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Thread: Injection pump transmission relationship

  1. #1
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    Default Injection pump transmission relationship

    Howdy
    1998 Sub with 6.5 4L80e

    Can a failing injection pump cause transmission no TC lockup? Or any other transmission issues?

    Will a failing pump throw codes?

    I know my pump is needing some work but can that cause lack of TC Lockup?

    Trans seems to work good with no problems or slipping. kinda mushy shifts but pretty normal.

    No SES, no Codes that I am aware of.

    Thanks!
    1996 Chvy 3500 CCDWLB 6.5 Heathed, NO vac, marine injctrs, ARB bumper, BIG pipe, 3" lift, bright lights, bypass oil system.
    1986 Chvy 6.2 M1009 blazer RAM AIR, Headers, Custom interior
    2001 Chinook RV, V10 gas
    1974 John Deere 1530 diesel tractor
    1993 John Deere 455 Diesel lawn mower
    1967 GTO, 1989 Honda Transalp
    2009 VW Jetta TDI, flashed and piped, 6speed, fun car!
    1998 6.5 suburban, stock, daughter's
    1993 6.5 3500 CCSWLB GM8, Heathed, big exhaust, gauges, Son's

    1984 6.2 ATS turbo 3500, SCDWLB - Son's
    3 kids, 1 wife, 1 dog
    Gunsmith, Tactics Instructor, Fabricator USMC 87-93 Semper Fi!

  2. #2
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  3. #3
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    Default

    Fairly sure but I have not run a scanner in real time. I will try that.
    Will a failing pump throw a code?
    As much as this thing is hoping around (fish-biting) going down the road I would think there should be a code and a light.....?
    1996 Chvy 3500 CCDWLB 6.5 Heathed, NO vac, marine injctrs, ARB bumper, BIG pipe, 3" lift, bright lights, bypass oil system.
    1986 Chvy 6.2 M1009 blazer RAM AIR, Headers, Custom interior
    2001 Chinook RV, V10 gas
    1974 John Deere 1530 diesel tractor
    1993 John Deere 455 Diesel lawn mower
    1967 GTO, 1989 Honda Transalp
    2009 VW Jetta TDI, flashed and piped, 6speed, fun car!
    1998 6.5 suburban, stock, daughter's
    1993 6.5 3500 CCSWLB GM8, Heathed, big exhaust, gauges, Son's

    1984 6.2 ATS turbo 3500, SCDWLB - Son's
    3 kids, 1 wife, 1 dog
    Gunsmith, Tactics Instructor, Fabricator USMC 87-93 Semper Fi!

  4. #4
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    Granby, Missouri, USA
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    Default

    Quote Originally Posted by Dvldog8793 View Post
    Fairly sure but I have not run a scanner in real time. I will try that.
    Will a failing pump throw a code?
    As much as this thing is hoping around (fish-biting) going down the road I would think there should be a code and a light.....?
    After I had owned my Tahoe for a while, I discovered the previous owner had removed the bulb in the SES indicator. I guess he didn't like looking at the light being on all the time!!

    It could be you simply have a missing or burned-out bulb in the SES lamp.

    Casey
    1995 K1500 Tahoe 2 door, 6.5LTD, 4L80E, NP241, 3.42's, 285/75R16 BFG K02's; 1997 506 block; Kennedy OPS harness, gauges, Quick Heat plugs, and TD-Max chip; Dtech FSD on FSD Cooler; vacuum pump deleted, HX35 turbo, Turbo Master, 3.5" Kennedy exhaust, F code intake; dual t/stats, HO water pump, Champion radiator; Racor fuel filter

  5. #5
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    Default

    My TC was unlocking at speed 60-65 mph
    no codes or anything , just an rpm jump .
    I replaced the brake light switch .
    So far so good no more erratic behavior
    Part was under $15 shipped .
    98 Tahoe
    Stock
    312k

  6. #6
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    Default

    Howdy
    SES light is functional, it lights up in the starting protocol.

