so tonight i pull out of my friend's shop, lay into the throttle a bit and as soon as i hit about 7-8psi it feels as though i'm hitting boost cut. i drive a little further, car still runs fine below 7-8psi, but as soon as i reach that boost level the car cuts.the car ran fine the entire day today and just now began to do this. i'm going to check for possibly vacuum leaks after the AFM on the intake tube, but does anyone have any other things to look for on this?
like i said the car still runs fine until you hit that boost level.
SR missing a cylinder
well, the saga continues....... today i started the car and it's running on 3 cylinders at idle. when i rev it it seems that all 4 eventually fire but as the revs stabilize it seems to drop back out again. last night it idled fine when i pulled in to my driveway and left it on the turbo timer.
i pulled the plugs and cylinder 3 looked kind of wet, but i couldn't tell if it was fuel or water. oil is clean. plugs overall were pretty clean, the top of the piston is what looked wet where the other 3 were dry with normal carbon buildup. did a compression test and got the same reading on all 4 cylinders. ran the car with the radiator cap off and no bubbles coming out of water when i rev the car. i kind of thought it could be a headgasket because the coolant was oddly low when i first looked. that's what i'm leaning toward at the moment, but i need to get my hands on a leakdown tester to tell for sure.
i pulled the plugs and cylinder 3 looked kind of wet, but i couldn't tell if it was fuel or water. oil is clean. plugs overall were pretty clean, the top of the piston is what looked wet where the other 3 were dry with normal carbon buildup. did a compression test and got the same reading on all 4 cylinders. ran the car with the radiator cap off and no bubbles coming out of water when i rev the car. i kind of thought it could be a headgasket because the coolant was oddly low when i first looked. that's what i'm leaning toward at the moment, but i need to get my hands on a leakdown tester to tell for sure.
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Hijacker
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'94 F-150 - Location: Fredericksburg, VA
you could have a busted injector. they sometimes freeze in a way that they run at full rich. i had a similar issue on my car, replaced the number 3 injector and my issues went away.
also, i'm going to suggest this again, check your timing. i haven't read your other thread to see if you responded about the timing issue. timing issues will make the car feel sluggish and it's hard to climb the tach when you're at lower engine speeds.
also, i'm going to suggest this again, check your timing. i haven't read your other thread to see if you responded about the timing issue. timing issues will make the car feel sluggish and it's hard to climb the tach when you're at lower engine speeds.
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themadscientist
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themadscientist wrote:Is it possible the coil on the affected cylinder is dying. It would explain the unburned fuel and why it runs ok up until a certain point; weak spark gets snuffed under power, just a thought
that is still a possibility, but i tested the coils per the FSM and they all checked out ok, 1ohm between pin #1 and pin #2 on the coil pack. unless they somehow die intermittantly and come back. i may test the igniter when i get home today just to see if that's possibly it.