Engine/Transmission (1998.5 - 2002) 2002 Dodge Ram - Fuel Pressure

[Deactivated (requested sold truck)]

I have a 2002 Dodge Ram 2500 with 24value Cummins HO. In 2006 at 127,000 miles I had the lift pump upgrade done at the dealership (lift pump moved to into tank). I just installed a fuel pressure gauge on the truck. What is the normal psi I should see?

 

[Cosmo]

You should see 18-20 at idle, no less than 14psi under load. Under 10psi and you're doing damage.

 

[Bob4x4]

there is no official pressure spec only a flow measurement... ... ..... everything else you read will be average numbers seen

 

[JLandry]

You should see 18-20 at idle, no less than 14psi under load. Under 10psi and you're doing damage.

This is incorrect information.



Read THIS ARTICLE on the Blue Chip Diesl website for some good information on lift pump pressures.



John L.

 

[cerberusiam]

The in-tank pump should give you 7-10 psi at an idle and no lower than 5 psi WOT, all things being equal.

 

[Cosmo]

This is incorrect information.

Read THIS ARTICLE on the Blue Chip Diesl website for some good information on lift pump pressures.

John L.

Nothing on that link says anything contrary to what I said.

What they said is 5psi provides enough lubrication for the lift pump at maximum power, however 15psi provides enough return fuel to the tank to cool the pump/electronics. At 5psi, you're not getting the return fuel and you're not getting the cooling.

Please don't tell people they'll be fine with 5psi, as they're going to cook their injection pump and electronics. The numbers I stated are extremely conservative SAFE numbers.

Blue Chip goes on to say that the best solution (in their eyes) is for a factory location (block mount) pump that flows at least 15 psi. I don't agree. They say that it's up and away from road salt (versus a frame mount) and they say that the in-tank pump is the worst. I don't agree with that either. They suggest that heat on the electronics is what kills their lift pumps, then turn around and suggest putting the lift pump back in the hottest place possible. The OE lift pump failed because it was a poor design and the heat and vibration of being block mounted kills them. In tank pumps have the best cooling. They're up in New Hampshire, so I guess road salt is an issue for them, and the trade-off may be worth it. The rest of the country, not in the salt belt or NE, doesn't really have to worry as much about salt corrosion, and getting the electronics off the engine works great.

So go ahead, run 5psi on your truck and see how long it lasts. I've seen a lot of conflicting information - at one point it was said that Dodge doesn't provide a pressure spec, only volume over time. It's hard to measure volume while you're driving down the road, so keeping an eye on pressure is a good way to stay safe.

In doing more searching, someone posted info from the factory service manual stating 10psi minimum while running and 7psi while cranking. Of course, there is always planned obsolescence to think about - if they can spec 10psi and make it last until just after warranty then they gain customer pay work.

Either way, it's a far cry above 5psi.

 

[JR]

I agree with you 100 percent, Cosmo. It only makes sense to maintain enough pressure to keep the return on the vp opened up all the time for maximum cooling effect. I personally keep my lift pump regulated at about 20 psi at idle, rarely will it drop below 17 psi when driving down the road with the engine under load. Ive never experienced any hard start issues that some claim you will have when running higher pressures.

 

[cerberusiam]

Doesn't make any difference what the pressure should be, thats not what the OP wanted to know. He doesn't have an aftermarket pump to adjust pressure with. He has an in-tank pump and wanted to know what pressure he should see with it.

 

[JR]

You are correct and you answered that question earlier.

What Cosmo was simply offering (and I agreed) was that the low fuel pressures offered by the factory set ups have been sub par at best. Dodge failed not once but twice at supplying a reliable lp for the vp trucks.

 

[Deactivated (requested sold truck)]

I ordered an Air Dog II (100 gph) system to put on the truck. That system should deliver 15 to 17 psi and it has 2 micron filtration. I will have to drop the fuel tank and remove the in-tank lift pump, but I think it will worth it. That way if in the future the lift pump fails, it a will be easy to get to. Also, since I am already on my second VP-44 and second lift pump, I am just not happy with the minimum fuel flow to the injector pump.

