Results 1 to 7 of 7

Thread: RPM Jumps from 1200 to 2000

  1. #1
    Join Date
    Sep 2019
    Location
    Cheshire Oregon
    Posts
    2

    Default RPM Jumps from 1200 to 2000

    the rpm of my 6.5 Jumps from 1200 to 2000 no matter how much i try to feather it.I replaced the accelerator pedal and the fuel pump. took it to the local diesel experts. they told me it came that way when sold new??*Ideas Thoughts??

  2. #2
    Join Date
    Jan 2001
    Location
    New Hampshire - Live Free or Die
    Posts
    6,057

    Default

    In neutral? Maybe not an issue.

    I've seen "twitchy" throttles caused by the wrong (to high) resistor in the PMD, but, if you have a new pump that shouldn't be a problem. If it is rebuilt, it depends...

    Is your lift pump healthy?
    The Constitution needs to be re-read, not re-written!

    If you can't handle Dr. Seuss, how will you handle real life?

    Current oil burners: MB GLK250 BlueTEC, John Deere X758
    New ride: MB GLS450 - most stately
    Gone but not forgotten: '87 F350 7.3, '93 C2500 6.5, '95 K2500 6.5, '06 K2500HD 6.6, '90 MB 350SDL, Kubota 7510

  3. #3
    Join Date
    Apr 2001
    Location
    Newberg Oregon
    Posts
    12,282

    Default

    The 6.5 should NOT jump RPM that much.

    You should be able to gradually raise the RPM from idle right on up to a very high RPM without the drastic jump.

    Internal injection pump issues most likely to blame.

    I would say that the fuel solenoid is getting worn and it is not responding properly.
    (1) 1995 Suburban 2500 4x4
    (1) 1997 Astro
    (1) 2005 Suburban (Papa Smurf)
    THIS IS BOW TIE COUNTRY

  4. #4
    Join Date
    Sep 2019
    Location
    Cheshire Oregon
    Posts
    2

    Default repairing the flat spot...

    I replaced the lift pump and PDM last year from leroy. thinking that would take care of it. sadly no.*I just spoke to my mechanic*about replacing the fuel solenoid. He tells me we should replace the injection pump at the same time to be on the safe side as it is the original.*thanks for the ideas of how to take care of the headache.
    I will post on the outcome when finished.

    Thanks again

  5. #5
    Join Date
    Apr 2001
    Location
    CA
    Posts
    13,573

    Arrow

    If it is original, 23 years of IP service doesn't leave much to complain about, really. If you aren't seeing a STS (Service Throttle Soon) lamp/code, I agree with the suspect IP.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  6. #6
    Join Date
    Jan 2001
    Location
    New Hampshire - Live Free or Die
    Posts
    6,057

    Default

    OK, I thought you meant the injection pump when you said "fuel pump". Yes, definitely, if it is original, it's a miracle it still runs!

    When you replaced the PMD, what did you do for a resistor?
    The Constitution needs to be re-read, not re-written!

    If you can't handle Dr. Seuss, how will you handle real life?

    Current oil burners: MB GLK250 BlueTEC, John Deere X758
    New ride: MB GLS450 - most stately
    Gone but not forgotten: '87 F350 7.3, '93 C2500 6.5, '95 K2500 6.5, '06 K2500HD 6.6, '90 MB 350SDL, Kubota 7510

  7. #7
    Join Date
    Apr 2001
    Location
    Newberg Oregon
    Posts
    12,282

    Default

    The fuel solenoid I referred to is not the shut off up on top, but instead the actual fuel control inside the INJECTION PUMP.

    This part is not normally a local shop replaceable item..

    A properly rebuilt injection pump that has been tested on a stanadyne test bench is the best route to go.

    Good luck
    (1) 1995 Suburban 2500 4x4
    (1) 1997 Astro
    (1) 2005 Suburban (Papa Smurf)
    THIS IS BOW TIE COUNTRY

Posting Permissions

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