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Thread: Fuel pump circuit

  
  1. #1
    OVER-BOOST!! Erics SVO's Avatar
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    Fuel pump circuit

    So, I thought I was gonna be able to fire it up this week... Found some wonky hookup of the fuel pump test wire to a relay with a wire also for aftermarket fan setup which In turn had the fuel pump running all the time. Pulled the relay stuff. Now nothing from fuel pump... Relay is fine as it kicks with the test wire... From a quick look at diagrams seems like it’s not getting signal from EEC relay. Gonna dig a little more into diagrams... Guess I’ll start at ignition switch and follow out.
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    OVER-BOOST!! Erics SVO's Avatar
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    Today’s update.
    12v good all the way to the fuel pump relay coil side red wire. It’s not pulling in with the other side of coil when turning key to “on”. FP & EEC relays checked and have continuity when coil is energized. Opposite side for FP relay is the tan/green dot, which shows back to EEC. It that a ground signal? I don’t want to do a continuity/ground check and cook something...
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    OVER-BOOST!! svono50's Avatar
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    The tan/green dot goes back to pin 22 on the EEC, with the EEC being the power source to the coil side. So check for voltage on that wire when you cycle the ignition, if not, you will need to back probe the EEC connector to determine if the EEC output is coming on to prime the pump.

    The red/black hash wire leads out of the coil side through the inertia switch to ground. Check to make sure you have continuity between the FP relay connector to chassis ground. If not, it could be a popped or bad inertia switch.
    Ted
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    OVER-BOOST!! Erics SVO's Avatar
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    Everything works with the test jumper. Meaning all is good except the signal from that tan wire from #22. The test jumper is tailed in on the tan wire. From what I tested, the EEC is the ground source/pulse. The positive comes to the red one as I found with meter and the diagrams. Gonna check that wire this evening. And check some grounds period. IF it turns out to be something ECU related, has anyone had capacitors in these take a dump?? Would that be a reason for this?



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    Last edited by Erics SVO; 06-16-2020 at 02:26 PM.
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    OVER-BOOST!! svono50's Avatar
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    The EEC generally is the grounding source, where the power goes through the 'blank' (chose your device) and leads back to the EEC, which switches the circuit on/off through grounding the circuit. I don't know if anyone here has played with the EEC capacitors, but I have heard chatter on other Fox boards about caps going bad.

    Just to jog my memory, are we talking about your 85 or 85.5 here? Reason I am asking is my 86 EVTM schematic is a bit different than what you posted.
    Ted
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    OVER-BOOST!! GAboySVO's Avatar
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    Just a thought, I had an entire track day ruined by the fule pump relay connector.

    I thought I lost the fuel pump relay and none were available at the local parts store. So I packed the car up and order some relays on line. Installed the new relay and still had the same issue.

    Looked a little closer and the pins in the relay connector had pushed back out of the connector so the relay pins were not making contact in the connector.
    Mike S

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    OVER-BOOST!! Erics SVO's Avatar
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    Quote Originally Posted by svono50 View Post
    The EEC generally is the grounding source, where the power goes through the 'blank' (chose your device) and leads back to the EEC, which switches the circuit on/off through grounding the circuit. I don't know if anyone here has played with the EEC capacitors, but I have heard chatter on other Fox boards about caps going bad.

    Just to jog my memory, are we talking about your 85 or 85.5 here? Reason I am asking is my 86 EVTM schematic is a bit different than what you posted.
    Quote Originally Posted by GAboySVO View Post
    Just a thought, I had an entire track day ruined by the fule pump relay connector.

    I thought I lost the fuel pump relay and none were available at the local parts store. So I packed the car up and order some relays on line. Installed the new relay and still had the same issue.

    Looked a little closer and the pins in the relay connector had pushed back out of the connector so the relay pins were not making contact in the connector.
    Ted, This is the 85.5, I got it running this past Saturday, finally. Not sure what my original issue was. HOWEVER I do still have to use the test wire to get fuel, which realistically isn't a big deal.

    Mike, I'll take a better look at the connector, they seemed fine. And I was actually back probing at the plug.

    I'll make another post with the vid of it running here shortly.
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  8. #8
    OVER-BOOST!! Erics SVO's Avatar
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    https://drive.google.com/file/d/1Ch_...ew?usp=sharing

    https://drive.google.com/file/d/1SEJ...ew?usp=sharing

    I think I copied the links as shareable. LMK. Also, I think the valvetrain is a tad noisy? 1.1 roller cam... Maybe the HLAs need more running?
    Last edited by Erics SVO; 06-22-2020 at 03:12 PM.
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    OVER-BOOST!! GAboySVO's Avatar
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    Looking at your engine video, it looks like the PCV hose is missing. I went to look at a car once and it was making a similar noise. It turned out to be that the PVC had popped out of the lower PCV hose. Plugged it back in and the noise went away.
    Mike S

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    OVER-BOOST!! Erics SVO's Avatar
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    Quote Originally Posted by GAboySVO View Post
    Looking at your engine video, it looks like the PCV hose is missing. I went to look at a car once and it was making a similar noise. It turned out to be that the PVC had popped out of the lower PCV hose. Plugged it back in and the noise went away.
    PCV is on the lower part going to separator, just nothing on exit of it right now. And no tubing off the VC vent.
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    OVER-BOOST!! GAboySVO's Avatar
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    Yep, that explains the noise. I assume there is a cap on the nipple on the upper intake; otherwise that would be one big source for un-metered air.
    Mike S

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  12. #12
    OVER-BOOST!! Erics SVO's Avatar
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    No cap on said nipple. So it will be this noisy with out the exit of PCV being hooked up?? Wow. Guess I'll look into hooking all that stuff back up, as it wasn't there when I got the car. p.o. did all the "mods' other than cam. From what I saw of his pics the couple years he had it it was bone stock for the most part for about a year.
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  13. #13
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    Yes, it will be noisy without the PCV valve in place or you install a remote oil catch can like the Stinger setup. That is what I have. What you are hearing is the noise of the rotating assembly echoing through the crank case vent.
    Mike S

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  14. #14
    OVER-BOOST!! Erics SVO's Avatar
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    Interesting, never would have thought the sound would make it that far through the separator and PCV to be heard at the outlet of PCV. I saw someone who put a small K&N filter on top of the PCV. And they have a catch can off the VC vent.
    -Eric
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