I'm new to the diesel world, I bought a 2002 3500 5.9L diesel dually from a buddy of mine and Ive been tinkering with it trying to fix it and I'm stumped. When the truck is in park or nuetral I can rev it for days with little/no throttle lag, but you don't hear the turbo until its almost redlined. If you put in any other gear (R, D, 2) you can't hit the gas hard, you had to slug it. My buddy put a new transmission in it before I bought it. I have the quadzilla chip that will show ECM voltage, but once I put it in a driving gear I lose the voltage. My engine coolant temp sensor goes all the way up, even when the key is just in the on position. I did the fourth gear hunt fix for the APPS thinkin that may help, and it did, for a short while, the fuel pump has been replaced with an aftermarket fuel pump that pumps out greater fuel pressure. I'm just lost in the sauce. Help please!

 

It seems like you might have some bad grounds that are causing in gages to peg. It you rev the engine with no load(in nuetral or park) it barely builds boost(normal). Check in drive gear.

 

In drive gears, the engine itself is really sluggish, even at 50% apps the engine acts like only 2% is pushed. The boost does not build up until its almost time to shift gears, it used to intermittently drive with all the power that it should have, but now it doesn't. I know I need an alternator change, because running my batteries only have 12.14 v, and I don't have the "no bus" or CCD on my HUD unless I remove the big wire from the fuse panel, what would cause it to have no power and throttle resistance in drive gears (under load)? Turning OD off doesn't make a difference. Where would I look for the ground on the gauges?
Thank you for your response!

 

First unhook the Quad see what it does .It might have a bad wire in the colum , also red lining the engine in neutral is not a great idea ,you need a load on the engine to build boost. I would be looking for a bad or dirty wire connection . also whats your fuel pressure look like,also the fuel filter?

 

Fuel filter was just changed, old fuel filter was BLACK! Unplugging quad made no difference. Fuel pressure is about 21 (at all times, WOT or not) I went through and cleaned up all connections (that I could easily access) with dielectric grease and everything, nothing really changed :/

 

Also, I forgot to mention, with the key just in the "on" position (even after days of no starting) no temp gauge pegs, regardless of what time it is, and very seldomly goes back to normal (but I guess it's a good thing that it does?) could the ECM be reading that the temp gauge is pegged and put the engine in limp mode? I've replaced both my thermostat and my engine coolant temperature sensor within the last week. After driving my battery gauge goes all the way down to 8 as well, but I can shut it off and put the key in "on" and it shows 12 volts

 

Are you sure the altinator is bad. The voltage regulator is a internal function of the PCM. Also have you checked to see if you have 5v at you coolant temp sensor.

 

I'm pretty sure it's the alternator that's bad, when I measure the voltage of each battery after I start it it shows only 12.14 volts, shouldn't it be 13.5? And last I checked I had 5 volts at my ect, how would I prove/disprove your theory?

 

Its the voltage regulator that tells the altinator to ramp up and charge the battery. If the voltage regulator does not work, you have only what voltage the batteries are holding. Without testing the alt. its hard to tell whats actually bad. Curious if you cleaned the grounds at the pcm and the ecm.

 

Actually, it's kinda funny you said that, in my PDC I've got that big 140A fuse for the alternator that's held down my two screws, in theory, of course. Mine was held with one, put a screw in there and problem solved, voltage is now 13.56-13.6 while engine is running. BUUUUUUUT I was sorting out everything in the fuse panel (holy crap it was a mess) and as I was putting grounds to chassis grounds instead of the metal in the fuse panel I came across my temp sensor acting right and my quadzilla chip showing 8 volts, definitely a start! I tried changing fuse 9, but once I lost it I lost it, is there any other wire in that area that could affect it? I just wanna drive it, and drive it properly! Lol. I checked the turbo and the turbines are spinning, I just did the APPS recalibrate on it, but that didn't do much good, still very sluggish, I think it's just an ECM voltage problem, but I'm not sure

 

Also, I can't quite reach the ECM to clean the grounds, but read somewhere that the ground for it is under the starter...is this true? If not where are the grounds that you suggest I clean?