Engine Running Rich, Did Koeo Test

Discussion in 'Fox 5.0 Mustang Tech' started by Dustin D Gomes, Aug 24, 2013.


  1. Dustin D Gomes

    Dustin D Gomes Member

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    My engine seems to be running really rich, strong fuel smell, and smoke, way to much
    .I just did a KOEO and received the following code. I haven't have a chance to check it out yet.

    #15 o EEC (PCM) Read only memory (RAM) test Failed
    I can go ahead and ignore this as the car is chipped ?

    #85 o
    CANP ? I checked the lines and they look good
    haven't checked the electrical wiring.

    #95 o Fuel pump secondary Circuit fault
    I will check the fuel pump relay but I do not see it under the drivers seat (88 mustang)
    will also test inertia switch.
    This car was also converted to MAF by previous owner.

    Car had been running fine, no changes then all of sudden this happens. Engine specifications are as followed.



    302 30 over 10:1

    Holley systemax intake
    Holley sustem max heads
    Pro m 75 mm MAF
    BBK 70 mm TB
    24lb injectors
    BBK cold air
    Lunati 51027 cam
    not sure about fuel pump but I believe aftermarket unit was added

    The car also had no smog, and has been recently deleted of the computer with a bama tune
    No change in problem. Car also has no 02's

    Any ideas guys ?
    Last edited: Aug 24, 2013
  2. 88LX5.Oh

    88LX5.Oh Advanced Member

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    Code 15 is actually a KAM code. It's Keep Alive Memory. And yes you should be able to ignore it since it is chipped.

    No 02's? Why?
  3. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    ive found that i can erase the code 15 by reloading my tune, but that wonf cause your issue, the can-purge code can. Do you have the smog equipment still on? What about the charcoal cannister?
  4. Dustin D Gomes

    Dustin D Gomes Member

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    Thanks for the reply. As far why no 02's ? I have no idea. I got the car in a trade, swapped a chevy truck for it lol. I don't see any o2's on the BBK shorty's, or on the x pipe set up, no cats
    Last edited: Aug 24, 2013
  5. Dustin D Gomes

    Dustin D Gomes Member

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    Again thanks again for the reply. Most of the smog is removed. Thinking this might be a problem I had bama tunes icorperate that into the chip. The charcoal canister is still there, I checked the lines and it looks ok, no visible cracks.
  6. 88LX5.Oh

    88LX5.Oh Advanced Member

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    You need O2's. If you don't have them, the computer goes to a base A/F setting and it'll always run rich. But you should be getting codes for it
  7. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    ah, another Bama tune gone awry?
  8. Dustin D Gomes

    Dustin D Gomes Member

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    Well the problem started before the chip was installed. No change after the chip was installed. I bought the SCT chip from American muscle and they got the free tune, for life thing with it. I am going to try a send it back for a second time, and have them change a few things. Any other recommendations as far as who I could send this chip too, and have it burned ? There are no dynos here. I am hawaii
  9. jrichker

    jrichker StangNet's favorite TOOL SN Certified Technician Founding Member

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    No O2 sensors = big problems. Spend the money and get O2 sensors: they are a must have item.
    Be sure that you have the O2 sensor harness that matches your transmission type. You need to use a 5 Speed O2 sensor with a 5 Speed transmission and an automatic O2 sensor with an automatic transmission. Do it any other way and you risk damaging the computer.

    Warning :I am about to dump a lot of technical data on you. If you don't read and digest large amounts of technical information easily, either find someone to help or do it in little pieces at a time.


    Code 95 Key On, Engine not Running - the following test path 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.

    [​IMG]

    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 driver’s 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. If there is good voltage there & at the Pink/black wire, swap the relay.

    Some Mass Air conversions neglect to run the extra fuel pump wire, and they always have a 95 code. See http://www.stangnet.com/tech/maf/massairconversion.html for more information on the Mass Air wiring conversion.

    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/ Everyone should bookmark this site.

    Ignition switch wiring
    http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

    Fuel, alternator, A/C and ignition wiring
    http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

    Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
    http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

    Complete computer, actuator & sensor wiring diagram for 91-93 Mass Air Mustangs
    http://www.veryuseful.com/mustang/tech/engine/images/91-93_5.0_EEC_Wiring_Diagram.gif

    Vacuum diagram 89-93 Mustangs
    http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

    HVAC vacuum diagram
    http://www.veryuseful.com/mustang/tech/engine/images/Mustang_AC_heat_vacuum_controls.gif

    TFI module differences & pinout
    http://www.veryuseful.com/mustang/tech/engine/images/TFI_5.0_comparison.gif

    Fuse box layout
    http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif


    Code 85 - CANP solenoid - The Carbon Canister solenoid is inoperative or missing. Check vacuum lines for leaks and cracks. Check electrical wiring for loose connections, damaged wiring and insulation. Check solenoid valve operation by grounding the gray/yellow wire to the solenoid and blowing through it.
    The computer provides the ground for the solenoid. The red wire to the solenoid is always energized any time the ignition switch is in the run position.

