tryn to figure out wats wrong with my truck

Cummins0154

cummins0154
Joined
Feb 12, 2009
Messages
54
ok when im runnin 40-60 mph it starts to hesitate kinda then today i was runnin 40 or so and gave it a little throttle and it almost died it dropped all the way to about 500rpms and i let off and got bak into it and the rpms shot bak up to normal im hopin it aint my injection pump if u got any ideas wats causing this please let me kno i dont feel like payin sum1 to tell me wats wrong with her thank you
 
Try having the codes pulled. What year is your truck and what, if any, modifications are done to it?
 
Id say throttle position sensor voltage too low! check the codes and replace or try adjusting it!
 
Probably APPS or the injection pump. Those are the 2 likely culprits. Check for codes, and check the APPS voltage.
Sean
 
I'll bet you a case of beer from Tyler that you have a APPS going south. Do you have a readout of any kind that you can display throttle %? If so, I'll bet it is going nuts. Mine did. Find someone that has p-pumped a 24V and has a spare APPS laying around. You can get them for free if you are a nice guy. $.02

Check you APPS volatage also.
---------------------------------------------



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
 
my mods r an hot edge juice, 155bd injectors, flo tubes, aaurora 5k turbo, ats arcflow, Fass 150, 5 inch exhaust, full suncoast tranny, hotrod Vp44, NOS by the way its an 01 2500 but thanks 4 helpin me out
 
according to my edge the lowest fuel pressure im cn is 14psi and high 19psi the fuel filters newer
 
APPS is my guess.

Or, you might be collapsing your air filter...

Do you have any codes? Cam position sensor? APPS? MAP?

Merrick
 
I'd check all the grounds because a loose ground can cause all sorts of weird problems in these trucks.
 
Mine started that a coupla years ago. I checked the APPS wiring connector and found 1 pin darker than the others so thinking it had a poor connection, I re-connected then disconnected the connector a few times. Abouta year later it did it again so I did the connection drill again with success. It's getting to be a year soon so I'll see if it returns again.
 
When my APPS went out I did not get a check engine light, or a code, but the dealer replaced under warranty because of the symptoms....
Merrick
 
sounds like injection pump...my truck started doing something similar to that a few weeks back and I ended up replacing the pump, I didn't have any codes pop up either.

I will say though check all the simple cheap things first before pulling the trigger on a new pump
 
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