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Thread: HELP lb7 wil not start when hot

  1. #1

    Default HELP lb7 wil not start when hot

    3-7-11
    Hard Hot Starts
    I Have A 2003 Gmc 2500 Hd Lb7 W/cal.emmissions Completly Stock 75000 Miles
    About 5 Months Ago I Had A Check Engine Light
    Code Said Glow Plug
    Replaced "all 8 Glowplugs" I Cant Be Sure. After That It Was Hard Starting.the Dealer Said They Would Diagnose It For Free. In 3 Hours First It Was The Fuel Regulator Then They Called And Said It Was The Injection Pump And If I Put Up $1500 They Would Replce It And If That Wasn't It They Would Give Me My Money Back.i Won't Pay For Parts Changers
    I Took The Truck Home And Found The Short Fuel Line Off The Filter Was Cracked I Replaced It And All Was Good For 2 Months
    Now It Starts Cold After 5 Second Of Cranking But When Its Hot It Will Crank But Not Start
    Any Ideas Out There
    Thanks For Reading
    Jt

  2. #2
    Join Date
    Mar 2008
    Posts
    79

    Default

    I hope you did not pay for the glow plugs, there is a 10 yr gm warunty on them

  3. #3
    Join Date
    Mar 2000
    Location
    Loyal WI US
    Posts
    10,792

    Default

    Injectors is where I would start. This has been a common issue with LB7's and the 2003's were known for hot start issues low power, etc. My guess is that your return rates or "leakback" is excessive. It is worse when hot soaked and you just can't build enough pressure to allow the ECM to start pulsing the injectors.
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  4. #4

    Default

    when the truck was at the dealer i asked about the injectors
    and was told no way
    and they started dicking me around 20 days before the warranty for the injectors was up
    now it would be on me
    i'm sure they would agree with you now about the injectors
    they had just eaten the glowplug replacment and they were looking for money to pay the mechanic so now my pump is gone-BS-
    on the scan tool the pump runs at or above the spec in the shop manual

  5. #5
    NutNbutGMC Guest

    Default

    Quote Originally Posted by zbm2 View Post
    when the truck was at the dealer i asked about the injectors
    and was told no way
    and they started dicking me around 20 days before the warranty for the injectors was up
    Red flag. "No way" is about the biggest tale I have heard all day. There's definitely a way for the LB7. Find a dealer, not a stealer.

    Read around on this forum and see for yourself.

  6. #6
    Join Date
    Feb 2000
    Location
    Montana
    Posts
    11,390

    Arrow

    Quote Originally Posted by zbm2 View Post
    when the truck was at the dealer i asked about the injectors
    and was told no way
    and they started dicking me around 20 days before the warranty for the injectors was up
    now it would be on me
    i'm sure they would agree with you now about the injectors
    they had just eaten the glowplug replacment and they were looking for money to pay the mechanic so now my pump is gone-BS-
    on the scan tool the pump runs at or above the spec in the shop manual
    If you have a documented service visit before the injector warranty expired for a problem that is later identified as being bad injectors, you may have just cause to get them replaced under warranty. The important thing is getting that service visit on record for the same complaint before the warranty expired.

    Jim

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