    Charcoal canister plumbing - one 3/8" tube from the bottom of the upper manifold to the rubber hose. Rubber hose connects to one side of the canister solenoid valve. Other side of the solenoid valve connects to one side of the canister. The other side of the canister connects to a rubber hose that connects to a line that goes all the way back to the gas tank. There is an electrical connector coming from the passenger side injector harness near #1 injector that plugs into the canister solenoid valve. It's purpose is to vent the gas tank. The solenoid valve opens at cruse to provide some extra fuel. The canister is normally mounted on the passenger side frame rail near the smog pump pulley.

    [​IMG]

    It does not weigh but a pound or so and helps richen up the cruse mixture. It draws no HP & keeps the car from smelling like gasoline in a closed garage. So with all these good things and no bad ones, why not hook it up & use it?

    The purge valve solenoid connector is a dangling wire that is near the ECT sensor and oil filler on the passenger side rocker cover. The actual solenoid valve is down next to the carbon canister. There is about 12"-16" of wire that runs parallel to the canister vent hose that comes off the bottom side of the upper intake manifold. That hose connects one port of the solenoid valve; the other port connects to the carbon canister.

    The purge valve solenoid should be available at your local auto parts store.

    Purge valve solenoid:
    [​IMG]


    The carbon canister is normally mounted on the passenger side frame rail near the smog pump pulley.
    Carbon Canister:
    [​IMG]


    O2 Sensor harness interchange and modification

    Originally Posted by 302EFI


    Revised 16-Oct-2011 to add O2 sensor harness warnings
    The wires for the 02's and low oil did not change throughout the years, they are all in the same place.
    The main ones you need to worry about are (on the harness end (ECU) that plugs into the 02 plug) is:
    \- 1. Lightblue / yellow
    - 2. White / Purple
    - 3. Purple / Yellow
    The White/Purple & Purple/Yellow gets looped for a automatic ECU
    The Purple/Yellow & Lightblue/Yellow for a manual ECU

    See http://forums.corral.net/forums/gen...manual-auto-differences-year-differences.html for more O2 sensor wiring harness info

    Basic premise to use with transmission swaps:
    Only run a 5 speed trans O2 harness with an A9L. Do not run an Auto O2 sensor harness with an A9L. Doing so will damage the computer’s internal signal ground.
    Only run an Auto trans O2 sensor harness with an A9P in a car that has an Auto trans. Using a 5 speed trans O2 sensor harness with an Auto trans will cause no crank problems.
    See http://www.stangnet.com/mustang-forums/749974-computer-issue.html#post7490537 for Joel5.0’s fix to the computer internal signal ground.

    90 model year harness only works with 90 model cars without inspection/rework.
    The 4 cylinder O2 harness uses 4 wire O2 sensors. It probably won’t work correctly without modifying it.
  10. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    I'd call up that flyin hawaiin. Oh, thats right, he's not actually in Hawaii. :moving on
  11. Mustang5L5

    Mustang5L5 Car used in adult film "Highway Gangbang-InDaButt" SN Certified Technician Founding Member

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    I believe code 15 is a result of the chip. Removing the chip should clear the code.

    Code 95 is due to the MAF conversion. Whoever did it did not run the single wire to the fuel pump relay as mass air cars monitor this. This one you can ignore, but usually most who don't run this wire also don't run the 2 wires to the VSS as part of the conversion. As a result, you may find some issues with the car stalling when coming to a stop.


    Reinstall the o2 sensors.....period

    As for the chip...this a custom tune? If not, remove it and sell it on eBay.


    Sent from my iPhone 4S using Tapatalk
  12. stang89bidges

    stang89bidges Member

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    How exactly do I perform this procedure? Do I need to cut into the wire shielding or probe it with a safty pin? Ground to the neg battery? More details please I need to fix KOEO 85.

    EDIT: And what do I blow into? when it's grounded and ignition is ON?

    Code 85 - CANP solenoid - The Carbon Canister solenoid is inoperative or missing. Check vacuum lines for leaks and cracks. Check electrical wiring for loose connections, damaged wiring and insulation. Check solenoid valve operation by grounding the gray/yellow wire to the solenoid and blowing through it.
    The computer provides the ground for the solenoid. The red wire to the solenoid is always energized any time the ignition switch is in the run position.
    Last edited: Mar 22, 2014
  13. jrichker

    jrichker StangNet's favorite TOOL SN Certified Technician Founding Member

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    I don't know how you could blow though a wire, and the check is on the solenoid valve itself. That doesn't leave you a whole lot of things you can blow though...

    A safety pin to probe the connector from the rear is usually sufficient. Just make sure you have a good connection to bare metal on the engine or battery ground.
  14. stang89bidges

    stang89bidges Member

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    what am I looking for when its grounded and key is on?
  15. jrichker

    jrichker StangNet's favorite TOOL SN Certified Technician Founding Member

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    That you can blow through the solenoid valve and it passes air when power and ground are applied. When there is no power or no ground, it blocks airflow. Check the resistance of the solenoid using a Multimeter/DVM on low ohms range. You should see 20-100 Ohms resistance.

    The car will run if the solenoid valve is bad because it doesn't open. Stuck open, it is a problem because it's a vacuum leak. The main problem is to make sure the vacuum hoses to and from the solenoid valve are in good shape with no cracking or deterioration. Vacuum leaks are a major problem with the aging hoses that are on these cars.

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