fuel/cold start issue

Discussion in 'SN95 4.6L Mustang Tech' started by Torinalth, Dec 3, 2003.


  1. Torinalth

    Torinalth Founding Member

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    ok, some might remember that i got rearended a month ago. well... the car is almost done, they just have one last problem that they can not figure out, so they asked me.... but i wanted to see what you guys thought because i know that some of you have more knowledge then i do.

    ok.. the issue is on cold starts... when you try and turn the car over it takes 4-5 seconds to start up (it was almost instant before the wreck). when the car finally does start it bucks, idles really rough and tries to stall... when the car warms up it runs flawlessly.

    the guys hooked up a few sensors to the fuel line to see what is going on... the FMU registers one number, but the actual numbers comming through are a bit lower... take off the hose going to the FMU and the actual numbers rise to be what the FMU was showing it to be... FMU connected or disconnected it does the same thing. they said it runs really rich till it warms up, then finally leans out to 14.7:1.....

    the fuel lines are all fine, no bends or crimps in the line, fuel rail is fine, checked the plugs and most were fouled because of the mass of fuel comming in, they cleaned them off but still no change.

    they are going to replace the fuel sensor since it is registering higher then actual output. I also suggested to get rid of the pump and try a 03 cobra pump and see if the new pump can take care of the issue.... also, could it be the computer? something just off on the readings that now just needs a reflash?

    anything you can offer would be helpful.

    Torinalth
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  2. Torinalth

    Torinalth Founding Member

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    nobody has any ideas? I want my car back from the shop :( its been two months now, and i'm sick of driving a lancer rental. they called Ford as well as the SVT department and nobody can figure it out. I just want my baby back :(

    Torinalth
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  3. '96&'01Stang

    '96&'01Stang New Member

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    Try changing the pump and sensor and see if that helps
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  4. Kristian98gt

    Kristian98gt New Member

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    Have you checked the fuel pressure before the key has been turned. I had this same problem a couple of weeks ago. The correct psi before the key is turned is suppose to be around 32-45 psi. Mine was at 2 psi! My car would take about 6-8 seconds to finally turn over. Once it was started it was fine and it ran at 30 psi. When I let it sit the pressure would bleed because the pump was bad. I replaced the pump, and all is well. It was my first time really working on my car other than detailing and everyday maintenance. It took awhile but I got it in. Hope this helps. If you need some tips about the pump let me know.
    :D
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  5. Torinalth

    Torinalth Founding Member

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    just got off the phone with the shop today... apparently the insurance guys gave them a used gas tank to use..... well, te tank had a bunch of sludge in it.. fouled the pump, fuel lines, FMU, rail, and plugs... had to replace them all and now its working fine... go figure.

    thanks a bunch though for the help! it was a pump issue caused by the sludge for the 4-7 second start time.

    Torinalth
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