Engine/Transmission (1998.5 - 2002) I want a pusher

[Ncostello]

A couple of pusher pump questions:



1. Assuming a low pressure hi volume pump like the ones so many use, which pump can be installed in series and fuel still be pulled through by the stock LP in case of pusher failure? Carters?



2. Should one install a low restriction filter between the tank and the pusher? In otherwords is the restriction by a dead pusher and filter setup a major restriction to an already ailing stock setup and would therefore overwork the stock one in short order. I'm thinking it is.



3. If the stock LP fails, can a pusher still pump through it?



4. I get the feeling the pusher pump should only run when the engine is running and not when starting to prevent overpressure at starts. Is it best to let the stock unit handle the startup and the pusher kick in once the key is in the run position.



I have read archives till I'm dead tired tonight. I've concluded I would like to install one cause I believe that 20psi idle shouldn't be fatal to the VP44 as we all know 0-8 psi can be. Thats my feeling. I'm willing to roll the dice on that one. I'm wanting to keep it simple on mine. Short answers are fine. Or elaborate if necessary.



I really admire the ingenuity of all those who have done this. You guys are really what keep these trucks going strong. If DC would only listen to all this and adapt it. Imagine, true 350,000 mile intervals without fuel problems. Wonder what the 03's use, the same old lift pump??

 

[fj40charles]

Here are my replies... .



1. Assuming a low pressure hi volume pump like the ones so many use, which pump can be installed in series and fuel still be pulled through by the stock LP in case of pusher failure? Carters?

>>> That is supposed to be the case, but I have not tried it out on my truck. Hopefully someone will chime in and verify.



2. Should one install a low restriction filter between the tank and the pusher? In otherwords is the restriction by a dead pusher and filter setup a major restriction to an already ailing stock setup and would therefore overwork the stock one in short order. I'm thinking it is.

>>> I don't know about this. I didn't install a filter before the pusher because I don't believe the majority of the pump failures are caused by debris in the fuel.



3. If the stock LP fails, can a pusher still pump through it?

>>> I would think so since our VP44 will still suck fuel when the factory lift pump dies.



4. I get the feeling the pusher pump should only run when the engine is running and not when starting to prevent overpressure at starts. Is it best to let the stock unit handle the startup and the pusher kick in once the key is in the run position.

>>> I turn on the key and wait to hear the pusher and lift pumps run for a while. After about 20 seconds the lift pumps will stop and the pressure will drop back down to 0 and then I'll start the truck.



I have read archives till I'm dead tired tonight. I've concluded I would like to install one cause I believe that 20psi idle shouldn't be fatal to the VP44 as we all know 0-8 psi can be. Thats my feeling. I'm willing to roll the dice on that one. I'm wanting to keep it simple on mine. Short answers are fine. Or elaborate if necessary.

>>> Got my lift pump kit from Piers. You can get it from Enterprise or ADT. I think they'll all about the same. Some have just moved the factory lift pump to the rear and have had good success. Gordon at Practical Solutions makes a wiring harness to help you with this. I have not seen or used this harness, but have bought other stuff from him. He makes great stuff at a reasonable price.

http://www.psdieselproducts.bizland.com/





I really admire the ingenuity of all those who have done this. You guys are really what keep these trucks going strong. If DC would only listen to all this and adapt it. Imagine, true 350,000 mile intervals without fuel problems. Wonder what the 03's use, the same old lift pump??

 

[EricBu12]

costello,

I did what you are refering to.



I wired mine up to a relay from the front pump wire and powered it so that when the fron is running, the back runs at the same time.



I did use a 30 micron filter from Racor a 600 series (45) and it has several in and out ports. one goes in, and out to the push pump (carter 7# 100GPH) and there is another "out" I used to a SS pipe to a one-way valve so that if the pusher fails, the lift will be able to draw through the valve from the filter. The restriction is a little bit but not much, I get 12# idle, 10-12 cruise, and 8# WOT. so i think it helped from being an over pressure issue. .



Bosch has said that the VP 44 can run at 0 to 12 psi and siad that over preassure is harmfull to the VP 44 so I told him what mine was and he said that was ideal.



