JHew84

So I was low on fuel yesterday, no lower than I've taken it before (just hit E, usually means I have ~8gal or so left), but decided not to fill up until today out of convenience. I go to start the truck this afternoon and it doesn't fire up on the first crank like usual, instead it turns over a few times. So I back the key off, puzzled, and try again, after about 5 cranks it fires up but is chugging and has no throttle response, and after a few seconds dies again and hasn't started since. I figured because my driveway is slanted that maybe it was enough to starve the pump so I went out and got a 5gal jug of diesel, didn't seem to make a difference, filled it up again and still no go. If I ran it dry initially this morning would that be cause for enough air to have gotten in the system? I primed it a few times after filling it up with more fuel, both times, and my FP gauge was only reading about 5psi. Both the lift pump and VP are under 20K miles old and have shown no signs of deterioration so I am finding it hard to believe that's the problem. I checked the FP not too long ago and it was right where it's always been at 13psi. Also no codes but I'll check them again tomorrow.

I don't think this is the problem either, but it did dip down below freezing last night. I just switched from PS to the opti-lube fuel additive which is supposed to prevent gelling, and even if it wasn't I don't think that's cold enough to make a difference, but I may go get some of the diesel 911 anyway just in case.

any ideas? I really don't want to have to bleed the injectors , so I'm hoping maybe it could be something else .

mishkaya

No need for diesel 911 at those temps. If you ran out of fuel as it sounds like you did, you will need to prime the system. I am sure you know how it's done, but just in case: loosen the line at the inlet to the VP44 and crank until fuel flows, tighten it back up. Loosen at least two if not three injector lines at the head and crank until fuel flows freely. Re-tighten and then start the truck. It's not that bad a deal really and doesn't take all that long. I doubt you have hurt anything too much. Good luck.

glenn-k

Also - if low and the tank had water or dirty fuel it could have plugged your filter.

JHew84

That's a good point, I'll pop the filter cap off and check the filter, I'm coming up on another service date anyway so I might as well just change it out.

I guess I'll have to get a buddy over here to help me bleed the darn fuel lines . It's at least encouraging to hear it's not that bad of a job, most people I've talked to about it make it seem like a huge chore.

Thanks for the tips guys, much appreciated!

nickg

I always chuckle when I see this (no insult intended) but the fuel pick up is at the bottom of the tank, so wether its full or empty of fuel, its still gonna pick up any junk/water off the bottom of the tank.

running your tank close to empty all the time is detrimental to your VP as it uses the fuel to cool it, so look at it as if your running your engine with 1 or two quarts in it.

same applies to gas vehs,once your below 1/4 the fuel pump is no longer submerged in the fuel and its life expectency is much shorter, as the fuel is what cools the pump

you can easily bleed the fuel system your self, no need for an assistant, as mentioned above. loosen the line at the VP (the one that lookes like a tire fill valve) go bump the starter so the LP will run for 20sec or so. **note ** even if you turn the key off after bumping the starter it will keep running for its predetermined time**

once you have a steady stream of fuel, tighten the line. then go loosen 2 of the first 3 injectors (or at least all the ones you can get at) crank the engine over a few times, it mighttry to start if thats the case stop and go tighten up the lines, it should fire right up, if not repeat bleeding at injectors.

In your post you say you "checked" your fuel pressure not that long ago??? what type of LP do you have?? and checking it is useless, you need a gauge installed if you dont already have one, a gauge whould have shown low/spiking fuel pressure before the truck stalled.

also 5gallons may not be enough to hit the fuel pick up if your not parked level

JHew84

I don't do it all the time, usually I try to fill up ~1/4 tank, but life happens and sometimes it goes a bit longer. Maybe I did more driving than I remember after it hit E but normally there is plenty of fuel at this point. I really think the determining factor was being low and then parking it at a steep point in my driveway.

As far as being detrimental to the VP if it's getting enough fuel to run I don't see how it's not getting enough fuel to cool the pump... ??? My EGT's are always at or below what other people seem to see while towing or driving empty, so I don't think I've ever run lean in the past, even when on E.

I'm sure it can be done alone but I'd prefer to spill as little diesel fuel as possible so having someone run the ignition while I tighten up the lines will work best. Also I seem to remember needing to actually turn the engine over to properly bleed the injector lines, because if you just bump the LP it will push fuel into the IP and then into the return drain, and not actually bleed the injector lines. I've done the bump and start method before when I change out my fuel filter but that only took a couple bumps and it started right up, didn't even chug. Unfortunately that didn't work this time , I guess I was just under the impression with a nice strong pump I wouldn't have huge issues purging the fuel lines without having to crack the injector lines open.

I filled it twice with a 5gal can, so there is a minimum of 10gal in it right now, I want to say the gauge is at 1/4 tank. I do have a FP gauge, that's how I checked the FP . It is always within spec, which is why I was finding it hard to believe it was a pump failure. Also after a little searching the 5psi I was seeing (which may have bled off from 6psi) is because when the ignition is in the start position the LP is only getting half power and only produces ~6psi, so I'm not worried about that anymore at all. The LP is an OE replacement, i.e. not a fass or other aftermarket unit. The shop I had replace my VP44 replaced it as well, they were aware of the pump issues these trucks have and claim to have had really good results with this particular pump, it's worked great so far.

