Engine/Transmission (1998.5 - 2002) Siphon effect.......

[Gary - K7GLD]

Sort of an interesting thread over on the Ford site related to sloppy fitting of the quick-disconnect Ford apparently uses at THEIR pump - seems they have a pronounced tendency to leak and suck air - which then causes all sorts of problems further down the line - dunno if OUR connectors might suffer the same weakness, but might be a good idea to not "exercise" them any more than absolutely necessary?



I suppose that would be another fringe benefit of the added pusher pumps, keep pressure all along the line, and avoids air leaks in the system from sucking fuel with the stock system...

 

[juicedcummins]

Big White Beast;

What is the micron size of that inline filter? Nice neat little unit as long as it isn't too fine for this application. From what I've seen in the past if you are buying unfiltered pump fuel you need a large capacity primary filter of around 10 mic, no less.



The siphon effect that this thread was started on can also be traced back to a bad or poor designed fuel cap. For the last 17 years{6 diesel powered pickups and 3 VW"S} I"ve had to drill a little hole in ALL my fuel caps because there should be NO vacume in the tank.

1 pound of vacume = 1 less pound of presure and more strain on supply pump.





Gary; ROTFLMAO Have you even put a tank of fuel through your ride since your install of your pusher? Probably not and it's already the cure for all. That's as bad as all the pro DTT stuff that used to go on around here. { not slammin DTT they make an top notch product and their customer service second to none}

Welcome to the dark side!{recent Comp install}

 

[WadePatton]

siphon/head

Yeah, whatever, I still keep the tank topped off, and advise it to others who are flying blind. ---now to go check out the Briar Hopper gauge readings.

 

[Gary - K7GLD]

"Have you even put a tank of fuel through your ride since your install of your pusher? Probably not and it's already the cure for all. "







'Scuse me? Exactly what are you trying to say here?



If the intended inference is that *I* am in any way attempting to claim MY particular install, components, or "engineering" are any better than anyone elses - or that what I specifically have done is an undoubted "cure-all" for LP or VP44 issues - please provide a quote from me to that effect...



I am as much a "babe in the woods" in this LP stuff as the next guy, and certainly don't claim to be otherwise... Any more than the Comp install will instantly transform MY truck into the fastest thing on 4 wheels...



Perhaps I misunderstood your meaning - I certainly hope so...

 

[EricBu12]

heres what I did. I have the shotbed so I had to hang this unit over the driveline fron the center crossbar above the tank. the pump ends up about half way up the tank and the filter is a 30 micron Racor. I have 12 psi Idle and I am thinking of replacing the pusher with a reg 15# for the added restriction of the filter.

 

[juicedcummins]

Gary, Don't sweat it, I'm just pushing your buttons.



Please keep us informed off any probs in the future if you have any, and the remedy if fiqured out. I know we are both trying something different and in the end they should both work.

The route I took is to see if the factory lift pump is realy the prob or if a badly designed system is to blame. All electric pumps fail in time just some sooner than others.



Off the top of my head it was either you or BWB that had mentioned wiring up the pusher supply. The relay I used to get power to for rear mount had 2 output terminals. This would work well if you used a heavy enough gauge of wire to feed the relay and each pump. This should give you a low pressure crank mode without using a switch. {I'm not sure because I haven't gone into depth with it yet. }



Good luck

 

[Gary - K7GLD]

The relay I used was a standard Radio Shack job that has a pair of double pole 15 amp contacts - the 12 volt actuating coil draws a puny 75 milliamps - hardly enough to notice. I attached using both relay wires to each of the 2 wires to the stock LP, and thus, the same startup control that actuates the stock LP momentarily, then shuts it down, does the same to my added pump - tho' IT has its own independent fused 12 volt supply line.



So far so good - time and miles will tell... I just today bought a digital camera, so plan to take a bunch of decent photos to post over on the web page pointed to in my "other" sig.



I might sorta annoy some of the longer term regulars here with the volume and content of some of my stuff - but subjects related to fairly significant problem areas - and the various "cures" tried by various owners has proved invaluable to me in my effort to head off future problems with my own truck - especially since the addition of some of the stuff has shifted virtually the entire warranty issue squarely upon ME for correction... I can only assume other "newbies" to these newer trucks, like me, will also appreciate as much info as they can obtain. I have no problem dealing with criticism related to my assumptions or comments related to this stuff, but one of my persistant failings, is my (jn)ability to absorb PERSONAL criticism or ridicule when all I'm trying to do is contribute what I feel is helpful information - in other words, attack the message if ya must - but be gentle with the messenger - he's old and crotchity! I like to kid - and can TAKE (and GIVE) a lot of kidding - as long as it's clearly indicated as such...



