Lift Pump Issues

[99 cummins]

Nothin in my fuel supply system is stock. Period. My fuel pick up comes off the front side by the bottom of the tank with a hose that runs into the tank to the same area that the stock pickup gets fuel from. This tube has a 4.5 inch long fine screen on the end of it. An AN/8 hose comes out of the tank and within 5 inches flows through two side by side High Pressure Pumps, both with pressure guages attached so that I can see what each is pushing. From there the line comes back together and flow through a fleetguard semi filter and then straight to the VP. On the return side I don't have a regulator valve anymore. It has a high pressure fitting in place of it that runs into an adjustable regulator set at 14psi. Have another pressure guage there so that I can monitor fuel returning to the tank.

This has been a flawless system until now. No matter what setting the Comp is on or what I'm pulling it has never budged even 1 psi until all this.

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99 Quad Cab, 4wd, Comp Box W/Pump Wire & Boost Elbow installed, K&N Air Canon, MBRP exhaust, Twin PE 4200 High Pressure Fuel Pumps W/Fleetguard inline filter, Isspro EV Pyrometer, Boost Guage, Fuel Pressure Guage, DT Pro Fab Trac Bar, South Bend 13-1.25 Con O Clutch, Royal Purple Synthetics all around

374.2/846.7 at 30psi

[99 cummins]

Originally Posted by R-N-R

I popped a fuse on the frame pump once, the truck kept running fine with the motor mounted pump but with less pressure. A couple of weeks ago I tried filling up with Super Diesel. The pump was running really slow so I bailed and finished up with regular diesel. About 5 minutes later the truck started gagging on the highway, pressure was gone. The fuse looked fine, I used the bypass and the trucks is running fine, albeit at a lower psi. The pump (carter) must have quite with the vanes blocking fuel. The first time the vanes must have been "open" when the fuse blew. My first LP to go out died slowly. Is there any chance yours is dying slowing with the vanes in different positions when the failure occurs?

Normally, this would be my first thought, but not with two pumps doing this at the same time. Both pumps also sputter at the same time, never has been just one at a time.

Thanks for all the replies.

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99 Quad Cab, 4wd, Comp Box W/Pump Wire & Boost Elbow installed, K&N Air Canon, MBRP exhaust, Twin PE 4200 High Pressure Fuel Pumps W/Fleetguard inline filter, Isspro EV Pyrometer, Boost Guage, Fuel Pressure Guage, DT Pro Fab Trac Bar, South Bend 13-1.25 Con O Clutch, Royal Purple Synthetics all around

374.2/846.7 at 30psi

[Mopar1973Man]

Originally Posted by 99 cummins

Normally, this would be my first thought, but not with two pumps doing this at the same time. Both pumps also sputter at the same time, never has been just one at a time.

Thanks for all the replies.

Sound like a power supply problem if both are sputtering... Loose wire, bad gorund connection, failing relay, corroded connection...

I'm thinking out loud in a post... There is a cause to this probem... I wish I could be there and look at it closely...:fist:

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Michael Nelson - 2002 Dodge Cummins

[99 cummins]

The power comes right off the battery through a fused link. The fuse is good. It is activated by the stock trigger wire through a dual relay system. I traded the fuel relay in the fuse box under the hood when I was having problems and it didn't change anything. The ground wire is also right off the battery connection so I am assuming that ground is good.

PS. Keep thinking out loud, I need all the ideas I can get.

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99 Quad Cab, 4wd, Comp Box W/Pump Wire & Boost Elbow installed, K&N Air Canon, MBRP exhaust, Twin PE 4200 High Pressure Fuel Pumps W/Fleetguard inline filter, Isspro EV Pyrometer, Boost Guage, Fuel Pressure Guage, DT Pro Fab Trac Bar, South Bend 13-1.25 Con O Clutch, Royal Purple Synthetics all around

374.2/846.7 at 30psi

[Mopar1973Man]

Are you using BIO diesel at all?? B-xxx I hope not...