Here's a pic of my install if you haven't seen it already

 

[ABrameloah]

>>> That is supposed to be the case, but I have not tried it out on my truck. Hopeful

Well I can chime in about the carter pumps, as a Federal Mogul stand point go,s you can not pull fuel through the P4600HP(8 psi 100 gph) or the P4601HP(18psi 100 gph) as well as any of our rotary vane pumps with out a vary vary high amount of vacuum and then the flow would be greatly reduced.

 

[Ncostello]

Eric, do you still use your stock LP, I assume you do. It seems to me that your pressure numbers are somewhat low since a good stock setup should produce 15psi and a little lower when your WOT. Your stock LP must be weak.



Or does your inline filter create the restriction that drops the overall final pressure to 12psi idle.



Seems like most who have done this are consistently displaying 20 or more psi at their guages.



Just wondering why yours does different.



Abrameloah, looks like we need to run bypass check valves around the pumps then. But those alone are proabably big pressure drops making the stock LP work pretty hard.



I guess it all depends on two things... . how much pressure can the VP 44 stand (during and after starting) and how reliable are pusher pumps.

 

[ABrameloah]

Pump kit

Well Ncostello we (F-M) do make a pump kit,( part # P4602RV ) that has a bypass valve in it along with the fittings to do the job. The pump was made for RV and off road use as a booster set up. The spec,s on this pump are 8PSI and 72 GPH and is made for a 3/8 line. If you would like to get just the bypass valve we make it to,part # 169-1002 . (the part numbers hear are all carter)

 

[RADdodge]

Ncostello – I used a set-up similar to Eric’s, though I don’t understand why his pressure is considerably lower. You can see the Racor check valve in his picture that allows the Lift Pump to pull directly from the Racor Filter. I have a switch in the cab to enable/disable the Pusher Pump. When the Pusher Pump is disabled, I see about 12 – 14 psi at idle. The check valve and the Racor Filter do not create much of a restriction when the filter is clean. (you can also use a Racor gauge to monitor filter health and water in the fuel. )



BTW, for those that feel that 45 gph is too low for their application, the fuel flow can be easily changed (60 & 90 gph) by replacing the spin on filter, though the larger capacity filters are longer so they will hang down a bit more.



As far as wiring goes, we used the Starter Circuit to power the Pusher Pump. This way the Pusher Pump runs when the Lift Pump runs except when the Starter is engaged. For a wiring diagram, see our pictures link at the bottom of this post.



Currently my pressure at idle is about 20 psi. At WOT it is about 12-14 psi. My next experiment will be to replace the Lift Pump with another “Pusher” Carter pump (7 psi). I’m expecting about 12-14 psi at idle and 8-10 psi at WOT.

 

[Red360]

Pusher pump can stop fuel

When my pusher pump failed, the truck just died. I used a piece of 3/8" fuel line to bypass the pusher, and after 20 cycles of the key, the truck started and ran fine. I do believe (Shooters) pusher pump died as well and his truck would not run until bypassed. Both pushers where installed on the same day in both trucks. This weekend I am going to remove the stock lift pump and install a Carter 4601HP where my "dead" pusher now lives. I believe that you really don't need to waste your money on a pusher... just install the main pump where Dodge should have put the damn thing and that is on the frame rail next to the tank. JMHO

 

[Gary - K7GLD]

WELL, it's too late tonite to run a check - but tomorrow I will disable my Carter 4600 pusher, and see what happens to pressure... Before the added pusher, I was seeing 16 psi at idle from the stock pump alone, and as I recall, down around 12 psi WOT... It's simple for me to disable my pusher - all I have to do is pull the relay that controls it, and see what happens - I have been intending to do that anyway just to see what effect it would have on the rest of the fuel system...



OH, yeh - WITH the pusher, I am seeing 25 psi at idle, 21 at cruise, and about 18 or better WOT on steep grades pulling our 5er, and with the Comp on 5x5...

 

[Ncostello]

This may be redundant but...

I really didn't study my new lift pump with a magnifying glass but... I thought it said Carter on it. I may be wrong. And these pusher pumps look an awfully lot like the stock LP. Are they different? They sure dont look like they are different. If they are it must be internally.



And if a high pressure pusher (15psi) is installed at the tank area to completely replace the stock LP, could one just make a wiring harness extension to run the stock LP wiring all the way back to the lone pusher and it would basically operate off the engine signal/power that used to go to the stock LP. Sounds simple... if these pusher pumps are OK to have duty cycle voltage drops (decreased pumping capacity in turn) and not burn up over time. Seems like I remember once that low voltages kills 12V stuff, like starters and perhaps lift pumps.



