Engine/Transmission (1998.5 - 2002) pumps, lines & whatnot

[Bent6]

Chris-
The only problem I can foresee with the in-tank pump scenario is that most applications using an in-tank pump have baffling to keep fuel available to the pump pickup. I don't know if our stock tanks have this. #ad
What Holley pump are you referring to for the in-tank scenario? - Will

 

[Arcticat]

As far as I know I am the only one that has tried the Summit pump. It has been on now for about 3000 miles, with half that towing around 8000 lbs and pulling a constant 20psi of boost running 75 or so on the interstate. As of right now it is performing flawlessly. I have the stock tank pickup, -8 line to the pump, -8 line to a drilled out filter housing, stock fuel filter on a drilled out post, and -8 to the injection pump. I take my pressure reading with an Autometer electric fuel pressure gauge with the sender mounted immediately after the fuel filter. I get 15psi at idle and no lower than 13psi at WOT. The pump is rated at 140 gph, so I feel safe running it without a regulator and letting the overflow valve on the injection pump take care of the excess fuel.

Now for my two cents on pumps in general - I have right from the begining of this saga thought that the BG or any other huge volume pump was overkill in this application. Actually I didn't come to this conclusion on my own, sportbike suggested that I get a smaller pump that had a lower output. So I chose the summit because it was the lowest output I could find besides the Holleys which were gatting a bad rap at the time. I don't personally see the need to mount the pump in the tank or put a pickup in the bottom of that tank. Anybody who has ever siphoned gas out of a gas tank can tell you that it isn't a huge amount of effort to get the thing to gravity feed if the pump itself is mounted at or below the bottom of that tank - fluid always seeks it's own level through whatever plumbing is there. I could be way off on this, but I think a good pump can live just fine as close as possible to the tank while still using the stock tank module location for the pickup tube. After all, there are almost 100,000 CTD's sold every year with the horribly positioned pump which is not only far away from the tank but also above the tank, which means it is always forced to suck fuel rather than push it. And yet most of these trucks run fine. Yes I know the sytem has problems, but it illustrates the point that a pump can work fine without actuall being submerged in a tank or gravity fed.

 

[csutton7]

Bent6--go to www.jegs.com and click on the online catalog--then fuel pumps-then I think electric pumps and then Holley in tank pumps--chris

 

[Mopar-muscle]

well , here we go again , todays test was interesting to say the least , and we believe we have it figured out .

added the carter HP 15psi 110gph pump on the frame rail next to the tank , -8 bulkhead in the bottom center of the tank , -8 line to the pump , -6 line from this pump to the inlet of an unmodified factory 2000 fuel filter housing , the rest of the system is as delievered from the factory except for a banjo bolt that had the schrader cut off and tapped to 1/8 npt for the gauge , the digital flow meter in the exact same location reading flow back to tank after the tee on the engine .

with DD2 , DDTM

psi volume
idle 11. 5psi 18gph

cruise 9psi 24gph

WOT 6 psi 30gph


with the HOT PE on any level

idle 11. 5psi 18gph

cruise 9psi 24gph

WOT 4psi 30gph

with the addition of the new pump and larger gravity fed pickup point the flow to the tank did not change , though pressure was up , the carter having an internal bypass is living with the backpressure on its output .

the concenus is the VP44 is the restriction . the return line from the pump is only returning the excess fuel from the VP44's own internal pump , the more you feed it the higher the backpressure on the line to the pump .

the guys with the large pumps , bigger lines and regulator mounted as close to the VP44 as possible have a large amount of the excess flow returned directly to the tank , this is not a bad thing ,( except that at a low fuel level it is possible to foam the fuel in the tank with the large amount of fuel dumping back into it from 2 sources ) but is really overkill as the vp44 uses a set amount of fuel and this is proved by the higher pressure seen with no increase in flow back to the tank .

again , the higher the pressure , the lower the flow , BillW explained it perfectly on the prime loc bashing thread and no one ( including myself) understood it or tryed to test it to see if it was true .

someone asked if there was a pump that was between 60 and 100 gph , again carter to the rescue , there street pump , 15 psi , about 70 gph , this pump mounted as close to the tank as possible is the best scenerio .

the factory designed the system to have the least amount of restriction with the most flow given the flow characteristics of the VP44 .

i have not seen the info on HVAC's 34 hp increase with fuel system mod , i will be talking to him to find out the poop on that .

we also felt what happens when you have no flow , we had a low fuel level in the tank and under the bulkhead at the botom of the tank , the engine cutout , if the 0psi had no flow , we would have experienced this same bucking .

next we will move the factory lift pump back in place of the carter hp pump

[This message has been edited by Mopar-muscle (edited 04-26-2001). ]

 

[B. Gill]

well ,it seems like when the pump demands more fuel the internal mechanism reduces the restriction,thus more flow and lower pressure and vise versa.

