Stalling Issue, arggggggg!

Discussion in 'The Garage' started by Matt94GT, Sep 20, 2006.

  1. Matt94GT

    Matt94GT Legend Retired Staff SN95 Supporter

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    Ok well ill explain what my problem is now a bit better.

    I dropped my fuel pressure to get rid of my back firing problem, this worked, I also upped my timing to 14*. Then I adjusted my air bypass screw? (one in my 70mm bbk throttle body) to get my hanging idle slightly lower. But ever since I did that its been idling funny, and I put it back to excatlly where it was.

    Anyways this is what happens... Now keep in mind I have a H/C/I 94 5.0 so I got the slight hanging idle issue. (better then it ever has been lately though)

    Crusing down highway, see red light, shift down, get down to 1st gear then put it clutch/pop into neutral untill I come to a complete stop....Now before I stop my RPMS hang for a full second at 1k rpm then drop down perfectly to approx 700 rpm...BUT as soon as I come to a COMPLETE STOP a second later they hop up about +300rpm then drop down to about 500rpm and the car stalls. Its weird because it doesnt stall untill I come to a complete stop I could be coasting down a hill in neautral and it will sit perfect at 700 rpm but as soon as I stop it surges up slightly then drops down and stalls.

    Now why not just turn up my idle via the throttle return screw? Because I did this, I set it to about 800ish rpm but then my idle would hang for about 2 seconds at 1500rpm then drop down to like 1100rpm hang again then finally drop to 800...this is annoying as hell, I would rather rev it at a light to stop it from stalling.

    ANY IDEAS?!!?!?
     
  2. d_punch

    d_punch Active Member

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    i'm going throught the same crap and on top of that i have a charging issue.

    i haven't had any time to mess with the car for the last couple of days . so i'm hoping tonight i can get my hands on it.
    but this is what i plan on doing http://www.muscularmustangs.com/iac.php once i get this charging issue out of the way.

    just remember if you try part three where you reset base idle, you have to re-adjust TPS voltage.

    i have the same hanging idle BS when i got the heads an cam changed. so after driving awhile it was much better. i guess the computer got use to it. but my trouble started cause i've had a MAc fender well CAI sitting for a couple of years now. and i wanted to install it, but i forgot why it's not installed. when my i upgraded to a pro-m maf i couldn't use the CAI cause it was for a stock MAF thats has the plate or bracket on the front end. and the pro-m is just a tube. so i thought easy fix i'll cut the flange or bracket on the end of the CAI and just put a rubber coupler, just like all the other joints on the CAI. well none of the autoparts stores carry a 3 1/2 inch to a 3 1/2 inch coupler. thay all have 3" and under. so i put my stock air box back on and bam rough idle, jumping stalling, chareging issue falls out of the sky.
     
  3. Matt94GT

    Matt94GT Legend Retired Staff SN95 Supporter

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    Im just going to reset my throttle stop screw, and reset my computer, then play with my air bypass screw I think it should help.
     
  4. ryclef331

    ryclef331 Well-Known Member

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    TWO things....ONE check your TPS voltage. Alot of 94-95 guys will say the computer automatically resets it everytime you start the car....Bullshit (Someone prove me wrong). Now If the TPS Sensor itself is worn out, it will send a faulty signal. I was experiencing the same hanging idle you were to for a long time. It got worse eventually hangin at like 2 grand. Checked the TPS and it was reading 2.46v (Key on, Engine Off) when it should be betwenn .95-.99v. Thats one thing. New Sensor, set voltage, problem solved. Clean you Idle Air Control valve as well. How many miles are on it? It maybe time for a new one all together. If the motor on the IAC is sluggish opening and closing the port, surging idle will ensue.

    SECOND THING. Our cars have a vehicle speed sensor. This causes the rpms to "hang" for a bit between gears to try to keep the bucking down when coming off the clutch. This is what causes you car's idle to hang for that little bit. Here is what you can do to disable this. Find pin #3 on the ECU and cut that wire. This will disable the hang between shifts and while you're slowing down. I don't know the color of the wire off the top of my head and also this works for some people and not others. For some it will cause the idle to drop too suddenly and the car will clunk out. Its worth a shot. If it doesn't work, then just splice the wire back together. No harm no foul. Again...the VSS (Vehicle Speed Sensor) Wire (#3 on the ECU, gray and black). I haven't done it b/c I haven't had a major idle hang or surge problem. I don't think its the best way to go about doing so either.
     
  5. Matt94GT

    Matt94GT Legend Retired Staff SN95 Supporter

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    My TPS is .98 last summer ill check it again, gonna play with it tonight.

    TPS, IAC etc are all stock I belive, I have like 54k miles on it. I have cleaned the IAC.

    Never heard about clipping that wire, kinda scared to do that haha.
     
  6. d_punch

    d_punch Active Member

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    i just finished cleaning mi IAC like in the link that i posted. and what a difference in idle. you should try it out
     
  7. Matt94GT

    Matt94GT Legend Retired Staff SN95 Supporter

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    Well I reset my comp, took off the negative batt cable and hit the brakes a few times turned on the headlight switch. Then I fired up checked my TPS, it was a bit out so I adjusted my throttle return screw till it was at .97, then reset the comp again and it runs good now...no stalling!!!

    :D