Hi, I just joined this site but had visited it for a while now. Lots of good info,Thank you!!! I have found similar threads related to my issue, but seems like thread ends before the problem is resolved or 99% of the time everybody narrow it down to junk vp. I got a 2002, 2500, 6spd, 4x4, qwd cab, with 130k, air dog, 100hp injectors, 3.55 gears, qwad with pulse, 5" pipe, Problem I'm having is driving on highway over 65mph pulling a trailer(rated 14k gross but about 8-10k total) at steady speed , when going up hill truck starts to surge but not much it's noticeable enough to know there is a problem. And if i turn up the fuel box up it gets worse. so it tells me it's fuel related. i got this truck a few years ago, and previous owner has changed vp under warranty, and at that time he put air dog, it may have 30k on pump. i change fuel filter once a year, but only put about 3-5k ml on it a year. other than that it runs relay good starts right up has plenty of power. i thought maybe it could be that transistor in vp but nut sure if i should have codes or can it be bad and not have codes. Any help would be highly appreciated!

I rarely go but I had a diesel shop go through my Apps and the same thing was happening for them as it was for me . The voltage would change on the apps everytime I moved the throttle. they checked the electrical thinking maybe it could be a pcm issue. they told me in the end that it probably the brain in the  vp giving bad signal. I picked up my apps sensor from a automotive shop it doesn't say the voltages on it so kind of sucks. I will look into that timbo sensor. 

17 hours ago, Dieselfuture said:

You're not stealing anything feel free, this thread is like 8 years old now. Which is crazy all on its own. 

 

You need a timbo apps, must have.

 

when i get down to a single sensor and dont have my spare i will replace it with a timbo but right now its a new OE assembly in the bracket and all that already calibrated. The plan is that when i do need to buy a sensor i will just buy a timbo and put it into my spare bracket and i'll have another new assembly ready to go.

 

i did happen to notice yesterday on my way home that as far as the mystery hesitation were experiencing goes, mine doesnt have to be at highway speeds. i got it to happen consistently at 1800-2000 rpm in all 4 gears at different points throughout my commute home. still no codes

 

i was wondering though... so i had to bleed my high pressure side last week and i didnt notice this hesitation before i did that. is it possible i over tightened one of the connector tubes? ive never had to bleed this truck before and thats a whole nother story in itself but i figure you just get them nice and snug and obviously not tighten them to oblivion which i didnt i just got them snug.

 

if your wondering why i bled it... i took a tight corner with little to no fuel in the tank and made it about 100 yards from there before it just shut off because it sucked air

 

7 hours ago, RyloBrez said:

I rarely go but I had a diesel shop go through my Apps and the same thing was happening for them as it was for me . The voltage would change on the apps everytime I moved the throttle. they checked the electrical thinking maybe it could be a pcm issue. they told me in the end that it probably the brain in the  vp giving bad signal. I picked up my apps sensor from a automotive shop it doesn't say the voltages on it so kind of sucks. I will look into that timbo sensor. 

 

the voltage is supposed to change as you press the pedal just so you know... if i remember right theres 2 sensor circuits and 2 ground circuits and the voltage between the 2 sensor circuits is the opposite of eachother. Meaning that on the 2 circuits that will show a positive voltage value on a volt meter will move in opposite directions. 1 starts at full voltage and goes down and 2 starts at low or 0 and goes up.

 

i may be wrong about that though. if theres just one positive voltage sensor circuits then you'll just worry about that one. but what you wanna look for is a fluctuation in the voltage that is inconsistent with how your moving the pedal. so if say your just slowly pushing the pedal down and you see the voltage suddenly jump or drop that would be an indicator that theres something going on with that sensor. but regardless of how many circuits give the PCM a positive signal throttle position circuits all operate on the idea that as your pedal moves the voltage changes and the PCM will always know that for example 2.0 volts might be 50% throttle and 3.0 volts might be 75%. you want these to be consistently the same voltages at the same position every time but the voltage itself will change based on throttle position

