Fuel Pump in the tank

[jelag]

My 04 had the factory fuel pump die twice..... once under warranty and once out... on the second failure we put the fuel pump in the tank service kit in...



We now have no start condition and we don't see any fuel when we cycle the pump based on the service manual procedure to crank it for 20 sec and the pump should run for 25 seconds after the cranking stops...



We now are draining the tank..... wouldn't you know that its full... . but the dealer has this module on the shelf and he's open tomorrow... .



We intend to test the circuit when we get the tank down... and look for 12 V to the pump during the cranking mode test... ... My question is there any protection for this circuit, fuse, circuit breaker that we need to look for when the tank is on the ground if there is no voltage to the pump during the test...



As soon as the tank is down... we'll test the wiring and power to the pump... BTW there is no fuel in the filter..... I can't believe that the sock is plugged... as most of the fuel this truck uses from a in bed tank thats pumped into the main tank... and that goes through a nice big filter... ...



Any thoughs would be invited... ...

 

[rbattelle]

I'd advise against cranking the engine for 20 seconds, you can burn out the starter. To get the fuel pump to run for 30 seconds, just bump the starter and it will run.



The fuel pump is fed directly from the ECM, so there is no fuse. There's a good chance it simply crapped out on you.



Ryan

 

[jelag]

Ryan



Thanks for the input..... Understand that I'm repeating what the service manual says... . It suggests a 20 second crank... . I thought it was long also... . but that's whats written...



The tank is now empty and on the ground... I'll test it later today... . I've got to be heading in the right direction... . when we pulled the lid on the fuel filter the canister was almost empty.....



Jim

 

[rbattelle]

I'm very interested to see what you find.



Ryan

 

[rjohnson916]

I'm very interested to see what you find.



Ryan

Ditto, as my dealer says he's never seen an in-tank fuel pump fail yet?

-Ryan

 

[jelag]

OK, here is the what we have found... .



When you make the change to the in tank pump the kit comes with a wiring harness that runs from the front of the truck... . to the rear... . and connects to the old pump wiring and the old wiring harness for the gauge..... these two sets become a 4 lead connection at the tank... the 2 outside connections are the pump and the 2 inside connections are the gauge... .



We had to pull the tank down to test it because we couldn't get a volt meter up to the connection at the tank... and we wanted to see how much dirt was in the tank.....



Some water, not more than an oz or 2... . it was dirty so it had some dirt in it... .



But we had no power at the tank to run the pump... ... we pulled the assembly and bench tested it... it has both good ohm value and ran well.....



I than went to the front of the truck where the wiring harness ties into the connection where the old lift pump was... ... and at that connection we had a good 12 signal...



To my surprise... I found a relay in the line between the engine compartment and harness going to the back of the truck..... in DC infinite wisdom they had decided to power the new pump with a relay and fuse... . with the feed line to the relay connecting to the positive term of the battery... . on the drivers side and they used a body ground close to the hood hinge... ... testing these connections with a volt meter found no voltage to the fuse... . the fuse to the battery connection is no more than 5 or 6" of wiring... .



What I found was the wire broken at the solderless connector... being held in place by the shrink tubing... . and they had used shrink tubing that has the melt in place glue... so as you heat the tubing it melts the glue and makes water tite connection... . as I pulled on the shrink tube and solderless connector they came apart in my hand... I'm guessing vibration caused the wire to shake, and break off..... thus there was no power to supply the relay or the pump in the tank..... I cut back the connection installed a new connector and once we got the whole thing back together with a new filter it started right back up... .



I hope this makes sense to most of you... .



Jim

 

[desertbull]

Thanks for posting this info... definitely a problem in 04-06 that I'm aware of... I lost the lift pump once and they put the new pump in the tank like on the new trucks--all good until---the Baja 1000 prerun.



This truck is a dually towing the big 26' foot flatbed dual axle heavy trailer made for Mexico Hwy 1 travel while racing---the truck lost the CP3 injector pump between Loreto & La Paz--got towed on a strap towing the trailer by another race team in a F**D towing a 30' trailer loaded with a Trophy Truck prerunner---we were 100+ feet going down the road--Comical.



Had to hire a semi-flatbed tractor trailer to haul the entire truck/trailer back to TJ and then we towed it across the border and got it to my Action Turbo at Tom Geviss shop and by the time we got home on the plane ATS Diesel - Mike Meineke had already shipped a new CP3 to the shop and we were rolling the next day---



Moral of the story---when I lost the first lift pump, most likely damaged the CP3 and just happened to take a crap while prerunning for the Baja 1000... bummer stuff...



Get a fuel pressure gauge and watch it...

 

[rbattelle]

Jim, please don't tell me you did the shoddy shrink tube wiring the first time!



Ryan

 

[MMeier]

OK, here is the what we have found... .



When you make the change to the in tank pump the kit comes with a wiring harness that runs from the front of the truck... . to the rear... . and connects to the old pump wiring and the old wiring harness for the gauge..... these two sets become a 4 lead connection at the tank... the 2 outside connections are the pump and the 2 inside connections are the gauge... .



We had to pull the tank down to test it because we couldn't get a volt meter up to the connection at the tank... and we wanted to see how much dirt was in the tank.....



Some water, not more than an oz or 2... . it was dirty so it had some dirt in it... .



But we had no power at the tank to run the pump... ... we pulled the assembly and bench tested it... it has both good ohm value and ran well.....



I than went to the front of the truck where the wiring harness ties into the connection where the old lift pump was... ... and at that connection we had a good 12 signal...



To my surprise... I found a relay in the line between the engine compartment and harness going to the back of the truck..... in DC infinite wisdom they had decided to power the new pump with a relay and fuse... . with the feed line to the relay connecting to the positive term of the battery... . on the drivers side and they used a body ground close to the hood hinge... ... testing these connections with a volt meter found no voltage to the fuse... . the fuse to the battery connection is no more than 5 or 6" of wiring... .



What I found was the wire broken at the solderless connector... being held in place by the shrink tubing... . and they had used shrink tubing that has the melt in place glue... so as you heat the tubing it melts the glue and makes water tite connection... . as I pulled on the shrink tube and solderless connector they came apart in my hand... I'm guessing vibration caused the wire to shake, and break off..... thus there was no power to supply the relay or the pump in the tank..... I cut back the connection installed a new connector and once we got the whole thing back together with a new filter it started right back up... .



I hope this makes sense to most of you... .



Jim

Hmmmm... makes me wonder if THAT wasn't my problem a few weeks back, wonder how many other trucks may have been diagnosd incorrectly if I'm reading this right.

 

[jelag]

The shoddy wiring was a Chrysler wiring loom that came with the lift pump kit to replace the engine mounted pump with the in tank unit..... I wrote down the part number and called the dealer... . he couldn't find it in the computer... . and told me that his best guess was that it was only available in the change over kit.....



Any other questions...



Jim

 

[MMeier]

O. K. , guess I'd better check the job they did on mine then when they switched it over.