99 Cummins Hard Started.once Then.never Didnit Again
How to Keep the VP44 in Your '98.five-'02 Cummins Alive
The dead pedal, the long-crank hot restarts, the engine dying of a sudden while driving downwardly the road, never to restart over again. Yep, sounds like a '98.5-'02 five.9L Cummins. This version of Cummins' 359 ci inline-six, the 24-valve ISB, came equipped with the Bosch VP44 injection pump—an electronic rotary pump that is notorious for failing unexpectedly. It followed a catamenia of time where the fully-mechanical Bosch P7100 aboard the 12-valve 5.9L offered in '94-'98 Contrivance Ram 2500 and 3500s wouldn't dice even if y'all were trying to kill it. Needless to say, the VP44 got a bad wrap from the get-go, effectively becoming the scarlet-headed stepchild of the injection pump globe.
Simply despite the VP44's unpredictable nature and the fact that many prospective Cummins owners avoid them like the plague, information technology still enjoys a loyal following. With knowledgeable diesel mechanics, injection system experts and enthusiasts in that post-obit, all of the VP44's weaknesses have been exposed, well-documented and some have even fixed past the manufacturer over the years. To be certain, the VP44 remains i of the ficklest components to always grace the legendary Cummins lineage, but at that place is now an unofficial protocol to follow in guild to keep 1 alive. Below, we'll highlight the central causes of VP44 failure and what can be done to forestall information technology from happening.
For more light reading on diagnosis and functionality of the VP44 from a highly reputable source, visit Blue Chip Diesel. It's a visitor that has specialized in the '98.five-'02 VP44 Cummins since information technology was introduced.
The Bosch VP44
To meet ever-tightening emissions standards on pickup trucks, Cummins introduced both a 24-valve cylinder head and electronically variable injection timing midway through Dodge's '98 model year. The '98.5 5.9L ISB Cummins was equipped with the Bosch VP44 distributor style rotary injection pump. A cam-driven, radial piston pump, information technology features iii internal pumping plungers, a fuel metering solenoid, a timing accelerate solenoid and a built-in figurer called a PSG (or EDC) that monitors and controls fueling. The VP44 is capable of supporting 1600 bar (23,200 psi).
Most Mutual Failure
The majority of VP44 failures tin can be traced dorsum to the PSG, the calculator that'south married to the meridian of the pump. Excessive oestrus and thousands of oestrus cycles take their toll on the lead-free soldering that was used in the PSG's internal circuit board, periodically interrupting the electric betoken. During PSG failure, several different symptoms surface, with the most frequent being long cranking when attempting to restart a hot engine. In contempo years, better soldering has become part of the remanufacturing process on VP44s, which has led to improved reliability.
Rotor Seizure
Rotor seizure in the distributor portion of the VP44 is another issue that was especially mutual on early on pumps due to an inferior de-burring process from the manufacturer. In essence, the sharp border of the rotor makes contact with the distributor, digging into both mating surfaces. Later enough contact (and damage), the rotor seizes upward, breaking the bulldoze plate. At that point only the VP44's input shaft is left turning, but pressurized fuel is no longer making it out to the injectors. This sudden failure will stop your truck dead in its tracks.
Diaphragm Failure
The diaphragm, which is located at the pump's distributor caput inlet and supplies fuel to the bores of the distributor shaft, is also notorious for failure in early VP44s. Thank you to being fabricated from a material that wasn't up to the task of dealing with high-force per unit area fuel spill pulses, it was prone to corking over time. The diaphragm's life is further shortened when it's exposed to lengthy periods with little or no fuel supply pressure from the lift pump. A hard common cold start is the biggest indicator of diaphragm failure. The revised, afterward model VP44s came with a solid steel backing behind the diaphragm, which eliminated the flexing that resulted in failures.