 

i hope that makes sense i have a hard time explaining things sometimes as it is and im pretty wiped out today

 

 

 

im gonna disconnect my edge for the ride home from work today and see if anything changes. if taking the edge off makes the problem go away im gonna look at my BUS connector again followed by MAP sensor connector. if taking the edge off doesnt do anything im gonna swap APPS because it seems to me like it happens around the same throttle position. i just dont know why that wouldnt throw a code for it now when its been giving me codes for months off and on with very minor symptoms that ive chosen to ignore

Been a while...

axle locator pin decided to push through the factory axle lift block.. axle was very crooked so that was a fun 200 mile drive home

 

1 week later...

 

u joint blew apart with little to no warning and wiped out my driveshaft and even wadded up the center bearing brackets so one piece shaft it is... 

 

back to the task at hand for the others-

 

BUS connector on my truck is iffy so i snugged it up with a ziptie for now but also swapped to my spare APPS sensor. Problem seems to be fixed for now. I did notice that when i swapped apps sensors that my truck shifts noticeably different. It really hangs onto first. First used to shift consistently almost regardless of throttle position at 19 mph. This apps makes first last until 24-26 mph and i have to feather the throttle to get it to shift into second and when it does it GRABS it man..

 

anyways hope the input helps. BUS connection is kinda crucial it completes the loop so if your connection isnt really good you lose your tuner momentarily depending on circumstance. Doesnt apply to you if you dont have a tuner running through your BUS connection.

Edited March 7, 20205 yr by 2000Ram2500

Still dealing with my hesitation. It actually went away for a good while. I’ve been chasing it again. My zip tie BUS connector fell off somewhere between Arizona and Florida.

 

but I have some new specific information I believe. 
 

95% of the time it happens under specific conditions.

 

speed: 55 to 65

trans: 4Lock (locks at 51mph)

apps% 20 to 30

conditions: under slight load or slight hill. At speed or under slight acceleration between the specified speeds, also considered a load in my book but someone else may make use of that detail.

maybe 4% of the time it will hesitate/jolt for a split second

 

only one time has it acted up in any other gears

 

i have some other details to add.

 

My battery connections could be improved upon. Voltage used to be 14 pretty consistently but I’m hanging out around 13.6 to 13.8 mostly now.

 

i had to bleed my injection lines about the same time this started happening.

 

hope someone has some experience with this. If I had to guess I’m leaning towards apps or BUS connector again or I accidentally overtightened my injector tube nuts and messed one up. Or possibly a leak elsewhere is another thought I’m having but wasn’t sure if this was consistent with what usually happens with fuel/air leaks

@2000Ram2500 check alternator for AC noise, do the WT mod and adress your battery cables, they are very important on these trucks. See what happens. 

28 minutes ago, Dieselfuture said:

@2000Ram2500 check alternator for AC noise, do the WT mod and adress your battery cables, they are very important on these trucks. See what happens. 

 

I did perform the WT mod. I have an extra ground from the timing case to the drivers battery and the alternator charges the passenger battery. I also replaced the diode about 2 years ago. I noticed huge improvements with the WT mod it was like a new truck.

 

i need to update my passenger side connection where the big cable crosses to the driver side it’s a little sloppy right now. I am using dual post optima batteries which made the WT mod pretty easy to do and for a while I got a good connection it’s just not holding up anymore. So in my case I just need to get a new side post terminal and I’ll be alright with the battery  connections. 

 

do APPS sensors get worn or dead spots after a while? I’m also kinda thinking it’s Timbo time..

 

thank you

2 minutes ago, 2000Ram2500 said:

do APPS sensors get worn or dead spots after a while? I’m also kinda thinking it’s Timbo time..

Yes, if you don't have timbo definitely get one, you won't regret it. 

You guys are awesome. One of these days I’ll be able to buy a membership and give back at least a little bit. I wanted to months ago and then I lost my driveshaft and had to repair my axle block under the leaf spring because it somehow slipped out of place. Then COVID hit.. my life has been a whirlwind