Engine/Transmission (1998.5 - 2002) Truck is surging

[RonnieGilman]

My truck has been surging for a while and i cant figure it out, it does it in the morning taking off in first gear and also going through the gears, and i can feel it on the freeway, but sometimes it goes away and then comes back its not a very hard surge but i can feel it mostly when taking off it will surge and if i throttle it it goes away till i shift, i do have a comp box on it but i turn it off and i can still feel it, my fuel pressure seems to be good so if anybody has any ideas let me know

 

[AFoulk]

I've had a similar problem with mine, and some people told me to check the APPS. Unfortunately I think the problem with mine is the injection pump because it surges even with the cruise control set.

 

[RonnieGilman]

How do i check the apps

 

[GHolcomb]

I have a theory about this, but it is just my opinion!



My truck does the same thing. Try putting it in cruise, does the surge go away? Mine goes away when I go to cruise, which leads me to believe it is the apps. However, I also believe cruise aggravates the situation. There seems to be a problem between cruise and the apps. If I am in cruise for between one and two hours, I get a high idle. If I cruise for over two hours, I get a dead pedal. Turning the truck off and starting it again resets the computer and everything is good.



My brother has the exact same truck as mine and we both have the same experience.



There are two things that we have found that will improve the situation for a little while.



One is to get out on the road and accelerate to wot fairly slowly and then back to normal driving. That seems to help.



The second is with the truck off, turn your ignition switch to on and slowly press your accelerator pedal to the floor and then slowly back off. From what I've read, that should reset your apps.



Both of these techniques involve going wot and back, so maybe they both do the same thing. However, my experience is that you have to do it every few weeks and just recently I noticed that after being on cruise, the situation pops back up almost immediately.



I'd be interested to hear if this works for your truck.



Greg

 

[NoSeeUm]

Any codes?



Jim

 

[Fishin Guide]

Is it under 40 degrees? The comp can cause surging or stuttering.



What is the rest of your setup? Comp only? injectors? turbo? ect?



Dave

 

[GaryOwen]

Had same symptoms with my 03 -worked fine on cruise, kept getting worse with when not on cruise. Tried pumping accelerator pedal about 20 times with engine off to shake things up! Worked for a while, but eventually even that wouldn't do much. Finally broke down and bought APPS ($374+tax from dealer) and installed yesterday - all symptoms are gone. Accelerates smoothly.



Gary

 

[GCULP]

it's most likely your APPS, they're a glorified dimmer switch. pushing the throttle to the floor and back is just cleaning the contacts for a short time untill the corrosion builds up again, and when using the CC the APPS is relaxed so you don't feel it, and when throttling through the surge you're just using a cleaner portion of the APPS. GHolcom, you're right, it shouldn't make any difference if the engine is running or not, and I personally don't think key on or off makes a difference either cause you're trying to clean the contacts by brushing them repeatedly. If you can, try swapping the apps with someone with a similar year truck that is running fine, you won't hurt a thing, Rip at Source Auto loaned me one for a weekend and sure enough is solved the problem. Good luck and let us know.

 

[GiesJ]

I too am having a surging. Changed the fuel filter thinking maybe it was bad fuel. I have some sand like stuff in the bottom of the canister but filter didn't look that dirty. New filter in and canister cleaned and it still is there. My fuel pressure is down about 1 psi to a heavy 11 psi. Going down the interstate at 1600 rpm I have the surge where the rpm doesn't change but the engine sounds like it is surging.

Is this the same symptoms you were seeing? Any help is appreciated.

Jason

 

[AFoulk]

thats the symptoms I have on mine too, the surging that you can't see or feel but you can hear it. Mine does it with the cruise on or off though. I've had several people tell me theres probably a good chance its my VP on its way out. No codes yet though.

 

[Texas Diesel]

The engine and transmission are rubber mounted which sets up an oscillation in the drive line that may be what you are feeling.



This was discussed at great length back in 2001 along with the "shudder" feeling from the rubber mounted center bearing in the two piece drive shafts.



All three of my trucks did the same "surging" as does my current 3500.



I let off the fuel for a couple of seconds and it goes away. Sometimes adding fuel for a couple of seconds will cause it to stop too. If you can kill your surging by manipulating the throttle, it is just the rubber in the mounts giving a little.

 

[John - K5AWO]

How do i check the apps

The so called Reset Procedure is defined here:
Diesel Truck Resource


and the voltage reset procedure is as follows (copied from somewhere).
I copied this from one of JetPoilot's postings. .
resetting it using this procedure copied from DTT's website:



--------------------------------------------------------------------------------

RESETTING THE APPS SENSOR.
(ACCELERATOR PEDAL POSITION SENSOR)
2ND GENERATION 24 VALVE TRUCKS ONLY.

LIST OF TOOLS NEEDED

DIGITAL VOLT METER
# 20 TORQUE BIT SOCKET
# 1 PHILLIPS
# 10 MM SOCKET

Proper service and repair procedures are vital to ensure personal safety of those performing the repairs. Standard safety procedures and precautions should be followed at all times to eliminate the personal injury or improper service, which could damage the vehicle or compromise its safety.
Although this material has been prepared with the intent to provide reliable information, no liability is assumed in reliance of this material.

It has come to my attention that a lot of people think by disconnecting & re-connecting the batteries and stepping on the throttle it is going to reset the apps, no, that is not correct. It is impossible to adjust your apps if you do not know where it is supposed to be set at. That is why you need the voltmeter.

This is the procedure I use to re-set the apps.

With the key on, engine off you need to probe the apps wire to see where your voltage is currently set at.
The best location to probe the wire is on the PCM (power control module) which is located off the passenger side of the firewall.

· You want the C1 connector, this is the connector closest to the engine,
· You want the orange wire with the dark blue tracer which is pin # 23
· Voltage should read somewhere around 0. 5 volts,
· At this point the voltage reading does not matter, it just has to be accurately written down for later reference.

*** TURN THE IGNITION OFF ON THE TRUCK ***




Resetting the APPS Sensor cont. page 2
(Accelerator Pedal Position Sensor)
2nd generation 24 valve trucks only.

· The apps sensor is located slightly above and a little to the left of the injection pump.

· Remove the black plastic cover that is located by your injection pump.

The two screws that are holding it are plastic, do not put any downward pressure on them or you will never get them off.

· Un do the 6 - 10 mm headed bolts that hold the bracketry in place.
(DO NOT REMOVE THE CABLES)

You will notice the apps is on the back of the bracketry that you just removed, it is held in place by 2 - 20 bit screws. These screws have a little bit of locktite on them so make sure you have a good socket and gently give a little tap with a hammer before attempting to loosen. Be very careful these screws strip very easily and you only get one shot at them.

· On the apps you will find a white tag that gives you the information on what the apps adjustment should be.

· After loosening the screws you can rotate the apps both clockwise and counter clockwise to get the adjustment you need.

· The reading you took at the beginning of the process on pin # 23 should match the white tag on your apps, if not adjust accordingly.
__________________

 

[GiesJ]

Texas D - you make a good point but I have had my truck for 8 years and this is a new feeling recently. It does it with and without the Cruise on. I am on my 5th VP44 over those 8 years and hope this one is not dying a slow death. THe other pumps were catostrophic failures and I was left on the side of the road...

 

[4xquadrod]

My buddy bought an 01, had a surging problem. Had the pressure pump replaced, still surged. He then bought a bilt trans thinking the trans was giving him trouble. The trans was swapped, still had a the problem. It ended up being a kinked fuel line at his lift pump. :-laf kind of an expensive way to figure it out.