Engine/Transmission (1998.5 - 2002) The Ultimate VP44 Q&A Thread

[Mark_Kendrick]

So if I get an ECM from an auto to bolt onto my HO I'll have the best of both worlds in the dodge OEM arena???





I'm not sure where the terminology '028' or '027' but muncie was who's who in performance and that's the way they distinguished between the two. .



Maybe referring to plunger sizes???



I can't wait to get that CD so I can get the basic understanding of all the components from Bosch. Right now most of what I know is second or third hand.



I wonder what would happen if you increased the size of the plungers??



Does the pump measure flow or does it do what should give the proper output? I would hope that the pump would not know that the plunger ass'y had changed.



increasing the plunger size would increase pressure given the same stroke.

 

[Cummins4Life]

If you put a manual ECM on an auto you get a real funky loping idle, like a cammed gasser. I dont know if it is damaging but its not somthing I would want to live with.

 

[Mark_Kendrick]

The fuel for a Auto comes on sooner to help spool the turbo and stays on longer because of the fewer number of gears.



The loping idle is strange. It doesn't make sense with a computer controlled motor. I believe the cams from the engines are the same. not like a gasser. manual gas engines have a diferent grind and a lower idle to help w/low speed engangement. Gas auto's idle higher to handle the initial load of the TC... something similar to 800rpm in neutral and 550-600 in gear.



I don't own an auto, so I dunno what to tell you w/CTDs.

 

[Pit Bull]

Question/statement. Hope I explain this correctly. I had a dead lift pump for a couple of thousand miles, I think, (don't really know when it died). So the VP44 had to suck all of the fuel from the fuel tank (did not know it was dead till I checked it with a guage, but it was working when I changed the fuel filter 3K before). When the new lift pump was installed, I checked it and it was 12 PSI at idle, 8 PSI cruise, 6 PSI WOT. This is the latest lift pump AA. I just checked it again today its been in for 2K miles and it now reads 15 PSI at idle, 13 PSI at cruise, and 9 PSI at WOT. Here is my question?? Did the ECM or the computer in the VP44 compensate for my dead lift pump and cause the VP44 to increase its suction to compensate for the dead lift pump? Then when a new lift pump was installed the VP44 was still sucking fuel at that higher rate which caused lower PSI from my new lift pump? Then after the new lift pump continued to provide fuel with positive pressure the ECM or VP computer adjusted the pump in the VP44 which increased the PSI reading on my lift pump? Does this make sense to any of you guys? I know that many cars adjust to now they are driven. Just wondering if the VP44 also adjusts?

 

[Mark_Kendrick]

The vp44 does not adjust to input FP. It is designed to suck fuel. The problem is that the vp44 life will be shortened by the lack of lubrication w/o the lift pump.



The presure differences you saw are likely due to temperature and electrical supply. if the grid heaters are running there is usually less than 14v and therefore less FP. The carter lift pump is on or off. . no adjustments.

 

[Pit Bull]

Originally posted by Mark_Kendrick

The vp44 does not adjust to input FP. It is designed to suck fuel. The problem is that the vp44 life will be shortened by the lack of lubrication w/o the lift pump.



The presure differences you saw are likely due to temperature and electrical supply. if the grid heaters are running there is usually less than 14v and therefore less FP. The carter lift pump is on or off. . no adjustments.

Thanks for the information Mark. When the new lift pump was installed the temp's were in the high 60's so no grid heater? Plus the engine was fully warmed up when I took the readings both times. I remember reading on one of these threads that one of the members posted that he had the design spec's for the VP44 and it was designed without a lift pump being required. Now I am not saying that we don't need a working lift pump for our trucks!!! But it seems strange that we all assume that a dead lift pump will shorten the life of the VP44 when we don't have any statistical data to prove that. There has been reports of VP44's failing shortly after a lift pump failed, but they all don't fail after the lift pump is dead. This would lead me to believe that some VP44's are marginal (dead lift pump equals dead VP44) but most are not. I guess my point is that there are too many CTD owners driving around without even knowing they have a lift pump on their truck (non TDR members) dead or alive. Based on the poll that was taken on the TDR on failed lift pumps, seems like half of the people driving 24 valve CTD's have bad lift pumps. If these failed lift pumps cause the early death of the VP44, either Dodge will be spending big $$$ on replacements under the 100K engine warranty or owners will be buying new VP44's shortly after the warranty is up and Dodge/Cummins will ruin their reputation in the market place. Either way that does not make any business sense??? Would a company jeopardize their position in the 3/4 and 1 ton truck market over a $130 lift pump? Bottom line we don't know what the VP44 is capable of doing and how long it will last without a lift pump Wish we did, I would then know when to trade