Thanks to all for your information! That's what I love about this forum, if I have the problem some else has too. :-laf

 

[Deactivated (requested sold truck)]

I ordered an Air Dog II (100 gph) system to put on the truck. That system should deliver 15 to 17 psi and it has 2 micron filtration. I will have to drop the fuel tank and remove the in-tank lift pump, but I think it will worth it. That way if in the future the lift pump fails, it a will be easy to get to. Also, since I am already on my second VP-44 and second lift pump, I am just not happy with the minimum fuel flow to the injector pump.

Thanks to all for your information! That's what I love about this forum, if I have the problem some else has too.

 

[PSpychalski]

Had the intank mod done at local dealer. Had 9 psi... wot went to zero when I was pulling my trailer (11,000#). That didn't last long as I installed FASS DDRP on the frame rail just forward of the tank. now I have 19 PSI and 13 wot.

 

[Deactivated (requested sold truck)]

That's the kind of numbers I'm seeing now. I get about 8-10 at idle and it drops to 2 at WOT. I have a 10,000 lb 5th wheel, but I haven't pulled it since the psi is so low. I'm sure it would drop to 0 psi if I was pulling it. I just do not want to harm the VP-44. That's a costly mistake and I do want to repeat it. I think the AirDog II correct the problem and provided great flow to the VP-44. Thanks for the insight!

 

[Raynedog]

I just installed an Air Dog Raptor 100GPH on my Dodge 99 5.9 1 ton. I bought the truck new in 98. I had 2000 miles on it and the
injector pump went out. Then replaced it again at 150k. Both with factory lift pumps. Now the truck has 190k and was stalling after start up. Loosing prime. I installed a gauge and it read 5psi at idle an 0 running. Truck lacked power. After Air Dog installed, pressure at idle is 20 and 15 at run.
Instant start. increased power. Runs strong. Made all the difference in the world. My pump is mounted on the engine and was very easy to install. $420 total with pump and gauge. Well worth it. I wish I had done it sooner.

 

[petersonj]

I also have 2002 Dodge Ram 2500 24 valve HO. It currently has 202,000 miles on it. I am the original owner. Everything is stock on the truck with the exception of an exhaust brake. My first VP44 pump failure symptoms showed up at 64,000 miles (with poor performance and codes set) and continued to worsen until I replaced the VP44 and lift pump under warranty at 87,000 miles. And, like yours, my replacement lift pump was installed inside the fuel tank

During the time before pump replacements I had hooked up a fuel gauge and rigged it so that I could monitor the lift pump pressure for several days at a time. It always stayed above 12 psi at idle and above 7 psi wide open throttle at 2500 rpm.

After the new VP44 and in-tank lift pump installation, I tested the lift pump pressure the next day with the same gauge. The lift pump readings were 6 psi at idle and 3 psi at wide open throttle at 2500 rpm. Cause for alarm? One would think so, but the VP44 had failed with good readings on the old lift pump, so that dampened my concern.

I brought this to the attention of the Dealer that repaired my truck and they said they would talk to Cummins. I never did hear back.

I now have 202,000 miles on the truck which means 115,000 miles on the new VP44 and the new in-tank lift pump. I have checked for codes regularly since these pumps have been replaced and so far, no codes have been set.

Last August my wife and visited Death Valley for a couple of days in the truck with our camper installed. The fuel system on the truck had a good test on the day we left. Leaving Death Valley we pulled a grade starting on the valley floor just below sea level at 116 degrees to 2000 feet above sea level at 105 degrees. The next day we left that location and continued up the pass to 5000 feet. The engine ran flawlessly and no codes were set. This is probably about as good a test one could make to check fuel pump performance.

I have spent a lot of time researching the VP44 pump failures and I do understand the importance of cooling the injection pump, but I really have not come to any specific conclusions as to why the first injection pump failed on my truck. I have read many posts from knowledgeable people (including ones on this page) that talk about the importance of maintaining certain lift pump fuel pressure readings under certain conditions. I believe that this would be very important if one is making modifications that would enhance the performance of the engine above stock. However, my experience with my stock truck is that the lower readings seem to be acceptable.