I've had this truck about 10 months or so.It's a 1999 one ton with dump bed,just turned 80,000 miles yesterday.This is a work truck only used to haul or pull trailer,not a daily driver.
Ever since I bought the truck I've not been able to rev. over 2400 r.p.m.When I do its like you turn the power off.A few times I've been able to go over 2400 with out it cutting off,most times not.Also has a slight irregular idle.So for ten months I just watch the tac.and shift before 2400.I've learned to live with it,but its getting old.
I took it to one of the best diesel shops in Nashville a month or so after I bought it.They ran codes and all the pressure test,came up with nothing for sure?I might add they didn't charge me a penny(Diesel Power Inc.)I ask what am I suppose to do?They said if it were mine I'd run it until you could tell for sure what the problem was.So thats what I've been doing.
Yes I have a fuel pressure guage.At start up its around 16.Going down the road its never gone under 13.Don't ask me what W.O.T. is cant go over2400.
I think that covers it.
Thanks,
tony3542

 

Id give this post a shot in the 24Valve section. Us undervalved guys kinda like fixin stuff with hammers and torches, lol

 

Thanks,just realized I put it on the wrong forum.

 

No one has an opinion or input on this on going problem?
thanks tony3542

 

Sounds like the typical 24v defueling scenario. Things just kind of go flat power wise. It should be around 2700 though.

Jeff

 

2400 does sound a little low for defueling, but then, I rarely let mine go over 2500 before shifting . If you have good fp, how about air? Do you have boost gage? I'm thinking maybe a leak in the intercooler line someplace or a waste gate problem. I'm sure the diesel shop checked all this, but they are the basics and someplace to start.

 

I read you guys talking about defueling and at what RPM it happens. I tried mine last night and it took it clear to red line with no defueling in site. Backed off and here I am. Is it normal for a dodge diesel to have no end in throttle? Pulled incredibly strong to redline. Scary! No chips or mods either. Thanks in advance.

Tom

 

Thanks guys for the input.Is it possible re-setting the APPS could help something like this?By the way I'm no mechanic,I just do simple things like oil and filter changes.
tony3542

 

You could have a MAD ECM in it without even knowing it. If it also does not defuel at takeoff, or between 1-2 shift, then yes you've got one. Consider yourself lucky like me, except I had to pay for mine separately.

 

Torque,
What does mad-ecm mean or stand for?
thanks tony3542

 

It's a reprogrammed Electronic Control Module, replaces your factory ECM.

 

The 99 trucks do not defuel like the 01 and up trucks..... Also on the upper end normally you can't feel the defuel, its a mild defuel to help with egt control. Our trucks should be able to pull to redline, a dyno is the best way to see the topend defuel.

As for Tony3542's truck I have seen VP44's going bad that showed similiar conditions. Another thought would be the APPS, try 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.

 

I second that... My truck does great down the highway all the way up to redline (3,200 RPM's) I normally only let it get too 3K even if I'm going hard and strong then shift.

 

If the wastegate is stuck closed, could the MAP sensor tell the computer about the high boost and the computer defuel early?

 

Yes that could cause it.