Hello all!
OK so I have a boost leak... I know I have a small one on the gasket of my aftermarket Y-Bridge.. but that's not what is concerning me. While doing the boost test, I noticed a lot of air coming out of downpipe connection at turbo.
Lets back up, I had a broken up pipe at egr bellows and am in the process of replacing it. Currently down pipe is out of truck and new up pipe is installed.
Back on topic... So I start reading on Mitchell OD and the factory procedure to test boost is to install tester on hot side after turbo (which I am doing) and to remove the cat and install a J-46091 to the exhaust. According to the manual "Failure to secure the J-46091 will cause excess air leak and hissing noise during the test" Since exhaust is disconnected, I put a Fernco 3" rubber cap over the exhaust part of turbo (fits perfectly). So now the boost leak is slower but I noticed air coming out of the PCV port that attaches to the turbo inlet horn (my intake horn is off right now). I can put my hand on the part to block the air, and when I remove it, you can hear the air whoosh out.
I've read a mix of reports that since the duramax doesn't have overlapping valves, you shouldn't have air leak out exhaust while testing boost.. Well I do... and I'm wondering why GM says you need to block off exhaust to test?
Secondly, why is air coming out of my PCV connection when I'm applying 30psi to tester?
Truck is a 08 LMM... EGR and DPF delete...
I was driving last week and noticed getting on it at 70ish, it would downshift and ran a little rough... no smoke out tail pipe though... After about 50 miles are so, the rough running after downshift went away. No noticeable smoking, idles just fine. Did lack a little power on acceleration, but that may have been because the huge hole in the up-pipe not allowing enough exhaust into turbo? I did notice one time my oil dipstick was out of the tube by about 1/2". I ignored it and just pushed it back in. Only happened once though.
Today, with tester on, pressurized to 30psi, takes about 12 seconds to go from 30 psi to 20psi.
I'm actually nervous about a cracked piston because the dipstick thing. But there is still good power and no white smoke. But why is air coming out of pvc tubing when air is supplied to boost tester?
Any ideas?
OK so I have a boost leak... I know I have a small one on the gasket of my aftermarket Y-Bridge.. but that's not what is concerning me. While doing the boost test, I noticed a lot of air coming out of downpipe connection at turbo.
Lets back up, I had a broken up pipe at egr bellows and am in the process of replacing it. Currently down pipe is out of truck and new up pipe is installed.
Back on topic... So I start reading on Mitchell OD and the factory procedure to test boost is to install tester on hot side after turbo (which I am doing) and to remove the cat and install a J-46091 to the exhaust. According to the manual "Failure to secure the J-46091 will cause excess air leak and hissing noise during the test" Since exhaust is disconnected, I put a Fernco 3" rubber cap over the exhaust part of turbo (fits perfectly). So now the boost leak is slower but I noticed air coming out of the PCV port that attaches to the turbo inlet horn (my intake horn is off right now). I can put my hand on the part to block the air, and when I remove it, you can hear the air whoosh out.
I've read a mix of reports that since the duramax doesn't have overlapping valves, you shouldn't have air leak out exhaust while testing boost.. Well I do... and I'm wondering why GM says you need to block off exhaust to test?
Secondly, why is air coming out of my PCV connection when I'm applying 30psi to tester?
Truck is a 08 LMM... EGR and DPF delete...
I was driving last week and noticed getting on it at 70ish, it would downshift and ran a little rough... no smoke out tail pipe though... After about 50 miles are so, the rough running after downshift went away. No noticeable smoking, idles just fine. Did lack a little power on acceleration, but that may have been because the huge hole in the up-pipe not allowing enough exhaust into turbo? I did notice one time my oil dipstick was out of the tube by about 1/2". I ignored it and just pushed it back in. Only happened once though.
Today, with tester on, pressurized to 30psi, takes about 12 seconds to go from 30 psi to 20psi.
I'm actually nervous about a cracked piston because the dipstick thing. But there is still good power and no white smoke. But why is air coming out of pvc tubing when air is supplied to boost tester?
Any ideas?