Another VP/TPS issue...

RockinRam96

Active member
So, I've researched this a bit multiple times with really no luck to help out my situation. I still have the question of "Is my VP bad or the TPS?" at the end of reading all of these threads.

I bought this truck in December of 2011 to start building into a puller. Last summer was the first summer I had it out and it was a street puller, pretty much stock with a Smarty on it then a Quadzilla. When I fist got the Smarty programmed at level 9 I would get a dead pedal after I made the shift into 6th gear at about 45 mph, under any amount of throttle. So, messing around I turned the Smarty down to level and and the problem went away. Which lead me to believe that my truck didn't like any added timing, resulting int he VP going bad. My uncle had a 2000 auto that the trans had blown up in and I robbed the TPS off of that to try out, and at the time it seemed to be no problem. I didn't even think about checking codes.

I then sold the Smarty to try out a Quadzilla. I never had any issues with the Quadzilla. Fall came and I decided to buy a snow plow for the truck and make some money. Not thinking that I'd pull it with a VP on it again, I sold the Quadzilla. I went all winter without any dead throttle problems. We had a couple days in March, and the truck froze up and died on my way to work.

April came and I was getting my 96 ready to get out of the shop and all of the sudden one day headed to the shop I got a dead throttle as soon as I made the shift into 6th gear. Got to the shop, checked all my battery connections, the TPS connection and fuse box connections. Truck drove home just fine, and make my 60 mile round trip to work and back the next day fine. That next night on my way to the show I got a dead throttle once again, this time bad. So I parked it and got my 96 out. I decide to take it out one day in June, drove about 20 miles with not a single hiccup.

Now I did check the codes when I parked it. It did have two codes that I thought could be an issue. It had an Apps Sensor Voltage low and a charging system voltage low code. My alternator had done a few goofy things throughout the winter, could this be my problem? Or does my problem remain in the TPS or VP?

The truck has 2 brand new batteries, new battery terminal connectors, Raptor 150 idling at 18 psi, and I put electric grease in the TPS connector when I put it back together. The VP is a reman VP from Dodge that was put on before I owned the truck. From what I gather after reading all of these threads and post is that, this is almost a trial and error process, unless you get a VP specific code.

Sorry for the redundant post. Any help is greatly appreciated.
 
Start simple and cheap. Pull the alternator and have it checked. Free. If it is good, swap TPS with a buddy and test it. Free. If no good, swap ECM with a buddy and test it. Free. If not, buy a VP. :D I ran that marathon once. Tried everything for two weeks. Bought a VP and ran like a champ.
 
^^^ Agreed. Start with the alternator. Bad alternators cause a lot of driveability issues with these trucks. Next would be a APPS (TPS) reset or replacement.
 
Well I had the alternator tested this morning and it tested out just fine. I did trade a TPS with my uncles truck that had been sitting for about a year at that time. Been running that TPS since last spring. I guess the next thing to test is the ECM. I don't know anyone with a 24 valve 6 speed I can trade ECMs with. I am wondering if Dodge can check it some how or flash it?

My uncles truck that I got the TPS from has automatic in it, but I probably can't trade that out to my 6 speed can I? Or does the PCM control the transmission?

EDIT: I can never keep the PCM and ECM straight. The PCM is on the passenger side fire wall and the ECM is on the engine block behind the injection pump, correct?
 
if equipped, check for dead pedal on cruse control. That pointed me to the APPS. (TPS is on 12v)
ECM is mounted on the driver side of the motor
PCM is mounted on pass. side fire wall
also pull all codes with a scanner or smarty.
 
So I got the truck out today and put the alternator back on it. Had 0 problems! Drove it probably 15-20 miles with no problems at all. This makes me believe that it can not be the injection pump. It is a dog shifting into 6th gear but ever other gear it will accelerate pretty hard in.

I'm going to our property in a couple weeks, which is an 160 mile round trip so that should be a decent test for it. I am just stumped with this electrical stuff.
 
So I've been driving my truck around a bit lately to see how it is acting. It's been pretty good up until tonight. I went for about a 30 mile round trip. With in the first mile I had a dead throttle. Couldn't get it to go over 40, and the cruise wouldn't work. Then all the sudden it came to life.

Ran and drove fine until about a mile from home. Again no throttle and no cruise.

I'm thinking it's the ECM. I think the TPS is good and I have to believe the injection pump is good. It was strong when I pulled it I don't see where the pump can be bad.
 
Just doesn't make sense that the pump would be bad. I feel like it should work or it should not.

Either way, going to check codes with a scanner today or tomorrow, clear them drive it around and check them again after dead throttle.
 
the APPS (TPS) sensor is the same
Timbo APPS
read the diagnostic write ups. helped me a bunch.

Thanks.

From reading this and reading Blue Chip Diesel's diagnosis I really think my issue is the APPS. I keep getting code P0122, Acceleration Position Pedal Sensor Voltage Low. The problem is so intermittent and I can be going down the road and it will surge and take off like a rocket. So I'm ordering an APPS from Blue Chip Diesel today.
 
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