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Fuel Pump Power Issues.....

Posted by femmeDSM, Nov 30, 2005

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  1. femmeDSM

    femmeDSM Proven Member

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    I am having a hell of a time trying to get my stupid fuel pump to power on.

    I bought the car with a botched re-wire and a bad fuel pump that was keeping the car from starting. I pulled all the old wires and re-did the fuel pump rewire correctly, and replaced the fuel pump with a Walbro 190 -- still won't turn on or prime w/ the key in ON.

    The ONLY way I can get the pump to turn on is to take the 12v power wire running from the battery and touch it to the wire going to the Fuel Pump.

    A list of things that I have checked/replaced so far:

    - New Fuel Pump

    - Re-Wire (double, triple, and quadruple checked -- everything is hooked up perfectly)

    - Fuel Pump will NOT turn on using the check connector in the engine compartment.

    - Tested voltage to MPI Relay, per FSM instructions. Tested out fine.

    - ECU is new

    - I can hear the MPI Relay click ON while cranking, and OFF a couple seconds after I try to start.

    - I have good spark, and good compression, engine will turn over but will not start.

    - When I revert the wiring to the stock setup (i.e. eliminate the 12v power wire from the battery, etc.) I get the same results.

    - Tested voltage on the black/white power wire from pin 3 on the MPI relay -- anywhere from 9.5v to 12v (however, it was dark and cold when I did this, so I am planning on re-testing this tonight in case I got a bad ground).


    I am at a loss here -- Is my only option now to trace that black/white power wire all the way from the MPI to where it connects at the FP rewire relay? Honestly, if that's my best option, I would almost rather just hook my FP up to a switch in the cabin. If all else fails, that would (SHOULD) work, right?

    I am at that point where I have tested so much crap that my brain is starting to hurt.

    I hope I am just overlooking something stupid, here........

    Rep points will be given for ANY and ALL input!

    Thanks much.
     
  2. BOBS90TURBO

    BOBS90TURBO Proven Member

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    A short term fix that should be enough power is to just run a power wire from the ignition space in the fuse panel under the dash, it will kick on and off with the ignition.

    Just wrap the end of the wire around a fuse and plug it back in or crimp a male speaker wire plug and plug it in an empty space. I would do that before a dash switch.
     

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  3. oldman

    oldman DSM Wiseman

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    Unlike 2Gs, 1G pumps will not turn on until you start cranking. With that said, you should still be able to turn the pump on using the check connector so I would say there are still some wiring issues.

    BTW you never did mention whether or not you can start the car in your post. Are you having problem starting the car or are you just trying to power up the pump by turning the key to the on position? Have you actually try and start the car yet?
     
  4. femmeDSM

    femmeDSM Proven Member

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    I am understanding your logic here, I think....I hadn't thought of that, actually......

    According to Chrysler FSM, fuses 2 and 8 are Ignition fuses that are not used for anything...So are you just saying to just try running a wire to one of those, or was there a specific fuse (that is being currently used by something in the Ignition circuit) you were referring to?


    Or maybe I am misunderstanding something. I do appreciate the help! :)
     
  5. femmeDSM

    femmeDSM Proven Member

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    Thanks for the reply :)

    In every 1g I have owned/worked on, I have always been able to put my ear up to the top of the filler neck with the key in ON and hear the pump priming....In my post, I didn't mean for it to sound as if I thought the pump should actually turn on with the key to ON -- sorry if I was unclear about that.

    With that said, though, the pump will not do anything at all with the key in ON or while cranking, so I suppose that is neither here nor there ;)

    In response to your question -- no, the car will not start.

     
  6. dsmotorsports

    dsmotorsports Probationary Member

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    A correct way of doing this is to use a hot wire relay system to the pump, here is how this is done.

    Run a wire back from the battery, as if you were putting in a stereo amplifier with a 15 amp fuse inline. Then take a 30 amp relay for fog lamps etc and put on the pump. Hook the hot wire up to the imput on the relay, run you a wire from ignition two, this is the ignition position where the heater motor etc. comes on, the fuse panel is set up on hot, ignition 1 and ignition 2, connect to a fuse that is powered up by ignition two, or connect to the harness going off of the igntion switch in the steering column, then run that wire back to the switched position on the relay, there will be a ground position on some relay's and you will have to connect it to the ground of the car, not only will this work correctly, but it will give you a quite bit more lph's than the pump is supposed to supply because the battery supply's about 13.5 volts when the wire off of the fuel pump relay under the radio only puts out about 1.8-12.4 volts...let me know if i confused you.
     
