Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

truck turns over a lot before starting. fuel pump??

Discussion in 'The Garage' started by XHitman396, Jan 3, 2007.

  1. XHitman396

    XHitman396 1/2 ton status

    Joined:
    May 3, 2002
    Posts:
    620
    Likes Received:
    0
    Location:
    Broken Arrow, Oklahoma
    my stock '87 turns over quite a few times before it starts. it turns over fast and strong, just more than it should. would this be the fuel pump. i know my buddy had this problem in his Grand Cherokee, and it was the check valve in the fuel pump mounted in the gas take. when he turned the jeep off, the check valve wouldnt seal all the way, and the gas would seep back into the tank, so it would crank until the gas reached the engine. i changed the fuel pump for him, and everything worked perfectly after that. have you guys had the same problem with your trucks? did you try the pump?? the filter isn't THAT old either.. but maybe time for a change...
     
  2. big dan

    big dan 1/2 ton status Premium Member

    Joined:
    Aug 1, 2005
    Posts:
    2,656
    Likes Received:
    29
    Location:
    Arkansas
    had the same prob on mine with the fuel pump. gas ran back to the tank and had to crank till it reached the carb. being carbed I have to pump the pedal a couple times before it will start otherwise it will just crank over for a while before it starts. since yours is tbi you shouldnt have to pump the pedal first but you might try it before you spend the money on a new pump.
     
  3. JEBSR

    JEBSR 1/2 ton status

    Joined:
    Dec 23, 2004
    Posts:
    1,541
    Likes Received:
    0
    Location:
    Clarksville, TN
    Mine does the same thing. Ignition is fine, when I built the new engine I replaced the distributor, installed accel cap and rotor, msd coil, and msd 6T. Still did the same thing. I have tried cycling the fuel pump several times before trying to start it, thinking the check valve was the problem as well. Didn't help at all though. It isn't a big problem so I haven't done anything to try and fix it. I would be intersted to see what you find though
     
  4. MaxPF

    MaxPF 1/2 ton status

    Joined:
    Apr 13, 2006
    Posts:
    2,207
    Likes Received:
    0
    Location:
    Chandler, Arizona
    Is yours a carb or TBI? Mine (TBI) does the same thing - always has. The fuel pump died, I replaced it, and it still takes a few seconds worth of cranking before it lights. Once it is warm it starts faster. I will have to ask my mechanic buddy at the Chevy dealership if this is normal or not. :dunno:
     
  5. JEBSR

    JEBSR 1/2 ton status

    Joined:
    Dec 23, 2004
    Posts:
    1,541
    Likes Received:
    0
    Location:
    Clarksville, TN
    TBI, has done it since I bought it. Never created any problems. That's why I haven't checked in farther.
     
  6. vortec

    vortec 1/2 ton status

    Joined:
    Jul 22, 2004
    Posts:
    1,472
    Likes Received:
    0
    Location:
    fort worth, texas
    whenever i start my '94 c1500 (yep, tbi), i turn the key to the run position only, leaving the start circuit open, for about 10 seconds, to let the fuel pump pressurise the lines, then go ahead and turn the key to start. it fires us fast. if i go straight to "start" which, of course, closes both the start and run circuit, it takes longer, since the fuel pump is repressurizing the lines while the motor is cranking. just extra strain on the battery and starter, i say. i know the system is supposed to stay pressurized for a while, but in reality, they tend to wuss out overnight. no big deal, imo.
     
  7. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    The fuel pump shuts off 2 seconds are ya do that, so no need to wait for 10 seconds. ;) I start our '94 Sub the same way. It starts much quicker in the morning if the pressure is up before cranking. :cool1:
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,979
    Likes Received:
    189
    Location:
    Roy WA
    I'd be testing the fuel pump relay by forcing the pump to run before starting on ALL of the trucks mentioned in this thread.

    I'd suspect TBI is the same as TPI for the starting where the ECM is concerned, and as I recall, it's 8 reference pulses (8 "sparks") before the ECM commands injector pulses. So you will have SOME hesitation no matter what you do, but when the relay fails, as some in this thread know, the oil pressure switch handles fuel pump running, and it takes approx. 5PSI before it will kick the fuel pump on. Thus, bad fuel pump relay=delayed start.

    This is NOT a statement that you should go out and replace the relay just because it takes a long time to start. Test the relay, then replace if it's the cause.
     
  9. XHitman396

    XHitman396 1/2 ton status

    Joined:
    May 3, 2002
    Posts:
    620
    Likes Received:
    0
    Location:
    Broken Arrow, Oklahoma
    yeah, the relay thing sounds like it could be the culprit. where is the relay, and how exactly do you test it?? thanks for all the help, guys..
     
  10. 87'k5boggin

    87'k5boggin Registered Member

    Joined:
    Dec 9, 2006
    Posts:
    76
    Likes Received:
    0
    Location:
    pascagoula,mississippi
    i have the same prob with my 87 tbi, i changed the fuel pump and sending unit altogether and it still does it. im lost to what can cause this
     
  11. JanneB

    JanneB Registered Member Premium Member

    Joined:
    Dec 9, 2004
    Posts:
    62
    Likes Received:
    5
    Location:
    Finland
    I have the Holley 950 Commander TBI MSD 6 & distributor.

    Allmost every time I start the engine I have to crank it too long in my opinion.
    I have the fuel pump on and I have a fuel pressure gauge so I know there is fuel pressure before I start to crank. It still does it.

    The MSD 6 got water in it once (my bad, stupid location for it) and whitout the MSD box it starts right away, every time?

    Could it be the voltage dropping too low for the MSD box?
     
  12. BlaKK54Speed

    BlaKK54Speed 1/2 ton status

    Joined:
    Dec 14, 2006
    Posts:
    242
    Likes Received:
    0
    Location:
    Omaha, NE
    mine cranks over a long time too. stock 305 mechanical pump and carb
     

Share This Page