First break down, and first post here. I think its awesome that there are resources like this site to help others. This is my first diesel and I love it. I have put about 40k on it the past 2 or 2.5 years. Majority Highway miles. it has about 254,000 on it now and had 213,000 a few years ago when i bought it. I really like wrenching and fixing things, but with this being my first diesel, and something new to me i am a little hesitant and nervous to do some stuff, but only because i dont really know exactly what im looking at. Well today on my way home I was passing a semi and then bam, no power(throttle) what so ever. Turned off radio, tried to restart, nothing. Put hazards on and let semi roll past and then pulled off to the side. I had a scan tool with me so i grabbed the codes out of the computer. P0253, P0252 and the dreaded P1688. Had the tow truck take me the rest of the way home. I also have a small red indicator light on my dash, cleverly hidden behind the steering wheel away from view from my vantage point in the seat. I think that its one of those low pressure indicator lights. The light would flicker occasionally, and i could only see it at night. But not really under full throttle, just at random times. After i lost power it was solid red. I do not really understand how the fuel system works, I do know that the VP44 is prone to fail, that there is a low pressure pump pushing fuel to the VP44 and that it provides high pressure to the injectors. Other than that I dont really know. ex, where is it located? I think that my VP44 may have been replaced before i got it, but im not sure how to tell. So i am pretty sure that im going to need a new high pressure pump, wether it be a VP44 or an aftermarket one. There is some info in my sig, and the rest of the truck is stock. Im not sure which model of the edge chip thing i have. it has a 3 position toggle switch. I did the crankcase vent mod and plumed it down underneath, and i have also adjusted my valves. Both of those were done not recently (not the cause of today) Any help or links to info would be greatly appreciated. I leave tomorrow early AM for some field work. No internet access, so ill check when i get home sunday evening. Did i mention this site is awesome? Thanks Zack

I didn't know about these pumps. I learned something today. I don't think the argument that the pressure drops when you hit the pedal holds much water. My raptor may drop from 20lbs to 18lbs but there is not a performance loss there. If you are comparing the drop against a stock pump then maybe that argument makes more sense. There is one fuse and one relay on my raptor and they are next to each other so checking them is pretty simple. I also think fuses and relays may be more available than spare belts. As for seeing more pump failures, this is a bit misleading too. How many Assassin pumps are in existence compared to raptor, fass, whatever? Maybe the Assassin pumps will stand the test of time but we won't know that until some time passes. I am interested to know how you bleed the system with these pumps. There would be no bumping of the key to let the pump run for 30 seconds right? The raptor pump I have makes a ton of noise under the truck. Sounds like the assassin maybe be a lot quieter. I also think the assassin looks a lot cooler under the hood!

Keep in mind these are my opinions and they have already been taken out of context. Lol pressure drops due to amp draw does hold up. But only under proper circumstances. If an electrical pump begins to get a little tired, and your nominal pressure consistently goes to 15-16 now when you add in that 2-3 psi drop your in the danger zone for cooling the VP when it's running at its hardest. So it matters then IMO. As far as the fuse goes. I do not have any experience with the other pumps as I stated, and I am NOT degrading them. But I carry 2 belts in my center console and I can change my belt in less than 3 minutes and I can purchase a belt at any local auto store without issue. The mechanical pumps have proven themselves over the years but for me they are simple and easy to fix. For that matter I intend to buy and carry the two seals and bearings and keep those in my truck also allowing for a complete rebuild roadside if need be. There is ALWAYS a possibility for catastrophic failure no matter what you use, I personally put more faith in gears than electrical motors though. As for the pump failures, I say this because I researched just as he is when I needed to buy a pump. I am NOT comparing mechanical to electrical for longevity. I am saying that through the course of my searching I found a lot of people complaining about their electrical pumps failing and lacking the quality/customer service of the earlier built electrical pumps. You can drop the pump from its mount and spin it up with a drill or crank the engine. The pump does not lose its prime, I have left my truck sitting for over two weeks and it stills starts faster than it ever did with the oem lift pump. I have taken my regulator apart numerous times and lose very little fuel, and it immediately starts when I button it back up, no priming, no issues. Hope this clarifies a little, and I am not saying the electrical pumps are lesser pumps, I just happen to like gears.

I was asking how to bleed it in case I ran out of fuel. I think the pump looks pretty cool. Raptor customer service is terrible and makes me wish this mechanical pump existed a few years ago.

