muddybeast

Just got the truck back from the tranny shop and got that rebuilt and a new lift pump put in. It was dropping in and out of overdrive erraticaly and that problem is now fixed but it is still having a loss of power at cruising speed. This happens only on the interstate, not during city driving or highway. You can just be cruising along at 70+ and it just seems like you let off the go pedal. You can take your foot off totally and jam it back down and it will go fine for a bit and then do it again. From what I have read it could be possibly the MAP sensor, where is this located and also where is the lift pump? I want to look and make sure it is new. Could it possibly be the VP44 and where is it located? I am also waiting on my guages so I know I need them. Any help would be great.

crobtex

Mine was doing the same thing in town and on the highway. It was the APPS.
Check here for reset procedure. https://www.dieseltruckresource.com/...n&onlynewfaq=1

You can find a map of the fuel system here: http://www.dodgeram.org/tech/dsl/mt_...l_sys_comp.htm

Hope this helps.

mr T

TPS sensor or the equivalent type sensor on ur 24 valve....i wouldnt panic...should be a smooth fix

ocliffie

muddybeast,

Have you tried the APPS reset yet. My 99 was doing the exact same thing. I checked the fuel pressure, cleaned the IAT sensor and replaced the MAP sensor and checked the vent on top of the fuel tank. I didn't know how to do the APPs reset until now which will be my next step. Let me know how you make out. That go pedal thing is a real style cramper especially if your in the passing lane!

muddybeast

I didn't have any luck with the APPS reset at all, it has gotten worse consistantly and last night I thought it wasn't going to make it. I am going to check the TPS again since last time it was running better and would not act up with the comp on it. Now surely it will, I couldn't hardly get it to go over 50mph last night.

ocliffie

muddybeast,

The procedure to do the APPS reset says to turn the key to the on position. Do you read this as turn the key two "clicks" until the all the idiot light s come on just as you would when your going to start it?? I tried it last night and no go. I'm going to pull some codes next. What's your plan from this point.??

phox_mulder

Yes, "on" is when all the idiot lites do their thing.


phox

muddybeast

Sorry, haven't been around in a while. I took the truck to a fuel specialty shop and they said nothing could be found that was wrong. SO I took it to a cummins dealer and they said the same thing. Ripped down the fuel system and everything checked out. I am at a loss for words at this point. I guess the only things left to try are getiing new sensors (TPS and MAF) , also it doesn't trip any codes. Any suggestions?

muddybeast

Also they said try filling the tank and loosening the cap to eliminate the possibility of a vapor lock and stuff being in the tank, that was also no go. So I am going to try and get a hold of a TPS. Where would everyone recomend getting one? Local parts junkies want $600 for one.

muddybeast

I just recieved my new TPS assembly today, I am going to install it tonight and I will let you know if it helps me out at all.

muddybeast

Well here is my update ocliffie......new TPS did absolutely nothing to help the problem. Any one else have any suggestions? What exactly does the MAp sensor do, Regulate Boost, and should I replace this also? What about the VP I know they checked it BUT it only does this after about 10min of interstate driving, from there it gets consistantly worse. I just CAN'T believe the truck has been this much trouble even if it runs to 400,000 I don't think it will justify its costs

ocliffie

The MAP sensor measures manafold air pressure. Did you check for codes yet??. I'm still having the same problem. I checked the overflow check valve in the VP this weekend and I can blow air through it. This also sounds like the cause of simptons we have been getting and apparently will also cause a VP failure code. Just picked up a checkvalve the other day but haven't installed it yet. I will definately let everone know how I make out. I already changed out my MAP sensor and still the problem exits. I even cleared the codes. Problem won't go away but I'm not ready for the dealer yet.

muddybeast

Mine hasn't tripped any codes where is the piece at on the VP you are talking about. I might have to take a look at it. We also have another appointment a different diesel mechanic that is willing to actually drive it as his for a day with the comp on it so hopefully it will act up for him.

ocliffie

See attached link for location of overflow checkvalve and Good Luck at the "dealer"

http://www.dodgeram.org/tech/dsl/mt_...l_sys_comp.htm

muddybeast

not going to the dealer, that will be a last resort if I even would then. keep us updated with the checkvalve.