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5.0 efi problem

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

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  1. bkd

    bkd Moderator Supreme Staff Member 2022 Sponsor

    so I swapped a fuel inj. 5.0 in place of the 289 in my cj6. The motor came out of a 88 Lincoln mkV11......speed density, ran great...all cylinders around 165-170. I used the old harness to begin with, couldn't get it to run right so bought a modifyed harness and computer from a outfit in San Bernadino .
    I can't get this thing to run right! It idles roughly, bumping from 800 rpm down to stalling. On the road it misses badly, especially over 2200rpm's.........I've tested the TPS, and the idle air bypass, it's timed correctly and can't find anything that even hints at a vacuum leak.........it has a rebuilt NAPA dizzy so the stator and TFI are new.......
    any ideas are welcome....I'm stumped :cry:
    Jim S.
     
    bkd, Jun 29, 2009
    #1
  2. EricM

    EricM Active Member

    Is it thowing any codes?
     
    EricM, Jun 29, 2009
    #2
  3. nickmil

    nickmil In mothballs.

    I agree with checking codes first. Also check if equipped the intake air temp sensor as they are problematic with getting coated with foreign material. If it has an air flow sensor check that as well....
     
    nickmil, Jun 29, 2009
    #3
  4. bkd

    bkd Moderator Supreme Staff Member 2022 Sponsor

    the guy who built my harness didn't include the testing connection....I asked him why and he said some map harnesses came w/ them some didn't :rofl:....not sure if that's bs or not so I didn't push on it ....yet
    Jim S.
     
    bkd, Jun 29, 2009
    #4
  5. bkd

    bkd Moderator Supreme Staff Member 2022 Sponsor

    as I understand that's the idle air bypass I mentioned....when it's running and I unplug it the motor instantly dies
    Jim S.
     
    bkd, Jun 29, 2009
    #5
  6. nickmil

    nickmil In mothballs.



    Idle air bypass is different. Idle air bypass is a computer controlled air leak past the throttle plate similar to what the idle adjustment does on a carburetor by adjusting the air gap between the throttly plate and throttle body.

    Sounds like the Idle air bypass may be carboned up which is really common as well. Pull off the throttle body and idle air bypass motor and clean the passage thoroughly. These were also very problematic back in the day as the passage would get carboned up not allowing the motor to work properly and the passage would not allow proper air flow to control the idle changes properly.

    Air flow sensor on these fords (going from memory with no manual handy) was a heated wire (assuming port fuel injection) that was cooled as air flowed past it. The air flowing past the heated wire would cool it and the computer could sense how much voltage it took to keep it at a certain temp. based on this the computer could calculate how much air was flowing into the intake. IIRC this system also had an intake air temp sensor to help compensate for ambient temperature. Again, this is going from memory with no help from a manual. hopefully Patrick will chime in and correct any mistakes here. Again, on these systems the heated wire was notorious for foreign material to get baked on and create bogus readings.
     
    nickmil, Jun 30, 2009
    #6
  7. Patrick

    Patrick Super Moderator Staff Member

    Yes.;)

    I can't really imagine owning/ running one of these without the data link connector...
    I'd be interested to see if it had any codes stored (thrown?)
    I'd also like to watch the data stream to see if the MAF, MAP,IAT, O2's, etc. are within parameters..
    Have you checked for vacuum leaks? These things like to leak at the lines at the back of the upper plenum.
     
    Patrick, Jun 30, 2009
    #7
  8. bkd

    bkd Moderator Supreme Staff Member 2022 Sponsor

    I'll check it out....thanks Nick

    I'm thinking I should pull the harness and send it back in exchange for one with the test plug. When I had the upper plenum off I checked the hoses, and I've sprayed starter fluid around the hoses to check for leaks....none that I could find.
    Jim S.
     
    bkd, Jun 30, 2009
    #8
  9. bkd

    bkd Moderator Supreme Staff Member 2022 Sponsor

    Ok.....taking the advice of Nick and Patrick I started checking all the sensors, they all seem within perimeters . I then started checking vacuum hoses. There's a hose that runs under the plenum, from the center to a branch on the side...when I grabbed it there was a change of sound ....hmmmmm. I checked it out and it seems it had collapsed shut. I removed the upper plenum, replaced the hose and fired her up.....BIG DIFFERENCE :D. I took it out for a cruise and it was doing great (slight miss here and there, figure the computer needs to learn) until I threw the serpentine belt, it had been damaged slightly so it didn't surprise me. All in all I think I've got it licked. I'd still like to get the data port wired in....we'll see after I've talked to the guy who made the harness
    Thanks you guys :beer:....Jim S.
     
