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Hmmmm, guess I'm playing catch-up here. You said "The only difference i see is that the timing is different between the old VP-44(which had no timing at all), and the new VP-44 (which does)." I was not aware of this. When did this electronics change take place?Have you considered that the voltage drop might be from a sudden load placed on the electrical system (electrical solenoid kicking on, faulty solenoid / wiring problem, or something) and the VR in the PCM is not responding fast enough to the load? Don't know how you could fix that if it's true. However, the voltage is not dropping below what your batteries can supply and that should be adequate for the electronics in the VP44. Just some thoughts.Jim

Hi guys,Just thought that I would add my two cents here. I moved from Anchorage AK to Roundup MT last May. We have had a really mild winter here and I haven't had any stalling problems to speak of this winter or spring. I'm not sure if it's the difference in fuel quality or what.The stalling problems I had started after the triple lock trans and larger injectors were installed. Don't think at this point that it is a VP44 issue, but I'm not ruling that out yet.I have an IAT fooler installed on a sw so I can use the IAT or a set resistance to tell the ECM what I want it to think the OAT is. When I forget to switch it back to the IAT normal setting before shutting down, and it is cold out It has a real tough time starting and running until it finally reads the real IAT sensor. Jim

In my experiance it has always been low pressure that causes the diaphragm damage not high pressure. Because of the way the pump is built there is support for the diaphragm if the supplied pressure is to high but no support to protect it from the high pressure side of the VP if the supply pressure is to low. That is why they usually develop a tear in the diaphragm when the factory lift pump fails and is not corrected in a short time.

If you find that you do need a VP44 take a look at this site, I've done business with him before and his prices are good. http://www.dieselautopower.com/ owners name is Jacob Kidd. BY PHONE 951-377-4844 or 801-618-2151 BY EMAIL dieselautopower@gmail.com BY MAIL Diesel Auto Power 577 N. Main st Kaysville UT 84037 U.S.A.

If your truck is running fine other than the hard starts I wouldn't be thinking about replacing the VP44 until it displays more problems or just outright fails. If you are at all mechanically inclined and have access to a garage and tools you can replace the VP44 in less than a day your self. I believe there are some real good instructions on Milks web site http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/25-fuel-system/126-bosch-vp44-injection-pump-replacement Haven't priced rebuilt VP44 in a while but I'm guessing around $1,000 exchange. All VP44s have to be rebuilt by bosh cert places unless it comes from china. I'm sure that if you started a new thread asking where is a good place to ger a good VP44 you would get lots of replies. Any VP44 you get today is a reman. You will need to know whether your pump is a SO or HO if the truck is a automatic trans it is most likely a SO pump.

The stock programming in the ECM turns on the LP for a second or so when the key is initially turned on. this builds the pressure that causes hard starting with an aftermarket LP running pressures over 10 PSI. To resolve this you can put on the switch to disable the LP until the engine starts (I believe Mike has the diagram for it) or you can find someone who has a SMARTY and have them put a SMARTY tune on your ECM then Put the stock program back on the ECM. What this will do is disable the initial one second pump run and also turn on the cold weather high idle and the 3 cyl high idle features. It should solve the hard start problem for you. Or as an alternative go to a dealer and pay $100 for them to do the same thing if you can convince them it can be done (they are usually in denial about the initial pump run and high idle features). I have a SMARTY and have done this on my 98 and a few others. I'm in Roundup MT so if you wanted to stop by I would do it for you, but it seems like a long drive from where you are for just that.

Well as the weather warmd here in Alaska my truck was getting worse and worse with the stalling when put in drive and then also in reverse. It was also getting harder and harder to start where it would spin sometines up to 10 seconds before firing off. I have an IAT fooler on the truck so I started playing with different IAT temp readings by adjusting the pot on the fooler to round 100 degrees when the actual IAT reading was over 140 because the truck was warm and had sat for 15 minutes. I found that it started much easier when the electronics thought the IAT reading was around 100 degrees. I still had winter blend fuel in the truck and the tanks were almost empty so I went and filled them with fresh summer blend fuel. I then hooked up the trailer with about 8K load in it and drove 50 miles and stayed with friends. The next morning the truck fired right up and no longer stalled when going into gear. It hasn't stalled since that was three days ago. This re afferms what I have experianced now for three springs. At least with my truck the winter/spring time stalling is caused by the fuel blend available here in Alaska. The problem may be exaserbated by the triple disk converter and larger injectors but the base cause is in the quality of fuel. I never had a stalling problem until the ULSD fuel was mandated. Jim