Worn Out Benefactor
Various internal components in the VP44 tend to wearable out over time, the rotor and distributor beingness a couple of them. The distributor's chore is to route fuel from the pressurized pumping chamber through commitment valves, toward the injectors. When the benefactor 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.
Lack of Fuel Supply
Being that the VP44 relies on acceptable fuel supply pressure level and volume in guild to operate, lubricate and go on it absurd, a failing elevator pump can spell disaster. Unfortunately, elevator pump failure runs rampant on '98.v-'02 Dodges. A self-priming, electric Carter lift pump came standard on the 5.9L ISB Cummins in Rams, just due to its being mounted on the engine block information technology is constantly exposed to vibration, which does not assist longevity. The manufactory fix was to replace the elevator pump with an in-tank unit of measurement, and while that helped it didn't provide the kind of reliability most customers expected. Lesser line: If the VP44 is not seeing at least 5 psi of fuel supply from the lift pump, it will not be happy.
Heat Is a Major Killer
A lack of fuel supply leads to hotter fuel being sent through the VP44—and every bit we've already alluded to, the VP44 doesn't like excessive estrus. Did you know the hottest the VP44 gets is really 15 to 20 minutes after the engine has been turned off? This is due to heat soak. So if you're driving a truck that makes frequent short trips and is subjected to a lot of hot restarts, your VP44's life expectancy can be cut in half. 9 times out of 10, having trouble restarting a warm engine means the VP44 is on its manner out. The only mode to ensure the VP44 stays every bit cool as possible is to feed it skilful supply pressure and volume.
12-15 PSI Is Platonic
To keep the notorious concatenation reaction upshot of a failed lift pump from starving (and so killing) the VP44, 5 psi of supply pressure is the minimum y'all should see during idle, driving and/or broad-open up throttle. Whenever possible, 12 to 15 psi worth of fuel pressure should be your goal. In the image in a higher place, the fuel pressure gauge is illustrating the fact that an '01 Dodge Ram 3500'due south not-operation manufactory lift pump is supplying zero positive pressure to the VP44. Hooking up a mechanical fuel pressure gauge to a '98.5-'02 truck is i of the commencement steps in diagnosing VP44-related failures.
Install a Reputable Elevator Pump
Aftermarket electric pumps from Fuelab, FASS and AirDog take proven more than than capable of delivering adequate pressure (again, 12 to 15 psi) to the VP44 on a consequent basis. For performance applications, both companies likewise offer comprehensive tank-to-engine fuel systems, complete with a high-flow electrical lift pump, added filtration and larger bore fuel lines. With good fuel supply, there is no reason why a VP44 can't become 150,000 miles, if not 200,000 or more. Just remember to run a fuel pressure guess in example you lot always have an issue with your lift pump.
Mechanical Aftermarket Elevator Pump
Power Driven Diesel fuel's Predator lift pump for '98.5-'02 Dodges is relatively new to the Cummins aftermarket, but it shows a lot of promise. Start and foremost, the pump is belt-driven and fully-mechanical, which means the faster you spin the engine the more fuel it pumps. 2nd, it features an internal pressure regulator valve that'south set upward to piece of work with the factory overflow valve on the VP44, which eliminates whatsoever possible overpressure scenarios. Last merely non least, its 400,000-mile design ways information technology will probable outlive whatsoever truck it's installed on.
Get a Fuel Pressure Gauge
To keep tabs on the health of your lift pump (even if you've installed an aftermarket one), do yourself a favor and install a fuel pressure gauge. Trust us, the sooner you notice your lift pump no longer keeping upward, the more coin you'll save in the long run by non having to fork over $1,000 or more for a remanufactured VP44. Some aftermarket gauges even offering a low fuel pressure alert light that you can configure to come on at whichever pressure threshold y'all deem as being too depression.
Curious to know what issues torment other generations of Cummins-powered Rams? Click here.
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Source: https://www.drivingline.com/articles/how-to-keep-the-vp44-in-your-985-02-cummins-alive/
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