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hesitation around 1500 rpm, fuel pump/filter?

This is a discussion on hesitation around 1500 rpm, fuel pump/filter? within the Technical / Maintenance forums, part of the General Discussion category; Hoping someone might be able to help with this issue. Basically what happens is I'll be at a stop light ...

  1. #1
    Registered User boosh71's Avatar
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    hesitation around 1500 rpm, fuel pump/filter?


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    Hoping someone might be able to help with this issue. Basically what happens is I'll be at a stop light or stop sign idling and when I take off there is a hesitation around 1500 rpm. It's more pronounced when there is a load on the truck (such as running the A/C or towing). I thought it was the fuel pump failing but a local auto parts store indicated that when those fail the truck will not get any fuel at all. I'm going to replace the fuel filter in a few minutes and also clean the air filter. A couple times it even died on me when taking off from a dead stop. Any ideas? Could it still be the pump?

    Thanks guys!
    -Brent


    '94 GMC K1500, 5.7L, z71

  2. #2
    Registered User boosh71's Avatar
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    Re: hesitation around 1500 rpm, fuel pump/filter?

    I just replaced the fuel filter and cleaned the air filter. No improvement. Any ideas?
    -Brent


    '94 GMC K1500, 5.7L, z71

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    Re: hesitation around 1500 rpm, fuel pump/filter?

    if its a 5.3 somebody recommended new wires and plugs on here to me, i have the same problem but its only after the first initial shift from 1st to second when cold, the engine rides 1500 rpms and just goes blank, i lose a little power and then all the sudden it shifts and runs fine..the engine dosen't misfire or stumble its just like the engine forgets what its doing
    2004 1500 5.3 standard cab long box Z85

    Stupidity is the number one sin

  4. #4
    Not Really Bob
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    Re: hesitation around 1500 rpm, fuel pump/filter?

    Can you give us a rundown of you truck? You didn't give any details in your post.
    99 Silverado ECSB 4X4, LQ4, Patriot Stg. 2 243's w/ 59cc chambers, TR224-112, Pacesetter LT's, Nelson tune, FLT Lvl 5.5, PI 3400, UD pulley, 160* t-stat, E-fans, 6'' Fabtech lift, 3'' body lift, 37'' XTerrains, 4.56's, 4'' shackle flip 13.3 @ 99mph on 37's or 13.0 @ 101mph on 31's

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    Registered User boosh71's Avatar
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    Re: hesitation around 1500 rpm, fuel pump/filter?

    Sorry guys, what was I thinking? It's a 1994 GMC K1500 5.7L TBI 268,000 miles on it. The last tune up I did was at least two years ago, maybe three. Back then I replaced all the plugs, wires, distributor cap, and rotor.
    -Brent


    '94 GMC K1500, 5.7L, z71

  6. #6
    Registered User JeffsJeep04's Avatar
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    Re: hesitation around 1500 rpm, fuel pump/filter?

    Sounds kind of like a fuel pressure regulator to me, especially since you already did the usual suspects (fuel filter and air filter). Generally when it stumbles then catches back up, it's a fuel or air issue in my experience. When it stutters under load at any RPM, that's usually when I'll start digging into the ignition system.


    1999 GMC Sierra RCSB 4.8L, NV3500, 3.73, 4x4 For Sale!
    2002 Trailblazer: Wifemobile with matching paint and Trifecta Tune
    1989 Jeep: little of this, little of that

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    Registered User ibeholden12's Avatar
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    Re: hesitation around 1500 rpm, fuel pump/filter?

    I have a 97 siverado i just did the pump on today truck stumbles hard on accelaration from take off and climbs out of it at 1st shift could this be regulator or firing,( cap,rotor)

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    Registered User boosh71's Avatar
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    Re: hesitation around 1500 rpm, fuel pump/filter?

    Quote Originally Posted by JeffsJeep04 View Post
    Sounds kind of like a fuel pressure regulator to me, especially since you already did the usual suspects (fuel filter and air filter). Generally when it stumbles then catches back up, it's a fuel or air issue in my experience. When it stutters under load at any RPM, that's usually when I'll start digging into the ignition system.
    I'll have to check in to that, is this a common problem?
    -Brent


    '94 GMC K1500, 5.7L, z71

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    Registered User JeffsJeep04's Avatar
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    Re: hesitation around 1500 rpm, fuel pump/filter?

    Fairly. I sold a bunch of them when I was working the parts counter. I know my dad had a very similar issue to yours on his NBS Z71 and the FPR cleared it right up.


