Now that we have been over the ups and downs of the first-generation, let’s take a look at the latest model of the 5.9-liter Cummins engine. In 1998, the 12-valve Cummins was phased out for the redesigned 24-valve.
The new design came in different platforms; the automatic transmission equipped trucks came out with the SO (Standard Output) 24-valve engine with 215 horsepower and 420 lb-ft of torque. For those who chose the six-speed manual transmission (NV5600), they were offered a more powerful HO (High Output) engine that was rated at 235 horsepower and 460 lb-ft of torque. The high-output models were designed to have higher compression and altered engine calibration to provide the additional horsepower and torque.
New Motor, New Problems
One of the most talked-about problems when purchasing a truck within this era is the 53 block scare. The 53 block refers to casting numbers, and affects engine blocks that have the number “53” stamped onto them.
The 53 blocks have a tendency to crack and create a leak which will lead to an engine replacement. If you are one of the “lucky ones” who do happen to have a 53 block and come to find that you do have a leaking case, you could make do by continuing to fill it with coolant as it leaks, but with the heat of the engine and cool down over and over, you will only be delaying the inevitable.
Knowing where to look for the "53" is the first step in knowing if you have a possible issue on your hands.
There are known temporary fixes if you’ve got the tools. Some of the options out are block stitching or JB Weld. But, as stated above, you are only delaying the inevitable. Should you choose to do this, it should only be because you are saving up to buy a used engine from a junkyard, or a new one from a dealer.
The problem with going ahead and trying to temporarily fix this problem is that the block in that area is so thin; stitching it will not permanently fix the problem. The block will more than likely re-crack. If you are shopping and find one of these cursed motors, negotiate a better price to account for the potential disaster.
Injection Pump Problems
The diesel industry is enormous and continuing to grow bigger and bigger every day. For most of the veterans in this industry when they hear the words “24-valve,” they instantly think of one thing – the VP44 injection pump.
After four years of running the mechanical P7100 injection pump, it was time to move on the new electronically controlled VP44 rotary pump. This pump quietly created a bad reputation due to the high volume of pump failures.
Here is a VP44 injection pump diagram that shows what each part is.
The most common mechanical problem with these pumps is that the rotor will seize up in the distribution section. This is partially caused by the lack of fuel pressure and lubricity in the new “ultra-low sulphur” fuel that is provided at gas stations. However, the biggest reason these pumps fail is because the factory fuel lift pump could not supply the VP44 with the desired amount of fuel it needs to continue its life.
The VP is cooled by the fuel that runs through it, so after a lift pump failure, the injection pump will naturally fail as well. The first recommendation to keep the pump alive is buying an aftermarket fuel pressure gauge to keep an eye on the pressure that’s feeding the pump.
A bad injection pump could make you dive into a repair like this.
It has been said that the adequate pressure for these pumps is between 17-20 psi. Anything less, and you could be looking at a shop bill for the replacement. For those of you who want the extra insurance, you can always purchase an aftermarket fuel system that will continue to keep your pump happy.
Another reason that these pumps frequently fail is the electrical portion of the pump. Over time, the computer on top of the pump develops a bad connection which will cause rough starts, hiccupping, and even white smoking while driving.
If a replacement is in order, be sure to check out options for performance VP44 injection pumps.
A good thing to look at when looking at this truck is the digital dash monitor. By simply turning the ignition on without engaging the starter a total of three times, if any error codes are present, they will appear on the display. This would save you the cost of having a repair shop hook up to the truck with a professional scanner.
Some error codes to keep an eye out for are P01689 (no communication between ECM and Injection Pump Module), P0216-(Fuel Injection Pump Timing Malfunction), and P0251-(Fuel Injection Pump Mechanical Failure). Keep this “key trick” in mind when looking at a truck; it may save you some serious headaches in the long run.
Dead Pedal Syndrome
The culprit of the dead pedal is usually the accelerator pedal position sensor, which can be seen above.
Another really common issue for the second-generation Cummins is the APPS (accelerator pedal position sensor) failure, otherwise known as the “Dead Pedal.” It is exactly as it seems – the pedal will physically move without throttle response.
The APPS supplies a signal to record the truck’s throttle position. The signal is directed towards the ECM, which controls the fuel flow into the engine and maximizes the combustion process.
A few good ways to check if you have run into a bad or failing APPS is to check your data trouble codes: P0122 (Throttle Position Sensor Voltage Low) and P0123 (Throttle Position Sensor Voltage High).
This is where the DTC (Data Trouble Codes) will appear on the dash display.
This sensor’s position in the engine bay makes it exposed to heat from the engine, as well as, dirt, debris, and moisture, which can cause damage or premature failure. The part runs around $125-150 if you are a do-it-yourself kind of person, or you can tack on some more money for the labor bill to have a local repair shop install one.
It’s worth trying to clean the sensor before spending the money on a replacement, although a replacement could be next on your to-do list. This isn’t a fatal flaw to these trucks, but it is a fatal enough problem that it can leave you stranded hundreds of miles from home.
Known to be a problem area is the Dodge automatic transmission, and in particular, the 47RE. The 47RE is a four-speed transmission and also offered is the 47RH. The difference between the two is the RH model is hydraulically controlled versus the electronically controlled RE.
Over time it seems as if the 47RE wasn’t designed to take the power and torque that the Cummins engine can produce. Truck owners run into shuttle shift problems in which the truck can’t decide which gear to go in, how long to stay in the desired gear, or even refusing to go into gear at all.
With the transmission out, it is a good time to upgrade to a performance torque converter. These are a couple of options from BD Diesel.
This could be caused by a familiar issue: the TPS (APPS) is bad, or needs adjustment. We have also seen issues where the torque converters would lock and unlock at the undesired times. The best option after encountering this would be to replace the torque converter with a stronger, better performing converter that can handle high demands.
When shopping for a truck, it would be a good idea to ask for the maintenance papers on the truck to see if the transmission has been gone through. If any slipping is felt during a test drive negotiating a lower purchase price to account for the repairs that may be needed. An average transmission rebuild costs around $1,600 in parts (on top of the labor from the repair shop).
When in the market, take the truck on a test drive on local roads and highways to get a good feel of how the truck performs and responds. It is a great time to check out the condition of the braking system to make sure it doesn’t try to pull from one side to the other.
Park the truck and let it run on a clean surface to test for leaks. Do a visual inspection for any oil, coolant or transmission fluid leaks. It is a good idea to talk to the seller about getting the past maintenance records to ensure that it has been regularly maintained.
Do your homework on the prices of pickups similar to the truck for sale to make sure you are not overpaying. Following this buyer’s guide will also give a lot of the information that is needed to help make a decision on your next second-generation Cummins diesel. Happy shopping!