The best way to start this explanation is to quote an e-mail that I found on the corporate Cummins website many years ago. We think you might like to hear about our findings.
A common problem with original pumps in through trucks, is the rotor seizes in the distributor section of the pump. This is also common in rebuilt pumps that don't have the upgraded rotor, distributor and coating.
This is why engines just die going down the road, usually when the throttle is released at high load and or high RPMs, and never start again until a replacement injection pump is installed. What actually happens when the rotor seizes, and this is from a Bosch Factory Rep, the slot in the rotor interferes with the distributor because of an inferior deburring process.
The sharp edge deflects and interferes with the distributor and galls both mating parts and then seizes. The drive plate then breaks and only the input shaft of the pump rotates, so no high pressure fuel is delivered to the injectors. The computer on the top of the injection pump is the most common component to fail and causes many different symptoms, as explained in our diagnostic pages.
This component fails due to "Lead Free" solder that secures the components to the circuit board. Heat and heat cycles make the solder crystalline over time and create an intermittent electrical connection, which makes the pump do all kinds of naughty things. The old style diaphragm can cause hard start cold, as it cracks over time with prolonged low lift pump pressure, and can be diagnosed with our diagnostic pages. As these pumps are getting older and the cores have more miles on them when we get them, we are learning of other components that just plain wear out and cause problems, such as the rotor and distributor.
There is no good way to test them, either mechanically or on the useless test stand, so sadly the end user gets to do the diagnosis more often than not. The result of a worn out rotor and distributor is a hard start hot, also explained in our diagnostic section. All it is telling you is that the timing is not advanced as much as the ECM wants for more than 5 seconds. This can be caused by low lift pump pressure or a worn out housing on the injection pump.
If you have good lift pump pressure UNDER LOAD and that code keeps coming back after you clear it, then you know the pump is getting tired, but that code alone does not tell you the engine is going to die soon and put you on the side of the road, as some vendors want you to think.
Pumps VP30, VP44/PSG-5
There have been a bunch of mechanical and electronic upgrades for these pumps made available from Bosch, and they have proven to be much better than those used when this pump was originally made. The mechanical upgrades have all been a winner in my experience. They seem to last a long time and are surely worth using in a rebuild scenario, but they cost money so when the typical rebuilder is trying to save money in a typical rebuild, they just aren't used.
All of our pumps have all of the mechanical and electrical upgrades on them. See our "Products" page to learn about the many pump choices you have when doing business with us! The importance of a fuel pressure gauge.
October 2, How do you measure lift pump functionality? July 27, Hard start hot! July 9, The usual problem - Your car won't start. The usual scenario is that the engine turns over ok, but will not start. You've tried Easystart or similar, but the engine still wont run, except for maybe a few seconds.
Maybe it has cut out and won't restart, or it just wont start when you try to start up. Fault codes P, P, P, P, P, P will be further confirmation that the fault lies with the electrics. If you have had recent problems with poor running, loss of power, black or white smoke etc, then this generally indicates a different cause altogether, and our service is not likely to help you. Note that if you have code P, you have a ruptured diaphragm - we can't help with this.
The transistor almost always fails in the same way - it is black and burnt up through overheating. The VP44's design relies on the fuel flowing trough it to keep it cool, and if conditions are such that there is too little fuel flowing, damage can result through overheating. We don't recommend you try to replace the transistor yourself - it's a very delicate operation to do so.
VP44 Injection Pump – What you need to know
Fortunately, we offer an economical fixed price transistor replacement service. We use top spec transistors with low resistance and high current specifications, that will keep as cool as possible and be capable of withstanding heavy loads. In addition, we make use of compounds to ensure that heat is conducted away from the transistor to the maximum possible degree. These precautions help ensure that the transistor runs as cool as possible and will continue to function for the rest of the life of the vehicle.
We don't recommend this option because there are dozens of different variations of the VP44, and each has its own version of EDU, and they are not interchangeable. Even if you did find an identical one, you would still need to get it coded to your vehicle, and of course, it could be faulty anyway. You can send us the EDU from your pump and we will replace the transistor for you.
Please first see our Stripdown page for how to remove the EDU from the pump. Engine will not start? Whether you're in the trade, or repairing your own, we show you how, and offer you economical solutions. VP44 solutions for your vehicle. Our happy customers "Thanks worked a treat Customer Satisfaction Guarantee to our customers Our materials and workmanship carry a full 12 months guarantee.