Well i just finished the install of the VP44.Ill put the lift pump, and the guage on tomorrow and the bleed it all.Hopefully it works.Just in case some one else needs this...The nut on the pump shaft is 1 and 1/16 (27mm) and you can use a steering wheel puller and some bolts(M8x1.25) to get the gear off if your supplier forgot to include the puller with your parts.I do have some questions about the guage install though. I got a kit and it came with a fuel isolator. It seems like its a diphram that keeps fuel on one side and something else on the other. is it just air on the other side? It mentioned something about a 50/50 antifreeze water mixture.Also, teflon tape on the threads, can i just use the standard white stuff or do i need to get some special diesel fuel safe stuff?Thanks again for the help!Zack

Isolator I would suggest you skip on. Most people end up removing it because it skews the reading of the gauge. A lot of times the isolator loses its antifreeze and the gauge drops out and the owner goes to panic mode not knowing if the lift pump actual died or the isolator died. Most times is the isolator but it will require removal and retesting. I've been direct plumbed for nearly 10 years and never had fuel leak in the cab. When your running air brake line with 600-800 burst strength I doubt a 10-20 PSI lift pump is going to cause it to leak not to mention its the very same stuff use for big rigs.Q: Why is it that people will direct plumb a oil pressure gauge from the engine with cheap nylon but go into panic mode when it comes to direct plumbing diesel fuel? :think:As with all plumbing connection I NEVER use any tapes or sealants. Automotive brass is self sealing and if done right it will not require any tape or pipe sealant. As with all my plumbing there is no Teflon tape or pipe sealant used anywhere. At least for me I don't have to worry about a small bit of tape or something flow to the injection pump and plugging it up.

Thanks Mopar man, ill go get a needle valve and some air brake line today.Also my Red low pressure indicator light seems to have stopped working. Any ideas why?Too long with no pressure burning up the sensor?

I got everything all put backtogether yesterday and then got a call that my mother got in an accident so i had to get a trailer and go get her and her car. I was able to bleed the air from the system and then got it running.I took it for a short spin and it ran great, got the trailer and headed out.Did the 200 mile round trip with no problems. Towed great, no lack of power.This morning i went to head out for the day, it started up and ran for a short time then died.I didnt find any fuel leaks yesterday or this morning, but i was able to get it started this morning by doing the cranking and resting thing to get the air out of the high pressure lines.It drove fine here, and i suspect that it will do the same this evening when i attempt to leave home.I think i may have an air leak or some thing in the high pressure fuel lines somewhere.Is it possible that it could leak air in and drain fuel from the lines or pump after sitting all night and not leak fuel?I almost have this all back to normal, excited to get my truck back.Also i thought i read that it takes 3-4 hrs to swap out a vp44, it took me alot longer, but this was my first venture in to the fuel system.Thanks for all the help!

Mine was doing this a while back and it turned out to be the return line on the back of the head and the return tee that joins it to the vp return. They are both hard to see until they leak enough for you to see fuel on the ground. I replaced the sealing washers on the line at the head and the o rings in the tee. Anything that lets air into the fuel system will let the fuel drain back to the tank. I would think if you had a high pressure leak it would be fairly obvious due to the high pressure present.

Thanks for the quick reply, ill go check it out now in the parking lot while its cool.

Ill report back tonight if/when i get home.

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Well no leak and it started up fine.

Maybe there was just some air trapped somewhere lower than the pump that allowed the pump or lines to drain.

It feels great to have a running truck again, thank you everyone for all the help!

Zack

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Well it started again this morning then died after about a second. looked all over and didnt find any leaks. finally when i decided to bleed the air again i put my hand on the inlet to the vp44 and found fuel on my hand. i bled the air and made sure to tighten it back upbetter this time. no fuel there after a 45 min drive. it seems to only happen overnight so ill see what it does tomorrow morning.

Did great for a few days. On firday it stumbled a little after start up. that cleared up. This morning it dies again. Tightned the overflow nut this time. Hopefully this fixes it.

Allright guys i have a few more questions.Thanks for all the help so far.I am attempting to install some gauges and im having some trouble with the compression fittings.First off, it leaks were it connects to the gauge. Red arrow.Its already pretty darn tight. Can i just put some teflon tape on these threads to seal it up?I also seems to be tightening the actual compression thing wrong.Each time i do it the line gets tweaked to one side and kinked.I thought the first one leaked, so i took it off to find out that the little inner brass piece was not aligned properly and kinda smushed.This second one seems to have done the same.How tight do i need to tighten these? Is that little bras piece supposed to deform to seal it?You can see here that the line is coming out at an angle. with a gap on the left of it where it enters the compression fitting.Thanks for all the help again guys, i really appreciate it.

