2000 Mustang GT CCRM/Fuel Pump issue

Discussion in 'SN95 4.6L Mustang Tech' started by mndtrp, Sep 2, 2010.

  1. Pulled the tank down, although it didn't seem necessary to take it all the way out. The only two things I could see that looked sketchy were, in the first picture, where the wires went over the top of the fuel pump, and right after that where the foam padding is cracked. Where it's cracked, it looks like there's an indention for the wires to lay, but the wires were going over a small hump. As near as I could tell, that's where the cables were prior to the tank coming down, but they may have shifted as the tank started to drop. We cut the sheath to see if the cables were crushed, but they appeared fine.

    We didn't see any other signs of rubbing, chafing, cuts or crushing. We tested the resistance through the C463 connector, but got no different readings than before, but we weren't sure where to put the lead for checking to the gas tank itself. The tank is coated, and the we weren't positive if the screws at the top by the fuel pump were what you were wanting the test from. We reconnected the fuel pump and did a couple quick cranks, the fuse didn't blow. Wiggling the connectors and wiring didn't seem to make any difference with our readings.

    We'll leave the tank down for a bit, as we have some other errands to run. Hopefully, you'll have a chance to read this, and will advise on whether or not you think the issue was simply the wiring being compressed between the tank and auto.

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  2. What I noticed RIGHT WAY is that the wire colors DO NOT match the factory wire colors. This tells me that the wires were spliced INSIDE the harness.

    There is a ground SHEILD inside the harness. The key to the problem is finding where the pump power supply lines have grounded to the shield. Since the wiring has obviously been altered, the shield does not extend beyond the end of the harness. Therefore there isn't an easy way to test to determine if the ground fault is still present.

    Pull the insulation back where the red and blue wires enter the harness. That is where you will find the problem. My bet is the new pump wires were spliced at that location and the individual wires were not covered with heat shrink insulation. When the factory harness was tapped over the splice, the ground sheild made contact.

    Again, we did not expect the resistance of the PUMP to change. What we are looking for is to remove the path to GROUND in the pump power supply lines. With the tank dropped, the path to ground is gone which makes sense the fuses is not blowing.

    Getting closer.
    #42 wmburns, Oct 9, 2010
    Last edited: Oct 20, 2015
  3. We put the tank back in, hooked everything up, made sure that the wiring did not go over any upraised areas, and the car fired up fine. We let it run for a bit, no issues. Unlike the previous times the car would start, pressing hard on the accelerator did not cause a drop in RPMs. We put in a couple gallons of fresh gas, and drove it around the neighborhood. No problems, the car ran as it did prior to parking it for several months.

    We did pull back the cable wrap that connects to the fuel pump. We saw no issues with the wiring, but didn't see any place where there was splicing. We did not pull back the second portion of wrapping, which in third picture has the light blue and white wires entering the wrapping. Therefore, we did not follow the wires back to a splice point.

    Do you recommend I drop the tank again, and continue the wiring back to the splice point? Is it possible that the wires were pressed too tight, and caused an issue without any visual damage to the cladding?
  4. Went back and looked at the C463 diagram. Note that pin #5 BK/OR is listed as a ground. Since pin 5 is right next to the faulted pin #6, is it possible the fault is in the connector itself? Perhaps from being pulled or twisted?

    To me, without finding a "smoking gun" it is somewhat "dissatisfying". And this also opens up the possibility that the fault could simply decide to return on it's own (vibration). Regardless of exactly where the problem is/was, there is evidence of it SOMEWHERE. If crush damage, the insulation had to been compromised in some way.

    I also understand that you are trying to "sell" the car. So that does change the thought process somewhat. On the other hand, I would not want to be the person that is the receiver of such a difficult electrical issue.

    However, the issue is only truely hard when you do not "know" where to look.

    So......how did it feel when you drove it around the block? You have fixed a problem that a professional mechanic was unable to fix. That has to be worth something.

    For anyone else reading this thread, this shows the benefit of testing before replacing parts. Likely the FPDM and the CCRM were good all along. Of course, the extra testing involves more time. And everyone has to weigh the cost of the part verses the value of your time. The answer is different for everyone.
  5. I had also hoped to find something more obvious.

    On the possible plus side, I am selling it to my father, if he still wants the vehicle. In the off chance it comes back, I do know where to start looking and what to look for.

