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Warm engine turns over but will not start normally


whippinboy's Avatar
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11-08-04, 07:50 AM   #1  
whippinboy
Warm engine turns over but will not start normally

I have 1996 Ford F150 w/300 ci straight 6 cyl motor, 5 sp man trans, 2 wheel drive standard cab, 8 ft box. dual gas tanks, 100,000 mi and is well maintained. Engine starts cold with a small pump of gas pedal but when it is warm will not start without turning over 10 to 20 times and then belches out a hugh plume of black smoke from exhaust. Sometimes it does not start at all unless I let it cool down for a min of 2 hours. I have had the unit that controls the amount of air that enters the engine at start up replaced but the engine revs higher and longer than usual until it finds it's idle speed. Last tune up was March 2004 where mechanic said that the engine overheated during testing. The engine has not overheated since to my knowledge. Once running, the engine runs smooth, quiet and has ample power. There is also a slight smell of gas coming from the engine compartment after engine is shut down.

 
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carguyinva's Avatar
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11-08-04, 08:28 AM   #2  
hmmm...

Engine starts cold with a small pump of gas pedal

it's fuel injected...why do you pump the accelerator?? injected engines start best if you DON'T touch the accelerator bofore or during the starting process.

Engine starts cold with a small pump of gas pedal but when it is warm will not start without turning over 10 to 20 times and then belches out a hugh plume of black smoke from exhaust.

black smoke is the result of over richness. over rich when the engine isn't running can come from a leaking fuel injector or faulty pressure regulator

I have had the unit that controls the amount of air that enters the engine at start up replaced...

the mass air flow sensor doesn't control air flow...your right foot does by controlling throttle opening...the sensor calculates how much air is flowing so that precise fuel delivery volume can be achieved


get some good fuel pressure testing performed...and find out what is causing the fuel smell under the hood, they may be related. my suspicion is a leaking injector and pressure testing should confirm that.

 
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