There was a thread here where Whitmore daughter got a cummins and she got a load of BIO and in the extreme cold the BIO separated from the diesel and gelled up good.

2 cycle oil will do nothing for it... You got to use PS 911 or Kerosene... Which we all don't like to do but sometimes you got to...

The only thing I can suggest is start over and double check everything... Fuel (Type, clean, etc), Fuel lines (clean, no debris), Filters (Fresh?), Power (Good solid 12V to the pumps)... You might even test the pumps by pumping into a container (bucket)...

It's either a fuel problem or its a power problem... Not much left...

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Michael Nelson - 2002 Dodge Cummins

[99 cummins]

Bad fuel is still my guess. I was on the road delivering a horse trailer over to Indy and on my way home when it started. I make a point to fill up each time I stop for a break that way if someplace has bad fuel I don't end up with a full tank of it. Been there done that on a few trips.

I may be wrong but I am assuming that nothing is clogged because I still ran at least 60 miles with no LP's runnin. If something was clogged I shouldn't have made it home.

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99 Quad Cab, 4wd, Comp Box W/Pump Wire & Boost Elbow installed, K&N Air Canon, MBRP exhaust, Twin PE 4200 High Pressure Fuel Pumps W/Fleetguard inline filter, Isspro EV Pyrometer, Boost Guage, Fuel Pressure Guage, DT Pro Fab Trac Bar, South Bend 13-1.25 Con O Clutch, Royal Purple Synthetics all around

374.2/846.7 at 30psi

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Last edited by 99 cummins : 01-29-2007 at 10:51 PM.

[99 cummins]

OK, it's cold outside negative numbers, and after 45 miles tonight on the highway I lost pressure again. So I don't know if it's the distance or the temp but something is triggering it. Poured in about 1/2 a queart of PS and half of 2 stroke tonight, see if the PS cleans anything out. Guess the next step, when I can feel my fingers out there is to drop the tank.

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99 Quad Cab, 4wd, Comp Box W/Pump Wire & Boost Elbow installed, K&N Air Canon, MBRP exhaust, Twin PE 4200 High Pressure Fuel Pumps W/Fleetguard inline filter, Isspro EV Pyrometer, Boost Guage, Fuel Pressure Guage, DT Pro Fab Trac Bar, South Bend 13-1.25 Con O Clutch, Royal Purple Synthetics all around

374.2/846.7 at 30psi

[Oregonpharmer]

It is not a great idea to pull fuel right out of the bottom of the tank, if I read your description correctly.

All the water in diesel, and any condensate, will drop to the lowest level in the tank and if that is your inlet it will create bb's of water that will freeze and thaw and create all sorts of problems. That is why all diesel tanks use a top mounted draw tube, or a bottom tube that lifts the intake at least 1/8" off the bottom of the tank.

If you use regular PS it will not clear the water. PS911 will dissolve the ice, but you will still have water blobs. PS has a tank cleaner that will clear the water, but it will return in a year or so. Drop by a John Deere or Case-IH outlet and pick up a quart of water disbursing additive, and add that at the designated rate, then just do that a couple times a year when the weather starts cooling and you will solve your problem.

[99 cummins]

It would be easy enough to lift the pickup off the bottom if it would make a difference. Just put a spacer of some sort on the pick up line. I used the PS in the white bottle, don't remember if it's the 911, but I don't think so.

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99 Quad Cab, 4wd, Comp Box W/Pump Wire & Boost Elbow installed, K&N Air Canon, MBRP exhaust, Twin PE 4200 High Pressure Fuel Pumps W/Fleetguard inline filter, Isspro EV Pyrometer, Boost Guage, Fuel Pressure Guage, DT Pro Fab Trac Bar, South Bend 13-1.25 Con O Clutch, Royal Purple Synthetics all around

374.2/846.7 at 30psi