car backfiring and running like crap please help!

Discussion in 'Fox 5.0 Mustang Tech' started by catman4115, Aug 15, 2006.


  1. catman4115

    catman4115 New Member

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    I just replaced my deffective granatelli mass air meter/sensor with a unit from c&l. The car runs a little better put it is idles low then will jump up and idle low again. It is also not responsive on the throttle at all, it is very hard to drive at low speeds and will jerk and just run like crap plus it backfires wuite a bit. I pulled the codes and this is what I got, 81, 82, 95 and 33. Thanks again
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  2. shewitt

    shewitt New Member

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    I had the same thing happen to me before i got a wideband and found out i was running to lean. Car would buck at low speeds and backfire when i would let off the pedel.
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  3. stang347notch

    stang347notch New Member

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    My car does that going slow through driveways no backfiring though
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  4. jeffbigwood27

    jeffbigwood27 New Member

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    Check timining and exhaust leaks.
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  5. vristang

    vristang Advanced Member

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    You just have some work left to do, it's not related to the MAF.

    33 - EGR valve opening not detected

    81- Secondary Air Injection Diverter AM2 solenoid circuit failure

    82 - Secondary Air Injection Diverter AM1 solenoid circuit failure

    95 - Fuel Pump Secondary Circuit Failure

    These are the code translations, but I am not sure how to trouble shoot them.
    Do a search for the code number and "JRichker" and you should find some good info. That dude is sharp.

    I would focus on the 95 code first, as this is likely to cause some erratic fuel control issues.

    good luck
    jason
    #5
  6. jrichker

    jrichker StangNet's favorite TOOL SN Certified Technician Founding Member

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    Code 33 - Insufficient EGR flow detected.
    Look for vacuum leaks, cracked vacuum lines, failed EGR vacuum regulator. Check to see if you have 10” of vacuum at the EGR vacuum connection coming from the intake manifold. Look for electrical signal at the vacuum regulator solenoid valves located on the rear of the passenger side wheel well. Using a test light across the electrical connector, it should flicker as the electrical signal flickers. Remember that the computer does not source any power, but provides the ground necessary to complete the circuit. That means one side of the circuit will always be hot, and the other side will go to ground or below 1 volt as the computer switches on that circuit.
    Check for resistance between the brown/lt green wire on the EGR sensor and pin 27 on the computer: you should have less than 1 ohm.

    See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host)

    http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

    http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif


    EGR test procedure courtesy of cjones

    to check the EGR valve:
    bring the engine to normal temp.
    connect a vacuum pump to the EGR Valve
    apply 5in vacuum to the valve.
    if engine stumbled or died then EGR Valve and passage(there is a passageway through the heads and intake) are good.
    if engine did NOT stumble or die then either the EGR Valve is bad and/or the passage is blocked.
    if engine stumbled, connect vacuum gauge to the hose coming off of the EGR Valve
    snap throttle to 2500 RPM (remember snap the throttle don't hold it there).
    did the vacuum gauge show about 5in vacuum?

    if not, check for manifold vacuum at the EGR vacuum valve.
    if you have manifold vacuum then connect vacuum gauge to the EGR valve side of the vacuum valve and snap throttle to 2500 RPM.
    should read about 5in vacuum

    The operation of the EGR vacuum regulator can be checked by using a test light applied across the wiring connector. Jumper the computer into self test mode and turn the key on but do not start the engine. You will hear all the actuators (including the EVR vacuum regulator) cycle. Watch for the light to flicker: that means the computer has signaled the EGR vacuum regulator successfully.

    Code 81 – Secondary Air Injection Diverter Solenoid failure AM2. The solenoid valve located on the back side of the passenger side wheel well is not functional. Possible bad wiring, bad connections, missing or defective solenoid valve. Check the solenoid valve for +12 volts at the Red wire and look for the Lt Green/Black wire to switch from +12 volts to 1 volt or less. The computer controls the valve by providing a ground path on the LT Green/Black wire for the solenoid valve.

    With the with the ignition on, look for 12 volts on the red wire on the solenoid connector. No 12 volts and you have wiring problems.

    With the engine running, stick a safety pin in the LT Green/Black wire for the solenoid valve & ground it. That should turn the solenoid on and cause air to flow out the port that goes to the pipe connected to the cats. If it doesn't, the valve is bad. If it does cause the airflow to switch, the computer or wiring going to the computer is not signaling the solenoid valve to open.

    Code 82 – Secondary Air Injection Diverter Solenoid failure AM1. Possible bad wiring, bad connections, missing or defective solenoid valve. Check the solenoid valve for +12 volts at the Red wire and look for the Red/White wire to switch from +12 volts to 1 volt or less. The computer controls the valve by providing a ground path on the Red/White wire for the solenoid valve

    With the engine running, stick a safety pin in the Red/White wire for the solenoid valve & ground it. That should turn the solenoid on and cause air to flow out the port that goes to the pipe connected to the heads. If it doesn't, the valve is bad. If it does cause the airflow to switch, the computer or wiring going to the computer is not signaling the solenoid valve to open.

    Code 95 - The following is for 86-90 model Mustangs. The 95 code is because at one time or another the fuel pump relay hiccupped and didn't provide power the pump when the computer told it to run. Sometimes this is a one time thing, other times it is a no run or runs poorly condition.

    To help troubleshoot the 95 code, follow this link for a wiring diagram http://www.autozone.com/images/cds/gif/large/0900823d80167162.gif

    Using the diagram, check the red/black wire from the fuel pump relay: you should see 12 volts or so. If not, check the inertia switch: on a hatch it is on the drivers side by the taillight. Look for a black rubber plug that pops out: if you don't find it, then loosen up the plastic trim. Check for voltage on both sides of the switch. If there is voltage on both sides, then check the Pink/black wire on the fuel pump relay: it is the power feed to the fuel pump. No voltage there, check the Orange/lt blue wire, it is the power feed to the fuel pump relay & has a fuse link in it. Good voltage there & at the Pink/black wire, swap the relay.
    #6
  7. MARX91

    MARX91 New Member

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