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jpgisme
New User
Dec 29, 2009, 8:18 PM
Post #1 of 4
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1986 Pontiac Parisienne doesn't shut off
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I have a 1986 pontiac parisienne with a 5.0 305. I've replace the carberator, air filter, pcv valve, plugs, wires, distributor cap, rotor, and oil. I replaced the carberator on christmas and everything else within a month before that. When i go to shut off the car it just sputters on and doesn't wanna shut off. It did this sometimes before i replaced the carb and gradually became an everytime thing. Only when its hot though, if I go turn it on then turn it off it'll be fine it only sputters when its warmed up and i turn it off. Also when im driving and give it gas it'll accelerate for a second then stop accelerating for a second and then resume acceleration. If anyone knows what the problem is i'd greatly appreciate your advice.
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Sidom
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/ Moderator
Dec 29, 2009, 8:44 PM
Post #2 of 4
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Re: 1986 Pontiac Parisienne doesn't shut off
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Well for both probs I would really be looking at the carb. Usually when they get a bad needle & seat it will leak just enough fuel on shut off to let the car "diesel" One other thing you can look at would be carbon build up on the pistons, if it gets hot enough, it can make an engine diesel but then again, you need some sort of fuel to diesel.....
The hesitation sound like a bad spot on the accelerator pump...
When the car is warm & you know it's going to diesel, have the air cleaner off & look down the throat when someone shuts it off to see if you can see any gas dripping, get the carb warrantied.
Also make sure the timing is set to the correct specs........ Seafoam makes a good product you can clean the pistons with.........
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jason32038
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Dec 30, 2009, 8:11 AM
Post #3 of 4
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Re: 1986 Pontiac Parisienne doesn't shut off
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Sounds like the timing for sure.
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Loren Champlain Sr
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Dec 30, 2009, 7:06 PM
Post #4 of 4
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Re: 1986 Pontiac Parisienne doesn't shut off
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Sidom is right on the money. Dieseling is caused by carbon particles glowing and igniting the fuel after the engine is shut off. Also, causes pre-ignition. These particles will ignite the fuel BEFORE the spark plug fires. Some call it a 'knock'. Obviously, this is caused by heat. We've done MotorVac cleaning on highly carbonized engines with good success. You need to make sure that the engine is running at normal operating temperature, not too hot. The air/fuel mixture needs to be correct. Too lean of a mixture will cause high combustion temperatures. A vacuum leak can cause a lean condition. Worn spark plugs. Low octane fuel. Sounds backwards, but the lower the octane, the hotter it burns. It takes more voltage to fire a lean mixture than a rich mixture...which, in turn, causes heat. Over-advanced timing will just add to the mix. Just to add to the mix....
Loren
SW Washington
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