Engine High Idle, Rough Start

Discussion in 'Fox 5.0 Mustang Tech' started by jcgafford, Aug 6, 2012.

  1. not starting as easily again. did code tests and cylinder balance test again. koeo code 89, 61 and 11. koer 11 only, cylinder test was 9.
  2. I looked in my Probst book and it doesn't have a valid reference for a code 89 for your year and model car. I haven't heard of a code 89 in a car without a computer controlled automatic transmission.
  3. got me, i pulled 89 out of it 8 times on four different test cycles. my pos haynes manual refers to 89 as "lock up solenoid"?
    after i got it running i took it for a drive, it ran great, gave it alot of throttle for the first time and maybe did a half mile total. brought it back and let it sit. all i get now is koeo code 11 five(5) times, koer code 11 two(2) times. no other codes. seems when it sits it thinks of problems to give me. when i do try to start it after sitting it acts like it is flooded, any ideas? thought it might be related to the nickel size hole i found in the mid pipe, passenger side. rechecked tps also and base idle is still around 600 - 700 (hard to put a number on it but quarter way above 500 rpm)
  4. came back from a long weekend. trouble starting. code 89 and 61 again. going to replace the canister purge solenoid and see if that is a miracle cure. i have seen that as a code on and off since i started trying to fix engine codes so i will say it is shot. still no idea on code 89 (koeo)
  5. Do you notice the torque converter going into lock up mode?
  6. no, not really sure what that would feel like. apparently there is some sort of electrical part on this tranny that can be unplugged or go bad. will research that and se whats up. but i can't figure on how the tranny would cause starting problems.
  7. The AOD auto trans in your car has no computer connection other than the NSS (Neutral Safety Switch). The NSS prevents the diagnostics from being run when the car is driven. Key On Engine Running test mode takes the throttle control away from the driver for several tests. This could prove hazardous if the computer was jumpered into test mode and then driven. In other words, the computer is completely ignorant of what the transmission is doing or what problems it may have.

    AODE in 94 and later Mustangs used the computer to manage shifting, and will set codes in the computer. The 94-95 Mustang GT used a U4P0 -computer to control the AODE auto trans.
  8. thats what i thought. never did get to look at it but parts stores have some sort of electrical "plug/valve" that they say "fits" my vehicle for the transmission. thought it may be there and causing problems. this is it:http://www.autozone.com/autozone/pa...yWord=transmission+solenoid&fromString=search

    so i will keep searching for the cause of the hard start.
  9. Part Number: TCS5
    Warranty: Limited Lifetime
    Application: A4LD Transmission model this is for the 4 cylinder Auto Transmission. The parts lookup isn't much smarter or more accurate than most of the counter help, so beware...

    Slow crank, no crank or cranks OK bit doesn't start?
  10. is there a tcc solenoid in the transmission that could be the source of code 89? i realize it should not cause starting and idling problems but it is another code i would like to not see back.
  11. Not unless you have a 4 cylinder car. There is no tcc solenoid on 5.0 Mustangs with an AOD.
  12. ok, just clutching at straws to get rid of that code. so the code 89 should just be considered as some sort of "phantom" code and ignored? just want all "11's" when i run the codes before i move on to getting it running 100% all the time.
  13. Ignoring it is the only answer besides a computer that has lost its semiconductor mind...
    jcgafford likes this.
  14. Sorry, just caught the last sentence here. Cranks and starts immediatly. Runs for a minute or two and then will just die. Starts back up but then runs terrible. Shudders and shakes and sounds awful and dies. This was the usual last week when i tried to let it run. Have not been able to play with it since. Throws no codes except that 89 (koeo) or the one for low coolant temp that goes away when it heats up. Once I restart it successfully, after the poor running restart, it runs flawlessly and will usually restart again flawlessly. Once again no codes ever except the two stated for koeo. Never any koer codes and balance test is always 9. This repeated every day upon start last week.
  15. Is this action more pronounced on a hot engine than on a cold engine?