MM while you are testing can you please test as to what pressure is the VP44 regulater in it set ? if you already know then post the #.
thanks
bob

 

[Strick-9]

Mopar,

Sorry, I take for granted that everybody on this site reads EVERY post like I do. #ad


Here is the quote from HVAC about the hp increase.

On the otherhand, although I will need Dr. Donnelly to explain what happened, my new fuel system showed results on the dyno!! I'm rather STOKED about that. This may be as simple as the age old axiom-fuel = power. I will need to back up the results on another dyno, but I am now running at 400(was 350) hp in street trim, 500(was 450) with the propane, and 600(was 550) with the Power Edge on. Please note that we achieved 586. 1 hp without the Nos! This is about 36 hp over my previous best, short of the Nos(new solonoid isn't hooked up). Could this be due to the improved fuel supply????

I will try to retest next week but at this time all I can say is the I had some very significant gains and the only performance modification I did was the revamp of the fuel system.

Here is the thread

-Chris

 

[B. Gill]

MM i am sorry i forgot to add ,what i asked is the set regulater pressure with engine shut.
thanks
bob

 

[Todd T]

MM, thats great news, i have been going over this, and Bill K's warning/hint to us, in my head the last day and a half. i got on here today to catch up and then post what i have been thinking about, basically with the readings you gave us from your first tests, I started thinking that we are on the wrong track trying to use as large of lines as possible. and with Chris's input too, i started thinking we just need, a little more volume to the pump, and a little more robust pump to handle that extra flow. then we need to leave alone the return lines. this will keep pressure up to the return side of the pump (that means its internal workings too) this will keep the pump lubed and cool, and the restrictive return will keep us from seeing the 0 PSI at WOT.

because the VP44 pump, will return ALL the fuel, it will use what it needs for the engine, and return the excess. all the while keeping the pressure above 0 and the pump well fed. as your findings indicate the low PSI is ok, as long as the lift pump or other keeps the VOLUME up.

with that said, i will take mine a step further, i plan to install a inbed tank with a bottom pickup and return (to keep foaming down)and will feed the system with a 70+GPH pump. this will insure the pump stays fed, the increased fuel capacity will be all the better, to keep the temps of the fuel lower. The factory tank will then become my reserve tank, which i will pump from it to the inbed one.

 

[csutton7]

Todd T---Brandon & I have talked about the same setup for the last month except with a bigger pump, so I like where you're headed with this--it should work awesome--the only thing I would be prepared to do is add a regulator if your pressure is to high at the VP44--I don't think you'll need to, but just in case--we know that the VP44 can handle a lot of fuel, but we don't know how much pressure it can handle before it gives up the ghost---good luck----

MM--again great info--and thanks for taking the time to figure this out---so now how are you going to setup your system--gravity fed or not--bigger lines or not--which pump--on the gravity fed tank bulkhead did you use the straight one & then a 90* fitting or the 90* bulkhead and did you use the poly washers or something else, any sealant of any kind ???---thanks chris

 

[TXRam]

OK, I have some info on our precious VP44 coming from Bosch. It is a CD-Rom for training technicians (?) on the pump. Cost about $25. I was told I would receive it in 1-2 weeks. Supposedly it will have internal diagrams, explanations of the inner workings and electronics, etc. At that point I should be able to better determine what the actual needs are, things not to do, failure mechanisms, etc.

When I get it, y'all will be the first to know!

MM, from what I understand, all the flow that you're seeing is what "by-passes" the injectors (per the service manual, excess fuel lubricates the injector and flows into in fuel return manifold - the "T" at the back of the block), not any coming from the the by-pass valve in the VP44, because it doesn't open until pressure reaches 14psi. So you still don't know that the VP44 is getting 100% of the fuel that it needs - the injector pump is pulling harder than the lift pump is pushing once the pressure reaches zero. This cannot be good for the pump.

Until I get the info from Bosch, I'm sticking to my original theory - anything above 0psi (2-3psi) should be adequate, but definitely not 0psi or below.

