fdfbuilds

I really like the low pressure light on the fuel gauge...hadn't ever noticed that was an available option. Thanks, John, for the check valve info! Dave

John, Thanks very much for the insights. I've been a little concerned about running the lift pump pressure so much higher than stock thinking there may be negative unintended consequences. Somewhere I had read higher lift pump pressure would lead to more return flow...didn't question it so thanks for clearing that up. What are the specs on the check valve you used for the the bi-pass system? I like your setup on the warning light. Thanks, Dave

My guess is the BlueChip diesel VP44 rebuild would have happily kept going for many more miles absent fuel starve problems caused by several repeated Raptor lift pump failures. Not sure going forward with new Oregon Fuel Injection VP44 rebuild what I'll do different. I have a mechanical fuel pressure gauge in the cab right now (don't really like the idea even thought I sealed the firewall penetration with fire caulk) and putting two or three gauge pillar mount is on the to-do list. Have a low pressure light in the cab but sending units failed quickly (mounted at the VP44, I didn't know until more recently that's a common problem; now I have a sending unit mounted off of a T after about 6' of flexible fuel line) so in the end that didn't help me much.

Problem is resolved...but it took me a ridiculous amount of time! There were multiple problems: First, the VP44 had failed - well, some part of it. Doing the hot wire method described by Bluechip Diesel, I was able to get it to start, but barely. Didn't run well. My mileage had gone down 20%+ leading up to the no start so I was not surprised. Second, I was getting erratic voltage to the lift pump (and it's set up with a relay triggered by ECM and fused power to the Raptor lift pump) and occasionally erratic to the VP44. So pulled EMC and sent off to Auto Computer Specialists for ECM diagnose and repair. That was done nicely and they recommended attention to the wire harness. (BTW, forgot to put my ECM back to factory settings with the Smarty tuner the previous rebuild attempt from another service, so now not able to use the smarty to put the high-idle function back on...anyone know how to reach anyone at Smarty or former Smarty to do a one-time unlock?) Third, pulled wire harness and sent to Auto Computer Specialists. They did a really good job (seems to me) cleaning the harness and replacing what needed to be replaced. Several wires, including a ground, were noted as being replaced. Fourth, self created problem...while removing the re-built VP44 to replace the tappet cover gasket while waiting for the wire harness rebuild, got distracted after removing the timing gear nut, pulled the VP44 and heard the ting-ting-ting noise of the lock washer falling down into the case. Well, I was leaking out the front crank seal so that was the impetus to replace with a seal & sleeve kit, which I should have done anyway, and retrieve the lock washer. Truck has been running well. Have a bunch of work to get to after current work project I'm on finishes up (ball joints, steering linkages, rear door latch, and cleaning off the Doug-fir sap that is covering the truck after being dead under one of our trees through a season). Also want to replace injectors since, well, these have now over 550k on them!

The used high pressure fuel lines bought on Ebay showed up right after I was slammed with work. Got them installed yesterday late afternoon, low pressure fuel flowing, new fuel filter, bled high pressure lines and up and running. Good fuel pressure. This morning, quite excited to drive it again, jumped in and lift pump didn't cycle on. Hard start too. Low pressure light on so shut it down. Hard start - could be air in line from a broken seal (e.g. fuel return line)? This afternoon, lift pump powered on for the brief run prior to cranking. I bumped the starter and the lift pump ran the normal cycle (25 seconds +/-). But no start. Might need to bleed the lines again or some other electrical problem. Anyway, I don't want to run it now until the lift pump not coming on is figured out and risk damage to my newly re-built VP44. There is a relay switched with the ECM transfer fuel pump circuit with fused battery power running the lift pump. Maybe ECM or wiring? I'll replace the sending unit assembly, since I have it already, to eliminate pickup tube concerns...on the next free weekend.

