Cranks OK, but No Start Checklist for Fuel Injected Mustangs

Discussion in 'Fox 5.0 Mustang Tech' started by jrichker, May 22, 2006.


  1. Ruthann Privitera

    Ruthann Privitera New Member

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    Have you figured out your issue with the no start? I am having a heck of a time getting my 92 5.0 to run! I just posted for help with my problem, and i hope someone can help me figure it out. :( Can you read my post and see if you have any suggestions.?. thank you! Happy New Year !
     
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  2. Blown88GT

    Blown88GT Founding Member

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    5.) Fuel pressure OK, the injectors are not firing.
    A.) The PIP sensor in the distributor tells the computer when to fire the injectors. A failing PIP sensor will sometimes let the engine start if the SPOUT is removed.
    A noid light available from any auto parts store, is one way to test the injector circuit to see if the injectors are firing. The noid light plugs into the fuel injector harness in place of any easily accessible injector. Plug it in and try to start the engine: it will flash if the injector is firing.
    B.) I like to use an old injector with compressed air applied to the injector where the fuel rail would normally connect. I hook the whole thing up, apply compressed air to the injector and stick it in a paper cup of soapy water. When the engine cranks with the ignition switch on, if the injector fires, it makes bubbles. Cheap if you have the stuff laying around, and works good too.
    D.) Pull an injector wire connector off and look for 12 volts on the red wire when the ignition switch is on.
    E.) No power, then look for problems with the 10 pin connecter (salt & pepper shakers at the rear of the upper manifold).

    See the graphic for the 10 pin connector circuit layout.

    Sorry, the 10 pin salt & pepper fuel injector wiring harness connector diagram disappeared with FordFuelInjection.com's website. The lawyers ate it up... :(

    It's Back
    [​IMG]


    The injector power pin is the VPWR pin in the black 10 pin connector.
     
    #22
  3. jrichker

    jrichker StangNet's favorite TOOL SN Certified Technician Founding Member

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    Thanks for reminding me that I need to update the sticky. This is the current graphic for the 10 pin connectors.

    [​IMG]
    The injector power pin is the VPWR pin in the black 10 pin connector. [/b]
     
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  4. Blown88GT

    Blown88GT Founding Member

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    That was my intention.
    You may want to expand the checklist. You can have correct pressure & not enough flow, which is my situation. It takes an incredibly long time to pressurize my new pressure tester, even with the fuel pumps running continuously with the jumper to ground on the Test Connector, by grounding the contact where the dotted red line joins the tan/green in the pic below. This info is in my Ford Service Manual. With the KOEO, grounding the contact will run the fuel pump continuously. BTW, fuel filter is new, old one looked normal when it was replaced several months ago.
    [​IMG]
     
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  5. jrichker

    jrichker StangNet's favorite TOOL SN Certified Technician Founding Member

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    Low flow and normal pressure would suggest a restriction in the fuel path somewhere or low voltage at the pump. Or the pump could just be dying. The stock pump is 88 Liter Per Hour, or 1.47 Liter per minute. Therefore, minimum flow would be about 2 liter bottle full of fuel every 82 seconds. You might want to check my math:) Since it is a positive displacement pump moving an incompressible fluid, the volume should remain constant throughout the pump's pressure range.
     
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  6. Blown88GT

    Blown88GT Founding Member

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    My in-tank pump is a 155 lph, installed about 20 years ago, as a replacement for the stock 88 lph. It feeds an 80 gal/hr Hypertech power Pump #4018. Can easily disconnect the relay for the Hypertech.
    Your math is good. I should be filling a 2L bottle in 46 sec or less. A very rough estimate is that my flow is about 1/10 of that. I'm almost surprised it starts & idles at all. I have to assemble some hoses to attach to the rail for flow testing. It's pumping about 20 oz/min. with the 155 only, with both pumps, about 32 oz/min.
    Walbro now has 255 lph pumps which can replace both of these. If the restriction is the Hypertech, it's coming out, & the new 255 will replace the old 155. If the restriction is the old 155, the new 255 will replace it & the Hypertech can be disconnected from power or removed. Either way, the tank will have to come out.
     