    I hadn't thought of the brake light switch but will change it out as I have one. Not sure if that is what the problem is because the IP is showing severe symptoms.
    I am just trying to figure out how the two problems could be related without a SES light or trouble code....?
    1996 Chvy 3500 CCDWLB 6.5 Heathed, NO vac, marine injctrs, ARB bumper, BIG pipe, 3" lift, bright lights, bypass oil system.
    1986 Chvy 6.2 M1009 blazer RAM AIR, Headers, Custom interior
    2001 Chinook RV, V10 gas
    1974 John Deere 1530 diesel tractor
    1993 John Deere 455 Diesel lawn mower
    1967 GTO, 1989 Honda Transalp
    2009 VW Jetta TDI, flashed and piped, 6speed, fun car!
    1998 6.5 suburban, stock, daughter's
    1993 6.5 3500 CCSWLB GM8, Heathed, big exhaust, gauges, Son's

    1984 6.2 ATS turbo 3500, SCDWLB - Son's
    3 kids, 1 wife, 1 dog
    Gunsmith, Tactics Instructor, Fabricator USMC 87-93 Semper Fi!

  7. #7
    Join Date
    Apr 2001
    Location
    CA
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    Arrow

    The brake lamp switch is the most likely suspect. Brake switch activation/deactivation would be seen by the PCM as a "normal" function, so if it isn't performing as it should, the PCM won't likely see it as a problem. The switch is multi-function, so it can be bad while still operating the brake lamps correctly.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  8. #8
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    Default

    Howdy
    OK...replaced the brake switch....no change, except now I know that the brake switch is new.

    This is a you-tube video of the symptom. It starts at about 30 seconds, watch the tach, If I set the cruise it will hold better going uphill than straight and downhill is the worst.

    http://youtu.be/ZGHiElOPBDU

    Near as I can tell I have checked everything that I can without a scantool. My laptop cable is out on loan. Once I get it back I will try a real time scan while running.

    Transmission runs through all gears with no slipping.
    Is this just the failing pump?

    Just cant figure why it would be so symptomatic without a code?
    1996 Chvy 3500 CCDWLB 6.5 Heathed, NO vac, marine injctrs, ARB bumper, BIG pipe, 3" lift, bright lights, bypass oil system.
    1986 Chvy 6.2 M1009 blazer RAM AIR, Headers, Custom interior
    2001 Chinook RV, V10 gas
    1974 John Deere 1530 diesel tractor
    1993 John Deere 455 Diesel lawn mower
    1967 GTO, 1989 Honda Transalp
    2009 VW Jetta TDI, flashed and piped, 6speed, fun car!
    1998 6.5 suburban, stock, daughter's
    1993 6.5 3500 CCSWLB GM8, Heathed, big exhaust, gauges, Son's

    1984 6.2 ATS turbo 3500, SCDWLB - Son's
    3 kids, 1 wife, 1 dog
    Gunsmith, Tactics Instructor, Fabricator USMC 87-93 Semper Fi!

  9. #9
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    Dec 2009
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    In the North
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    700

    Default

    Looks to me like your FSD is going bad...

    it seems like its "fixhbiting"

    does the cruise still work ok?
    1999 chev suburban C2500
    300,000 mi

  10. #10
    Join Date
    Nov 2010
    Location
    NE PA
    Posts
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    Default

    That's what mine was doing before my PMD failed .
    Mine was still under the hood but not on injector pump but on the side with a heat sink .
    I picked up a extension cable and a DTech PMD and relocated to the front behind center of bumper .
    My pump acted up for about a week before it gave up the ghost , After that was replaced the rpm jumping showed up {after a while} but that was related to the brake switch ,I too thought it was related to injector pump , since{brake switch} been replaced all has been good .
    98 Tahoe
    Stock
    312k