    bkd, Jun 30, 2009
    #9
  10. cj6/442

    cj6/442 Sponsor

    bkd , pretty much all those lines that connect to that tree under the pelum dry rot and go bad from the heat. they might look good but if you pull on them -then you can see all the cracks.glad you might have found the problem.
     
    cj6/442, Jun 30, 2009
    #10
  11. Patrick

    Patrick Super Moderator Staff Member

    How did you check sensor data without an ALDL? Did you check every sensor with a DVOM?

    I repair vacuum leaks on those all the time.;)
     
    Patrick, Jun 30, 2009
    #11
  12. bkd

    bkd Moderator Supreme Staff Member 2022 Sponsor

    I googled the sensor, then checked as advised w/ a multi-meter...after I get the data port taken care of I'll put a code reader on it
    Jim S.
     
    bkd, Jun 30, 2009
    #12
  13. bkd

    bkd Moderator Supreme Staff Member 2022 Sponsor

    yup....shoulda repaced them to begin with :rofl:
    Jim S.
     
    bkd, Jun 30, 2009
    #13
  14. AKCJ

    AKCJ Active Member

    Sounds like you're on to the problem. I had a 5.0 in a 90 F150 similar to yours. Don't overlook the basics. Nearly every time it wouldn't run correctly the problem turned out to be something simple - nothing to do with the sensors or computer control. One of the biggest improvements was changing out the coil!

    As you found out, you can test most of the sensors but you have to use the correst test proceedure. For some of them there isn't a real good test so you almost have to change with a "known good part". I was lucky to have a buddy who worked at the local dealer and he gave me the factury EEC-IV engine control manual (fat 3 ring binder). It was full of good info about the systems and sensors.

    You might consider sending the injectors out to get the rebuilt (cleaned and balanced). Witchhunter has a good reputation for this.

    Good Luck
     
    AKCJ, Jul 1, 2009
    #14
  15. sdcj6

    sdcj6 Sponsor

    So, you happy now?
     
    sdcj6, Jul 1, 2009
    #15
  16. bkd

    bkd Moderator Supreme Staff Member 2022 Sponsor

    R) gettin there :)
    Jim S.
     
    bkd, Jul 1, 2009
    #16
  17. bkd

    bkd Moderator Supreme Staff Member 2022 Sponsor

    well took it out for a hours drive, ran fine at 2500rpm/60mph for the first 7-8 miles.......came to a stop and it was idling erratically......then missed badly the rest of the way home. I'm stumped, wondering if it's a fuel delivery issue as AKCJ suggested. Motor ran great before pulled from the donor :?
    Jim S.
     
    bkd, Jul 4, 2009
    #17
  18. cj6/442

    cj6/442 Sponsor

    jim does that a vss sensor?if that is not hooked up it can have the same symptoms,
     
    cj6/442, Jul 4, 2009
    #18
  19. bkd

    bkd Moderator Supreme Staff Member 2022 Sponsor

    unfortunately what I thought I was getting w/ this" custom" harness and what I got were two different things. The harness came w/o a data port, w/o a connection for the fuel pump relay, and w/o a hookup for the vss. I have a vss in the T18, and I have the fuel pump relay. I tried calling the company that built my harness....but they didn't return my calls last week. If I can't get help from them then I'll have to find someone else to complete the harness I guess. Pretty frustrated right now :mad:
    cj/442....if you have contact info for your harness guy can you PM it to me?
    Jim S.
     
    bkd, Jul 5, 2009
    #19
  20. cj6/442

    cj6/442 Sponsor

    that vss is a bugger only some times it will be needed. some run great with out ever hooking it up.my buddys bronco would spudder and stall with a manual trans with clutch pushed in.what was kind of cool was when we went to the junkyard the donor car (90's crown vic or some thing like that) vss bolted right up to a 68 bronco transfercase. sure jim------ I will get that # for you today.I think he's in tustin /pomona area.
     
    cj6/442, Jul 5, 2009
    #20
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