Ok hear is the deal, I am trying to help a friend of a friend out with his truck. It is a 02 2500HD with a 408 and STS@12psi (67mm Turbo) He does not have a wideband, I preached to him to get one so hopefully he does. The truck has roughly a 12" lift and 35" tires on it. It was at one point tuned on a dyno, this is the part that is wierd ( told him to get me a copy of the dyno sheet) Like 480 something hp and 680tq. Those #'s are way out of wack! Anyway it is non intercooled and no meth, couldnt get the truck above 70% throttle without hearing what sounded to be detonation.. It was very faint, not like I have heard before on other setups. It pulls good for a lifted big *** truck, has forged internals, LS6 cam, stock 317 heads, TR6 plugs. Did a couple logs yesterday and didnt see as much as a blip of KR, 0 Zilch. It doesn't seem possible unless someone basically turned off the KR sensors. My theory is 170 IAT's, 12psi, 22 deg timing, no intercooler, no meth, pump gas = Bad situation. I didnt read his tune yet, just logged it for awhile. His LT fuel trims are like 12 to 20, and another thing I found wierd is that in one part of the log at like 5100 rpm, 80 or so Throttle % and 12psi his MAF reading was like 51lb/min..... That seems awfull low to me for that setup, I figured he would be maxing the MAF really soon. Whats everyones thoughts on this, I am stumped, too many things dont seem to make sense to me here. Sorry for the rant.

 

Making 12psi with a 67mm turbo on a 408 is going to create some REALLY hot air. In fact I didn't even think it was possible until reading this. He needs to turn the boost down and start the tuning there. He might not actually be seeing 12psi either give the MAF readings. It could be a bad boost gauge or something. What does the MAP read?

 

Well the MAP is maxed being that he is only running MAF no 2bar or anything. 104kpa is what it reads as soon as he hits boost.

 

He needs a bigger turbo to make power -- and he needs an intercooler to run that much boost + 22* timing.

I'm pretty sure he isn't running 12psi and 22* of timing with no intercooler or meth. Given the 170* IATs, I'm with Vanilla... that boost gauge is whacked.

 

Like I said, the whole deal seemed messed up to me. I told him it seemed like a disaster waiting to happen with no intercooler and that much timing.

 

Yep it is.

You know -- maybe he's running super super rich and washing the cylinders (although to me that sounds like a burbling and the truck would fall flat on its face). Maybe the tuner told him to do the same stuff you did and your friend didn't want to hear it so the tuner set him up with a tune to keep from blowing up.

 

Well I thought of that but 22 Degrees timing??? Also I see in my logs that whoever tuned it is not commanding anything less then like 12.5afr until above 4800 rpm. I personally think there was some shaddy stuff going on and so does this guy.. He deleted the tow haul setting becuase he said if not it would hurt his engine??? Um last time I checked tow haul only affected shift properties and if he was that worried about that then copy and paste the tables from the normal to the performance table, dont actually unhook the tow haul button.... Correct me if I am wrong here.... So much stuff just doesnt jive that I am not sure if I really want to open that can of worms. At this point he wants it tuned to be reliable even if it means less boost, I guess this is his 2nd engine First one lasted a day. The guy seems like a nice guy, I just wonder if someone didnt use that to there advantage... He is not very knowledgeable about the setup.

 

I told him he should turn down the boost, and get a wideband.... I would really like to know what his KR settings are because I cant beleive it isnt getting any KR at all with the way it is setup. I also told him a intercooler would be a wise investment. I havent read the pcm yet just because I dont know if I really want to get into it.... As messed up as all of it looks to me it all needs to go back to square one and be taken from there. I also dont know if any damage has already occured...

 

Based on what you said above, run screaming away. And not the manly kind of screaming either...

How close a friend is this? Sounds like a huuuuuge headache.

 

This is why I havent read the tune yet, if he gets a wideband I will consider messing with it but only to make it safe. Like lower boost, more conservative timing table etc. Based on the IAT's and timing I seen I dont think that there is anything in the Base IAT timing table it flatlines at 22 degrees and doesnt move regarless of IAT. The dude just wants to make it so he doesnt have to worry about it ( Makes me wonder why do a 408 with hi boost then) not the perfect setup for someone to drive and forget by any means. From what I have seen in the logs I dont like the timing table, commanded AFR or the base IAT table. Also the fuel trims are way pos. Big can of worms here when I dont have any exact specs on the engine. At least I know I am not the only one that thinks its way out of wack.