IBMobile, thanks very much for the link! Your link popped up A LOT more alternatives than my simple search engine query. After looking through a lot of Ebay adds on used (hadn't occurred to me, but since my truck has just about 545k miles, most looked better than mine) found a seller where the ends looked great and very little corrosion on the lines. Here is hoping. BTW, saw in your truck specs you have 4.10 gears. Did you change yours or did that come factory? Plenty of times I wished I had 4.10's, for towing especially, but having never done differential work I'm very hesitant to attempting a front and rear gear swap.

Finally purchased a rebuilt VP44; it arrived yesterday & the swap was today's project. Replaced the factory VP44 11 years ago. And apparently, I significantly over tightened the high pressure lines on the back of the replacement VP44 because I really struggled to get them off. Modified a 17mm crows-foot flarenut wrench to get enough back pressure then I was able to get the line nuts to finally brake free. My guess is i was trying to get the lines to not leak. Now the ends are mushed over (see pic). Hard for me to believe I tightened them that much but obviously I did (I was broke down out-of-town...might have had something to do with it). Anyway, does anyone have a good source for a replacement set of high pressure fuel lines? Geno's shows a set in their catalog (the set, tax and shipping looks like is just under $1k and after buying the pump, I'd like to save some $'s if possible). Thanks,

Have a no start condition with my 2000 Dodge Ram 2500 Quad 4x4 Cummins Diesel (approx 545k miles I think...been a while since it was running). Went through the “BLUE CHIP DIESEL – NO START TESTS”. Truck started when I hot-wired the VP44, which stunned me! But before the hot wire: initially had 12.7v on pin #7 of VP44 plug (with respect to battery…had the charger on the batteries) in “run” key position, dropped down to 12v while cranking (“start” position). Testing between pin #6 (ground) and pin #7, had 12.7v with key in “run” position…then in “start” voltage dropped down to 6v and fluctuated between 6v and 11v not coming back up to 12v until key was back in “run” position. With negatives of both batteries disconnected, Fluke Mod 325 meter didn't register any resistance between #87 at the Fuel Pump relay and pin #7 on the VP44 plug (but in no-load condition...don't know how to do that). Had the ECM re-built by Car Computer Guys in November 2023. I was having troubles with my PureFlow lift pump (RP-100). Subsequent to the ECM re-build, PureFlow replaced the lift pump on warranty. Since my lift pump difficulties, fuel mileage dropped significantly (trips I was getting 19.5-20 mpg barely achieved 15 mpg). The blue wire with red tracer was already cut & capped. Even though I don’t remember doing it, makes sense I may have done that back in September 2013 while diagnosing another no start…turns out I had a bad Crank Shaft Position Sensor. I replaced the VP44 with a rebuild in August 2013 at 325k miles. Probably have more than one nail in my tire...so perhaps new VP44, injectors (they have 545K, original equipment), and??? Don’t know what to do next. What are the next tests I should do? Some helpful advise would be greatly appreciated!

Warranty replacement RP-100 is installed and the Cummins is back to life! No issues through test drives. Presently, I have the lift pump pressure set at 19 PSI during idle (as measured at the VP44 inlet fuel banjo bolt); full throttle under load (accelerating to freeway speed) pressure drops to 11 PSI...such hard throttle is almost never used. I'm still curious about the air in the clear tubing I saw. Maybe the lift pump was the significant contributor after all - in addition to failing to pump fuel? So for now, the not-running-problem and associated air-in-fuel-line is solved. Getting into the weeds a bit: apparently, the original lift pump supplied by PureFlow Technologies was done through their heavy duty (and medium duty?) truck business. Some time later (probably after my 2014 warranty replacement) the light duty side split off. So there was a bit of back and forth where the heavy duty folks (the phone number on my 2014 warranty replacement invoice) sent me to the light duty folks who couldn't find my paperwork in their system...because they never had it. Light duty folks sent me back to the heavy duty side where my warranty claim (transaction was found in their system - but my saving the paperwork was very helpful) was processed quickly.

