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Discussion Starter · #1 ·
Hi Guys I recently bought a low fuel pressure warning light that comes on when pressure drops below 8 psi. I hooked it up and wouldnt you know it the light was on all the time even just off idle. So I went to cummins and got a new lift pump and put that in yesterday. Everything was great after that, no light on at any rpm. So I waited for the truck to cool down and then sprayed engine degreaser everywhere to clean up the mess and hosed down the engine bay. Now today I take the truck out and the low pressure light starts flickering at about 2100 rpm and comes on after that intermitently. What do you guys think? Do I have water from the engine shampoo in a connection or the lift pump housing. any help or ideas would be greatly appreciated.
 

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My take on it is that a lot of the lift pump failures that lead to dead vp 44s have to do with the cap on the fuel filter housing. It is easy to cross thread, easy to have a leak at the o-ring, and if that happens, air can sneak in making the vane type factory lift pump lose it's prime. I would suspect that might be what is going on. I had that happen when I forgot to replace the o-ring on the cap when I changed out a fuel filter. If that's it, you might notice it cranks a little without starting immediately. The vp has a diaphragm that helps prime it, but the engine has to crank to make it do it's thing.

Or not, just my thoughts. I would note that 8 psi is a pretty high pressure to kick a warning light on. I would have gone more like 4 to 5 psi. I am almost certain that the factory lift pump is a restickered Carter vane type pump except for the plug and the straight threads (Carter aftermarkets use NPT tapered) and I don't think those pumps are even rated to make 8 psi. The only reason to run higher pressure is to FORCE fuel through ports that are too small for it (banjo fittings) so if your sensor is at the vp, 4 psi should be fine. ANY pressure at the injection pump means it's not going dry.

In short, I think your warning switch is too high of pressure, and there is probably nothing wrong.
 

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I have the BD warning light also which comes on about 20-25 miles after a filter change or any time you open the filter cap. I just had the truck in the shop for 3 days becuase of a stumbling issue, which they could not find, and everything is fine. They checked all if the pressures and informed me that that lowest they could get my pressure to drop was 8psi at the VP. They told me that my light was coming on even at 14psi so the lights are pretty much useless. I plan to keep it in until I get a pressure gauge and will not worry about the light unless it stay on constently.
 

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Discussion Starter · #5 ·
Ok I guess I better start shopping for a fuel pressure gauge kit. Anyone got any suggestions? It would be nice to get a complete kit.
 

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any mods done to the truck?

a better L/P is always a good idea and so is a gage :thumbsup
 

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Hey check out my posts about the idiot light and fuel pressure gauge cause I had the same problems.
 

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ive got the same problem with my kit and im running a new fass 150 gph pump! My light's sensor is located at the vp 44 and it flickers above 2100 and intermittedly after that, while me edge juice which is also brand spanking new, shows 16 psi?! only difference is that the attitudes sensor is located on the outlet side of the fuel filter.
 

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i think those lights are junk and a waste of money. get a gauge, then you'll know for sure.
 
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