Idle staying at 2,000 RPM

Discussion in 'Fox 5.0 Mustang Tech' started by savegoodautonfg, Apr 18, 2007.

  1. The fuel injector lines will line up with the injectors they go to. Tag and mark ALL the old harness connections when you remove it. Use it as a guide when you install the new harness.

  2. Thanks for all your help jritcher and everyone else. I can't wait to put the new harness in and fire the car up. i hope this was the problem. it's got to be though, it makes sense. everything points to it.

    theres the one i bought. looks like its in great shape to me. what do you guys think?
  3. Well i got the harness, it was in great shape. took about 2 hours to install with little breaks in btwn. i fired the car up and still running rich and its idling like i have a lopey cam in it. i dont understand.

    but now when i play with the wires it doesnt effect the idle like it used to with the old harness. so that's good but i still dont understand.

    TPS- .99
  4. Dump the codes, you may have other problems that either came with the replacement harness or are the result of the installation.
  5. It's just weird when i touch the wire harness now i dont get any idle change like before i did. so this harness is mostly likely fine. i also inspected it and it looks great.

    i will dump codes tonight or tommorow. i'll let you know. thanks.
  6. This might be important.

    If i set the TPS to .98 to 1 and then i try to set the idle with the idle screw at the TB, it will idle at about 700rpm and it sounds like **** and then if i try to make the idle be at like btwn 750-900rpm i can't do it wen i turn the screw it stays at the 700rpm point and then jumps to 1000-1100rpm. its really weird. any reasons for this..

    thought this might be helpful to help with my problem.

    Jritcher, i mean it seems my old harness was defiently bad, and this one doesnt have a ground issue anymore, but the idle problem is still there and i thought it would of been gone after the harness change.
  7. Setting the TPS at .98 or almost anything else will not have any positive effect on performance. The computer reads the voltage when it first powers up and sets that value as zero. Any setting between .5 and 1.0 is good enough.

    Go back to the "Surging Idle Checklist and do the base idle setting procedure.
  8. Fix the idle issue. Had same problem

    Alter many months of listening to experts and wasting tons of cash replacing TPS and idle bypass valves, ect. I found a honest mechanic in Flagstaff AZ.

    The issue was..........
    Grand pause...........

    The negative battery cable! I was slightly corroded (not visible by looking at it). The computer is obviously very touchy about it's juice.


    Hope this helps
  9. Jrithker,

    but what would make it not allow me to set it anywhere btwn 800-1000rpm