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Discussion starter · #23 ·
Yes this has been the same theme since the new head. I did all the work myself, and admit i'm not a perfect mechanic, but if there was something i didn't know i followed the manual to a T. I realize that the problems coinciding with the the new head are likely not a coincidence, i'm just trying to work backwards to find the problem. I've already got way more time than i ever thought i would vested into the head debakle, and am just trying to get it fixed to protect my sanity. I will give the dealer a call tomorrow to see what they quote me for the pcm update, i just know you are hard pressed to find a dealer by me that will work on anything for less than an hours labor (95-115$.) I guess i will see what they say.
 
I contacted 06colorado2.8 to see if he had found a solution and here is his reply to me.

" I ended up taking mine to the dealer as the idle needed to be reset after everything that took place. The truck didn't run perfect for a few weeks as it had to relearn, but now it runs just as good as it ever did."
 
im having the same problems with a 09 2.9 I bought with a rod knocking. we own a machine shop so I rebuilt the motor put it in fired it up and run perfect drove it down the road and it shutoff after it warms up I drove it for a week hoping it would relearn itselfand still done it. I let a friend whos been a gm mechanic for years look at it and hes had it for 2 weeks and has replaced about every sensor and actuator on it and it still does it. so what all did 06 Colorado 2.8 have done and can I get the tsb or whatever he found out about it to get it done? or u can call or text me 803 707 4780 tia curtis
 
im having the same problems with a 09 2.9 I bought with a rod knocking. we own a machine shop so I rebuilt the motor put it in fired it up and run perfect drove it down the road and it shutoff after it warms up I drove it for a week hoping it would relearn itselfand still done it. I let a friend whos been a gm mechanic for years look at it and hes had it for 2 weeks and has replaced about every sensor and actuator on it and it still does it. so what all did 06 Colorado 2.8 have done and can I get the tsb or whatever he found out about it to get it done? or u can call or text me 803 707 4780 tia curtis
Hey how did you make out on your trucks?


here is some follow-up info on mine.

I changed the Temp sensor and the thermostat. The sensor was reading about 15F lower than it should. When I changed the MAF
it was with a Delphi and it started making the truck run very rich in combination to the previous problems.

I finally started to understand the fuel trims, Long term 0 is perfect +- 5 at times seems to be good. 10-20+or- is not good.

I am thinking that the PCM stores different fuel trims for different conditions/mode ie, Idling, decelerating, ect.
I also think that the MAP is used largely to recognize what mode it is in ie, Idling, Accelerating decelerating, ect.

I brought the truck to another shop for his input on why it was dying at idle. His experiance with the Colorados was that
it had to do with the Variable valve timing. ( The truck does still have a lot of Cam chain noise at start-up ) He felt,
because of the looseness in the Cam chain, that the cam position might be changing when the oil pressure got low. So he
dumped a Qt of Lucus Oil additive to thicken up the oil.

THE DYING AT IDLE STOPPED!

I knew my MAF was not reading right because my fuel trims would go up into the -20s. It was way too rich and the PCM could
not get it into control. So I replaced the MAF with the original and the fuel trims looked good ranging from 0 to 5.

At that point it would not die at idle or when slowing down. Starting when hot was not as good as it had been if it was started
immediately after stopping the engine (0-3 min).

I tried an Oil flush and changed the oil again (Also pulled the Actuator solenoid to check for screens and debrie). I used Mobil 1
15w-50 synthetic.

So about 3 weeks of using it around town and road trip and it has idled down and died once and the PassLock has come on once. Not too bad.
It was normally dying 4 to 10 times a day and a long trip in traffic it would die every time I slowed down.

I am thinking about redoing the Cam Chain tensioner, cam chain and the oil pump and pick-up.

Any thoughtS?

Thanks,
John
 
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