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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29427
Experience:  GM Grand Master Technician 2007. 14 years experience.
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Chevrolet Silverado 2500: I have a 2005 duramax and just put

Customer Question

I have a 2005 duramax and just put new injectors and fuel pump and clean out all the carbon from the tubes and intake. It start running perfect for about 20 minutes then it started to make a hiss noise about every 1.5 second then it started running really bad. check the compression and seems like number 3 has 0 compression..
Thoughts?
Submitted: 1 year ago.
Category: Chevy
Expert:  GM Tech (Cam) replied 1 year ago.
Welcome. Can you tell me what happened originally? Was there a chip or programmer in the truck? MY thoughts are possibly a valve issue or bent push rod.
Customer: replied 1 year ago.
no chip or programmer. the truck was sitting at idle and running perfect. then it started making a noise then went to a sort of knocking noise then also missing. we put air to the intake and it blew out the oil fill.
Expert:  GM Tech (Cam) replied 1 year ago.
Not good. What happens if you put air in #3 cylinder, where does it come out?
Customer: replied 1 year ago.
oil fill
Expert:  GM Tech (Cam) replied 1 year ago.
OK hole in the piston? DO you have a scope to look down the hole into the cylinder from the injector?
Customer: replied 1 year ago.
I have one just need to get a smaller tip. but I am just surprised that it happened under no load and was running perfect.
Expert:  GM Tech (Cam) replied 1 year ago.
so am I but I have seem it before on this engine. Was it chipped at one time?
Customer: replied 1 year ago.
I really don't think so. just got it. the guy had it sitting for over a year because he didn't have the money to fix it. they told him the fuel pump and maybe the injectors were bad. So I changed the injectors and fuel pump. started with no problems, ran for about 20 minutes perfect. did have black some when I rev it up when it first started.
Expert:  GM Tech (Cam) replied 1 year ago.
I would also want to see what the rockers are doing .
Customer: replied 1 year ago.
how would the rockers arms cause the air to come out the dip stick
Expert:  GM Tech (Cam) replied 1 year ago.
IF a valve stuck open and hit the piston.
Customer: replied 1 year ago.
that might of been what happened.
Customer: replied 1 year ago.
could have a piece of carbon got caught into the rocker arm and created this problem?
Expert:  GM Tech (Cam) replied 1 year ago.
Not above, not carbon, maybe in the guide itself.