Efi 351 backfiring
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Efi 351 backfiring
94 f350 5 speed 4x4 70,000 miles 351 5.8
Truck will backfire at return of throttle to almost ide position or after shifts. Runs strong and as it should when cold, replaced air intake sensor no change, unplug the air intake sensor and seems to run as it should with no backfire, have also cleaned throttle body, and replaced spark plugs, has enough power to drive bust still think that it should have more. Any ideals??
Truck will backfire at return of throttle to almost ide position or after shifts. Runs strong and as it should when cold, replaced air intake sensor no change, unplug the air intake sensor and seems to run as it should with no backfire, have also cleaned throttle body, and replaced spark plugs, has enough power to drive bust still think that it should have more. Any ideals??
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From: Ottawa, Ontario
Could be a lot of things. Start by pulling codes, if this comes back all clear(code 111) then don't waste another second with anything EFI related, look instead at the non computer controlled things like spark plug routing and crossfiring(run the engine in the dark with all the light off), and do a compression and leak down test. Also test fuel pressure at the rail, should be 32-35psi at idle and it should jump to 39-45psi with vacuum removed from the regulator or when the throttle is goosed.
FTE Legend
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From: Ottawa, Ontario
This is a computer controlled fuel system and it would seem you don't quite understand how it works, that's not a jab at you most people don't understand EFI too well, so don't guess at the cause of the problem pull the codes and then you will know what the computer knows and you can make an informed decision on what your next move is.. with help from members here of course.
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Just one mabey 2 loud bangs out of the exaust only at mabey a half an inch from idle position of pedal
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STOP what your doing and check CODES. Your just throwing money at it hoping and praying I'll work. PULL THE CODE before going any further.
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You are correct, but have also had all codes pulled and replaced these parts due to the codes shown, only thing I haven't tackled yet is egr code.
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Were they active codes or stored? Did you try erasing the codes and see what codes come back? Even if the codes are there you should check the part to see if is actually bad before replacing it. Throwing parts at the truck gets really expensive.
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They were stored codes, didn't have any active.
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