 

[Mark_Kendrick]

all electronic fuel distribution systems are rather fragile compared to their mechanical brethren.



the lift pump is a problem and the VP44 should live w/o it, but since I'm my own warranty station I'll be keepin that lift pump in tip top shape



the lift pump supplies extra fuel for lubrication and cooling so as long as it's not a restriction it is a good thing.



DC should've put a FP gauge on from the factory and a sensor to indicate fuel filter clogging.



They could easily set a code in the ECM to indicate a lift pump problem with nothing more than 2 FP senders.

 

[Pit Bull]

Originally posted by Mark_Kendrick

all electronic fuel distribution systems are rather fragile compared to their mechanical brethren.



the lift pump is a problem and the VP44 should live w/o it, but since I'm my own warranty station I'll be keepin that lift pump in tip top shape



the lift pump supplies extra fuel for lubrication and cooling so as long as it's not a restriction it is a good thing.



DC should've put a FP gauge on from the factory and a sensor to indicate fuel filter clogging.



They could easily set a code in the ECM to indicate a lift pump problem with nothing more than 2 FP senders.

Mark, I could not agree more!!! FP gauge with some type of alarm would be cheaper for DC then new VP44's. What bothers me is that now the new 03 CTD will have a different injection system and lift pump, so will DC just try and bury this problem? Ford is doing the same thing with their CACKLE problem and now coming out with a new diesel. The Ford guys are affraid that Ford will continue to ignore their CACKLE problem since they will be replacing the PSD. Talk about Brand loyality, what about customer loyality!!

 

[jstarnes]

check this out

issue 36 tdr page 41 DD says they have preformance vp44 good for 75+hp WTF? any one know about this?

 

[Mark_Kendrick]

Call them up and get some info...

 

[TxDieselKid]

Re: check this out

Originally posted by jstarnes

issue 36 tdr page 41 DD says they have preformance vp44 good for 75+hp WTF? any one know about this?

Since May Maddness just happen, I would put money on the fact that all of their trucks with a VP44 was modified.



Andrew

 

[jstarnes]

OK I called DD they said thet the turck at may madness had the pump installed (Idont know about all but at least 1 had it) they said that it was still in testing at the moment (to test longevityof pump life) I also found out that there UFM was tweked and tuned to sute there injectors FYI there you have it

 

[Mark_Kendrick]

Nice to know.



Marco???? where'd ya go???

 

[Marco]

Sleeping!

Hey what? Who? Me???



Rrrrrrrrr-Schhhhhhhhhhhhh

Rrrrrrrrr-Schhhhhhhhhhhhh

Rrrrrrrrr-Schhhhhhhhhhhhh



(That's me sleeping)





Remember, I'm in Italy. That puts me a "few" hours ahead of you.

In other words, when you wake up it's nearly time for lunch for me. When you enjoy your lunch, I'm back @ home for dinner... .

Then I sleep a little and you go on typing and typing and typing...

Hey that's NOT fair... . :{



I agree with you on the FP unit. One would be enough!

What I don't get is why you already want to BOMB the VP.

Do you already KNOW how it works?

I mean before you modify something, you should know perfectly how it works... .



Marco

 

[Marco]

One more time..

I've forgotten to mention.

WHY would you need to mod the VP. To tell you the truth, from my point of view, there's no need to do so.



Let me explain a little. The only real limit the VP has is the time in which it can deliver fuel. Once the compression of the plungers has ended, end of fuel delivery.



