turbo problems

[aztortuga]

I have a c7 in a 2005 travel supreme envoy which I have owned since new. Over the years I have had frequent turbo over boost codes including red lights, yellow lights, de rating etc. These generally go away when the engine cools off (over night) or when I restart the engine. Looked at the turbo linkage, hoses, etc, changed sensors for turboboost,\ control, oil sensor (oil pressure jumped up 10 pounds when condition occurred) and examined each sensor input on the harness. Its been a real pain over the years. Latest event took me to the the cat dealer again. They couldnt find the problem either and we agreed it was an electrical problem but to trouble shoot the harness and each connection would cost a plenty. Tech said he would try a new atmosphere sensor. I thought a waste of another $200. So lived with it on my latest trip. Still had problems, so called the closest cat dealer (item was on sale for $150) and installed it. WOW - This cat now runs like a cheetah. Cant believe the difference. Hope this helps someone else as I have posted here before and no one has seen this particular sensor go bad, as far as I know.

[Cat]

Originally Posted by aztortuga

I have a c7 in a 2005 travel supreme envoy which I have owned since new. Over the years I have had frequent turbo over boost codes including red lights, yellow lights, de rating etc. These generally go away when the engine cools off (over night) or when I restart the engine. Looked at the turbo linkage, hoses, etc, changed sensors for turboboost,\ control, oil sensor (oil pressure jumped up 10 pounds when condition occurred) and examined each sensor input on the harness. Its been a real pain over the years. Latest event took me to the the cat dealer again. They couldnt find the problem either and we agreed it was an electrical problem but to trouble shoot the harness and each connection would cost a plenty. Tech said he would try a new atmosphere sensor. I thought a waste of another $200. So lived with it on my latest trip. Still had problems, so called the closest cat dealer (item was on sale for $150) and installed it. WOW - This cat now runs like a cheetah. Cant believe the difference. Hope this helps someone else as I have posted here before and no one has seen this particular sensor go bad, as far as I know.

Yes the atmospheric sensor is a critical sensor. It not only informs the engine ecm of the air density, it is the sensor the engine ECM uses to calibrate all the pressure sensors. So when you turn your key on with out starting for 7 seconds the engine ecm looks at the pressure on the atmospheric sensor and uses that as the base or zero of all the other pressure sensors. So if it isn't accurate it can mess up all the pressure sensors. Safe Travels