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  7. Blown88GT

    Blown88GT Founding Member

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    Replaced fuel pump with Walbro 255 lph HiP. Old pump sock looked very bad. Boost pump is removed.

    Car was running 6 days ago, enough to get to the gas station. It was running rich, but making good power & idling fine. Pulling vacuum line from FPR had no effect on gauge reading 40psi, even though FPR has dedicated vacuum line & vacuum is 18-20 inHg. Removed FMU & now vacuum line connected to FPR has desired effect of reducing fuel pressure. Not sure what FMU has to do with it because it doesn't begin to close until pressure builds in vacuum line. It's all new except for the housing. Bench testing verifies it's all good.

    Take it out again 1 day ago, & engine is breaking up under load like nothing was ever done.

    Today. disassemble FPR, all looks good. Disconnect return line fitting at tank & blow out entire line with compressed air from the FPR. Then blow from disconnected hose to tank where it seemed it dislodged a blockage in the hose. If there was something in there, it's now in the tank. Reassembled FPR, connected remote Fuel Pressure Gauge to the Schrader valve & road tested. Power is good, fuel pressure is good, but now it won't idle.

    Found Schrader adapter for remote pressure gauge to be defective, too tight or too lose would not allow fuel to pass through it; modified it & now works as it should.
    http://www.actron.com/product_detail.php?pid=16173

    Bad Codes, all codes were cleared before testing today.
    29-C -Insufficient input from vehicle speed sensor. Not connected to EEC, don't care.
    66-C - MAF sensor went below 0.4 volts during the last 80 warm-up cycles.
    67-O - Neutral safety circuit failure.
    95-C - Fuel pump secondary circuit failure. The EEC senses infinite resistance to ground from the fuel pump on the Fuel Pump Monitor circuit.

    67 & 95 make no sense at all. 66 may account for the no idle condition.

    Every time I fix something, another gremlin appears.
     
    #27
  8. jrichker

    jrichker StangNet's favorite TOOL SN Certified Technician Founding Member

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    Code 29 - Vehicle Speed Sensor (VSS) is an electronic sender mounted on the speedo pickup gear on the trans. It works the cruse control for both 5 speed and auto trans cars. The VSS is used to tell the computer to speed up the idle as you slow to a stop. This helps keep the engine from stalling when you slow down for a stop sign or stop light.

    Check to see if the electrical connector is plugged into it. Clean the connector & contacts with non flammable brake parts cleaner prior to replacing the sensor, as that may fix the problem. The sensor cost is under $30 and it is easy to replace.


    Code 66 MAF below minimum test voltage.
    Insufficient or no voltage from MAF. Dirty MAF element, bad MAF, bad MAF wiring, missing power to MAF. Check for missing +12 volts on this circuit. Check the two links for a wiring diagram to help you find the red wire for computer power relay switched +12 volts. Check for 12 volts between the red and black wires on the MAF heater (usually pins A & B). while the connector is plugged into the MAF. This may require the use of a couple of safety pins to probe the MAF connector from the back side of it.

    There are three parts in a MAF: the heater, the sensor element and the amplifier. The heater heats the MAF sensor element causing the resistance to increase. The amplifier buffers the MAF output signal and has a resistor that is laser trimmed to provide an output range compatible with the computer's load tables.

    The MAF element is secured by 2 screws & has 1 wiring connector. To clean the element, remove it from the MAF housing and spray it down with electronic parts cleaner or non-inflammable brake parts cleaner (same stuff in a bigger can and cheaper too).

    Changes in RPM causes the airflow to increase or decease, changing the voltage output.. The increase of air across the MAF sensor element causes it to cool, allowing more voltage to pass and telling the computer to increase the fuel flow. A decrease in airflow causes the MAF sensor element to get warmer, decreasing the voltage and reducing the fuel flow.

