Engine/Transmission (1998.5 - 2002) Cheapest performance gain for towing

[Gary - K7GLD]

First time I have heard of the two injection event capability of the VP44.



Up till now I had thought that a fueling box just maintained the fueling signal, coming from the ECM, for a few micro seconds longer. Common internet knowledge led me to believe that it just piggy backed on the ECM signal. In effect just keeping the fueling solenoid valve closed for a longer duration vice letting it open via the normal ECM signal dropping out and then sending a isolated second signal for it to re-close and allow more fuel to flow. A bit hard on the pressure pop injectors I would think.



This thread has taken a wild turn... .



Edit:

Suppose this is the reason so many people report VP44 shudder at high fueling box fueling levels?



Jim

Often, useful but little known info comes from these discussions - lots of Dodge owners with trucks using the VP-44 are totally unaware that the VP-44 is not something quickly dreamed up between Cummins and Bosch specifically for our use, but were in existence well before our application came calling, and used in a half dozen or so other brand vehicles - mostly in Europe. And, undoubtedly, SOME of those applications DO use both injection pulses, even though ours does not - at least in stock OEM form.



What other engines use the VP44 Injection Pump?



BMW 320d

Ford Focus td

Opel dti

Saab

VAG V6 tdi

John Deere 6. 8L diesel

Case tractors and construction equipment



That capability of multiple injection events HAS provided us with the capability for pretty decent power enhancement tho, as Edge and others have activated that additional injection event for some of us power mad guys! :-laf



SO, it wouldn't be much of a stretch for a guy with one of the half-dozen or so other vehicles that also use the VP pump, and DOES use both injection events to ASSUME they all do in all VP applications - and thus confusion and misinformation arises.



Nothing radical perhaps, or even interesting to lots of guys - but it's a good idea to sorta keep facts straight and info accurate...

 

[ThrottleJockey]

Gary, you don't know anymore about the VP than anyone else does, I was simply told how the thing was designed to work. Marco's test was performed by MARCO! Not Gary :-laf

If Marco loaded the sensory input to simulate a larger vehicle, fine. Marco was simply interested in some software gain, he didn't test the ECM software under all conditions. He could'nt possibly.



I NEVER said Marco wasn't an expert on the thing. I believe he is. I don't beleive Gary knows any more about the VP-44 than anyone else. You can argue all you want, and that's fine. I have no idea. I was just regurgitating information. My truck spins a large turbo with small injectors while towing, I set it up the way I was told to do so. It tows heavy very well.



SNOKING said something interesting. How does the VP-44 (ECM know it's towing? I was told by software and sensory input. The APPS, MAP, IAT..... etc. I was desperatly trying to get the guy I was talking to to admit the VP was'nt all that great. He was trying to convince me THEY (Cummins) hoped it would be the next great thing. Yeah, right.



As far as what is in the software, WE don't know. We can only listen to what insiders like Marco and Bosch let us in on.

 

[SnoKing]

I'll stick with Gary on this one. I think that he was the one that went with a rebuild of his own pump and has studied it alot more than the average guy.



TJ, if you read the link I put up it does talks a bit about how and why it pulls different fueling maps. Again towing is the wrong wording, boost, engine speed, water temp, air temp and even fuel temp are mentioned.



If it switched to dual injection cycles, I think we would all hear or feel that happen. As I load my on a hill with a 12K 5er, I never feel a surg or any other change in how it is producing power. Just see boost and EGTs start coming up. SNOKING

 

[ThrottleJockey]

You may feel it, you may not. Mine sure does act different when towing, but I guess I misunderstood the guy. I don't believe I did, but it happens. That's why we talk about it on the boards here.

 

[Gary - K7GLD]

You may feel it, you may not. Mine sure does act different when towing, but I guess I misunderstood the guy. I don't believe I did, but it happens. That's why we talk about it on the boards here.

At the risk of irritating you further (NOT my intention!), I suspect that the guy you were talking to was perhaps thinking more along the lines of what the VP possiby DOES do on his VW as your conversation began:

Our conversation started because he said his car, a VW of some kind, had the same injection pump as our trucks.

He may, or not been aware of functional differences between applications on various engines - the fact he was a "Cummins engineer" doesn't necessarily mean he was fully proficient on the Bosch fuel system as supplied on our trucks - his expertise could easily be geared to cams and valves. Sometimes just because a guy "works" for a specific company, we automatically assume they are "experts" on everything that particular company is involved in - when in fact, they may just be on the janitorial staff...



In the past years, I've seen *3* different quotes, all supposedly from "Bosch engineers", where they EACH quoted entirely different "recommended" VP-44 inlet PSI's - 3 " company experts", 3 different specifications!



I tend to side with Marco on the multiple injection issue, because his current business is producing power devices to interface with the VP-44 - and a precise knowledge of exactly HOW they normally function is both necessary and CRITICAL to making his product operate properly - and UNfamiliarity with injection functions would be a total disaster in the end product...



Cheers!

 

[ThrottleJockey]

Truth be told, I don't think he was an engineer. I think he was an intern. He may have been speaking pump capability, I was hearing software profiles. I admit I was trying to get him to fess up on the reliability issue. He never caved. Nice guy, though.