    I would check/replace the ECT since it is a cold engine startup problem causer. Here is the code 21 test path. Use the temp to voltage and temp to resistance charts to check your current sensor readings at the computer connector to check the wiring for intermittent or poor connections.

    Code 21 – ECT sensor out of range. Broken or damaged wiring, bad ECT sensor.
    Note that that if the outside air temp is below 50 degrees F that the test for the ECT can be in error. Warm the engine up until you get good hot air from the heater and then dump the codes again.

    The ECT sensor has absolutely nothing to do with the temperature gauge. They are different animals. The ECT sensor is normally located it the passenger side front of the engine in the water feed tubes for the heater.

    The ACT & ECT have the same thermistor, so the table values are the same

    ACT & ECT test data:

    Use Pin 46 on the computer for ground for both ECT & ACT to get most accurate readings.

    Pin 7 on the computer - ECT signal in. at 176 degrees F it should be .80 volts

    Pin 25 on the computer - ACT signal in. at 50 degrees F it should be 3.5 volts. It is a good number if the ACT is mounted in the inlet airbox. If it is mounted in the lower intake manifold, the voltage readings will be lower because of the heat transfer.


    Voltages may be measured across the ECT/ACT by probing the connector from the rear. A pair of safety pins may be helpful in doing this. Use care in doing it so that you don't damage the wiring or connector.

    Here's the table :

    50 degrees F = 3.52 v
    68 degrees F = 3.02 v
    86 degrees F = 2.62 v
    104 degrees F = 2.16 v
    122 degrees F = 1.72 v
    140 degrees F = 1.35 v
    158 degrees F = 1.04 v
    176 degrees F = .80 v
    194 degrees F = .61
    212 degrees F = .47 v
    230 degrees F = .36 v
    248 degrees F = .28 v

    Ohms measures at the computer with the computer disconnected, or at the sensor with the sensor disconnected.

    50 degrees F = 58.75 K ohms
    68 degrees F = 37.30 K ohms
    86 degrees F = 27.27 K ohms
    104 degrees F = 16.15 K ohms
    122 degrees F = 10.97 K ohms
    140 degrees F = 7.60 K ohms
    158 degrees F = 5.37 K ohms
    176 degrees F = 3.84 K ohms
    194 degrees F = 2.80 K ohms
    212 degrees F = 2.07 K ohms
    230 degrees F = 1.55 K ohms
    248 degrees F = 1.18 k ohms

    Diagram courtesy of Tmoss & Stang&2birds


    See the following website for some help from Tmoss (diagram designer) & Stang&2Birds
    (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/

    Ignition switch wiring

    Fuel, alternator, A/C and ignition wiring

    Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs

    Vacuum diagram 89-93 Mustangs
  16. this is a cold start issue. once warmed up (either by a good first start up or repeated attempts) the vehicle runs fine. looking into that temp sensor now.

    when warmed up that code is not present. still car runs for a minute then either shuts off like someone turned the key off or bogs down and sounds weird running, or after just shutting off like the key has been turned off upon restart it sounds bogged down and struggles to stay running. ran codes again after it did it again today and there are none koeo or koer. was not able to probe the ect sensor yet running. (kids were ballistic today)
  17. ect checks out normal. reread the crank but wont start checklist. going to check the tfi and related equipment, all the rest has been checked. clutching at straws as it will eventually start but figured why not check everything.
  18. this video shows what my car is doing. contacted the member with the video. he said it was the distributor. does this make sense?
  19. The PIP sensor inside the distributor isn't easy to test without an oscilloscope engine analyzer. It can and will cause strange problems.

    From the Cranks OK, but No Start Checklist for Fuel Injected Mustangs - see paragraph 1 B

    B.) PIP sensor in distributor. The PIP sensor supplies the timing pulse to trigger the TFI and injectors. A failing PIP sensor will sometimes let the engine start if the SPOUT is removed. See paragraph 5A – Using a noid light on the fuel injectors will tell if the PIP is working by flashing when the engine is cranking.

  20. i know where a complete distributor with cap and everything sits. if this is the problem what should i pull from it if not the entire thing? i can grab it all friday for dirt cheap more than likely...