No harm o no foul!

 

[TomGolden]

Gary,



I got my helper pump in on Saturday. I now have 21. 5PSI at idle and at least 16 PSI while cruising down the road. Where did you get the pre-pusher pump fuel filter you're using? That is my next search, to find a good filter.



Oh, and in case you hadn't seen my threads in the Local/Regional events forum, I'm working on getting together another diesel BS & drag racing session in Sacramento for this next Saturday August 3rd.



Tom

 

[Gary - K7GLD]

Tom, the Purolator filter I used was from Kragen Auto - learned after I got it home that it has metric threads - I was able to thread required fittings in far enough that I'm not concerned about it, and no leaks - but will be looking for a similar but US threaded one as a spare and for future use.



I've seen your info on the get-together in Sacramento, and sure would like to make it - but have camping reservations up at Pollock Pines for the weekend - y'all have a GREAT time tearing up that asphalt!

 

[Bigsaint]

I don't know guys, 21 psi's at idle still seems like too much of a good thing in regards to the VP44 for me. I'm not flaming anyone, if it works it works I guess. I can say that it's beyond overkill regarding what is needed, at least for me with no banjos inbound. My current pump is set at 16 psi's at idle and I can't drag it much below 10 psi's at WOT, I might see 9 for a fleeting second, then it quickly rebounds to 10-12 at WOT. If nothing else, you all have done some great work on the installs. I really like Tom's idea of dual ball valves to wade off the diesel bath.



Kinda interesting, tonight I filled up as I was at 1/2 a tank. This time I watched my mechanical pre-filter FP gauge carefully and it rose by . 5 a psi when full compared to 1/2.



Scott W.

 

[Steve Campbell]

Scott...

Is that increase in fuel pressure what is known as "statistically significant"

 

[Gary - K7GLD]

Scott, I agree - my pressure is a bit higher than I had expected or wanted, but it's what I got, and probably will reduce slightly as the stock LP and the added pusher wear in a bit. Also, I expect that my use of all the stock lines and fittings provide a small amout of restriction that make guage readings somewhat higher than the VP44 is really seeing.



As it is, at idle and coasting, I frequently see an indicated 25 psi - this weekend's RV pull up the Sierras will give me a better idea of WOT readings under full load and Comp settings...

 

[15w40]

I did a quick calculation to find out how much pressure is needed to raise diesel fuel one foot.



Diesel fuel has a density of 0. 815 to 0. 855 g/cc. I’ll use 0. 835 for the calculation.

There are 454 grams per pound. There are 29. 4 cm per foot. There are 6. 45 square cm per square inch.



To lift diesel fuel 1 foot will take 0. 349 pounds per square inch of pressure. A near empty fuel tank will change your pressure reading by about this amount.



I think I have WAY to much time on my hands!

 

[Bigsaint]

Steve, I doubt it's significant, just an observation. My FP reading on the mechanical gauge is always +/- 1 psi, depending on the outside temp. / fuel temp, etc. I'll watch it again at the next fill up and see if it does the same.



Gary, I know that Steve St. L, probably the first to use a pusher pump, checked with a Cummins Tech. and was told that the high pressure of the added pump won't hurt the VP44. Others that I have spoken with, that know a heck of alot more than me, say it's too much . The good thing is that many have been running the pusher pump set up for quite awhile, I don't recall one stating that they had a VP44 die on them while using the pusher.



My goal is to find a single pump that will stand the test of time without the need of a return regulator or a true gravity feed set up. The one I have now looks promising, but they all do when new. If it makes it to the fall, I'll remove the zip tie and give it a more permanent mount, as it has earned it .



Scott W.

 

[Steve Campbell]

Accidental experiment...

I just installed a rear mount 4601HP on a friends rig yesterday. I took the factory unit off, extended the wires, used the fitting from the tank side of the lift pump on the filter (internal dia was way larger) and put a spring on the fuel lines at the pump where I had to bend them (To keep them from collapsing). Just as we were ready to start the truck we bumped the key to prime the system. The owner was looking at his SPA (Thanks HVAC) guage and said "negative 4 lbs". Well we reversed the wires on the lift pump and all was right in the world.



I guess the thing that was notable was the -4lbs in the suctioon mode and the 15lbs in the pressure mode. These things really do PUSH better than they SUCK fuel.