Now, for another question (or thought rather). When the stock LP dies, the VP44 assures its own fuel delivery, albeit only enough to keep the engine running perhaps while not doing much for lubrication and cooling. Anyways, when a single pusher back by the tank has replaced the stock LP, and it dies, will the VP 44 be able to overcome this dead pump as we all know it can with a stock LP. Seems like some say when a auxilliary pusher (in tandem with the stock LP) dies, the truck runs out of fuel, unlike when a stock LP dies all by its lonesome. So perhaps they are fundamentally different.



Good discussion here. Lots of ideas to whip the LP problem. At least we are all aiming at one thing... 15-20 psi fuel pressure at the VP44 inlet, all the time, for as long as we drive these rigs. No road side repairs would be nice too.



Sorry I'm long winded here, but one more idea for those using both LP and pushers. I bet somehow you could get an electronic device/switch that switches on 12V power to a pusher pump after a predetermined amount of time, say 30 seconds. So then you could start the truck on stock LP circuit, idle for a bit and then the lift automatically turns on. That would cure any hard start problems due to over pressure. And you could wire it from about any 12V (ignition hot) source. You could easily have a toggle underhood to disable completely if you wanted to have the stereo on only or something with the key on.

 

[fj40charles]

Gordon at Practical Solutions makes a wiring harness if you want to relocate the stock lift pump.



http://www.psdieselproducts.bizland.com/



I have no doubt that it is well made. I've bought stuff from him and they're all high quality.



Disclaimer: not affliated with any vendor.



Charles

 

[Red360]

Wiring harness

Instead of buying a wiring harness from PS, all I did was buy the extension plug from Cummings which is 7" long lengthen it to run the pump that I'm installing today. I even bought a spare pump. You can buy two Carter P4601HP's for the cost of one stock lift pump.

 

[Gary - K7GLD]

"I bet somehow you could get an electronic device/switch that switches on 12V power to a pusher pump after a predetermined amount of time, say 30 seconds. So then you could start the truck on stock LP circuit, idle for a bit and then the lift automatically turns on. That would cure any hard start problems due to over pressure. "





As promised up above, I tried disabling my Carter 4600 pusher, got in the truck, started it up, and ZERO fuel pressure! The truck started and idled OK, but I wasn't ABOUT to try driving it that way!



SOOooo, that sorta kills the quoted suggestion up above - when/if the added pusher dies on ya, you stand an EXCELLENT chance you will be left with a MAJOR VP44 killing obstruction in yer fuel line!

 

[Ncostello]

Gary, I'm not surprised...

Anyone... I need something answered... is a 15psi pusher pump (Carter) basically the same as the lift pump supplied on the engine from Dodge. They both are Carter right?? They look the same. Are the internal pumping mechanisms the same? Or are the factory ones that come with the truck made to slightly different specs than what you could buy aftermarket (known to these discussions as the pusher pump). I figured Dodge or Cummins told Carter to supply a pump like the pushers except with some diffierent volume requirements or ???



Gary, I took my "dead" factory lift pump apart and can see why if the electric motor totally stops spinning, the pump impeller is basically a "dam" blocking fuel flow, or severly restricting it.



I have developed a theory I believe is true from my observations, findings, readings etc. I believe on a totally stock truck, most lift pumps dont totally stop rotating completely. I believe either the bypass valve spring weakens and they just pump fuel around themselves... . resulting in low pressure, low volume but not blocked off fuel. Or they operate at some slow motor speed and give a little volume and not much pressure. (If they completely stopped, fuel would have little chance getting past the pump impeller the way its designed). I believe since its so close to the injector pump, the VP44 is able to "draw" or suck some fuel out of the dis-abled lift pump. Not much, but enough to run OK.



I believe that if any factory lift pump completely stops, fuel would have a very difficult time getting past it, causing engines to quit running or run very poorly as if out of fuel. If trucks continue to run on a "bad" lift pump, the pumps must have not stopped spinning totally. So what happens is the VP44 draws its own fuel in past the failing lift pump. The lift pump is not really giving pressure, or volume but at least since its rotating, its not blocking the fuel from going through itself.



