Help me create the "Surging Idle Checklist"

Discussion in 'Fox 5.0 Mustang Tech' started by jrichker, Apr 10, 2005.

  1. Your right about the typo too many keys not enough fingers : )

    That fixed it !!!! for the first time in I don't know when this beast IDLES at about 900 rpm's Thanks!!

    set the idle screw.set the tps at .098, bored the IAC motor slightly cleaned it and it worked.
  2. i have a problem with mine since i installed a granatelli 75mm my car surges up and down cold or hot. it takes about 2 or 3 minutes to find the steady idle. i have cleaned everything now going to try stock meter next.
  3. well iput a stock meter back on and it runs great. so i guess i had two bad meters from granatelli.
  4. Did you replace the 2-wire sensor or the tube?

    Just curious which was the problem source.

    Congrats on finding the solution!!!
  5. I am 99% sure the surging idle that I had was being caused by the stator on the distributor. I replaced the dist. and have 5 hours of drive time on the car w/ no surging.
  6. Did you ever dump the codes and get a code 14 (- Ignition pickup (PIP) was erratic)? Just curious...
  7. never got the codes when My moms 94's stator went out. Whenever you run the code, it gets cleaned up somehow before it shows it. but the check engine light sure was on when the car wouldnt start.

    My car has bad grounds. Thats another one that should be added to the list. I fixed my ground from the battery to the motor mount, and VOILA no more surging, or messed up mornings when the car wont start.
  8. I'm sure this won't help very many people but I am happy that my idle was restored even though this is a pretty unique situation. When I put my engine back in my car I took it to the dyno. They said I was running really lean and turned up my fuel pressure. After many failed attempts at restoring my idle, i eventually discovered I had forgotten to reattach the ground to my O2s. After that my car was running super I checked my fuel pressure and it was at like 70psi. Anyway...turned it down to what it is supposed to be at and my car idles perfectly.
  9. Got the surge demon with my new LX.

    Got codes 41, 91 and 34, while KOEO. I replaced my O2 sensors, and got code 41, and 34 still.

    The oxygen sensor is not all the way in (I heard a lil exhaust leak) would that still trip code 41?

    The idle on a cold start is about 1k, then drops to about 700 and stays there. When the car gets to running temp is when it starts to surge. When at a stoplight it goes from about 500 - 900, sometimes even shutting off.

    I cleaned my TB, IAC, and EGR, but still surging.

    Any suggestions?
  10. Code 34 Or 334 - EGR voltage above closed limit - Failed sensor, carbon between EGR pintle valve and seat holding the valve off its seat. Remove the EGR valve and clean it with carbon remover. Prior to re-installing see if you can blow air through the flange side of the EGR by mouth. If it leaks, there is carbon stuck on the pintle valve seat, replace the EGR valve ($85-$95).

    If the blow by test passes, and you have replaced the sensor, then you have electrical ground problems. Check the resistance between the black/white wire on the MAP/BARO sensor and then the black/white wire on the EGR and the same wire on the TPS. It should be less than 1 ohm. Next check the resistance between the black/white wire and the negative battery post. It should be less than 1 ohm.

    Note that all resistance tests must be done with power off. Measuring resistance with a circuit powered on will give false readings and possibly damage the meter.

    Let’s put on our Inspector Gadget propeller head beanies and think about how this works:
    The EGR sensor is a variable resistor with ground on one leg and Vref (5 volts) on the other. Its’ resistance ranges from 4000 to 5500 Ohms measured between Vref & ground, depending on the sensor. The center connection of the variable resistor is the slider that moves in response to the amount of vacuum applied. The slider has some minimum value of resistance greater than 100 ohms so that the computer always sees a voltage present at its’ input. If the value was 0 ohms, there would be no voltage output. Then the computer would not be able to distinguish between a properly functioning sensor and one that had a broken wire or bad connection. The EGR I have in hand reads 700 Ohms between the slider (EPV) and ground (SIG RTN) at rest with no vacuum applied. The EGR valve or sensor may cause the voltage to be above closed limits due to the manufacturing tolerances that cause the EGR sensor to rest at a higher position than it should.

    This will affect idle quality by diluting the intake air charge

    Look for a vacuum leak - that would account for the idle problems and the code 41.
  11. Blow into the part that connects to the EGR spacer right?

    "if it leaks" Meaning i the air goes through that lil baloon lookin thing inside the EGR?
  12. Blow into the hole in the EGR valve that doesn't have the pintle sticking out. That will test the pintle valve's ability to properly seal and not leak.
  13. My IAC needed replacing due to a low spring tension on the plunger inside the IAC housing. It was dying on startup, then would run with a "hunting" idle, 200-300 rpm), after restarting. I bought a new IAC and it took care of the problem. The new IAC had a much stronger spring tension.

    Jim Lane
  14. thanks alot guys this checklist relly helped me alot.
  15. idle

    Thanks for making this a sticky. An interest side note. Ive tracked mine down to bad O2 sensors and have to wait till payday to get some. So I disconnected the IAC motor and when it goes into closed loop its reading rich and then jacks the timing to full advance and of course the idle goes up
  16. How are you guys getting the 10 pin connectors apart? The salt and pepper shakers. I've been trying for an hour and already snaped 2 clips off. What a pain in the ass. I took the plaque off with the Torx bits.

    Any tricks?
  17. anyone have the link that gives the directions on adjusting the idle ? I did a search and i didn't find it.
  18. See the very first post in this thread. It is in there...
  19. well i am still have idle problems again. i only seem to have a problem on start up. every time i start my car, cold or hot, it will surge from 1500 to 500 almost dying. i don't understand why it suddenly started this but can a vacuum leak cause this? it runs and idles fine after say 3 or 4 mins. tops. but it happens everytime i start it. really sucks when you stop to get gas and then you cann't leave til you your car starts to idle right.
  20. Have you worked your way through the checklist at the first post on this sticky? I revise the checklist whenever someone posts a new item that fixed their problem, so it changes periodically.