Engine swapped motor, having starting issues(wmburns?)

Discussion in 'SN95 4.6L Mustang Tech' started by paintballpyro1, Mar 2, 2013.


  1. paintballpyro1

    paintballpyro1 Active Member

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    So i recently just swapped my 96 gt motor out for an 04 with 59k. While waiting for parts i came across a 5-speed conversion with everything minus computer for $600 which i thought was a deal. Swapped out ecu's for a manual one. Fast forward swap goes ahead and it bolted into the car, it runs, it starts(kinda)

    Well first start, it cranked and cranked...and cranked then finally started. Idle was all over shut off and checked plugs found out 2 were swapped. Fixed that and it idled a lot better but had some hesitation between pushing the gas and car actually responding to it, it still has this problem slightly.

    It seems like it starts better in gear then it does in neutral. It takes at least 5 or more turns of the key till it starts running, each turn it gets better and better till it fires and then normally idles fine. Once it starts 5-10 min it still starts ok but after sitting 40min+ it starts having a hard time.

    Ive tried priming the fuel pump by cycling the key on then off a couple times and then starting but still had hard starts.

    I replaced the iac, new plug wires,new plugs(not installed yet), checked the vac lines, crankshaft sensor and im just at a loss at what it could be.

    I also got a check engine code finally. P-117, both sensors are brand new,for the temp sensor by the thermostat i tapped into the side of the block(looked on here and was suggested a few times either thats or drill and tapping which i didnt want to do)
  2. 95Vert383AOD

    95Vert383AOD Active Member

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    How are the grounds? Block to chassis, Battery to chassis. Get a volt meter and put one lead on the battery positive and start checking it against the motor.
  3. paintballpyro1

    paintballpyro1 Active Member

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    When i pulled the motor i dont remember seeing a ground cable from motor to chassis. Where should it be located?

    Also used my multimeter and was seeing about 12.8-13volts. Wasnt sure where to check but tested over alternator, thermostat housing, block and all came back at 13.

    Im assuming my fuel regulator is ok since the priming didnt help. My fuel pump is oem replacement but only 2-3yrs old and i never run the below 1/4 tank. How would i test if the ball check valve in it is dead?

    After work tmw im gonna stop and hopefully pick up fuel pressure tester. what should i be at with the key off and the key on?

    Im assuming my issue is fuel related since once its started it runs fine for the most part aside the lag/bog when pressing gas.
  4. paintballpyro1

    paintballpyro1 Active Member

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    Tried using the fuel pressure gauge. Not sure if the gauge is broke or what but hooked it up key on engine off needle didn't move, started the car needle still didn't move. Shut the car off and pressed the little fuel valve and had no pressure. Assuming bad fuel pump possibly since fuel regulator seemed to check out ok?
  5. trinity_gt

    trinity_gt Advanced Member

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    You wrote "Swapped out ecu's for a manual one."

    Can you talk a bit more about this? What year was this PCM from?
  6. paintballpyro1

    paintballpyro1 Active Member

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    Ecu was for a 96-97 4.6l.5-speed. Zxa4 was the code on the ecu.
  7. paintballpyro1

    paintballpyro1 Active Member

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    After some search when you have the key on,engine off there should be 30psi at the rail. I pressed the schrader valve down and only got a quick squirt then it just barely trickles out. Assuming then this would indicate bad fuel pump since fuel regulator tested ok?
  8. trinity_gt

    trinity_gt Advanced Member

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    Fuel pump relay or wiring fault could be the issue as well.
  9. paintballpyro1

    paintballpyro1 Active Member

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    Once the cars running its fine. Where is the fuel pump relay located?
  10. paintballpyro1

    paintballpyro1 Active Member

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    Finished the spark plugs and doing the fuel pump, still having the issue but not as bad I think. Once running if I tap the gas it bogs a little a few time then the issue goes away.
  11. paintballpyro1

    paintballpyro1 Active Member

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    drove it around the block and was not running right at all, boggin down, even tho i shifted into 2nd and 3rd rpms never dropped, was revving to 2500-3000. It felt like i was driving my busted auto not cycling gears....im at that point im losing interest of my car and thinking of just putting the car up for sale.

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