 

[Mopar-muscle]

chris , bills truck has a straight bulkhead and a 90* hose end , to me its very vunerable and if you should decide to go that route you need to add a skidplate of some sort , you never know what will or could happen .

next we are going to put factory pump in place of the HP pump . expect the same results .

as far as the return scenerio , i really doubt that much fuel is coming from the head alone , the overflow from each injector can't be that large , there is a greater flow on the input to the internal pump of the VP44 , that is the bulk of the return , put mot\re on it and all you are doing is straining your lift pump , adding a regulator at the input will help the VP44 and help your lift pump , but do you really need 300 plus worth of pump and regulator , plus another 500 in bigger pickup and braided lines when what is supplied from the factory is doing the job ? relocating the stock pump and cleaning up the banjo bolt restriction is all you really need to do , i'm over 500hp at the flywheel with the factory pickup and -6 lines , no stumbling .

txram , i'm not saying that 0psi is acceptable , until i got a flow meter on the truck in the return path i thought i was starving the engine for fuel , the eyeopener was adding a higher volume pump and a larger gravity fed pickup line and not see an increase in flow back to the tank . having 2-3 , maybe as much as 5 at wide open throttle is enough , more than enough , its these guys with 20 psi at the inlet to the injection pump that are going to possibly have a problem , maybe a $1000 plus if they hurt something inside the VP44 .

chris , not sure my final setup yet , but it will be with the factory pickup tube and - 6 lines and possibly a 70 gph pump of some sort , the VP44 only uses 45gph in an unmodified state , no need to feed it 220 gph .

 

[TXRam]

First off, I went back and re-read a couple of my posts - I hope nobody took anything the wrong way. I just get to typing what I want to say and don't watch how I say it. No offense and not trying to sound arrogant or anything like that. Really and truly just trying to help out here - this is something that I've got to fix on my truck, too. And if I know something that my help someone save a few bucks, i'm going to speak up. Now we can all just have a big group hug? #ad
You too Bill! #ad


I guess what I am trying to say is that, in a sense, if you have 0psi (or less, who knows once it hits zero), you are "starving" the pump. It is pulling more fuel than the lift pump is pushing on its own - exactly what we all agree is not the best thing for any pump. It may not give you any signs before it destroys itself.

The other thing I want to make everyone aware of is that if you come off of the bottom of the tank, but leave the pump in the original location, you have done absolutely NO good for the pump. The two things that really matter are 1)distance of pump from the tank - the closer the better, and 2)height relation of pump to fuel level (tank) - for example, if the pump is located at the same level as the middle of the tank, and the tank is half full, it doesn't matter whether the fuel hose comes from the bottom or the top, once the system is primed. Think about this - when you syphon gas from a tank, once it starts, you just keep the end of the hose below the level of gas in the tank and it keeps flowing. If that hose went into the bottom of the tank, again, just hold the hose lower than the gas level and it keeps flowing - no difference except that you had to get it started for the hose going in the top. Does that make sense?

 

[Mopar-muscle]

TX , no worry , i have gone off on a couple different tangents myself over the last couple weeks , i also agree that though my testing has shown that at 0psi i haven't lost fuel flow , its not giving me a warm fuzzy feeling , somewhere between 2 and 5psi is more than adequate .

as far as pump placement , to me and a lot of others, moving the pump rearward is a must for pump longevity . i have the factory pump moved back , we are waiting for a fitting so we can head home and check this phase .

keep in mind all testing is being done using the factory supplied voltage to the pump , no matter which pump or where its located .

the next test after this, should it pan out ,is with the stock fuel pickup and stock pump relocated to the rear . right now its bottom fed from the tank with a -8 line , we drilled the stock pump for a 1/4 npt on both ends , no turning back .

[This message has been edited by Mopar-muscle (edited 04-26-2001). ]

 

[Mopar-muscle]

did a preliminary test on the way back , strange happenings led us to believe that we were low on fuel , fueled up and still had problem , did some checking under hood and found a wire disconnected from the map sensor to DDTTPM , after reconnected , all back to normal . testing being done with factory line ,unmodified banjo bolts between the filter and inlet to the VP44 and factory power supply to the pump .

DD2 , DDTT

psi gph

idle 11. 5/12psi 18gph

cruise 10psi 24gph

WOT 5psi 30gph


quick check with PE on level 3 saw fuel pressure not drop below 2. 5psi and 30gph . moving the stock lift pump back to the tank with a -8 line and fed from bottom of tank has made the 0psi concern no longer a concern , will do more testing in the AM .

also note that cruise psi is up with the factory lift pump moved rearward .

tomorrows last test will be to reconnect the factory pickup with the factory lift pump at the tank , should be interesting to say the least .

