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Thread: Hard start cold or hot but runs good

  1. #21
    Senior Member Bitsyncmaster's Avatar
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    Quote Originally Posted by northeast dmc View Post
    Well round 2 of updates, last for today. Well did deep cleaning of tank, AGAIN, left pump out, put fuel in and checked tank was crystal clear. Drove to mgas station running as usual, shut it off put about 8 gallons of 91 ethanol free in started it and same result, limped home. Checked the voltage at the fuel pump connection and read 11.5. Went to the back and checked the jumper post and read around 14 volts. Is the voltage reading of 11.5 low enough to cause an issue? I did check the voltage earlier today to verify the positive wire just to be sure and with the car off it read 13 volts. So is pressure gauge my next move, and where do you get the adaptor for the banjo bolts to go to the gauge? If it cools off enough I will try to get a reading at the pump with it cool tonight just for curiosity. Wont get to it until end of the week with work and all. Let me know if I should order the tester, probably cant hurt I assume.

    Thanks for the help.
    11.5 volts on the fuel pump should work but if your dropping 2.5 volts somewhere you should find out where and fix it. Connectors, bad connections, RPM relay.

    Limited engine RPM could be fuel or ignition. Best to do a fuel pressure check for fuel Since it hard to test for marginal ignition.
    Dave M vin 03572
    http://dm-eng.weebly.com/

  2. #22
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    You could also be losing voltage across the inertia switch and the ground circuit. The other thing to check is the plug up inside the washer bottle bucket. Make sure you had the recall done on the inertia switch.
    David Teitelbaum

  3. #23
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    fuel issue

    Thank you for all the response, obviously things to look at. One thought as I was talking with a buddy of mine and going through the sequence of events. Is it possible for the frequency valve to be vulnerable to the heat when I shut it off? and would it cause the type of issue I am having? Like i mentioned if I get out and manually manipulate the throttle and the metering plate I can make it run fine, leading me to believe I have sufficient fuel from the pump.I dont recall in thinking back that I hear it when I go to restart after reaching the gas station. Just a shot in the dark.

  4. #24
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    I remember there's a test for the FV, jumping pins on the RPM relay socket....like the test for the fuel pump.

    Anybody here recall what it is? I remember seeing it in a post from Dave S, I think.
    Livin' the dream....

  5. #25
    Senior Member Bitsyncmaster's Avatar
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    Quote Originally Posted by Rich_NYS View Post
    I remember there's a test for the FV, jumping pins on the RPM relay socket....like the test for the fuel pump.

    Anybody here recall what it is? I remember seeing it in a post from Dave S, I think.
    You can jump the RPM relay connector to power up the FV and lambda but I just use that to remove the rest pressure before I need to pull a fuel hose.
    Dave M vin 03572
    http://dm-eng.weebly.com/

  6. #26
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    fuel issue

    Which wires are used for the FV/Lamba ? I know the ones to power the fuel pump.

  7. #27
    Administrator Ron's Avatar
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    +1 on the fuel gauge --You'll need it later anyway.

    I'm unclear about the symptoms still being intermittent or not. Assuming it currently acts up only after running a while, the coil may be breaking down. So while waiting on the gauge, I'd try a jumper from the battery (+) to the coil (+), AFTER it acts up to eliminate connections etc for that side. If no luck, maybe ohm out the coil or borrow one for a test next...
    Since you keep finding more trash in the fuel, I'd suggest you let the return line dump into a suitable container and recycle it until that is resolved. (Strain it as it goes in...) Assuming the fuel filter isn't getting clogged because the screens are doing their job, you might want to check the screen(s) in the WUR/CPR (and FD). Trash could be packing up in them, until you shut it off relieving most of the pressure... You'll be able to identify this and a lot more with the gauge set.

  8. #28
    Senior Member Bitsyncmaster's Avatar
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    Quote Originally Posted by northeast dmc View Post
    Which wires are used for the FV/Lamba ? I know the ones to power the fuel pump.
    You jumper the large brown wire to the double yellow/red wires and that turns on the FV and lambda ECU. No need to turn on the key. You will hear the FV buzz. It takes about 60 seconds to dump a full rest pressure back to the return line. You will hear the FV buzz change tone when pressure goes to zero.
    Dave M vin 03572
    http://dm-eng.weebly.com/

  9. #29
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    Quote Originally Posted by Ron View Post
    ~snip~ Assuming the fuel filter isn't getting clogged because the screens are doing their job, you might want to check the screen(s) in the WUR/CPR (and FD). Trash could be packing up in them, until you shut it off relieving most of the pressure... You'll be able to identify this and a lot more with the gauge set.
    I like the looks of this assessment....it smells to me like one of Ron's infamous obscure tips that fixes a problem!
    Livin' the dream....

  10. #30
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    fuel issue

    Quote Originally Posted by Ron View Post
    +1 on the fuel gauge --You'll need it later anyway.

    I'm unclear about the symptoms still being intermittent or not. Assuming it currently acts up only after running a while, the coil may be breaking down. So while waiting on the gauge, I'd try a jumper from the battery (+) to the coil (+), AFTER it acts up to eliminate connections etc for that side. If no luck, maybe ohm out the coil or borrow one for a test next...
    Since you keep finding more trash in the fuel, I'd suggest you let the return line dump into a suitable container and recycle it until that is resolved. (Strain it as it goes in...) Assuming the fuel filter isn't getting clogged because the screens are doing their job, you might want to check the screen(s) in the WUR/CPR (and FD). Trash could be packing up in them, until you shut it off relieving most of the pressure... You'll be able to identify this and a lot more with the gauge set.
    I recleaned the fuel tank on Sunday and with a suggestion of using the camera to see I did find and clean the deep corner and verified the rest was clean. I am going to order the tester. I have also changed the main fuel filter several times through out this struggle just to be sure nothing getting in the heart of the system. The issue arrise after say 10-15 minute drive. Everytime I shut it off, it restarts and idles fine, its when I try to accelerate that I have the issue. Even after the last cleaning of the tank, I drove to the gas station feeling pretty good, only to have it happen again. If I get out and manipulate the metering plate and the throttle manually it will run fine at any rpm as long as I have the two timed so to speak. It would almost seem like a vacuum leak, but I would think it would be there right from the start, or if it somehow was heat related it would have shown up when I just drove around for 20 minutes. This is what has me thinking the frequency valve not working when I restart it hot and not letting the fuel go back to the tank like it should creating excess pressure in the fuel distributer. Just me stuck on that thought. But the running issue has happened every time I drive and shut it off. But being some what new to this adventure I am all ears and grateful for all the information.

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