Dodge Cummins Diesel Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
424 Posts
Discussion Starter #1
Hello! Replaced the factory block mounted lift pump and I've been running a Raptor100 for 10 years, 20,687 miles on the pump, 93,540 total miles on truck, don't drive it a lot. 10 years holding 17 psi at idle, with normal minimal pressure decline under load until recently. New rebuilt VP-44 3 months ago, fuel filter change 2 weeks ago. Now pressure varies at start-up depending on the day, and stays at that pressure the remainder of the day, sometimes normal 17 psi, lately often 10-12 psi at idle which is a significant loss. I don't want to just dial up the pressure on the pump, that won't solve the issue. Called Pureflow today and they said probably ECM is bad. Funny, no codes pulled for that, no other electric issues going on, are they blowing me off or what could this new intermittent pressure loss be attributed to? I have searched for answers but non fit my scenario. Many thanks in advance for suggestions.
 

·
Registered
Joined
·
424 Posts
Discussion Starter #2 (Edited)
Just to clarify a bit, when I turn ignition first stop to 'wait', the lift pump engages for a couple of seconds and the fuel gauge shows for 2 seconds what pressure the pump is pushing at, could be 17lbs, 12lbs, 10lbs, etc and that's the pressure it will run at for the rest of the day. Doesn't look like ECM is involved in the problem because the truck hasn't even been started yet as I glimpse at the gauge. All brainstorming welcome!
Aaaaahhh, now it's at 6 lbs, is there some maintenance I should be doing on this unit, Pureflow is 3 hours ahead of my PST and they're no help anyway. If I need a new lift pump, they are not ingratiating me to buy another one of their products.
 

·
Registered
Joined
·
141 Posts
What kind of gauge do you have? Electrical or mechanical? Sounds like a gauge problem to me.
 
  • Like
Reactions: littlebuddie

·
Registered
Joined
·
424 Posts
Discussion Starter #4
Thanks so much maxwedge572, I would not have thought to check the gauge functionality - too easy. I have 2 mechanical gauges (overkill), both glycerine filled (double overkill). One is copper tubed (triple overkill) into the dash, the other mounted on the fuel filter canister. As per your suggestion I looked and the one on the canister reads 15 lbs - never thought to look there 🙃. The dash mount gauge, the one I have been sweating about shows @ 6 lbs. Time for a new gauge and I owe you a cold beverage of your choice. Thanks for helping out a 68 y/o gal, no one else in my circle understands the kind of trouble I get into, much obliged! 😀
 
  • Like
Reactions: maxwedge572

·
Registered
Joined
·
141 Posts
Ha that's funny, I just had a similar issue with a glycerine gauge. The one that is wrong, see if it has a rubber plug on it's bezel. If it does, pop the plug out a bit with the engine running to release pressure in it's case. It should start reading normal but have a paper towel ready to wipe up the fluid.

I'm new to glycerine filled gauges and put a VP Max (Vulcan) fuel pressure gauge under my hood last Monday. I have a Fass system and have checked the pressure before with a Mac pressure gauge and it was always at 17 psi. This gauge I put on showed 3 psi! I freaked and I didn't drive it to work on Tuesday! Brought my Mac gauge home Tuesday night and sure enough, 17 psi! Then I looked into this some and found out about re-leaving the pressure in the case.(y)
 
  • Like
Reactions: littlebuddie

·
Registered
Joined
·
141 Posts
PS, not far behind you at 63!:LOL: But not retired yet!:rolleyes:
 
  • Like
Reactions: littlebuddie

·
Registered
Joined
·
424 Posts
Discussion Starter #7
That's what it's all about here, sharing experiences and resolutions, your determination to remedy your problem helped fix mine too, isn't that awesome! Welcome to the forum!!! I'm fairly certain the faulty gauge has a plug, I'll try purging the pressure as you suggested to see if that helps but the gauge is over 10 years old and the face has been uglified and stained by sun exposure over the years so I I'm thinking new gauge would be more readable. Thanks so much for stepping up and helping out, I will sleep well tonight. 🤜🤛
Bless Ya,
Laurel
 
  • Like
Reactions: maxwedge572
1 - 7 of 7 Posts
Top