Ok... First let me say I am new to diesels and this is my first post so any help would be greatly appreciated!!! I am going to walk you through my history of the truck so you can see exactly what I have done and maybe were I went wrong. Dont worry, I have only had it for about a month. I bought a 96 Chevy C3500 Quad Cab, Dually with the 6.5 TD for towing for my company. I new it had some problems but for $3500.00 I figured it was worth the work. When I bought the truck it wouldnt go anything over 65Mph and there was no Turbo wistle what so ever. After doing allot of needed maintnence on it I discovered the first real problem. SERIOUSLY CLOGGED fuel filter... This thing was black as night no kidding. I replaced it along with my other upgrades to the driveline.. (shocks, breaks, ect.) and took it for a test drive. The difference was night and day! Now the truck would nearly haul *** and would do 85 all day long! After that, It had a GM-5 Turbo and I then replaced it with a GM-8 as I knew the current one was bad. I also put on a 4" Turbo-back exaust from SSDiesel, PMD Isolater with heatsink with #9 resistor from SSDiesel, HO Injectors from SSDiesel, Spring type wastegate controller from Heath Diesel, High Flow cooling upgrade with newer Duramax fan from SSDiesel, High Flow Intake kit from SSDiesel, and 80 HP ECM from SSDiesel. Now here are my current problems... I have yet to install the ECM as it was delayed and I do not have it yet, but the engine is throwing a code P0238 (Turbo Boost Sensor). When I start it up it drives fine and then I can get on the pedal and as it starts to really put down power but then all of a sudden you can litteraly feel the engine cut power and it doesnt want to go over 2500 RPM. Sometimes it throws the code and sometimes it doesnt but either way you can feel the truck cut power. When it doesnt throw the code all I have to do is turn off the engine and then refire it and it goes along as its supposed to.
If you have any help I would greatly appreciate it!!! I have a EGT and Boost gauge but I havent gotten to install them yet, I also have replaced the lift pump with no change in condition as well as the Turbo Boost Sensor with no change. I have also adjusted the wastegate spring up and down to increase/decrease boost and that has had no change either.
PLEASE HELP ME!!!!! And also what should I be looking for on the gauges when I get them installed?
Thanks.... Chris

Wheeww. that's a long post! Welcome, Chris. :)

Please take a couple of minutes to fill out your signature. This way we can see your vehicle specs without having to go back to your original post.

You're getting an overboost code because the turbomaster gives more boost than your stock ecm says it wants.

Install those gauges ASAP! you do not want to increase boost without KNOWING EXACTLY what you have increased it to. Stock ecm wants no more than 7 lbs boost. We can't tell you anything that's more important than what your boost gauge can tell you (once you install it). You must monitor EGT's to avoid serious engine damage. You've already got a sizeable investment in your truck. Don't jeapordize it.

Aside from that, it sounds like everything is ok.

Hi Chris welcome to the site, do not install the upgrade PCM until AFTER INSTALLING GAUGES since you are new to the truck you don't know previous treatment it was subjected to, fuel filter though should give you an idea it wasn't maintained as well as it should have been.

Black smoke means it was running for Lord knows how long without turbo assist, black smoke at load means high EGT, so do not hot rod it until you have run it some sensibly to know if it is up to all the extra capability you have given it now.

Gauges at this point are a must go to FAQ for the info where to locate the EGT probe, for you until you get a feel of how engine is performing go conservative max 950F turbo inlet.

Hi boost code should clear with the reflash.

SS Diesel FSD on intake needs to be relocated to a spot outside the engine bay you will want an extension harness from Kennedy Diesel http://www.kennedydiesel.com/ or Heath Diesel (google search).

FSD on intake drivers will most probably fail, you have just made it last a little longer than on the IP, and made it easier to change at that location.

Lastly use welcome link in my signature for info on how to update yours