    Ughh, it reminded me why I bought the car in the first place, it's such a fun vehicle. Since it had been so long since I had driven it, it was like having a completely new car all over again. For a minute, I almost thought about keeping it, until I reminded myself just how little it has been driven over the past few years, not even counting the mechanical downtime.

    But, it was a nice feeling to have it running. While, as you pointed out, there wasn't anything definitive, the thing is now running as it should. I learned quite a bit, and got over some more of my trepidation with regards to working on vehicles. I've never felt comfortable doing things other than the simple brakes and whatnot, but coming at this like a project made it a bit easier. Having someone TELL me what to do, instead of just DOING IT for me, which is usually what seems to happen when someone helps in person, also helped reinforce the situation. Changing my frame of mind from a problem to a puzzle also made all the difference, somewhat surprisingly, really.

    Anyway, I greatly appreciate the help you've provided, as well as the other two that popped in with suggestions. It hadn't occurred to me that someone would spend this much time and effort over the internet to assist. Learn something new every day.

    Thank you very much.
  6. FWIIW, I am not above accepting small "tokens" of Paypal "appreciation". :D

    I maintain a small library of service manuals and Alldatadiy.com annual subscriptions that are actually the source of intelligence behind the curtain.

    All kidding aside, in many respects, this is what the hobby is all about. Pushing ourselves to tackle bigger projects and expand our skill set. For my own part, I am more willing to invest time when the OP is actually performing the tests and doing the work.

    I have to honestly say, there were a couple of times I thought about pulling the plug for lack of detailed responses. In the end, everything worked itself out.
  7. Great info
  8. Actually, I was concerned that this would happen prior to starting the thread. With me not knowing the full spectrum of work performed, symptoms witnessed, and lack of general knowledge on my part, the info was definitely going to be lacking. I'm glad you stuck with it.
  9. Well, the car isn't completely fixed. My father came up to get the car yesterday, so we went to fill up the tank. We noticed that there was fuel leaking out of the tank area. We got the car home, and started looking at things. The fuel would leak with the car running, as well as off.

    I've read several threads, as well as the posts in this very thread, that said the common cause is the grommet for the filler pipe. Even before dropping the tank, I could see the fuel was not coming from that area. Full disclosure: when my friend and I dropped the tank a month ago, we did not fully drop the tank. There was sufficient clearance for the cabling inspection with only dropping one side of the tank, the side opposite the filler pipe. We never did pull the filler pipe out, therefore never swapped the grommet.

    Like I said, though, there is no fuel leakage from the filler pipe area. The fuel leak is coming from the top of the tank, spilling over the front edge, and then dripping through the plastic protection piece before dripping to the ground.

    We drained the tank again, and once we pulled it down, we couldn't find any fuel lines that had been disconnected or were loose. By the time we got the tank down, the fuel had evaporated, so we couldn't pinpoint where it was coming from. We did find that the fuel pump itself wasn't tightened down all the way, so we tightened that back up. Hoping that was the cause, we put everything back together, and drove to the station to fill up the tank again. Again, there was leakage, although it did seem to be a bit less.

    This time, though, the car ran fine to the station, but had issues on the way back. When pressing the throttle, the RPMs would dip considerably, and the car would almost die. I was able to nurse it back to the house, where we drained about 1/4 of the tank to stop the leaking. Our current thought is the gasket for the fuel pump is bad, so I went to the parts store for one of those. There were none for the actual vehicle, but the parts store guy gave me a roll of rubber and verbal instructions on how to make a gasket. My neighbor also gave me a tube of Ultra Flange II, some sort of silicone-y sealer he said would work. We'll be getting started on the gasket this afternoon.

    My main reason for this post: is there a correlation between the leaking fuel and the poor RPMs. The first time the car leaked from the gas station, there was no performance problems to or from the station. The second time, the performance was only an issue on the return trip. When the car only had a few gallons of gas, the car ran with no issues whatsoever.

    Thanks in advance.
  10. A couple of points here. Raw fuel and fuel vapors are very hard on rubber parts. Likely dropping the tank weaken the filler pipe to grommet seal. Since the report also indicates there is fuel leaking from the fuel pump hat. To me this means the tank has been overfilled. If so, likely there has been raw fuel has been drawn into the EVAP vapor recovery system. This means that the charcoal canister has been contaminated with raw gas.