The DPDT switches I have used had 6 solder contacts on them. The two in the center were the common contacts and switched to the two on the right when the toggle was moved left and switched to the left when the toggle was switched to the right. I suppose that the one you have could be built so it switched to the left when toggled to the left and to the right when switched to the right, not seen one like that yet though. Check it out with the meeter and believe what the meter tells you. Jim

balsip: I think you are making the assumption that the vp44 somehow meters the volume of fuel being injected and only injects that volume regardless of the injector size or duration of the injection cycle. I think with further checking you will find that the VP44 injects the volume of fuel based on an injection cycle time. Therefore, with bigger injector holes or more holes more fuel is injected in the same injection cycle time frame. The ECM regulates the injection cycle time frame based on several sensors one telling it the engine RPM (CPS) and the other telling it the throttle position (APPS) it uses these readings to locate in the fuel map how to change the injection cycle time frame to achieve the RPM requested by the throttle position. So in essence what you are saying is true but not in the way that many people would think. There are other factors that affect atomization than just the number of holes or hole size. Hole position, smoothness, and angle are important for proper atomization and probably have the greatest effect. Earlier timing of the injection does not necessarily mean better efficiency and mileage. I think that Mike has proven that with the IAT fooler. With colder intake temps the ECM advances the timing in an effort to warm the engine (combustion occurring earlier causes the engine to fight the compression stroke and retain more heat). When the fooler comes into play and feeds the ECM info that the intake air is over 130 degrees the ECM retards the timing giving better winter mileage. As I've said before some claim better mileage with larger injectors but many get worse mileage. I would like to think that those of us that get worse mileage just don't have as good of driving technique as those that get better mileage. I for one just cannot seem to get as good mileage readings with larger injectors than stock no matter how carefully I drive. Jim

The injector is purely mechanical and cannot affect timing unless the pop pressure is lowered below 300 bar. below 300 bar the injector opens earlier in the cycle (read nanoseconds) and will marginally affect the timing to be earlier. earlier timing is NOT necessarily a good thing and can cause poorer mileage because the explosion has to fight the upcoming piston. It can also cause overheating of the piston. Injectors with more holes have slightly smaller holes than injectors with a lesser number of holes. If you dump in more fuel than there is air to burn it you ger the black smoke. But good luck with it.

Keep in mind that you can tell when a salesman is not telling you the truth, because his lips are moving. Of course the sellers of a product will make claims of bigger better etc. they are trying to sell their product. Will they guarantee it and give you your money back + the cost of shipping when you don't get better mileage? No, they will say you are driving differently because you have more power now and that is what is affecting your mileage or ask you to prove worse mileage. Usually once the sale is made they don't want to hear any more about it. I have had +80 injectors and lost mileage, I currently have RV275 (about +40) and got some mileage back. My best mileage was with stock injectors. That's my experience with larger injectors. The larger the injector the more fuel they dump in when they fire, stands to reason as they have larger holes in them or more holes. the VP44 puts in more fuel by increasing the length of the injection cycle, not by changing the pressure. At a given pressure only so much fluid can be put through an injector in a given amount of time, so the larger the hole size the more fuel will be injected. Some say they gained mileage with larger injectors maybe they have I don't know and it has not been my experience. If they have there had to be some inefficiency in the engine setup that the larger injectors solved to give better mileage. No two engines are exactly the same and most of the people on the forum have modified their setups for more power which usually results in poorer mileage. It takes fuel to make power and less fuel to make better mileage, you can't have both at the same time. That's one reason the programmers are so popular, they only increase fuel consumption (more power) when you ask for it. bigger injectors give more power all the time. That's my worth. Jim

New injectors may help a little if you stay stock or go to RV275 injectors, but usually only if your current injectors are worn out or very dirty. Tire size, tire pressure, and tread design make a huge difference. Driving habits make the most difference, if you drive like a nearsighted grandma easy on the fuel and slow on the brakes using the techniques the big rigs use you will improve your mileage the most. Automatics get worse mileage than standard transmissions unless you high rev the engine in every gear with the standard. Automatics get poor mileage until the TC lockup happens then they get better mileage but still not as good as a standard because of more internal friction in the trans. Rear end ratio makes a difference also. The condition of the vp44 and fuel pressure to it also make a difference. A clean air cleaner makes a huge difference. All of the above and much more contribute to your mileage. Average????? no one is average. Jim

The smarty instructions specifically say not to combine the smarty programs with advance with a programmer that does advance.

Your stock one lasted 12 years, will you still be running the truck 12 years from now?

I would be checking the engine and transmission mounts and all the cross members first looking for broken/loose bolts and mounts. Then I would be checking the u-joints and spring hangers. From what you have said something is broken or not tight causing the jumping around and shaking. Also check the fluid levels in the drive train. There is also an outside chance of internal rear end damage.