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5.0 efi problem

Discussion in 'Early CJ5 and CJ6 Tech' started by bkd, Jun 29, 2009.

  1. cj6/442

    cj6/442 Sponsor

    http://www.kolibar.com/ rick kolibar1 714 287 9261 he always answers email and not his ph too much tell him spyder from fallbrook sent you .
     
  2. bkd

    bkd Moderator Supreme Staff Member 2022 Sponsor

    thank you
    Jim S.
     
  3. bkd

    bkd Moderator Supreme Staff Member 2022 Sponsor

    from the reading I've been doing I'm starting to question fuel delivery. I installed a in tank YJ pump and checked the pressure at idle 32lbs, and at WOT 30+lbs but havn't checked it under load......I think I need to rig up the gauge so I can read it while under driving conditions, seems bad pressure or volume could be the culprit as well?
    Jim S.
     
  4. hudsonhawk

    hudsonhawk Well-Known Member

    With out the ability to read codes it will be hard to diagnose. I had a similar problem with Megasquirt on my 258. It turned out the signal from the MAP sensor was erratic and caused the computer to fire the injectors erratically becuse ti assumed the engine was accelerating and decelerating. I basically told the computer to ignore the MAP for acceleration purposes and the problem went away.

    I know you have a completely different system but the symptoms are the same as I was experiencing.
     
  5. hudsonhawk

    hudsonhawk Well-Known Member


    Is 30 lbs enough? I thought it needed to be around 45 lbs for MPI?
     
  6. bkd

    bkd Moderator Supreme Staff Member 2022 Sponsor

    yea that's what I remember hence the need to recheck the pressure....I'll have the gauge tomorrow so I'll know then.
    I have talked to the guy who made the harness......he'll replace the one I have with the above mentioned items, but I want to check out a few other things first
    Thanks for the input....Jim S.
     
  7. bkd

    bkd Moderator Supreme Staff Member 2022 Sponsor

    checked the fuel pressure with my mechanic at work.....32lbs at idle.....42-43lbs at WOT well within reason for my stock HO.
    Also checked the vacuum pressure....again good readings.
    Took my guy on a long drive so he could see for himself the issues....he's convinced the TPS is bad and suggested new wires and plugs as well.....I didn't replace them when I swapped motors :rofl:......I'm gonna try these recommendations before I throw in the towel, my guy hasn't let me down before....I told him his rep was on the line R)
    I'll update after the parts are installed.....Jim S.
     
  8. cj6/442

    cj6/442 Sponsor

    you should be able to set the paramiters of tps with ohm meter? need at least 40 at idle ,get a hi pressure pump from a f150 .did you ever check the spray from the injectors?new or used/? are you running a acumulator? some people do some don't . where is the pump close to the tank or far away. that needs to be close. so many questions you need to call rick.............................
     
  9. bkd

    bkd Moderator Supreme Staff Member 2022 Sponsor

    Donor ran great before pulling the motor
    I never messed w/ the injectors.....I'm running a in tank YJ pump.....I will call him
    Pm me your ph# bro
    Jim S.
     
  10. cj6/442

    cj6/442 Sponsor

  11. bkd

    bkd Moderator Supreme Staff Member 2022 Sponsor

  12. hudsonhawk

    hudsonhawk Well-Known Member

    I can see a bad TPS causing those issues.
     
  13. bkd

    bkd Moderator Supreme Staff Member 2022 Sponsor

    put the new TPS on, new plugs and wires.....drove into town 4 or 5 miles at 50-60mph and it seemed to be doing great......through side streets still great. Came to a stop at the gas station and it idled very erratically. Left the station and it was back to missing badly like before in all gears and all rpm's. Parked in the garage and after a minute or so it smoothed out at about 800rpm's.
    One thing I noticed is it ran ALOT cooler than before....205-210 before......175-185 now
    As has been stated I think at this point it seems to point to the lacking VSS hook up.......AAARRRRGGGHHHHHH!!!!!!!!!!
    Jim S.
     
  14. cj6/442

    cj6/442 Sponsor

    does that tps need to be adj with an ohm meter?
     
  15. bkd

    bkd Moderator Supreme Staff Member 2022 Sponsor

    Napa says not but.............
    Jim S.
     
  16. hudsonhawk

    hudsonhawk Well-Known Member

    Have you checked to see if something is blocking the pickup in the fuel tank?
     
  17. bkd

    bkd Moderator Supreme Staff Member 2022 Sponsor

    no....wouldn't the pressure suffer if that were the case?
    Jim S.
     
  18. hudsonhawk

    hudsonhawk Well-Known Member

    Yeah, it should.
     
  19. bkd

    bkd Moderator Supreme Staff Member 2022 Sponsor

    so let me update.........I towed the 6 down to San Diego a week ago to get a axle upgrade, while there I was given the name of a guy/shop who knew the 5.0 well. I dropped the jeep off there for him to look at. He found several issues.....timimg off a bit, idle stop needed adjustment, idle air needed adjustment, one inj. coil bad, 2-3 inj partly plugged..........after all this it ran better but still idled badly :(, . The mechanic has been good through this as I've wanted to stay on top of expense. His determination is that the harness has a issue somewhere that is causing a "hole" in the computer inj. signal.


    I thought long and hard about a solution......the cost to have a new speed density harness built would be substantial (don't trust another old modded harness) and the mass air system is a huge upgrade over SD system I have sooooooooooooooo I authorized the shop to upgrade/change the componets to MA. So in the end I'll have new inj's, new harness, new MA meter etc......
    guess the Holly projection on the old motor wouldn't have been so expensive after all :rofl:R)
    Jim S.
     
  20. Patrick

    Patrick Super Moderator Staff Member

    [​IMG]




    :D

    Sorry.