    The charcoal canister works only with vapors. Raw fuel will turn the charcoal into jelly which blocks the flow of vapor. This ruins the canister.

    IMO, a plausible explanation for the poor running is the excessive raw fuel and vapor in the charcoal canister being drawn into the engine during an EVAP purge.

    What to do? The only way to fix this correctly is to fully drop the tank. Be sure to fully cut out the old grommet before removing the filler neck. If this is not do, damage to the filler check valve WILL result.

    Reseal the fuel pump hat. Buy a NEW grommet from Ford ($20). Lube with petroleum jelly before re-inserting the filler neck.

    I'm afraid that a new charcoal canister (about $80) should be considered. The charcoal canister is part of the EVAP and venting system. If blocked, expect various problems such as DTC codes and other issues related to fuel venting and vapor recovery.
  11. We looked all around the filler neck, and couldn't see any evidence of fuel leakage, while we could see it all around the fuel pump top. With the tank half dropped, we fired up the car to make sure the fuel wasn't coming from any of the fuel lines, just to make sure. We then pulled the top off of the fuel pump, and the gasket wasn't sitting properly. We put the gasket into its proper place, and then used the stuff my neighbor gave me to make a better seal. After letting that set up, we left the tank partially down, and filled the tank back up, no leakage. We pulled the lines off of the charcoal canister, and they were completely dry on the inside. Put everything back together, and the car ran fine with no leakage.

    Since it was mentioned previously, I checked the wires from the fuel pump, due to the change from factory coloring. The wires go from the top of the fuel pump, all the way to the C463 connector, no splices. When we pulled the top off of the fuel pump, however, we found the red and black wires were pinched between the top of the fuel pump and the fuel tank. They were pinched pretty good, but the cladding didn't seem to have been compromised. With power to the fuel pump, we wiggled the wires a bit, but the fuel pump never shut off. Therefore, we didn't end up doing anything with those wires, other than moving them out of the way when tightening the pump into place. I took pictures, and sent them with my father in case something should happen again.

    Ultimately, this whole mess seems to have come from a simple fuel pump replacement. My father got the car home last night, which was about 4 hours away. He has all the information on what was done here, as well as the filler pipe grommet we never used, in case he has to do more work on it himself. I also sent along the instructions given above, so that he has more info, if needed.

    Thank you again, for the quick response.
  12. Smoking gun alert!

    It seems like we finally KNOW for sure what caused the original problem (wires trapped between the hat and the tank).
  13. Helpful information, stayed up reading this last night as I have the a delivery problem also.

    Thanks to Both of you guys for staying with it. I was going to drop the tank and do the pump until I ran across this thread.

    2000 GT 60,000 miles, my weekend car so to speak although it has been a couple of months - with starter fluid all is well.

    What I am looking for is the plug to the fuel pump I can unplug and check the function of the pump directly with 12 volt supply.

    Is this the plug and which end goes to the fuel pump? Looking at the plug is it the left side with the pins (male) or the right (female) side?


  14. This is the correct plug to directly power the fuel pump. The female side goes to the fuel pump/tank.
  15. Glad I asked I was headed with the Male side thinking power will always be on the female plug.
  16. Finally had a chance to check this out, lots of sparks, charger meter reading about 13 amps and I did not hear the pump run or it's real quiet. I will read over this thread again but it looks like a fuel pump.

    Okay, I see the other guys was pulling 7 amps with a working pump, mine showing 13-14 amps is pulling too much.
  17. Does it matter if I go with a Motorcraft pump over a Ford OEM branded pump?
  18. Anyone?
  19. I failed to loosen the fuel neck and with a full tank of gas I broke the end piece off the fuel neck that extends inside the tank.

    The special tool removed the fuel line from the filter but not from the fuel pump, it took several hands and dental type tools to bend the tabs back so the fuel line would release from the fuel pump. Being that it was hard to remove and the rubber inside the lines are 11 years old I replaced the fuel line between the pump and fuel filter.

    With a new fuel line, filler neck and fuel pump it cranked up without hesitation.

    Thanks for your help.

  20. Probably the same as Motorcraft is Ford owned - which one did you go with? Did anyone measure voltage to ground on the pump inertia switch I should only see 12V on one side correct?