Fuel Four problems that are probably connected

Discussion in 'Fox 5.0 Mustang Tech' started by outlawjay, Dec 17, 2012.

  1. outlawjay

    outlawjay Member

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    I have a 100k mile stock GT thats been giving me trouble. I have had to DD it for a couple of months after my truck got hit by a moving truck. I feel like these problems must be intertwined...

    1) Poor gas mileage
    2) Gas smell after driving for awhile
    3) Gas cap hisses at me for an extended period when I unscrew it
    4) Impossible to fill up without the gas splashing out at me... it should trigger the nozzle to stop sooner
    5) Hard to start, takes about three times... but this may be the starter going out on me

    I don't know much about the EVAP system so that's what I'm trying to learn about currently. I had a shop in East Atlanta Village replace the sending unit and they didn't raise any concerns about the condition of the tank or connections when they had it out. These problems started before then but I wasn't driving it daily so it was easy to ignore.
     
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  2. gearheadboy

    Mod Dude

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    Check the vent hose on top passenger side of the tank. Mine was pinched between the tank and body when I bought the car. Check the hoses at the front passenger side frame rail near radiator. There is a charcoal canister there and the hoses may be plugged off . It sounds as if the tank is building pressure and not venting. The small hose at the filler neck may be pinched. Fuel smell front or rear of the car?
     
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  3. outlawjay

    outlawjay Member

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    Can't tell. It fills up the cabin, but I haven't figured out where from.
     
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  4. f8tlfiveo

    f8tlfiveo My wife likes my spool and blow-off valve.

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    +1 mine was the same way
     
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  5. jrichker

    jrichker StangNet's favorite TOOL
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    Dump the codes: Codes may be present even if the Check Engine Light (CEL) isn't on.

    Dumping the computer diagnostic codes on 86-95 Mustangs

    Revised 26-July-2011. Added need to make sure the clutch is pressed when dumping codes.

    Codes may be present even if the check engine light hasn’t come on, so be sure to check for them.

    Here's the way to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.

    Post the codes you get and I will post 86-93 model 5.0 Mustang specific code definitions and fixes. I do not have a complete listing for 94-95 model 5.0 Mustangs at this time.

    Be sure to turn off the A/C, and put the transmission in neutral when dumping the codes. On a manual transmission car, be sure to press the clutch to the floor.
    Fail to do this and you will generate a code 67 and not be able to dump the Engine Running codes.

    [​IMG]

    [​IMG]

    If your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.

    [​IMG]

    The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.

    89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.

    [​IMG]

    The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.


    WARNING!!! There is a single dark brown connector with a black/orange wire. It is the 12 volt power to the under the hood light. Do not jumper it to the computer test connector. If you do, you will damage the computer.

    What to expect:
    You should get a code 11 (two single flashes in succession). This says that the computer's internal workings are OK, and that the wiring to put the computer into diagnostic mode is good. No code 11 and you have some wiring problems. This is crucial: the same wire that provides the ground to dump the codes provides signal ground for the TPS, EGR, ACT and Map/Baro sensors. If it fails, you will have poor performance, economy and driveablity problems

    Some codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

    Dumping the Engine Running codes: The procedure is the same, you start the engine with the test jumper in place. Be sure the A/C is off, and clutch (if present) is pressed to the floor, and the transmission is in neutral. You'll get an 11, then a 4 and the engine will speed up to do the EGR test. After the engine speed decreases back to idle, it will dump the engine running codes.

    Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

    Your 86-88 5.0 won't have a working Check Engine Light, so you'll need a test light.
    See AutoZone Part Number: 25886 , $10
    [​IMG]



    Alternate methods:
    For those who are intimidated by all the wires & connections, see Actron® for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.

    Or for a nicer scanner see Equus - Digital Ford Code Reader (3145) – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.


    Code 85 is fro the Evaporative Emissions control system.

    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]
     
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