Dead on the side of the road. Out of town. Please help.

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Heath
Posts: 231
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Car: 1992 Q45, 2000 Excursion (towrig), 2003 Yukon Denali (Wife's Ride)

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Driving on the freeway, going 70ish. Car dies. I can't hear the fuel pump fire at all.

I went and picked up a new fuel pump, put it in and still I can't hear the fuel pump come on at all. It cranks great, but still no catch.

New Fuel Pump
New Filter

Any other ideas that I can check here in the parking lot? I'm out of town and need help ASAP please.

Thanks,

Heath


marcyprojects
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sounds like your fuel pump control unit is out. Look up info here on how to jump connections on the unit to feed direct power to the pump. Do that and you should be on your way.

3Q Jay
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Heath wrote:Driving on the freeway, going 70ish. Car dies. I can't hear the fuel pump fire at all.

I went and picked up a new fuel pump, put it in and still I can't hear the fuel pump come on at all. It cranks great, but still no catch.

New Fuel Pump
New Filter

Any other ideas that I can check here in the parking lot? I'm out of town and need help ASAP please.

Thanks,

Heath

Heath- PM sent.
Jay

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Q451990
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I assume you're up and running again, but here's the picture of the pin that you'd ground to bypass the controller.

Image

Heath
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Oh I only wish I had found out about jumping the pin before I towed the car 100+ miles to my friends house! I'm waiting for another FPCM to arrive from Jay now. It should be here Saturday and then I'll go down and put it in the car.

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Q451990
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Heath wrote:Oh I only wish I had found out about jumping the pin before I towed the car 100+ miles to my friends house! I'm waiting for another FPCM to arrive from Jay now. It should be here Saturday and then I'll go down and put it in the car.
:picard: I'm sorry I didn't see it sooner. :couch

Heath
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Thats okay man, at least I know for next time! Hopefully that won't be for another 100K miles though. :D She just turned 184K :D

marcyprojects
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Dang man that really sux about the towing. I thought when I posted up you'd be able to search for that pic on your phone or something. I know that tow must have hit your pockets hard, especially now you gotta find a new control unit. I had something similar happen to me on my first Q, I got stuck like 45 minutes away from home and no knowledge about cars at all. Fancy shop that I got towed to told me they could only get the control unit from the dealer. The control unit, relay, and pump cost me $900 to fix. Had no choice since I was supposed to be moving to FL that weekend.

Heath
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Car: 1992 Q45, 2000 Excursion (towrig), 2003 Yukon Denali (Wife's Ride)

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Okay so I see the pics of the Alligator clip in there for the jumper, but aren't you supposed to plug it back in somehow? I mean what are the other pins for?

Are you supposed to just have that alligator clip in there with a wire going somewhere to a ground like a bolt in the trunk or something? Not plugged back in? I guess I'm confused on exactly how this is jumped.

My car is currently about 1.5 hours from my home still. Is it safe to jump that and drive it that far/long or should I just leave it where it is until the part arrives in a few more days? Its safe where it is at my friends house, not in the way or anything, but would be nice to not have to use the gas to go back for it AGAIN once the part comes in...

marcyprojects
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yes do exactly that. Run that jumper to the body of the car. there should be a spot there in the rear deck you can un bolt something and make wire contact to the body. heck u could even tape it down to the right spot if you had to.

Heath
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So if this does it and she fires am i good to drive her that way for a few days until my new part comes in?

3Q Jay
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Heath wrote:So if this does it and she fires am i good to drive her that way for a few days until my new part comes in?
??? your rebuilt part arrived today, yes?

but to answer your question-- the jumper wire is the same as running your fuel pump on the highest of the 3 speeds of the fpcu controller all the time. think of it as completing the circuit with battery on the high side of the fuel pump and the low side is open (pump wont turn) until you put in the ground wire, or connect a functioning fpcu. The speeds of the fpcu is essentially a 'fan switch' in the return path, but it auto selects the switch speed based on engine load.
you'll see that the rebuilt fpcu has a monster size ground wire soldered in (it's white, but color doesn't really matter). it's the ground path in the factory fpcu's that opens up and then the pump won't turn since current wont flow.

but, yes, you could drive on high speed all the time, might add extra pressure on pump, filter, hoses, pressure regulator. but it might actually be a good thing for a short while.....still a temporary fix, though.

Heath
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Car: 1992 Q45, 2000 Excursion (towrig), 2003 Yukon Denali (Wife's Ride)

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Yeah, new part is here. I'll get it in tomorrow.

I posted that question yesterday. I went ahead and drove it home and it ran fine. However I'm looking forward to getting the new part in and putting my car back together!!!

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thrill
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That is a tough one. Just happened to me on the 23rd of November. Don't throw away that FPCM. If you open it up you can resolder the pin that enters the board from the wire harness male connecter. Good luck getting it back on the road.

Heath
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Yeah, I'm back up and running now. I'm going to send my old FPCM to 3Q Jay so he can rebuild it for the next guy that needs one... I have to admit I wouldn't mind picking up another to have for a spare though... :D

3Q Jay
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Heath wrote:Yeah, I'm back up and running now. I'm going to send my old FPCM to 3Q Jay so he can rebuild it for the next guy that needs one... I have to admit I wouldn't mind picking up another to have for a spare though... :D
Heath- No worries if you want to keep your core--or, if you want me to rebuild your core and send it back to you let me know.
Jay

Alex L
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Car: 1992 Infiniti Q45

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So I'm having the same problems with the FPCU in my 1992 Q45, After disassembling the unit, I can see some light burn marks on the pin in question, but there is still continuity from that pin to the printed circuit path on the board. I don't see any other burn marks anywhere on the board and I can't find any spare FPCU's in any wrecking yards here in Salt Lake City. Any suggestions? Does anyone have a schematic of the board in the FPCU?

Heath
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The irony, I was in SLC when this happened to me!

I have my old one that I need to send back to 3Q Jay so he can fix it for the next guy.

If you just need to move your car you can do the jumper trick (this will also tell you for sure if its your FPCU).

Alex L
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So I ended up soldering a jumper from the pin on the connector to another point on that printed circuit path on the circuit board, even though it still showed continuity anyway, and now the FPCU works fine. Just in case though, I installed a semi-permanent jumper to ground via a "hidden" switch under the rear trunk deck. This way, should it happen again, I shouldn't need to tear the trunk or back seat apart to access the FPCU connector...just flip the switch and off I go again (in theory anyway).

Heath
Posts: 231
Joined: Wed Oct 15, 2003 11:29 am
Car: 1992 Q45, 2000 Excursion (towrig), 2003 Yukon Denali (Wife's Ride)

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Alex L wrote:So I ended up soldering a jumper from the pin on the connector to another point on that printed circuit path on the circuit board, even though it still showed continuity anyway, and now the FPCU works fine. Just in case though, I installed a semi-permanent jumper to ground via a "hidden" switch under the rear trunk deck. This way, should it happen again, I shouldn't need to tear the trunk or back seat apart to access the FPCU connector...just flip the switch and off I go again (in theory anyway).
Nice... Not a bad idea on the switch either.


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