I'd think it'll be more usefull to be able to deliver more fuel during the compression time on the plungers. In other words bigger injectors. No today there aren't injectors able to deliver MUCH more fuel and maintaining a good spray pattern, but that can be

done.



Sure, reprogramming,adapting, the ECM for those injectors is needed, but also that can be done...



Voila' you'd get a RELIABLE and Powerfull system, without getting all the smoke you're producing today.

BTW, every time your engines smokes ( I mean BIG black smoke)

you're waisting fuel and harm the engines performance.



Marco

 

[Mark_Kendrick]

I have some injectors that flow MUCH more fuel. I'd like to know what the purpose of the FCM is if the ECM does all the decision making.



I'd also like a setup that interfaces w/the pc that would allow me to tweak the curves for my shower heads. but I understand that that's not exactly an easy task. I would really like something similar to the gasser standalone FMS/ECMs. full adjustability, ability to control a vp44 would be nice.



Understanding that everything is Better Off Modified Baby is a start.



I was thinking that increasing the ability of the pump to deliver fuel would be a back door way of increasing the fueling parameters.



I really want to overcome the limitation of the 24v motor to make HP. Is seems to be fuel supply. I believe the VP pump can deliver the flow the problem is getting it to do it.



Outline your hypothetical plan for doing so and then maybe we can set out accomplish it and head for 650+ hp on #2 only!!!

 

[Marco]

injectors

I dunno about your injectors, the ones I've tested ( about every injector availabel on the market-and not) had a very poor spray pattern and were poorly matched. Got anlayzed a set of injectors that were within 15% from the lowest to the highest injector.

Go figure...



To get efficently more fuel into the combustion chamber we'd need stuff with more and larger holes, not only honed larger holes. Also needle lift would need to be increased...



The FMS has mainly to calculate degrees into time and time then back to degrees. It needs to do so in order to be able to determine when to inject fuel and after how much time the solenoid has been activated the requested fuel is injected.



It also has to adjust fuelling upon fuel temp and voltage from the battery.



Marco

 

[Mark_Kendrick]

Marco,

My injectors have more, bigger holes and are flow matched.



So if I follow you the VP44 pumps fuel for a ceartain number of degrees not for a certain amount of fuel??



I am suprised that there is not a flow meter or at least flow calculation.



The flow ratings you spoke of on the pump. . are they max's, min's mean, or flow at xrpm and y* of rotation??

 

[SmokinJoe]

Re: One more time..

Originally posted by Marco

Sure, reprogramming,adapting, the ECM for those injectors is needed, but also that can be done...



Voila' you'd get a RELIABLE and Powerfull system, without getting all the smoke you're producing today.

BTW, every time your engines smokes ( I mean BIG black smoke)

you're waisting fuel and harm the engines performance.

Some of us are ready for whatever you decide to send across the pond. I am getting impatient and wanting BullDog V's and an Edge Comp Drag box to hold me over. I am told both will be supported but I am still skeptical...

 

[Marco]

My injectors have more, bigger holes and are flow matched.



How many holes? What's their flow rate?



So if I follow you the VP44 pumps fuel for a ceartain number of degrees not for a certain amount of fuel??



Yes.



I am suprised that there is not a flow meter or at least flow calculation.



No flowmeter, otherwise bigger injectors would'nt give more power. Fuel calculation is done by fuel metering valve closed time.

Which in other words is degrees rotation of the pump



The flow ratings you spoke of on the pump. . are they max's, min's mean, or flow at xrpm and y* of rotation??



Which flow ratings? If you mean the ones on the engine label, then it's the fuel flow at rated Hp for each injection stroke.



In the case of my engine that's 92 cubic mm @ 215 hp and @2700 Rpm.



That flow rate can be increased via the ECM, but now comes the time, read degrees of rotation into the game. That's the reason also the ECM can't do miracles.



Gimme an large enough injector to flow all the 92 cubic mm during the degrees of injection stroke and I can deliver them all into the cylinder via the ECM... .



Marco

Marco