    Measure the MAF output at pins C & D on the MAF connector (dark blue/orange and tan/light blue) or at pins 50 & 9 on the computer. Be sure to measure the sensor output by measuring across the pins and not between the pins and ground.

    At idle = approximately .6 volt
    20 MPH = approximately 1.10 volt
    40 MPH = approximately 1.70 volt
    60 MPH = approximately 2.10 volt

    Check the resistance of the MAF signal wiring. Pin D on the MAF and pin 50 on the computer (dark blue/orange wire) should be less than 2 ohms. Pin C on the MAF and pin 9 on the computer (tan/light blue wire) should be less than 2 ohms.

    There should be a minimum of 10K ohms between either pin C or D on the MAF wiring connector and pins A or B. Make your measurement with the MAF disconnected from the wiring harness.


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

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

    Computer,. actuator & sensor wiring
    http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

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

    Vacuum routing
    http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg



    Code 67 –
    Revised 5 Jan 2012 to add warning of possible idle surge condition due to code 67

    Cause of problem:
    clutch not depressed (5 speed) or car not in neutral or park (auto) or A/C in On position when codes where dumped. Possible neutral safety switch or wiring problem. This code may prevent you from running the Key On Engine On tests. External evidence from other sources claims that a code 67 can cause an idle surge condition. Do try to find and fix any issues with the switch and wiring if you get a code 67.

    The computer wants to make sure the A/C is off due to the added load on the engine for the engine running tests. It also checks to see that the transmission is in Neutral and the clutch depressed (T5, T56, Tremec 3550 & TKO)). This 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.

    The following is for 5 speed cars only.
    The NSS code 67 can be bypassed for testing. You will need to temporarily ground computer pin 30 to the chassis. Computer pin 30 uses a Lt blue/yellow wire. Remove the passenger side kick panel and then remove the plastic cover from the computer wiring connector. Use a safety pin to probe the connector from the rear. Jumper the safety pin to the ground near the computer.
    Be sure to remove the jumper BEFORE attempting to drive the car!!!



    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
     
    #28
  9. Blown88GT

    Blown88GT Founding Member

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    Looking at the bigger picture. all these weird codes, here today, & gone tomorrow & different ones the next day can only mean 2 things EEC or 60-pin connector. I have no faith that any of these codes have any true meaning, individually, but collectively, they point to the EEC or the connections to it. The wires will always ohm fine backshell to backshell. If you de-mate the connector, the conditioned have changed so the test is not valid
    It's a computer, therefore, Garbage In = Garbage Out. The S&P connectors have never been separated in 24 years & look new, but will tighten them up as much as possible. Will do the same for the 60-pin.
     
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  10. Ted87GT

    Ted87GT Founding Member

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    Maybe I am missing something regarding the NOID light. I have been to the local parts stores and check the usual online places. No one that I can find has any NOID lights that connect to the fuel injector harness. Do you have a place to get them or am I wrong about them plugging into the FI harness?
     
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  11. jrichker

    jrichker StangNet's favorite TOOL SN Certified Technician Founding Member

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    The noid lights plug into the individual fuel injector connectors in place of the fuel injector.

    see
     
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  12. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    jrichkter, you sure this is correct in step 1??
    Don't you mean remove the coil wire from the coil and see if it sparks using your test method??
     
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  13. jrichker

    jrichker StangNet's favorite TOOL SN Certified Technician Founding Member

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    No. Do it as directed. Remove the high voltage wire from the center of the distributor cap and leave it connected to the high voltage connector on the ignition coil and hold it 3/8” away from the engine block Then crank the engine as described above.
     
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  14. Dusty1961

    Dusty1961 Member

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    Hey Steve, wanted to say THANKS!!! for your post,You were right on the money with you post,I went ahead and replaced the 10uf,and the two 47uf caps fixed my problem(ie:"fuel pump constantly runs")

    Thank You Very Much!!!
     
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