dynoboss
04-06-2006, 09:59 PM
Hello all. Sorry to ask so many ?? on my first post, but I have been searching for awhile to find more specific details about the injector failures and need someone to tell me if I have this right. I have an 02 GMC with 51000 miles and am glad to know the warranty is extended on injectors, but I am still concerned about how I will troubleshoot failed injectors when the warranty is finally gone (or when I feel the dealer is giving me the runaround!). I don’t put many miles on this truck and warranty will run out of time way before miles. From what I have read so far, I am thinking two different types of failures occur on the injectors:
It appears to me one failure is erosion of the ball/seat area resulting in high return rate and poor fuel delivery into cylinder- this failure is diagnosed by checking return rates or cutting out cylinders with a tech II. I am assuming this failure by itself is not what causes the fuel to leak into the crankcase?? Is there other more affordable scan tools besides tech II that can effectively diagnose this failure??
The other failure mode that I am more concerned with and uncertain of is when the injector body cracks and allows fuel to leak into engine. I am thinking right now that the fuel leaking out crack travels up and pours out into crankcase between injector body and cylinder head (not out the bottom of nozzle and then down past the rings) . Am I thinking right on this?? If so, can the cracked injector always be diagnosed by return rates (if the crack is after the seat area I am thinking return rate could still be in spec)?? Bottom line is, I am concerned it may be difficult to diagnose one cracked injector and that I will someday have to replace them all because the cracked one can’t be isolated. Is this why all injectors are changed when crankcase fills with fuel on 01& 02 LB7?? Someone please tell me if I am way off base here. Thanks.
It appears to me one failure is erosion of the ball/seat area resulting in high return rate and poor fuel delivery into cylinder- this failure is diagnosed by checking return rates or cutting out cylinders with a tech II. I am assuming this failure by itself is not what causes the fuel to leak into the crankcase?? Is there other more affordable scan tools besides tech II that can effectively diagnose this failure??
The other failure mode that I am more concerned with and uncertain of is when the injector body cracks and allows fuel to leak into engine. I am thinking right now that the fuel leaking out crack travels up and pours out into crankcase between injector body and cylinder head (not out the bottom of nozzle and then down past the rings) . Am I thinking right on this?? If so, can the cracked injector always be diagnosed by return rates (if the crack is after the seat area I am thinking return rate could still be in spec)?? Bottom line is, I am concerned it may be difficult to diagnose one cracked injector and that I will someday have to replace them all because the cracked one can’t be isolated. Is this why all injectors are changed when crankcase fills with fuel on 01& 02 LB7?? Someone please tell me if I am way off base here. Thanks.