If a fault should develop at any time over the 12 month period, simply return for a free repair. QER Ltd.The dead pedal, the long-crank hot restarts, the engine dying suddenly while driving down the road, never to restart again.
It followed a period of time where the fully-mechanical Bosch P aboard the valve 5. Needless to say, the VP44 got a bad wrap from the get-go, effectively becoming the red-headed stepchild of the injection pump world. To be sure, the VP44 remains one of the ficklest components to ever grace the legendary Cummins lineage, but there is now an unofficial protocol to follow in order to keep one alive.
For more light reading on diagnosis and functionality of the VP44 from a highly reputable source, visit Blue Chip Diesel. A cam-driven, radial piston pump, it features three internal pumping plungers, a fuel metering solenoid, a timing advance solenoid and a built-in computer called a PSG or EDC that monitors and controls fueling.
The VP44 is capable of supporting bar 23, psi. During PSG failure, several different symptoms surface, with the most frequent being long cranking when attempting to restart a hot engine. In recent years, better soldering has become part of the remanufacturing process on VP44s, which has led to improved reliability.
Rotor seizure in the distributor portion of the VP44 is another issue that was especially common on early pumps due to an inferior de-burring process from the manufacturer. In essence, the sharp edge of the rotor makes contact with the distributor, digging into both mating surfaces. After enough contact and damagethe rotor seizes up, breaking the drive plate.
This sudden failure will stop your truck dead in its tracks. A hard cold start is the biggest indicator of diaphragm failure. The revised, later model VP44s came with a solid steel backing behind the diaphragm, which eliminated the flexing that resulted in failures.
Various internal components in the VP44 tend to wear out over time, the rotor and distributor being a couple of them. When the distributor section of the pump is on its way out, hot restart issues will be present, and many times rotor and distributor failure go hand-in-hand. Being that the VP44 relies on adequate fuel supply pressure and volume in order to operate, lubricate and keep it cool, a failing lift pump can spell disaster.
A self-priming, electric Carter lift pump came standard on the 5. Bottom line: If the VP44 is not seeing at least 5 psi of fuel supply from the lift pump, it will not be happy. Did you know the hottest the VP44 gets is actually 15 to 20 minutes after the engine has been turned off? This is due to heat soak. Nine times out of 10, having trouble restarting a warm engine means the VP44 is on its way out.Answering repeated queries and wishes of our customers we have expanded our offer. Our website is being updated, but please do not wait, just send the number or photo of the pump by e-mail, and we will promptly answer at what date and for what amount we will repair it.
We restore the damaged pump to full efficiency, of course we give a month warranty for the correct operation of the pump, but in practice the pump works reliably after our repair for many years. We guarantee the highest quality of service at an attractive price.
You pay after days since the repair is done, after receiving the invoice. You can become one of them, too.
If you repair a damaged driver or injection pumpyou can gain hundreds or even more than thousand Euro, as you do not have to spend money for the purchase and assembly of the new pump. BOSCH common rail high pressure pumps that our company repairs occur in engines with a capacity of 1.
To repair the driver you do not need to dismantle the whole pump out of your car. The repair of the driver makes that the car regains its previous efficiency, and the cost of the repair is a few times lower than the cost of the exchange whole pump.
Our solution is strongly recommended to used car dealers and workshops as it makes your profit a few hundreds or sometimes even a thousand of euro higher. Sample numbers of these pumps are:. Repair of the pump involves replacing all seals as well as all damaged parts with new ones, including piston of the injection timing mechanism, solenoid of fuel dose or membranes. Regardless of the amount of elements replaced for the new ones, price for repair of the pump is fixed at or euros net, this is a very attractive offer.
We are pleased to inform you that our company successfully began repairs of the drivers type PSG with two plugs for injection pumps type VP Repair of this type of drivers is very complicated and parts needed to repair them are difficult to get, but our company ZIPART GmbH overcome these difficulties and now offers, as a one of few, such a repairs.
Repair in our company costs only EUR net and solve the problem as a whole. We believe that this is a very attractive offer. Please do not hesitate to check us out and send us the driver with two plugs to repair. Regardless of the amount of elements replaced for the new ones, price for repair of the pump is fixed at euros net, this is a very attractive offer.
Now it is no longer a problem, because instead of expensive replacement driver for the new one and necessity of programming it again, you can send it to us and we will fix it for you at a very attractive price of euros net. Our offer allows you to fix all 4 injectors engine for the price of only 3 unit injector, that means one free repair. Our offer makes that for euros net, you can fix all 4 unit injectors and have a guarantee that for at least next 18 months, regardless of the number of kilometers driven, injectors will be efficient and reliable.
