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1999 Ram 2500 Diesle Power Loss

04-27-2010, 11:54 AM
This started last summer on vacation when driving about 70-75 mph the engine suddenly started losing power. The speed went down and the RPM's dropped, and accelorator is to the floor. After letting off of accelerator all was well. This continued mostly on uphill climbs and the outside temp was in the 80s and my AC was on. When off of the interstate and kept below 65 mph this did not occur. Most of the time letting off the accelerator for 2 seconds and you feel the engine kind of jump and everything seems OK, until the next episode.
It did not do this again until back on interstate and it was hot outside again, last Thurs. (Only on interstate one other time and it was winter.) It did this again last Friday but this time I was only doing 45 mph. and on a state route.
Mechanic said the code calls for either Fuel filter, Fuel pump, or Lift Arm. Tried the filter (2 weeks ago and all was well on interstate but only a short test run), and the lift arm was replaced a year and a half ago. Getting the pump now but saw something about the computer on the pump, may actually be the problem and when getting the pump replaced I should have the computer replaced as well???? Does this seem right or can you make a suggestion I can ask my mechanic? Pump is VP44

Chris Stewart
04-27-2010, 09:02 PM
Welcome to the site ,
Your Dodge/Cummins has fuel mileage and power capabilities far beyond a basic gasser but it isn't gas-n-go like a gasser's a bit involved but not difficult to manage.
Obtain a repair manual at your favorite auto parts store so you can get up quick on your truck. You also need gauges to get info from your truck but more on that later..
Your 24 valver has a Lift Pump that takes fuel from the fuel tank and delivers it to your Injector Pump(VP44). This VP44 is the weak link and because it's so expensive, it deserves extra consideration. For years the Dodge Diesel guys have been trying different things to get the VP44 to live and through basic R&D, they've discovered a few things that help most and are running up the miles.
Fuel lubes and cools the VP44 and we watch that with the Lift Pump fuel pressure. We generally like to see 13-15psi idle, 12-13psi cruising hwy speed and no less the 5-7 psi at wide open throttle(WOT). A pressure gauge installed in the cab, connected by pressure line to the outside fitting on the top of your fuel filter housing will get you lift pump fuel pressure to watch.
Diesel fuel has very little if any lubricating abilities so fuel treatments like Power Service, Howes, Lucas and Stanadyne add lubrication to the fuel. I use the MFG's recommend on dosages.
There is fuel returned to the fuel tank from the fuel system and because some of it comes from a passage in the cylinder head of the motor, it's hot. This is fine in the winter because diesel fuel can gel in very cold temperatures BUT in the summer, it can get hot enough that it won't cool electrical components in the VP44. Most folks are keeping their fuel tank 1/2 full or better. We're currently looking for an end all fuel cooler that does not restrict flow or pressure.
Many folks have found that they had no lift pump pressure after they install a gauge or change the fuel filter so be ready for that.

Your symptoms could mean a fueling, boost pressure, MAP sensor, battery voltage or even a fuel pressure issue.
What was the trouble code?

05-01-2010, 01:45 AM
was you trouble code for a injector pump timing....To isolate the lift pump or injector pump, you need to do a flow test from the lift pump..

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