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  1. #1

    Default Right bank running rich

    This doesn't happen every time I start my truck, but over the last few days, at least one or twice a day, it will run really really rough and black smoke comes out of the right exhaust and I can smell the gas so I know its running rich. It only runs like this for 5 minutes or so and then levels out.

    My first though was the fuel pressure regulator, but I pulled the vacuum hose and no fuel sprayed out, plus that would cause both banks to run rich. I don't think its the MAF either or that too would cause both banks to run rich.

    The only thing I can think is that an injector is getting stuck open and as it runs a bit it stops.

    How do I check to see if injectors are working correctly?

    Could it be anything else?

    Thanks for any help!
    Current Daily Driver:
    2003 Chevrolet Silverado 1500 - 4WD - 4.8L V8 - True Dual Exhaust Setup, Cat Delete, Cherry Bomb Glass Packs

  2. #2

    Cool right bank running rich

    One easy way to check injecters, be careful here, start the truck and hold one end of a long screwdriver on the injecter and the other end to your ear. You should here a loud clicking noise from each injecter. If one is not clicking like the others than most likely thats your bad injecter. Also try putting a pressure gauge on and after you shut the engine of if the fuel pressure drops quickly than a injecter is leaking.

  3. #3
    Jr. Engineer hundojoe's Avatar
    Join Date
    Feb 2010
    Elk River, Minnesota


    Might be oxygen sensors going bad, the ****ty thing is is that there is 4 of them. 2 per side and 1 in front of the cat and 1 after the cat. You can ohm out a injector. the closer they are to 12.5 ohms the better they are, anything less the 77 ohms id look into getting a new one.

  4. #4


    I, too, would probably look at the O2 sensor. 1st thing I'd probably do would be to put a scanner on it and see if there are any DTC's (or pending DTC's) that would help. Then I'd probably follow that by looking at the PID's to see if the right bank O2 sensor (#1) is reading rich (near 1 V) or lean (near 0 V). If the O2 sensor is seeing a lean condition when it is really rich, then I'd suspect something's up with the O2 sensor.
    '98 K1500 Suburban LS 5.7 L 4L60E NV246 ARB
    '92 Ford Explorer XLT 4x4 4.0 L A4LD BW13-54 Trac-loc rear
    "My toys were the greasy cogs and springs and pistons that lay around all over the place, and these, I can promise you, were far more fun to play with than most of the plastic rubbish children are given nowadays." Danny in Roald Dahl's Danny The Champion of the World

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