 

[csutton7]

been looking at the #'s that Mopar Muscle has posted and it's got me thinkin'--hold the jokes please---but anyway we see that basically the VP44 returns 18 to 30gph to the tank depending on the throttle position---so if you have a pump that's putting out 60gph that leaves 30-42gph in the lines to keep the truck running, but we know it doesn't take that much, so we got a lot of fuel being pumped that's not getting used or returned and so what's it doing??? if you don't have pump with an internal bypass(if I'm correct in my thinking) your pump is pumping against a lot of fuel--I don't think this is to good for a pump no matter what size it is---do we need another regulator/return line to the tank besides the stock is my question?? It would sure seem so if my thinking is correct---get the excess fuel back to the tank so your pump stays cool and is not working against itself----am I off base here----I know I said earlier that I didn't think we needed another return line with the smaller gph pumps, but these #'s got the noggin churning, so now I'm wavering---chris

 

[Bill Kondolay]

If you pump too much fuel does the fuel get hotter or cooler?

At what temperature does diesel fuel lose its lubrication capabilities and will it affect the vp44 pump?

Since we now know the vp44 pump does not share its bypass system with the lift pump, will the higher back pressure have a negative impact on the vp44 pump?

 

[Un-Hemi]

Gentlemen:
According to the Chrysler 1999 Ram Service manual, page 14-80, in the Overflow Valve Test procedure item 6, it says "Internal check valve should release, and air should pass through valve at 97 kPa (14-16 psi). If not, replace valve," Item 7 reads "Reduce regulated air pressure to 10 psi and observe valve. Valve should stay shut. If not, replace valve. "
If the valve is *closed* when pressure is less than 10 psi, then where is the fuel that is returned to the tank coming from?
TXRam, I tend to agree with your assessment that the bulk (if not all) of the fuel that MM is seeing returned to the tank is from the injector fuel drain manifold passage (page 14-77). However, the last paragraph of that section says "A small amount of fuel is returned from the fuel injectors, while a large amount (about 70% of supplied fuel) is returned from the fuel injection pump". How much is a "small amount"? A "large amount"?
MM, while I appreciate the tremendous effort that you and your cohorts are putting into this, I would be more comfortable with your results if your flow sensor was installed in the "fuel return line from pump overflow valve" (page 14-78 Fig. 17) between the fuel injection pump overflow valve and the 'T' at the rear of the engine.
I also think some of us are getting too carried away with Bernoulli's theorem; this just ain't that complicated. For a given restriction, pressure = flow.
There. I've said my piece; Flame away, boys!
Tom

------------------
Tom Glover - VE7DQ, C-GWTG
99 QC SLT, LWB 4x2, ETC/DGP, Wht/Agate, etc.

[This message has been edited by TommyTurbosaurus (edited 04-27-2001). ]

 

[mikel]

Can anyone clarify the statement about the vp44 not sharing it's return with the lift pump? I thought that I read earlier that the vp44 return opened at 14psi, leading me to believe that the lift pump would never be working against more than maybe a few psi higher than that.

Is this correct, or am I confused as usual?

Thanks,
Mike

 

[TXRam]

Mike - I think you're right. Except that too large a pump could overwhelm the return line, thus necessitating a second return. I believe that's why people are discussing that.

Tommy - That's why I said what I did. Unless the supply to the VP44 is greater than 14psi, is anything returning from it??? Or just from the injector lines?

Bill - The fuel will heat as it is pumped, but not near as much as a gas heats when compressed. The only real heat generated is by the friction, etc. in the pumps themselves. So the fuel cools them, thus heating up some.

Once I get that training material, I should be able to answer most of our questions.

[This message has been edited by TXRam (edited 04-27-2001). ]

 

[Bill Kondolay]

I have had the pressure as high as 60 psi at the inlet of vp44 pump with no increase of flow on the return line. The same results at 20,30,40,50 psi. If the vp44 pump shared the bypass with lift pump i should have seen some sort of increase of flow on the return line.

I have been testing since the Prime-loc thread. I DO NOT SELL PRIME-LOC But BillW got a raw deal. I have not spoken to Bill but a spoken to a Swagelok engineers,and Parker Hannifin. They confirmed what he wrote and my testing told me the same thing.

Bill Kondolay
Diesel Transmission Technology