Thanks again for the replies guys, I'll probably get around to bleeding the lines tomorrow morning.

nickg

I don't do it all the time, usually I try to fill up ~1/4 tank, but life happens and sometimes it goes a bit longer. Maybe I did more driving than I remember after it hit E but normally there is plenty of fuel at this point. I really think the determining factor was being low and then parking it at a steep point in my driveway.

Understandable, but some people just put in enough fuel to just stay above empty

As far as being detrimental to the VP if it's getting enough fuel to run I don't see how it's not getting enough fuel to cool the pump... ??? My EGT's are always at or below what other people seem to see while towing or driving empty, so I don't think I've ever run lean in the past, even when on E.

EGT's are no indication of how much fuel your vp is getting, your VP only uses 30% of the fuel it recieves the remaining is sent back to the tank, the excess fuel lubricates and cools the pump internals and electronics, so if you have just enough fuel to make the engine run, and little or no fuel return your overheating and wearing out your VP, you CANNOT lean out a diesel and cause damage(egt wise), you can overfuel and cause engine damage, when folks say they are worried about a lean (air vs fuel ratio) condition in a diesel it means NOTHING, as the best thing for a diesel is a lean condition or less fuel. on a gasser its the exact opposite
I'm sure it can be done alone but I'd prefer to spill as little diesel fuel as possible so having someone run the ignition while I tighten up the lines will work best. Also I seem to remember needing to actually turn the engine over to properly bleed the injector lines, because if you just bump the LP it will push fuel into the IP and then into the return drain, and not actually bleed the injector lines. I've done the bump and start method before when I change out my fuel filter but that only took a couple bumps and it started right up, didn't even chug. Unfortunately that didn't work this time , I guess I was just under the impression with a nice strong pump I wouldn't have huge issues purging the fuel lines without having to crack the injector lines open.

up at the injectors you might loose a teaspoon of fuel or so, at the VP it could be a cup depending how long you leave the line open, still, its good that your conciencious, for bleeding the VP you only need to "bump" the starter, until you get no air, you are correct you need to crank the starter to have fuel show at the injectors

I filled it twice with a 5gal can, so there is a minimum of 10gal in it right now, I want to say the gauge is at 1/4 tank. I do have a FP gauge, that's how I checked the FP . It is always within spec, which is why I was finding it hard to believe it was a pump failure. Also after a little searching the 5psi I was seeing (which may have bled off from 6psi) is because when the ignition is in the start position the LP is only getting half power and only produces ~6psi, so I'm not worried about that anymore at all. The LP is an OE replacement, i.e. not a fass or other aftermarket unit. The shop I had replace my VP44 replaced it as well, they were aware of the pump issues these trucks have and claim to have had really good results with this particular pump, it's worked great so far.
Common opinion is that 10psi under all running conditions is acceptable, although if not running and just doing the bump it will be lower. My orginal VP was run for countless miles as at the time of purchase I drove it for a few months without a gauge, just did a "spot" test. edventually instaled a gauge and found out under certain conditions after an hour of running or so I was at 1-0psi, at the time of replacement my vp had 340,000kms on it and was working just fine, it had no codes or drivability issues, I was just worried from all the hype, and I since my truck is my source of income, I changed it more for peace of mind than any other reason....that and I wanted to reduce my chances of a break down while on a hotshot.

Thanks again for the replies guys, I'll probably get around to bleeding the lines tomorrow morning.

1longbed

This is exactly what happen to my rig and it has 1/2 tank of D haven't had time to mess with it yet,would you please post your findings.

mishkaya

What are the specifics of your truck? (IE model year, mods, etc....)

JHew84

Yeah there was just air in the system like I had thought initially, even though I hoped it would be something else .

It really wasn't that bad to get it cleared out and started up. Bumping the LP didn't do the trick though, I definitely had to turn the motor over to bleed the system and get it to start. Didn't take long to get it done and it was really painless. If you have 1/2 a tank of fuel I would look elsewhere for the culprit as it's not likely you starved the pump.


Yeah Nick when I fill up it's always topped off, I used to play that $10 here $10 there game, in the end you spend the same amount of money and are always at the gas station, just frustrating .

Thanks again for the help guys, I was really hoping it WASN'T air in the lines because of all the complaining people do about having to bleed the system, but it really wasn't bad. I could have done it on my own if I needed to but it was nice having someone tell me when the injectors really started flowing . Regardless I'm going to be A LOT more careful about running it low in the future, that is for sure!

1longbed

Thanks JHew I really hope I got air too, but either way theres a new LP on it's way since I still got the stock one.The truck is a 00 with 4"turbo back,ex brake,high ram,banks ottomind thanks guys

mishkaya

Do you have a fuel pressure gauge? If you don't, it should be at the top of your priority list. Lack of fuel pressure will kill a VP44...