Forgive me if this has ever come up and/or if there's a simple answer under my nose that I haven't thought of. I would appreciate it if anyone could offer me some advice....

I work for a small Kansas bank. From time to time we get repossessed vehicles in from our star borrowers. My newest truck is one such case.

This truck is a 2001 Chev 2500HD 6.0. I took it apart to the sheet metal from front to back. Engine/trans/interior. All had been trashed. The engine and transmission had been on fire and "rewired" to work. The transfer case had been run bone dry and had a little sludge and bits of metal in the bottom.

Basically it needed a lot of attention. I went back with a 2005 6.0L engine from a Yukon Denali. This engine has 6,500 miles on it. The transmission is from a '99 2500HD as is the transfer case. Both with about 68,000 miles on them.

Problem, if you haven't spotted it yet, is that the timing, or so it would seem from driving it, is off on the engine. All sensors and other electrical hooked right in with the exception of the rear-top oil sender. I replaced that one with the proper one for an 01.

Basically the engine is performing extremely sluggishly and without much power. At times it seems like the computer is trying to adjust the timing and it kicks up and does fine. Other times it seems like it is adjusting it ahead and then back in rapid fashion. When you get all the way into the throttle it throws the transmission down and seems to have some power until the timing advaces too far and it pings wildly. Then, a code is thrown and the GM garage that is looking at it right now said that it is saying that #2 and #6 aren't firing.

They tried to program it to a VIN from an 05 pickup. Wouldn't run at all. I didn't have the heart to tell that the the throttle body was electronic on an 05 rather than manual like the 01. Maybe they figured that out. They are supposed to be programming it back to the real VIN now.

The GM garage is going to try a mass airflow sensor next. They seem to think that might be it. I think it is much deeper. I really hated to take it in there but I have a "friend" who works there and he wanted to look at it.

As I understand it the compression is 10.1:1 in the 05 engine. The compression on the 01 should have been 9.4:1. This no doubt plays into the timing as well. Maybe I can just put a new cam in???

So, I hope that adequately describes the problems. I avoided the 05 computer thinking that it would save me having to rewire the dash and everything else. I hope I can find something that will simply mess with the timing. Is there such a device on the market that costs less than the GDP of Argentina? Or, better question might be is there something out there for this sort of mess at all?

I've only been told, "You can't get there from here" one time in my life. I was in Kentucky trying to get across the Mississippi to Missouri. I'm afraid I might be there again with this truck.

HELP!!!

 

they might be right with the maf you might need one for the year of the motor. also if you have a k&n on it you might wont to cleen the maf with carb cleaner and let it dry, sometimes over oiling can cause a drivability provlem. hope i helped, good luck.

 

Thanks, Allout. I started thinking more about the MAF once I posted this. Could be a possibility. Also, some more detail.

Seems to run MUCH better when the engine is still cold.

Also has a noticeable momentary surge in most gears. Comes and goes in other words.

I wondered some about fuel delivery until I calculated the first full tank of gas. 10.4 MPG so I know it's getting fuel...

Finally, has a "hiss" (for lack of a better description) that you can hear when it warms up and isn't running properly. I sprayed some gasoline around the injectors and no noticeable increase in rpm @ idle. So I don't think it's a mis-seated injector.

I may try the MAF. GM wants $200. Any suggestions for off brand lower cost solutions?

 

Update- I installed a new MAF. It seems to have steadied the engine some. There is less surge. However, it still seems to have a severe lack of power. I have driven the truck considerably more now and I have noticed that things change distinctly when the engine is cold as compared to when it hits 180 degrees. When the engine is cold it runs like a striped *** ape. When the engine hits 180 it falls on its face. Does this offer any insight?

 

Final Installment -

The problem was a plugged cat converter. Replaced the MAF, PCM and still no luck. Pulled the front O2 sensors out on a whim and it ran much better. Tested the cats and the passenger side was almost completely plugged. Replaced it and it runs great.

Thanks for the advice.