1991 F150 Custom Problem
New User
Joined: Mar 2008
Posts: 7
Likes: 0
From: Hewitt TX
I will check it out it acts up at the same time every time when it hits normal running temp when i hit between 55 and 65 and when i put it in 5TH all three things happen at about the same time one more thing it smokes now sometimes a lot other times not much at all
Senior User
Joined: Dec 2007
Posts: 128
Likes: 0
From: Florida
Probably just running rich.....cause of the EGR position
Well the smoke could be valve seals, worn piston rings, or even a small leak in the head gasket developing.
More then likely valve seals if any of the above (common with high mileage).
White smoke would be water, and black is oil or a rich fuel mixture.
The EGR valve may be incorrectly opening more. and the fuel is not compensating correctly or quickly enough, making too rich of a mixture and blowing it out .
You should be able to smell the slight differences.
Pull your plugs , they should tell you whats happening at "ground zero".
The deposits will be built up on the gap.
Black is rich (oil / Fuel) , white is lean (oxygenation), yellow is a lean glazing of the richer substances.
More then likely valve seals if any of the above (common with high mileage).
White smoke would be water, and black is oil or a rich fuel mixture.
The EGR valve may be incorrectly opening more. and the fuel is not compensating correctly or quickly enough, making too rich of a mixture and blowing it out .
You should be able to smell the slight differences.
Pull your plugs , they should tell you whats happening at "ground zero".
The deposits will be built up on the gap.
Black is rich (oil / Fuel) , white is lean (oxygenation), yellow is a lean glazing of the richer substances.
Lead Driver
Joined: Feb 2002
Posts: 7,959
Likes: 592
From: Greater Austin, Texas
I think those 2 are not related. These trucks eat EVP sensors regularly.
My bet on this one is the pickup coil in the distributor. Either that or the ignition coil but the pickup coil is a more common failure on this kind of symptom.
My bet on this one is the pickup coil in the distributor. Either that or the ignition coil but the pickup coil is a more common failure on this kind of symptom.
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