I have a 99 Dodge Ram 3500 4x4 diesel and I am getting codes, PO237PO251PO252P1688P1693 I know what they read, just not sure I know where to start first. Any suggestions would be greatly appreciated. Thanks!!

Get a scan tool and erase the codes first, then drive it around for a bit, or start it up and see which ones return.The P0237 is an over boost code, not to worry too much yet.The P0251, P0252 mean that you are needing to get a new VP 44 injection pump because the internal moving parts are broken/stuck. You might try some 2 stroke oil in your fuel to see if that helps the codes. As the 2 stroke will add lubrication to the fuel for the VP. For your use, you might try 1.5 ounces to 1 gallon of fuel for the first tank. Then go to 1 oz to 1 gallon for the rest.The P1688 means there is an internal failure in the VP.The P1693 is just a companion code to tell you there are other codes set in the PCM/ECM. Not to worry about.The codes that have me concerned are the P0251, P0252, and the P1688, these are generally the death codes for the VP.Others will chime in.

Stodg is for the most part correct... P0237 - http://forum.mopar1973man.com/threads/2571-P0237-Map-Sensor-Voltage-Too-Low P0251 - http://forum.mopar1973man.com/threads/2573-P0251-Fuel-Inj.-Pump-Mech.-Failure-Fuel-Valve-Feedback-Circuit P0252 - http://forum.mopar1973man.com/threads/2648-P0252-Fuel-Valve-Signal-Missing P1688 - http://forum.mopar1973man.com/threads/2627-P1688-Internal-Fuel-Injection-Pump-Controller-Failure P1693 - http://forum.mopar1973man.com/threads/2631-P1693-DTC-Detected-in-PCM-ECM-or-DTC-Detected-in-ECM

Stodg is for the most part correct... P0237 - http://forum.mopar1973man.com/threads/2571-P0237-Map-Sensor-Voltage-Too-Low P0251 - http://forum.mopar1973man.com/threads/2573-P0251-Fuel-Inj.-Pump-Mech.-Failure-Fuel-Valve-Feedback-Circuit P0252 - http://forum.mopar1973man.com/threads/2648-P0252-Fuel-Valve-Signal-Missing P1688 - http://forum.mopar1973man.com/threads/2627-P1688-Internal-Fuel-Injection-Pump-Controller-Failure P1693 - http://forum.mopar1973man.com/threads/2631-P1693-DTC-Detected-in-PCM-ECM-or-DTC-Detected-in-ECM

Thanks so much for the info. I sure will try that and I will let y'all know.

Sorry for the delay in getting back with y'all. After testing, there is no doubt i need a pump. Thanks again!

Sorry for the delay in getting back with y'all. After testing, there is no doubt i need a pump. Thanks again!

Here is a few vendors to look at... http://mopar.mopar1973man.com/cummins/dealers/dealers.htm

Thats a good point Mike. We all should use them if we can.

Thanks MM!! Looks like DAP has the best kit deal. Who would you recommend? Also, where would you recommend purchasing a low pressure fuel gage kit?

I purchased my isspro fuel pressure gauge from Genos garage but there are alot of places that offer gauges at good deals-Jordan-

Thanks MM!! Looks like DAP has the best kit deal. Who would you recommend? Also, where would you recommend purchasing a low pressure fuel gage kit?

Try looking at manufactures... http://mopar.mopar1973man.com/cummins/manufacture/manufacture.htm Then check out the vendors... http://mopar.mopar1973man.com/cummins/dealers/dealers.htm