So I put in new fuel line between the RP-100 and fuel filter canister...glad I did it but no improvement. After chatting with a mechanic buddy, and thinking more it's the lift pump (but "...probably more than one nail in the tire" as said by Doug at Blue Chip Diesel) called for warranty support on the lift pump. They wanted to see a fuel pressure gauge on the outflow of the lift pump and direct 12v and ground wired to the pump. So that was this weekend. Saturday, for a short period of time, the pump was delivering 18-20 PSI, drawing 5.7 amps (Fluke 325) and no air in the clear tubing between the fuel filter canister and VP44. Then pressure dropped along with current to where no pressure was being delivered, current measured 0.5 amps concurrent with lots of air in the clear tubing. My original RP-100 was put into service in 2009. Current pump I replaced on warranty in January 2014. So here is hoping the new lift pump gets me going. Fuel pressure gauge T & line volt to lift pump_2023-10-01.pdf

Thanks very much for the link. The local hydraulic shop sounds like they can make a fuel line up for me when I bring in the ends connecting to the fuel filter canister and the RP-100. Then I'm looking for a delivery from Geno's!

The fittings on the RP-100 pump look like the female fitting on the rear (inlet) side of the fuel filter canister...which to me look like the pics of JIC fittings on McMaster-Carr's web site - but I'm not fitting savy. The canister fitting has a thread pitch of 1.50 but didn't measure the fittings on the pump (yet). Since I had clear tubing in two locations: between the VP44 and fuel filter canister showing lots of air in the line and between the RP-100 and fuel filter canister (with tiny bubbles) are there other likely entry points? Is running new fuel line between the fuel filter canister and RP-100 worth it? Maybe a little crack in the steel tubing fuel line?

Thanks, IBMobile. I'll order two banjo bolt gaskets for the bottom of the canister...and get some extras.

My 2000 Dodge 24v (with 540k mi) started to run rough then stopped. Thought it was the VP44. Installed clear tubing between fuel filter canister and VP44, purged air and got running. Like someone flipped a switch, LOTS of air showed up in clear tubing, engine faltered and I shut it down. Put clear line between Raptor RP-100 and tank: purged air, got running, no air, then engine shut down on its own. Put clear tubing on pressure side of RP-100 with additional clear tubing back between filter canister and VP44: tiny, tiny bubbles by RP-100 and then, like someone flipped a switch, aquarium aerator bubbles after fuel filter canister. Replaced canister top, put new "O" rings on water/fuel separator with no change. Not seeing evidence of leaking between RP-100 and fuel canister. Fuel supply fitting to the fuel filter canister was pretty snug. Any suggestions other places air may be getting in? Is there a replaceable seal at the fuel heater? Thanks!

Vehicle Nickname: Dave Frankovich Date Added To The Garage: 2023-09-12 Garage Link: Dave Frankovich

Went back and checked to hear the "click" and I did but the raptor did not come on. Will double check again and call Pure Flow in the morning. Read somewhere to check the resistance accross the pump too: should be between 0.2 and 200 ohms on a stock LP, think that might be true of the raptor also? If I can scrounge up some connectors and an inline fuse I'll try to direct wire the lift off of 12v too. Really appreciate the feedback!!!!

Th raptor is mounted on the frame. Found a blown 25 amp in-line fuse between the PDC and a coil mounted near the PDC. Didn't have a 25 amp but a 20 amp put power back to the pump location...once pump was plugged back in it still did not cycle on. Does that give more weight to the raptor being fried?

Thanks for the info! Not finding a fuse for the raptor...the chilton's wiring diagram looks like power for the lift pump is coming directly off the ECM. Is there in inline fuse or?

My lift pump (Raptor 100) is not coming on...the idiot light came on just a mile away from my home so pulled in the driveway to check it out. Not hearing the pump cycle when I bump start. Did not see voltage on yellow wire or illuminate a test probe light during 25 sec bump. Truck starts and idles (from little lift pump in vp44?). I'd like to test continuity from the ECM plug to the lift pump but don't know what pin hole is the right one? Or any other suggestions? Really appreciate some help! Thanks,