GM Truck Club
Founded in 2004 ~ We're the #1 Chevy Truck & SUV Forum.
Silverado & Sierra | Tahoe & Yukon | Suburban & Yukon XL | SUV & CROSSOVER
Results 1 to 4 of 4

Thread: Fuel issue

  1. #1

    Default Fuel issue

    I have a 1988 Chevrolet 3500 with a 454 and when you switch from left tank to right tank truck engine leans out...i have personally changed both pumps ( 1 in each tank) i have changed the switch valve and the switch in the cab, new lines from tanks to switch valve and for the heck of it i just changed the right tank pump again. The reason i know it leaning out cause you can hear the difference in the motor when switching and while watching my scanner i can see block learn(145) going up and the integrator staying low(128) on the right tank and the block learn and integrator matching on the left tank.....any ideas?

    Thanks ...Bruce

  2. #2


    Not sure if this would have 2 different fuel filters, (one for each tank) but are all the equipted fuel filters new and clean? I belive that between then fuel pump and the sending units on those there is a rubber hose conecting the pump to the SU. Make sure that its not leaking or that it has a hole in it. Or that any possable rubber hoses in the system arn't kinked a little. Do both pumps also have new fuel strainers on them as well?

    Hope this helps a little good luck!
    1995 C1500 4.3L 2WD. JET TBI Spacer, JET stage 1 chip, 10mm Taylor custom wires, Pulstar Iridium Pulse Plugs.
    260k miles and still going strong...

  3. #3


    Fuel strainers in both tanks are new..fuel line from tanks to fuel switch valve new, there is 1 filter and its a common filter that is after the fuel switching valve.

    Not sure if computer tied in to fuel tank switch or not...these computers back then where so primitive.

  4. #4


    I'd take a look at the grounds for the pumps. If one of them is a little loose or dirty, it will affect the pump's ability to work correctly.
    Good Luck and God Bless

Similar Threads

  1. Fuel issue
    By maxjordan1982 in forum Performance & Fuel
    Replies: 9
    Last: 06-13-2011, 02:18 PM
  2. 02 Yukon SLT 5.3L Flex Fuel, fuel line issue
    By TRyan9441 in forum Chevy Tahoe Forum (GMC Yukon, Cadillac Escalade)
    Replies: 2
    Last: 06-02-2011, 12:19 PM
  3. Fuel Gauge Issue
    By jake's silverado in forum Performance & Fuel
    Replies: 3
    Last: 04-11-2011, 06:12 PM
  4. Chevy 7.4l fuel issue
    By JOHNNYBLACKEYE in forum GM Powertrain
    Replies: 2
    Last: 02-08-2010, 11:04 AM
  5. Fuel gauge issue
    By ladder344 in forum General Chevy & GM Tech Questions
    Replies: 5
    Last: 05-02-2009, 12:33 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts