Question about 1999 Chevrolet Suburban

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Fuel injectors are dumping fuel

As you turn the key to on postion (but do not start) it floods the engine. It's like the injectors are on all the time. When you start the truck normally, it acts like you've just poured raw fuel down the intake. The exhaust fumes also smell like raw fuel. I put new injectors in about 1 year ago. New plugs, cap, rotor, & wires were installed about 2 weeks ago. I took the truck to my local Chevrolet dealer and they told me it was the fuel pump. When I tested it, it had 60 psi. I went ahead and installed a new fuel pump. This didn't fix my problem! I took it back to the dealer and they said they would look at it again. That was a joke. I was told 3 different people drove it and it ran fine. I have read thru the repair manual, but cannot figure out the problem. If you have any insight to this problem, I would really appreciate your help. Thank you,

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  • rjjbdills Jan 01, 2009

    Hello geharbison,
    It seems to idle fine, but when it's under a load, it acts very fumy and seems to miss. When it's in park, it will rev up fine. It does not idle up or down in either park or drive. Tomorrow I'll try the paper trick. Also, when this problem started, I was driving down the road and the engine light came on. It was flashing over and over and using a ton of gas. I found out that if I unplugged the injector harness and put it back on it would run fine for a while.
    But trying that again, doesn't work any more. I took it to get the code read and it was 420 (low bank 1) & 303 (a miss fire). I am going to replace injector # 3, but don't think that is the fuel problem. I pulled the spark plugs and they all seemed to be wet.

  • warlock61
    warlock61 May 11, 2010

    just for the heck of it try unplugging the alternator, I have seen instances where the alt caused interference with the computer

  • Evan Harbison
    Evan Harbison May 11, 2010

    How does it run? When it idles, does it have a steady rhythm or does it idle up and down? Stick a piece of paper in front of the exhaust pipe, what shows up on the piece of paper? What color is the exhaust? How does it behave when you are driving?



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  • 341 Answers

Sounds like the fuel pressure regulator diaphragm has ruptured. When this happens fuel is drawn in from the manifold vacuum and if the leak is severe enough the fuel pump pressure will push it in as well. The unit is a small component that resides on the fuel injector rail and will have a vacuum hose running to it. Remember you are working with GASOLINE and lots of it so be careful!

Posted on Dec 31, 2008


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