So if you have a pusher in addition to the stock lift pump, and the pusher completely stops rotating, fuel is most likely blocked and the stock lift pump can not pull fuel past it well, if at all, thus 0 psi.



Next, larger delivery fuel lines should be used. Friction loss in small diameter line is so great, increasing the size could cut that in half or more. For example, four 2. 5" dia. fire hoses can not flow as much as one 5" fire hose at a given pressure. Just cause a fuel line is 3/8" diameter does not mean that fuel flows through it in a 3/8" flow stream. The fuel in contact with the walls of the line does not move well if at all. Its called laminar flow dynamics... so only some portion of the central core of the filled fuel line actually contributes to delivery volume. So if you increase line diameter, fuel more volume can be pumped through much easier, at the same 15 psi pressure, with way less loss to friction and easier on the pumps. Thats why people like bigger Banjo holes.



I believe the stock lift pump mechanism looks a lot more suitable to push fuel than it does pull fuel. One look at the impeller kinda gives that impression. I think Im gonna put mine back by the tank all by itself. That shoud do it. I would like to hear from those who have done this move. NOTE: I'm talking the stock lift pump moved back to the tank... no pushers involved.



Finally fuel pressure guages are super, extremely needed to monitor this vital info. Without them all you can have is theories like me.



And the only thing I am absolutely positively sure of without a shadow of a doubt in all that I have mentioned above is that I do NOT have a guage yet. The rest is just a theory... hehe. But I like thinking, and I will do some testing on my old dead pump.

 

[Gary - K7GLD]

Myself, I'm thinking that when I next have to pull my pusher/filter assembly to change the filter, I will fabricate a simple bypass AROUND the Carter 4600 to steadily allow a SMALL volume of fuel to simply circulate from output-to-input on the Carter - perhaps a 1/4 inch copper line permanently attached - I already have LOTS more pressure than I really need, and even a relatively small 1/4 inch line would allow enough fuel flow to reasonably keep the Cummins in operation, even if the added Carter DID fail - NOR would such a setup even require any operator intervention, as some fellas have done with similar arrangements using various valves, etc. , to manually re-route fuel flow in such an emergency...



After all, who wants to be crawling around in the dark under their trucks on a cold, wet saturday night - in their good duds on the way to a dance, cuz their pusher pump failed...

 

[Cliffman]

How much is too much

EricBu12, Did Bosch happen to mention how much preasure was too much?

 

[EricBu12]

He said the operating Peramiters were -02 psi to 15 or 16 PSI He had to try to convert Bars to Psi but he was close... He did say that around 20 or more was harmfull to the internal componants of the pump. . I would say that since he was from Bosch, he knew what he was talking about. Since -02 is the lower of the operating perameters, if it was run that way long enough, it would kill it especially under load... . so my #6 are good, right in the middle for load conditions.

 

[Cliffman]

Wow!!

That goes against everything I've read or heard . DC says nothing lower than 8-psi. I'm running the helper pump kit from Enterprise. It's a Carter hooked in series. My Idle pressure is 18, my driving pressure is 15 and at WOT I'm down to 10. Well, at least I’m not in the 20 psi overpressure range

so I guess I'm safe

 

[Gary - K7GLD]

"He said the operating Peramiters were -02 psi to 15 or 16 PSI He had to try to convert Bars to Psi but he was close... He did say that around 20 or more was harmfull to the internal componants of the pump. . I would say that since he was from Bosch, he knew what he was talking about. "



AS has been commented on before, in relation to the above claim by the Bosch guy, I think it would be adviseable to find exactly at what POINT in/on the VP44 those pressures should be registered! After all, we KNOW from long past experience that they will, and DO fail pretty predictably when psi drops below 5 psi or so... We also have a fair number running over 20 psi without failure - mine is at 25 psi at idle, 21 at cruise - and to date, *I* have only heard of ONE VP44 that failed due to fuel leakage at the pump seals, *possibly* due to excessive pressure - tho' we are told SOME guys have operated them up close to 50 psi successfully.



Bosch "expert" or no, *I* will take MY chances, and gamble my money on MORE psi, rather than less...



After all, WHO is gonna warrantee yer VP44 - DC, or that Bosch guy - regardless of his credentials and good intentions? - I prefer to conform to, and benefit from, "real world" experience, rather than what comes from behind some distant "experts" desk...

 

[Cliffman]

Ahhh ya, what Gary said!!