Yet another idle issue.....

Discussion in '1994 - 1995 Specific Tech' started by jdl95stang, Apr 16, 2011.


  1. jdl95stang

    jdl95stang New Member

    Joined:
    Dec 27, 2009
    Messages:
    86
    Likes Received:
    0
    Trophy Points:
    0
    Hey guys. I am having an issue that I know a million of you are having too. I have a 95 3.8L, 5-speed car. I did a 5.0 swap and it is having problems idling. :nonono: I put a Aeromotive fuel system on it and also, a MSD Pro Billet dist. This dist doesnt fit under the stock fuel rails, so I put a 3/4" spacer under the intake. I set the fuel pressure and timing to stock specs with my buddy holding the throttle just enough to keep it running(about 700rpm). The car runs awsome off idle but dies at idle. It revs up, down, back up, and dies. Air and fuel filters were replaced with minimal, if any improvement. I think I have a leak in my intake maybe where I installed the spacer. How do you correctly prove this to be the problem? If this is not the problem, Where can I find the list of instructions to fix idle issues?
    #1
  2. toyman

    toyman SN Certified Technician

    Joined:
    Jul 20, 2007
    Messages:
    1,821
    Likes Received:
    38
    Trophy Points:
    49
    The definitive test for vacuum leaks is a smoke test.
    #2
  3. jdl95stang

    jdl95stang New Member

    Joined:
    Dec 27, 2009
    Messages:
    86
    Likes Received:
    0
    Trophy Points:
    0
    Meaning that I would puff smoke around the intake gaskets by the spacer and see if it sucks it in?
    #3
  4. RIO5.0

    RIO5.0 Mustang Master

    Joined:
    Feb 17, 2001
    Messages:
    6,873
    Likes Received:
    3
    Trophy Points:
    88
    I'd think you could hear a nasty hissing if you had that bad a leak on that intake spacer.. you did a gasket top and bottom on the spacer? a vac gage reading would be helpful at this point to see if its steady or low & jumping.
    cant you run propane or something like that along where you suspect a leak and it'll pick up idle the minute it gets a hit of the propane...i know theres something you can use. starter fluid?? i forget which it is???

    Did you ever do a full idle reset on the car?? sounds like it could use that after all those changes. Does the idle improve if you disconnect the IAC plug? sometimes that'll help surging/stalling. I'd try the idle reset when its cold and go from there. To me if its surging constantly then it lost its idle strategy as a vacuum leak big enuf to make it surge constantly should make it run like its firing on 7 cylinders...you say it runs fine under power.

    I run that MSD dizzy & the stock rails...dont get the spacer for clearance??

    Idle problems blow...:(
    #4
  5. toyman

    toyman SN Certified Technician

    Joined:
    Jul 20, 2007
    Messages:
    1,821
    Likes Received:
    38
    Trophy Points:
    49
    A smoke test can be done by the better shops. They have a smoke generator that pressurizes the intake system. If there is a leak anywhere in the systems (including hidden vacuum lines) smoke from the leak will be detected. Spaying with an inflammable has its risks and won't find leaks in vacuum lines located in fenders or the dash.
    #5
  6. jdl95stang

    jdl95stang New Member

    Joined:
    Dec 27, 2009
    Messages:
    86
    Likes Received:
    0
    Trophy Points:
    0
    RIO5.0, I agree, idle issues do blow. These rails that I have are huge. Maybe there are two sizes? And yes, it runs great as long as I am on the throttle. Any throttle at all keeps it running. I can't run an idle vac test since it wont idle at all.
    toyman, I have'nt thought about that. I learned about this in school at UTI, but just breifly. I was taught how to work on cars in a dealership setting with all the diagnostic tools and such. Have to learn to do it without them now. It is a whole different ball game. Makes me feel like an idiot.

    Where can I find the complete idle reset instructions?
    #6
  7. jdl95stang

    jdl95stang New Member

    Joined:
    Dec 27, 2009
    Messages:
    86
    Likes Received:
    0
    Trophy Points:
    0
    RIO5.0, could you post a pic of how your fuel lines are run with these rails and dist? I amgoing to take mine out and redo them a different way. they are crammed in there now and they look terrible
    #7
  8. RIO5.0

    RIO5.0 Mustang Master

    Joined:
    Feb 17, 2001
    Messages:
    6,873
    Likes Received:
    3
    Trophy Points:
    88
    #8
  9. jdl95stang

    jdl95stang New Member

    Joined:
    Dec 27, 2009
    Messages:
    86
    Likes Received:
    0
    Trophy Points:
    0
    Ohh, ok. I misread your post. I thought you said that you had the same dist and rails. Makes sense now. Sorry.
    Thank you for the link. I'll take a stab at it asap and let ya'll know what happens
    #9
  10. jdl95stang

    jdl95stang New Member

    Joined:
    Dec 27, 2009
    Messages:
    86
    Likes Received:
    0
    Trophy Points:
    0
    So, if you unplug the IAC, shouldnt the car stay running? It dies and wont restart untill I replug it. Whats up with this?
    #10
  11. jdl95stang

    jdl95stang New Member

    Joined:
    Dec 27, 2009
    Messages:
    86
    Likes Received:
    0
    Trophy Points:
    0
    Is this just showing me that the idle screw needs to be adjusted?
    #11

Share This Page