Hey Everyone!

My stock lift pump decided to take a crap about a month ago. So I installed a new raptor RP-150HP pump on my truck. The truck ran great for about a week with no issues. It held around 32psi of Fuel Pressure. Then last week it started losing pressure and dropped to around 20psi. I checked for leaks and did not find any so I installed another guage and pressure stayed the same at 20psi. I removed the guage and installed a new filter still no change so I installed a new OFV from Tork Tek (which those Guys are great to deal with). Still no change in pressure. So on my home last night the trucks fuel pressure dropped to 15psi now. so when I got home I pinched the return line and the pressure did not rise at all. You could hear the load on the pump more but no change in pressure. Does this sound like a bad Fuel Pump to you Guys? I called Pure flow (Boy where they a big help) . I told the guy my issue and what all I did. his answer to me was its not the pump? I said ok so what do you think it might be? his reply was I have no idea but its not the pump. So he told me to take the pump apart and check the orings? I have no clue about pumps. Then I asked what should I do and he told me I could mail my pump back and they would test it but I would be wasting my money cause the pump was fine. WOW!!! that is customer assistance! what happen from the time I bought this pump a month ago till now? Did someone else buy Airdog or something? I dont Know what to do now. I just spent $400 on a pump thinking I would have better reliability and I am starting to think I was wrong. Does anyone have any Ideas what could be wrong with my fuel system? I replaced the line from the tank to the injection pump. new filters. I just have no clue what it could be?
Thanks
Eric

 

This pump shows coming pre-set at 25-30 PSI per the Mfg. website, is it possible the setscrew jam nut came loose? I do not know much about these things other than people seem to always have issues, but from the picture, it looks like there is a set screw on the side of the body that to me appears to be how you would adjust the pressure. I would be tempted to loosen the jam nut, give the screw a couple of turns, and see if the FP comes up.

One thing is for sure, if the pressure didn't come up by pinching the line, the pump is not producing the pressure it should, could be internal leak path ( O-rings) or the pressure relief valve ( what I mentioned above ).

 

Thanks for the info!
I was on my way home tonight and the pressure started at 20 psi dropped to 5 psi at one time then after sitting in traffic for 45 mins the pressure came up to 25 psi? What gives with this thing?

 

I did try to change the pressure with the adjustment screw but the pressure did not change at all.

 

Then it has to be an internal issue. Perhaps a bit of trash on the relief valve seat?

 

Check your voltage at the pump connector while its running. How close is it to battery voltage.
Check the inlet line connections. Any slightest leak will pull some air before it pulls fuel. Air won't pressurize like fuel.

 

I have the same pump and it is pretty new. I am having issues but don't have a pressure gage set up to test the function.
However I am a mechanic and the trouble shooting path would be to check the pressure before it enters the filter. Then you would know about the pumps pressure output. no return fuel seems a little like to far down the path to troubleshoot the issues.
I am as I write this looking for a temporary pressure check system.

 

I set up the pressure gauge and found the press set on my raptor pump was 14psi at idle and 7 & 8psi at WOT.
Adjusting the pressure to 28 pounds (because it was an initial engine off, stab in the dark adjustment) and went for a drive. It died and wouldn't restart. I adjusted it back down to 23 psi and it started right away and ran perfectly. Now it is set at 20 psi at Idle and drops to 17 or 18 psi at WOT.
I completed a drive from Seattle to Coeur D'Alene ID today. 300 plus miles, not one issue. Not a run away, a stumble, not even an at idle misfire. In Fact 21 MPG looked pretty good.
I am cautiously beginning to believe (again, Ive done this before) that this might have been the fix.

 

I left Coeur D'Alene today and everything was going great until we hit the top[ of the pass and began coasting. I could hear a intermittent cycling of the engine. like throttle changes, small changes. I was on cruise.
Then all hell broke loose and the throttle response went to zero. I pulled off and read the codes.
#1-p0857
#2-P02122
#3-P02121
After that everytime I used the cruise, it acted up.
I stopped using cruise and viola, no issue.

Now I am interested in the FCA (what ever that is).

Can the FCA and Cruise connect at a code level?