    1999 GMC Sierra RCSB 4.8L, NV3500, 3.73, 4x4 For Sale!
    2002 Trailblazer: Wifemobile with matching paint and Trifecta Tune
    1989 Jeep: little of this, little of that

  10. #10
    Registered User boosh71's Avatar
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    Re: hesitation around 1500 rpm, fuel pump/filter?

    Quote Originally Posted by JeffsJeep04 View Post
    Fairly. I sold a bunch of them when I was working the parts counter. I know my dad had a very similar issue to yours on his NBS Z71 and the FPR cleared it right up.
    Thanks, is it located in the throttle body?
    -Brent


    '94 GMC K1500, 5.7L, z71

  11. #11
    Registered User JeffsJeep04's Avatar
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    Re: hesitation around 1500 rpm, fuel pump/filter?

    Drivers side fuel rail, about half way back is where it's at on the NBS trucks. Really simple replacement job. Half hour and some needle nose pliers.


    1999 GMC Sierra RCSB 4.8L, NV3500, 3.73, 4x4 For Sale!
    2002 Trailblazer: Wifemobile with matching paint and Trifecta Tune
    1989 Jeep: little of this, little of that

  12. #12
    Not Really Bob
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    Re: hesitation around 1500 rpm, fuel pump/filter?

    Quote Originally Posted by JeffsJeep04 View Post
    Drivers side fuel rail, about half way back is where it's at on the NBS trucks. Really simple replacement job. Half hour and some needle nose pliers.
    He has an OBS TBI truck without fuel rails. The FPR is actually part of the throttle body injection unit. Sooo... most likely that is not his problem, but still could be...
    99 Silverado ECSB 4X4, LQ4, Patriot Stg. 2 243's w/ 59cc chambers, TR224-112, Pacesetter LT's, Nelson tune, FLT Lvl 5.5, PI 3400, UD pulley, 160* t-stat, E-fans, 6'' Fabtech lift, 3'' body lift, 37'' XTerrains, 4.56's, 4'' shackle flip 13.3 @ 99mph on 37's or 13.0 @ 101mph on 31's

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    Re: hesitation around 1500 rpm, fuel pump/filter?

    will this problem throw a light on the dash on NBS?
    2004 1500 5.3 standard cab long box Z85

    Stupidity is the number one sin

  14. #14
    Registered User boosh71's Avatar
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    Re: hesitation around 1500 rpm, fuel pump/filter?

    Well guys, here's an update. I've replaced the fuel filter, cleaned the air filter, and just replaced the fuel pump and screen. Still a hesitation between 1000-2000 rpm. Is the engine just tired? I just want my truck to run like it should be! I usually tow quads to the dunes or the mountains but lately haven't really been able to because the power just isn't there. I mean I could still tow, but when I hit any hills I drop down to like 38 mph! Any Ideas?
    -Brent


    '94 GMC K1500, 5.7L, z71

  15. #15
    GMC RULZZ NEUMANNZZ's Avatar
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    Re: hesitation around 1500 rpm, fuel pump/filter?

    check compression to find out.
    O2 GMC RCSB 4.8L V8 AUTO 3.73's
    rebuilt/beefed up 4L60E(at 43,000miles)
    Matching Ninja 500r


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    Registered User toomanyballs's Avatar
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    Re: hesitation around 1500 rpm, fuel pump/filter?

    is it cold or when the engine is warmed up?

  17. #17
    Registered User boosh71's Avatar
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    Re: hesitation around 1500 rpm, fuel pump/filter?

    Quote Originally Posted by toomanyballs View Post
    is it cold or when the engine is warmed up?
    Both when it is cold and warmed up. To be sure I'll warm it up before I leave for work tomorrow.
    -Brent


    '94 GMC K1500, 5.7L, z71

  18. #18
    Registered User JeffsJeep04's Avatar
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    Re: hesitation around 1500 rpm, fuel pump/filter?

    Fuel pressure regulator...still sounds like the issue to me.


    1999 GMC Sierra RCSB 4.8L, NV3500, 3.73, 4x4 For Sale!
    2002 Trailblazer: Wifemobile with matching paint and Trifecta Tune
    1989 Jeep: little of this, little of that

  19. #19
    Registered User boosh71's Avatar
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    Re: hesitation around 1500 rpm, fuel pump/filter?

    Well guys I found the problem. The timing was off 9 degrees! It runs so much better now! Thanks for all the help.
    -Brent


    '94 GMC K1500, 5.7L, z71

 

 

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