dead pedal

[edward pac]

I have a 98.5 ram diesel with no mods and it gave me intermittent dead pedal for a week and now staying dead. idles nice though
codes are
p1688
p0463
p1693
I cleaned all the grounds I could find but couldn't get the one loose behind the starter..tryin penetrating oil and all. tomorrow morning ill take off the starter to get that ground out and clean it up. any other ideas? lift pump? fuel filter? it did seem to happen only at start up a few days, worse when colder
thanks

 

[KATOOM]

Check alternator AC voltage...

With a basic muti-meter that reads in both DC and AC, switch to AC voltage 200. Start the engine and turn on all electronics, air conditioning, and blower on max setting. Have a friend ramp the engine up to around 2000 rpm. Take the red lead of the multi-meter and touch the main outlet on the back of the alternator. Then touch the black lead grounding directly to the alternator housing.

AC voltage is caused by the alternator generating DC voltage. If the rectifier / diodes are bad then it will generate too much AC voltage which feeds back into the engine electronics causing harm to sensitive electronics like the PCM, ECM, VP PSG, and transmission solenoid.

AC voltage wave should be as low as possible but anything under .05v is considered acceptable. These trucks are just very sensitive to AC voltage. Just make sure you perform the test as I described and DO NOT try to pull a reading through the battery terminals because the battery will filter AC noise and give a false reading.