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  7. oldman

    oldman DSM Wiseman

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    No problem, I only did it for the rep point. :p Electrical isn't my thing so I will go away now. :)
     
  8. femmeDSM

    femmeDSM Proven Member

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    Haha, like you need anymore rep points!
    ;)

    You get one anyway, LOL.
     
  9. cb3016

    cb3016 Proven Member

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    check all of the fuses with a volt meter check the amp's and make sure they match the fuse, also make sure the fuses ARE the correct amps not that they match what they say they are....meaning who ever had the car before may have but in a 15 where a 20 should have been, electrical is about all i'm good for =P :dsm:
     
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  10. femmeDSM

    femmeDSM Proven Member

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    Wow! I think I am getting what you're saying, but let me run this by you, in case I am missing some largely important part of your post ;)

    Basically, you are saying to take my re-wired pump (that is already on a 30A relay) and, instead of running one of the wires to pin 2 on the MPI Relay as it is now, run it to the #2 fuse (or another Ign2 Fuse) in the fuse panel under the steering wheel area.

    In fact, I will provide a little ghetto diagram illustrating this as I understand it....Hopefully this is right. haha.
     

    Attached Files:

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  11. femmeDSM

    femmeDSM Proven Member

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    Thanks :) One of the things I forgot to mention in my original post is that I replaced ALL (*yes, every single one*) of the fuses, both the mini fuses in the dash panel and the larger fusible links in the engine compartment.

    I will double check those tonight, though, in case I accidentally mis-placed one. I didn't think to check voltage on them. I suppose I could have replaced a good fuse with a "bad" one......Stranger things have happened.
    :thumb:
     
  12. BOBS90TURBO

    BOBS90TURBO Proven Member

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    Hey, fuses are not going to be your problem, you must have a short somewhere, and yes, if you run a big power cable off the batt, like to a car amp, the pump will have more juice, but like I said earlier, either one of the empty ignition fuse slots will work just fine, they will supply more than enough power to run your pump, just run one wire from the fuse panel , to the fuel pump wiring and then just splice the wire where needed, this is a quick easy fix that will supply plenty of power.
     

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  13. Old Mitsu Tech

    Old Mitsu Tech DSM Wiseman

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    - Fuel Pump will NOT turn on using the check connector in the engine compartment.

    - Tested voltage to MPI Relay, per FSM instructions. Tested out fine.

    - ECU is new

    - I can hear the MPI Relay click ON while cranking, and OFF a couple seconds after I try to start.

    - I have good spark, and good compression, engine will turn over but will not start.


    I wish I had my schematic here. It's at work. I agree with oldman. You have a wiring problem if the pump relay is sending power and the pump is not getting it. That is backed up by the check connector not helping either. I'm at a loss as to where. Here's what you can do. Apply fused 12 volts to the check connector. Go back to the fuel pump and check for voltage. You probably won't have any. Using your schematic, start moving forward. At some point you will suddenly have voltage. It's at this point you probably will see what is wrong. Just be careful to use a fuse or 5 amp relay as a safety device. Wouldn't want to see how good your local fire department is would you? LOL

    Personally, I have a signal tracer. It's safer and faster. Somewhat expensive, but it works for us old people.

    When using your schematic, pay particular attention to connectors, and changing wire colors.

    Good Luck
     
  14. femmeDSM

    femmeDSM Proven Member

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    I knew you would show up eventually ;) To the rescue, as usual, LOL.
    :thumb:

    OK, just to clarify, you are talking about following the black/white wire from the fuel pump relay (back of the car) to where it plugs into the MPI Relay / Pin 3, correct? By looking at where it goes from the FP relay, it appears that it runs along the side of the car, probably under the driver's side door panel, behind the steering column area, and to the MPI Relay......(?)

    I re-tested voltage tonight on that wire, both at the MPI Relay end and the fuel pump end, and both ends are consistently getting 9.5x volts (while cranking), instead of the 12.x volts that I would expect to see.

    It would appear from these tests that the 9.5v that is being supplied to that wire is simply not enough voltage to power the pump. Is this logic correct? How much voltage does the pump actually need to power on? I always assumed that it was 12v, but you know what they say about assumptions. ;)

    Also, is it theoretically possible that the MPI Relay itself is not receiving 12v? I know that I hear it click ON and OFF when I should, but does it require a full 12v to click on? Am I even making sense? Haha...

