I own a 1999 3/4 LWB QCab 4x4 with automatic that I purchased new. My truck has 125K miles on it and until I had 100K never put the truck under a load condition.

I have questions that I hope to get an answer here for.

In the past 6 months I have had 3 oil pressure sensors go bad. The first unit had been on the motor for 120K miles and failed while I was on the freeway and the pressure dropped to "0". The next unit failed a month after I installed it. It began by loosing pressure as seen on the gauge, then the pressure would come back. A few days later it happend again. This went on for several weeks until finally the pressure dropped to "0" and did not recover. Cummins honored this unit and replaced it.

The oil pressure sensor that I currently have installed is showing the same issues after operating normally for 3 months. Drops to zero then recovers.

I have noticed that I see the problem happening twice as many times when I am coming up to a stop, almost like there is a loose ground on the ECM.

Something that might be tied to this is 4months ago when I would start my engine in the morning and it was colder than normal for Arizona the voltage gauge was slow in showing any voltage output and then the needle would slowly rise up and the check engine light would turn off. This too has been happening more frequently.

The dealer want to flash the ECM. An aftermarket shop is stumped and also says maybe the ECM. I am leaning towards a bad ground or possible the alternator.

In the past 18 months I have had 4 sensors fail. A turbo overpressure that shut down the turbo, a transmission sensor that kept the tranny in 1st gear and a antilock sensor. The oil pressure sensor is now the 4th to fail.

Also Cummins sells this sensor for 1/4 the cost that my Dodge dealer is charging. $75.00 verses $325.00

 

Have you found a reason for the sensors going bad? Mine just did it today. Do you have any idea where to plug in an aftermarket gauge? Where is the sensor at?

 

It might be worthwhile to have alt bench tested. Brushes are suspect at your age. Remember the thread about wiring at ac compressor being rubbed by pulley and freaking things out. Not very difficult to go over all battery connections. I ran a extra ground from engine and cowl to the right side battery on mine. Extra alt wire to right side positive also.
This makes the electrons flow in circle and give more output, Sort of like magnets on fuel line rearranges molecules in fuel line for extra performance.


HA