  11. #11
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    Default

    Welll....
    PMD replaced
    Brake switch replaced
    fuel filter replaced
    Lift pump replaced
    Same issues so it looks like the IP is next....
    Oh well....230,000 on the factory pump isn't bad.
    1996 Chvy 3500 CCDWLB 6.5 Heathed, NO vac, marine injctrs, ARB bumper, BIG pipe, 3" lift, bright lights, bypass oil system.
    1986 Chvy 6.2 M1009 blazer RAM AIR, Headers, Custom interior
    2001 Chinook RV, V10 gas
    1974 John Deere 1530 diesel tractor
    1993 John Deere 455 Diesel lawn mower
    1967 GTO, 1989 Honda Transalp
    2009 VW Jetta TDI, flashed and piped, 6speed, fun car!
    1998 6.5 suburban, stock, daughter's
    1993 6.5 3500 CCSWLB GM8, Heathed, big exhaust, gauges, Son's

    1984 6.2 ATS turbo 3500, SCDWLB - Son's
    3 kids, 1 wife, 1 dog
    Gunsmith, Tactics Instructor, Fabricator USMC 87-93 Semper Fi!

  12. #12
    Join Date
    Nov 2010
    Location
    NE PA
    Posts
    43

    Default

    Quote Originally Posted by Dvldog8793 View Post
    Welll....
    PMD replaced
    Brake switch replaced
    fuel filter replaced
    Lift pump replaced
    Same issues so it looks like the IP is next....
    Oh well....230,000 on the factory pump isn't bad.
    I've had all the same replaced haven't had to get to IP......yet
    Only other thing I got would be hows the injectors themselves ?
    Both expensive , But just me would want to be sure that its just not one injector giving me all the trouble
    98 Tahoe
    Stock
    312k

  13. #13
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    Dec 2009
    Location
    In the North
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    I have three FSD's,. all are mounted on heat sinks with long extension cables,.
    the one right now thats running the truck is just tossed on the inner fender over by the master cylinder,. the one on the front bumper quit after two surges a while back (i must remember to mount the spare properly)
    The third one i have will run the truck but the motor has much less performance with it and the cruise doesn't work,.
    so its just an 'emergency' emergency back up

    My experience with injection pumps, is they either work or they don't , nothing in between,.
    yrrmv.
    1999 chev suburban C2500
    300,000 mi

  14. #14
    Join Date
    Apr 2001
    Location
    Newberg Oregon
    Posts
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    Default

    A failing PMD will many times not toss a code. A failing DS4 will usually code when its having issues, but I have seen them do exactly what you are seeing.

    Best thing to do is get a top notch scanner on the beast and watch the readouts "realtime" and see whats going on.

    Another thing would be to get a fuel pressure gauge on it and watch the pressure while running.

    First thing is to swap the PMD and see what shakes.

    PMD is always a likely suspect.

    Driving down the road though and having a PMD fail while rolling usually will set a pulse width error code.
    (1) 1995 Suburban 2500 4x4
    (1) 1997 Astro
    (1) 2005 Suburban (Papa Smurf)
    THIS IS BOW TIE COUNTRY

  15. #15
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    Sep 2014
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    USA, Kansas
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    Have you thoroughly checkd for air leaks yet?

    Replaced the lift pump too. Did you drop the tank, inspect the sender and replace the fuel strainer too?

    If the answer is NO to both of those questions, might hold off on condemning the IP just yet..

  16. #16
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    Walla Walla WA
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    Default

    I didn't see if the Burb was 2WD or 4WD. I had previous issues with the connectors on the front diff engaging device and connections on the transfer case. Both can cause you to drop out of and stay out of OD.
    1994 K2500 ext cab. Recently repowered with; Non-cracked 599 block, factory compression, used old DSG girdle for main caps. Factory for what remains. Changed diffs to 3.42. Fuel economy Hwy 22.5 mpg US, in town without lcokup in 2nd/3rd - 18 mpg US.
    1994 K3500 CC LB Silverado. Next project. Built for endurance, power and gearing. Plan on opened up intake and exhaust sytem, best cooling mods, 4.11 gearing 4L80E, followed by Gear Vendors OD. Need to be able to split all gears and have lockup in 2nd/3rd/4th. Tan interior cloth, Bad ass dark blue (coming) aluminum wheels and air ride (coming)

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