    Thanks again for the help......*sigh*
     
  15. steve

    steve DSM Wiseman

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    Claire, I suspect that the battery voltage is dropping to 9.5v when your cranking, not just to the fuel pump. You might want to charge the battery before the next round of diagnostics.

    If you see voltage at the pump connector when cranking and when you put 12v at the check connector then the wiring should be good at least that far, leaving the last foot to the pump and the ground questionable. That may require pulling the pump again to check the rest.

    Steve
     

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  16. femmeDSM

    femmeDSM Proven Member

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    Thanks, Steve :) Battery voltage is 12.x volts while not cranking, and drops to about 11.x volts while cranking, per my tests a few days ago. I will give it a charge -- it definitely could have drained in that time, with all the electrical work and cranking we've been doing. Now that you mention it, it did seem to turn over a bit slower than usual during the last round of tests.

    As for that last foot of wiring, I assume that you are referring to the last bit of stock wiring left that is coming from the top of the FP bracket, and hooked into the re-wire relay, etc. Am I correct? If this was bad, wouldn't we NOT be able to get the pump to turn on at all, even when applying 12v to it directly? As it is, if I take the hot wire from the battery off of the relay, and touch it to the wire coming directly from the FP (that last foot of stock wire), the FP will turn on...But that's the only way it will turn on, hence my decision to run the FP to a dash switch if all else fails......

    My logic could be completely off-base here, though. Please correct me if I am being embarassingly stupid! LOL. It seems that simple logic doesn't ALWAYS work in one's favor when diagnosing these cars' problems ;)

    ----------
    BTW, not sure if I mentioned this or not, but as soon as I put the new ECU in that you sent, I got spark. So thanks for your help in that dept. too :thumb:
     
  17. steve

    steve DSM Wiseman

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    Right.

    If the pump runs when you take the new wire from the battery and connect it to the Fuel Pump wire that checks the last few feet. It proves that the wire to the pump and the ground are good. Does the car start when you do this?

    You said you do see voltage on the old pump wire that goes to the relay when cranking but that it was 9.5v during the last test. What pin on the new relay to you have it connected to?
    It would be good to know exactly how you have the relay wired, do you have a picture?

    Steve
     

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  18. femmeDSM

    femmeDSM Proven Member

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    No, it does not. Much to my dismay..... :confused:

    I do not have a picture at the moment, but I will illustrate how I have the relay set up. If you still need to see a picture, I can get one.

    Power Wire from Battery - 10 gauge wire - Pin 30
    Fuel Pump Wire - 12 gauge wire - Pin 87
    MPI Relay Wire - 14 gauge wire - Pin 86
    Ground Wire - 14 gauge wire - Pin 85


    I also gave my battery a good charge as you suggested. The voltage now reads 12.x volts not cranking, and 11.6x volts cranking. I should mention that the battery is brand new.

    The power going to the Fuel Pump wire now reads 11.2x - 11.5 volts while cranking.

    When I hook the hot wire directly to the FP wire, as stated earlier to make the Fuel Pump come on manually, I should also mention that the FP appears to stay on while cranking. At first I was afraid that the voltage drop was turning the Fuel Pump off as soon as I started cranking, but I was able to hear the "whine" while standing over the hatch as a friend cranked the car.

    I am at a loss, and am about ready to tow her to a mechanic, as I am reaching my wit's end. :barf:

    Anything left for me to check? Could a fuel line be clogged? Injectors? Ugh. :confused:
     
  19. steve

    steve DSM Wiseman

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    You can check the relay function by connecting pin 30 to pin 86. The relay should click and battery voltage should show up at 87. Sometimes the relays have diodes in them on one of the coil terminals. If yours doesn't activate when you apply 12v to pin 86, make sure you have a good ground on 85 (the other side of the coil) and try reversing the two, grounding 86 and putting the MPI relay wire on 85. Based on what you've told us so far the problem seems to be at the relay and once you can make it work the pump should.


    I forget how much other troubleshooting has been done to the engine and the other sensors. Double check or remind us on the status of the basics, compression, spark and fuel.

    Do you have a datalogger? One thing that often keeps the engine from starting is the Engine Coolant Sensor. A datalogger can tell you if the sensors are working and reporting reasonable values. it will also allow you to test the solenoids and fuel pump MPI relay.

    A little starting fluid in the intake might be an interesting test even with the pump not functioning.

    These things are always frustrating, you've done a lot of good stuff so far so don't let it get you down.