After the test, we repair the injector, replace both the electronic and mechanical components, we assume the new seals and re-test the SIEMENS unit injector. The repaired unit injector SIEMENS is exactly the same, which was damaged in your car, so during the installation it is not necessary to set the pusher lever according to the instructions of assembly of unit injector.
Home Bosch 2.Welcome to world's most trustworthy automotive forum. Automotive Workshop Manuals. Thread Rating: 77 Vote s - 2. Reputation: Hey fellas! I just got an electronic unit from a VP44 Bosch injection pump.
Well, i attach 2 images to show you the actual damage of the unit. Hopefully somebody can post a full tutorial about repairing this type of control units Have a nice day!
Reputation: 0. Hi please check PM. Hi please check PM can you send it to me to thanks in advance. Reputation: 6. Automotive tutorial. Replies: 4. Last Post by rs Author: the tecnician. Replies: 0. Last Post by the tecnician. Last Post by mikevee Bosch Vp44 Repair Manual. Replies: 7. Last Post by Poptest. Evaporator core replacement Mercedes-Benz W Last Post by Brakstrom.These control units do not have diagnostic lead connected to any pin into the OBD2 socket, it is necessary to connect diagnostics directly to a pin of the control unit.
Ford IDS does not allow diagnosis of this control unit. Please note that only VP44 fuel pumps installed between are supported. Other systems e. Denso, Lucas use different control units and this page does not apply to them! The control unit of pump contains only a hybrid circuit board, which is not repairable in normal work conditions.
Consumption of the ECU can be up to 8A, it is necessary to get connected to a fused wiring. On the other hand, FCOM has ability to program used fuel pumps. OBD2 Diagnostics Wiki diag.
Create account or Sign in. Pump control unit description The control unit of pump contains only a hybrid circuit board, which is not repairable in normal work conditions. Click here to edit contents of this page. Click here to toggle editing of individual sections of the page if possible. Watch headings for an "edit" link when available. Append content without editing the whole page source.
If you want to discuss contents of this page - this is the easiest way to do it. Change the name also URL address, possibly the category of the page. Notify administrators if there is objectionable content in this page. Something does not work as expected?
Find out what you can do. General Wikidot.In a previous post, we covered common rail injectors, why they fail, and what is being done to correct some of the failures we are all seeing when these injectors come from the factory. Through our internal Research and Development department at BDG, we have also been investigating the major causes of the Vp44 fuel pump failures, and what could be done to make the pump last longer, operate more efficiently, and gain some reliability.Bosch VP44 Reman Process - Diesel On Demand
The result of this research, how the VP44 works, why it fails, and how we are improving the design, is described below. The VP44 fuel pump is an electronic rotary pump that delivers fuel at extremely high pressures, and additionally controls the fuel flow rate and timing for the engine.
The added responsibility of controlling the flow rate and timing means additional electronics, and also means that the VP44 has, in addition to physical part failure due to the constant high pressure and wear inside the housing, the opportunity for electrical failure through the on-board PSG, or ECU. These two failures account for the vast majority of VP44 fuel pump failures.
As stated earlier, the VP44 not only provides pressure, it controls engine timing and fuel delivery. As the timing is constantly changing, the internal component that moves to create this timing movement, the timer piston, is under constant motion, and under constant pressure. With time, the friction of this movement creates wear and grooves in the pump housing. Since the timer piston works under a pressure principle, it needs to maintain pressure on one side to cause movement.
Once wear and grooves are created in the pump housing, fuel leaks from either side, balancing pressure, and the piston ceases movement. Once this starts to happen, the pump loses timing advance, the engine loses power, and you consume more and more fuel.
The repair for this condition is replacement of the pump housing and internal parts. Each VP44 fuel pump has a separate computer connected to two internal sensors.
The main cause of failure we see here is with the wires connecting the two internal sensors to the PSG. The pump itself creates considerable heat, and after enough heat cycles, the wires and connectors become brittle, split, crack and fail. Additionally, we have seen failures of the PSG and sensors themselves, though this is less common.
The solution here is to replace the entire PSG. With the addition of the re-manufactured VP44 fuel pump to the Common Rail parts we offer, we replace ALL common causes of failure, regardless of cost.
Internal Housing Wear Failure. What Does Baileys Do? More Info. Posted In: On Highway.