Engine/Transmission (1998.5 - 2002) ? about APPS

[MAllen1]

Here's my dalima---Over the past year I have been having a problem while cruising around town and my APPS goes dead. Wasn't a problem until recently when, in the morning, it would stumble so bad I was afraid to pull out on the freeway. I took my powerpuck off and it settled it down, but didn't completely solve the problem (it's still there while cruising around town). Here's what I know---My truck is a 99 w/a 5-speed and it has the aftermarket computer, from Cummins, to bring the torque to 500 lb-ft. and a Banks wastegate actuator. All the connection between the ECM and the injection pump and the APPS look clean. The codes that pop up are 1693 (DTC detected in the PCM), 0121 (APPS and idle validation disagree), 0234 (Turbo boost limit exceeded), and 1689 (no communication between fuel pump and ecm). Before I checked the codes, I checked my fuel pressure, and it was at 14-15 psi at idle and at W. O. T it would dip to 10-11 psi for a second and then come back to about 14-15psi, so I feel good about the transfer pump ( I know, duh!). After I checked the codes, I ran it down the road with the road with the scanner hooked up to see what the MAP would tell me because originally I though I might be having an overboost problem with the 0234 code. The boost NEVER got over 26 psi, so I shouldn't have a problem with overboost ( i've been told 30-32 psi and the MAP will pull the plug). The only thing that looked out of place, with the scanner still plugged up, is while puttering around town is that the Idle Valve Switch (locate within the APPS circutry) wouldn't turn off until the APPS was at around 13%. To make a long story short, I am leaning torwards the APPS, I just would like some validation ( and suggestions on aftermarket, if any) before I drop $700.

 

[JLandry]

MAllen,



DON'T buy the standard Mopar replacement APPS for those huge $$$.



If you spend a little time searching the forum you'll find you can replace the throttle position sensor only which is located on the side of the cast aluminum APPS housing. It can be ordered from Williams Controls. The only modification needed is to fabricate a wiring adapter to plug between the Dodge harness and the connector on the new Williams sensor. You can do-it-yourself or save the trouble and order a complete replacement kit from forum member "timbo" for a very reasonable price (used to be about $120 before Williams' prices went up recently). Send timbo a PM to order.



If you decide to do-it-yourself, the Williams part numbers you would need are:



131973 - Sensor Kit



131165 - Wire Harness



The sensor "kit" contains extra parts you won't use for a Dodge truck... just throw those away.



The wiring harness plugs into the Williams sensor, but needs to be modified to plug into the Dodge wiring harness. This is done by cutting off the two 3-pin WeatherPak connectors on one end, and in their place installing a single 6-pin Deutsch DT series connector (part number DT04-6P).



See this post for more info:



Anatomy of an APPS - The SEQUEL!



Best regards,



John L.

 

[24V-DSL]

I paid ~$350 a few years ago from Cummins.

 

[Joe Mc]

Blue Chip Diesel Performance Specialists - CATALOG - APPS - Accelerator Pedal Position Switch $175



Not trying to sell Blue Chip, but I was shopping for a VP (BC too expensive for me) and I happened to come about this on their site. May be of help to you.



Ah, my 99 just lost the VP @ 175k miles - tooling along not a care in the world and it went out like someone pulled the plug on it - poof! just died - got it home and there it was PO1688. Good luck with the APPS.