fuel pressure

[2kreeks]

The 2kreeks hauler has been missing at hiway speeds 'cruise 50/65 mph' every other speed is ok. If truck is acelerating no problem, pulling hard 10k up everything nornmal. The lift pump was replaced approx 3500 miles with a generic AIRTEX BRAND. This was replaced during a oil change when I found out the new carter was starting to fail. Now with new instruments the fuel pressure at idle is 21.5lbs and wot is 16lbs. My basic idle time is approx 5mins and some time more depending on how long of pull and how heavy..Does this high of fuel pressure hurt the vp44?Could this high of fuel pressure cause the missing?Only codes showing with key trip, is 1693 which was left over from a p0122, which is gone now after replacing the apps.larry

[LiveOak]

P1693 = DTC Detected In ECM Or PCM P0122 = Accelerator Pedal Position Sensor Signal Voltage Too Low It would appear the APPS is out of calibration or gone bad. You my luck out and do a recalibaration on it and it this eliminates the miss. If the recal. does not work. You may have to replace the APPS. I suspect the miss may be due to a bad spot on the APPS potentiometer. You might try working the accelerator pedal all the way done and up (similar to pumping the gas pedal on a big gasser engine during a cold start. This may help clean up the conneciton on the APPS potentimeter. It is not a fix but may help eliminate the miss for awhile until the bad connection recurrs. Replacing the APPS may be the final solution. Did you replace the APPS with a new or used part? You may have a gotten a bad APPS. 21.5 psi is borderline too high. I suspect the fuel return valve in the IP that vents excess fuel back the tank may be sticking. The fuel pressure I seriously doubt is the miss problem.

[Mopar1973Man]

Updated web pages and information of the site... Here is the write up for fuel pressure now... http://mopar.mopar1973man.com/cummins/2ndgen24v/fuel-pressure/fuel-pressure.htm