Are you using another wrench for a back up to tighten the compression fittings? Are you sure you have the ferrels installed correctly? (the little pieces inside the fitting) Those pieces are what makes the seal, not the threads

the little brass ball that the hose goes through is supposed to deform and compress against the fittings and hose creating seal. you can get new ones at ace hardware for pennies.

Well im glad that they are supposed to deform. I guess that makes sense.The compression fitting part works just fine, no leaks. But my leak is where the compression fitting threads on to the gauge.The threads are not sealing it and its cranked down tight.Any tips?

Well im glad that they are supposed to deform. I guess that makes sense. The compression fitting part works just fine, no leaks. But my leak is where the compression fitting threads on to the gauge. The threads are not sealing it and its cranked down tight. Any tips?

The compression ring is supposed to seal to the line, the inner edge of the compression nut, and the fitting on the gauge. The threads on the nut do not seal any thing, the inner portion of the nut that contacts the compression ring is supposed to form the seal. I have seen plumbers dope up the threads on the compression nut to stop a leak, but they know that is not a proper solution. It will get them by,but under your hood it will start leaking again. From your picture you can see the line is crooked and that is why you have a leak. If every thing is seated properly the line would be straight and the leak should stop. I would suggest you pickup some extra compression rings and try to get the line seated straight and your leak should be fixed. They are very cheap at the hardware store. Not trying to be d--k here, but the ring and not the threads should be forming the seal.

Yes, i now understand how the compression fitting works. I am just not getting what i want to say across to well.

There is an outer nut, Which squishes the tiny ring against the body creating the seal. The body then, threads on to the gauge.

My compression fitting is working fine. The part that leaks is where the fitting threads onto the gauge.(RED)

Green is the outer nut on the left, ring inside and the body on the right.

Red is where the fitting threads on to the gauge.(LEAKS)

Ill take some better pictures tomorrow with a non cell phone camera in the day light.

There is an outer nut, Which squishes the tiny ring against the body creating the seal. The body then threads on to the gauge(Leak is here).

Color coded. Hopefully this helps.

the ring and not the threads should be forming the seal.

Totally agree with you, but there is another set of threads that it leaks from.

Thanks

Zack

I gotcha now. Do you have any anti seize? It works great as a thread lubricant. Teflon tape is good also, but you could get a chunk of tape in the line and into your fuel system. The problem lies when you put dry threads together, there is friction created when tightening them down and you don't always get them torqued down as tight as they should be. I like to take just a dab of anti seize around the first thread or 2 (I'm talking small amounts, otherwise you end up with a mess) and try tightening it down again. If you can use a back up wrench when tightening that also helps. I know some will say the anti seize is not necessary, but you have to remember when talking about torquing bolts the only way to achieve proper torque is with lubricated threads. If you took the exact same size bolt/nut configuration and put one together dry and the other one together lubed the lubed bolt would actually require less torque to achieve the same tightness as the dry bolt. Thats because the threads on the dry bolt have more friction which creates drag and requires more torque to over come. Pipe threads are more critical than bolts, they rely on the threads to make a seal. Which is where teflon tape and teflon based pipe dope comes into play (lubrication to help bury the threads without galling them) With fittings as small as your working with, niether one of those are very practical which is why I reccomended the anti seize. We run a lot of threaded stainless steel pipe and we use anti seize in place of pipe dope alot, it works great as a lubricant.

The compression nut on my gauge and the fittings we use at work would fit directly to the threads on the gauge. Are you saying you have 2 nuts, the compression nut and another one between the red and green circle?

DRipley it looks to me like the threads in the red circle are pipe threads, either 1/8" or 1/4" it is hard to tell by the picture.

He definitely has something extra there, either reducing the size of style of thread. Even so the brass on brass ought to be sealing with out any help. Both of the gauges i put on mine came set up for the compression nut to screw directly onto the gauge.

That is the general consensus here, but I respectfully disagree. You may get away with it in this instance because of the low pressure but as a rule of thumb when pipe fitting it is a cardinal sin putting any kind of pipe together dry, regardless of the material. As you stated Brass is soft so it does seal itself easier than carbon steel or stainless, but it still can gall. The whole purpose of pipe dope is not to dry and make a seal but a lubrication for the threads to allow proper sink without galling or stripping the threads. I'm sure you know that, just putting it out for some that may not.