    Steve
     

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  20. femmeDSM

    femmeDSM Proven Member

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    My hat's off to you, Steve. You have certainly earned your "wiseman" status here. :thumb:

    I will check the relay tomorrow per your instructions and report back.


    The car is getting spark on all 4 cyl. I am a bit concerned about the plug wire on the #3 cyl, as I noticed spark trying to arc through the boot once, so the wires will have to be replaced, but it appears strong enough to start the car.

    Compression is 138-138-138-148, approx.

    As for fuel, tomorrow's plan of action includes pulling the fuel line from the filter to the rail while cranking to see if any fuel is actually making it that far, then working back/forward as necessary. I was previously more intent on solving the issue of power getting to the pump as a first step, but as it stands now, I have realized that I will need a better understanding of exactly what is going on throughout the fuel system in its entirety, so plans have changed slightly.

    After lots of cranking, pulling a plug indicates no fuel or fuel smell on the plug or anywhere in the cyl. that I can detect.

    EDIT: One thing that I figured I would mention, just in case:
    While cranking, the stock boost gauge goes absolutely crazy, jumping from 0 to 7, back to 0, then up a bit past 7 for the duration of cranking. Having not had a non-starting DSM in quite some time, I am unsure whether this is a normal occurence that I just overlooked in previous cars, or if it might indicate something fishy.



    I do not have a datalogger yet, but was planning on purchasing one in the next week or so. I will definitely proceed with that now. In the meantime, I will see if I can't borrow one for temporary testing purposes.

    You know, I was actually thinking about that earlier today. I am not sure if this is a viable test for DSMs, but in my old Volvo 740T, I actually put a cap full of fuel directly into each cylinder and cranked it over. Would that not be advisable in a 4g63? Or would the starter fluid in the intake approach accomplish exactly the same thing?


    I bet you thought you would be rid of me once my ECU dilemma was solved -- alas, here you are again, helping me solve all of my DSM problems! LOL.

    Your tireless efforts are much appreciated, for sure :D
     
  21. steve

    steve DSM Wiseman

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    Not great numbers but the engines cold, they are above min spec.

    I haven't noticed the boost gauge jumping around during cranking, I have to think about what it might be telling us. Does this car also have a real vacuum/boost guage?

    I assume you have a laptop with a serial port or older Palm sitting around somewhere.
    A passive datalogger cable is trivial, the big expense is the DB9 connector, the wire and on nice cables the connector for the diag port.. Inside there is only a diode and resistor. Let me know which computer hardware you might have and I can throw a cable in the mail. You'll need a hotsync cable or cradle for the Palm. The logging software for either platform can be downloaded for free.

    Putting gas in the cylinders should have the same effect as putting some starting fluid in the intake but may foul the plugs too. It's a bit easier to pull the PCV or brake booster line and give it a shot of starting fluid than pulling all the plugs.

    Steve
     

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  22. femmeDSM

    femmeDSM Proven Member

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    It does, and appears to be hooked up correctly (amazingly, making it one of the only WORKING electrical features that came with the car! ;) )...

    I do not have a Palm, but I do have a laptop (Sony Vaio, running WinXP Home) that travels everywhere with me. It has both the 9 pin and the 25 pin serial ports.
    I remember reading that the datalogging software was open source, but wasn't sure where to get it.

    I greatly appreciate the offer -- if you have a spare cable that would fit my setup, I could definitely use it. You are the best. Let me know what I owe you :)

    Great, I will do that and report back. I have a sneaking suspicion that the car just might try to start with the starter fluid......

    Thanks again. :)
     
  23. steve

    steve DSM Wiseman

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    I suspect it has a 9 pin serial port and a 25 pin parallel port. I haven't seen a laptop with a 25 pin serial in over a decade.

    I don't know if the TMO datalogger software will work on XP but it should.

    I'll make you up a cable for a PC this weekend.

    Steve
     

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  24. Sharkcus

    Sharkcus Proven Member

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    Just wanted to chime in and correct this to make sure nobody is confused. Every 2G i have worked on does NOT turn the pump on until you start cranking. Thats all.
     
  25. steve

    steve DSM Wiseman

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    Thank you for clearing that up. Not owning a 2G I couldn't say for sure and can only go based on what I've read. The 2G tech manual talks about the 420A PCM turning the pump on when you first turn the ignition on but is silent about the 4G63. I read people claiming the 2G 4G63 ECU doing the same thing but questioned if that was true.

    It really should take longer than a fraction of a second for the fuel system to come up to pressure, so it shouldn't need to be primed.

    Steve
     

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