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Thread: Fuel Problem in '95 4.3 litre vortec in a 4WD Blazer

  1. #1

    Default Fuel Problem in '95 4.3 litre vortec in a 4WD Blazer

    I have a 1995 Chevy Blazer with a 4.3 litre vortec engine. The engine only has 20k. I have replaced the fuel pump, sending unit, and the fuel filter. When the vehicle is driven up a hill it spits and sputters. After about a week of normal driving conditions or if driven a long distance in a day. The fuel will no longer come out from the injector tips into the manifold. After the vehicle sits for 3 or 4 days then it will start normally. I have also replaced the computer twice to ensure that this was not the problem.

  2. #2

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    Did you check for any trouble codes? Another possible cause could be the fuel pressure regulator.

  3. #3

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    How about the gas cap vent? Next time it acts up take the gas cap off and see if it runs better. Simple first!

  4. #4

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    take off your intake hose that is between your mass airflow sensor and your air filter. There could be a leaf in there or lots of grime on the sensor wires. Shoot some electronic clean into the sensor to clean the wires. (of course with the engine off). this may be the problem
    ________
    CB250
    Last edited by redbandit; May 8th, 2011 at 11:41 PM.

  5. #5

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    check the cpi unit itself. they are prone to failure (mostly the diaphram on the fuel pressure regulator.) since the fuel pressure regulator it incorperated into the unit.

  6. #6

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    I would verify that there are no powertrain DTC codes first and if so address those before you go any further, also check closely for any type of fuel leaks while the vehicle is running and also after the vehicle has not been started for a couple of days.

    I also know that different types of fuel can also cause this same problem and changing your fueling station may also surprise you, but if all checks out okay then I would do the following.

    If the fuel pump is supplying the correct fuel pressure (58 to 64psi with a PCM and 55 to 61psi with a VCM-A with the ignition on and the engine off and the small rubber hose was also replaced along with the fuel pump) then I have seen many customers complain about no start, hard start, rough idle after start and surge under a load.

    Remember not to activate the fuel pump more than twice without starting the engine because this could flood the engine and cause hard starting.

    The first thing that I would do is clean out the CPI injector completely because under certain conditions fuel elements may deposit on the poppet balls, seats or pintles, which can cause the poppet balls to either stick in an open or closed position.

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