JeepSJ
05-04-2007, 15:24
I have had the beast back from the body shop for a couple weeks now and have gone through things mentioned in the last thread. I still have the sound and have not been able to identify the source. If I had to give an example of the sound, I would say that it sounds similar to a collapsed lifter. But, it only does it under a medium to moderate load.
After really looking over everything under the hood and really paying attention to when I get the noise, I have discovered the following -
I do have an exhaust leak. Right at the turbo outlet, I have a small leak at the band clamp. I can hear the leak -it is distinct and there all the time (except for deceleration). It is barely audible, but I can hear it. The noise that I am concerned about is much louder.
I have found that if I drive easy - just real easy on the throttle, I never get the sound. If I accelerate a little faster from a light, I will get the noise and it will stay a while under cruise and acceleration. So, getting onto the freeway, the noise will appear. If I cruise for a while on the freeway, most times it will eventually subside. Other thing I noticed - if I have the noise and the TC is locked and RPM is low and I get on the throttle and load the engine it feels like I have a miss.
At this point, I think I have it narrowed to one of two possibilities -
1 - Exhaust leak - first, I found that my exhaust only has a hanger at the very rear. The weight of the front of the system is on turbo/band-clamp. This also allows the front of the system to swing left-to-right (remember, the TE06H has a rear facing outlet, not bottom facing) and it pivots around the turbo outlet. I am thinking that maybe if I accelerate hard the movement of everything misaligns the turbo and exhaust and causes a bigger leak, then when I cruise it all kinda moves itself back into position. Also note that when my exhaust was built I had a bad trans mount - the new trans mount raised the back of the engine and changed the alignment between the exhaust and turbo, which may be contributing to the problem. This would not explain the feeling that it has a misfire.
2 - Bad injector - is it possible that an injector could have a problem that would cause it to stick (open or closed) when more fuel is introduced? So with the light throttle it works OK, then with a certain amount of fuel it will fail? This would explain the misfire, but I have no visible white or black smoke that are the typical indicators of a bad injector.
Also note that there is NO noise at idle. I also cannot get it to make the noise by standing on the brake and giving it throttle to load the engine.
Oh dang - I just realized that I should go check my crank end-play to make sure that isn't the cause.
What say you all about the exhaust and injectors? I am going to pull the injectors and get them tested. There is a place here that is a Detroit dealer and they can test them there. I am also going to get a front hanger added to the exhaust and maybe get a piece of flex installed to take up the misalignment.
Thanks everyone!
Mark
After really looking over everything under the hood and really paying attention to when I get the noise, I have discovered the following -
I do have an exhaust leak. Right at the turbo outlet, I have a small leak at the band clamp. I can hear the leak -it is distinct and there all the time (except for deceleration). It is barely audible, but I can hear it. The noise that I am concerned about is much louder.
I have found that if I drive easy - just real easy on the throttle, I never get the sound. If I accelerate a little faster from a light, I will get the noise and it will stay a while under cruise and acceleration. So, getting onto the freeway, the noise will appear. If I cruise for a while on the freeway, most times it will eventually subside. Other thing I noticed - if I have the noise and the TC is locked and RPM is low and I get on the throttle and load the engine it feels like I have a miss.
At this point, I think I have it narrowed to one of two possibilities -
1 - Exhaust leak - first, I found that my exhaust only has a hanger at the very rear. The weight of the front of the system is on turbo/band-clamp. This also allows the front of the system to swing left-to-right (remember, the TE06H has a rear facing outlet, not bottom facing) and it pivots around the turbo outlet. I am thinking that maybe if I accelerate hard the movement of everything misaligns the turbo and exhaust and causes a bigger leak, then when I cruise it all kinda moves itself back into position. Also note that when my exhaust was built I had a bad trans mount - the new trans mount raised the back of the engine and changed the alignment between the exhaust and turbo, which may be contributing to the problem. This would not explain the feeling that it has a misfire.
2 - Bad injector - is it possible that an injector could have a problem that would cause it to stick (open or closed) when more fuel is introduced? So with the light throttle it works OK, then with a certain amount of fuel it will fail? This would explain the misfire, but I have no visible white or black smoke that are the typical indicators of a bad injector.
Also note that there is NO noise at idle. I also cannot get it to make the noise by standing on the brake and giving it throttle to load the engine.
Oh dang - I just realized that I should go check my crank end-play to make sure that isn't the cause.
What say you all about the exhaust and injectors? I am going to pull the injectors and get them tested. There is a place here that is a Detroit dealer and they can test them there. I am also going to get a front hanger added to the exhaust and maybe get a piece of flex installed to take up the misalignment.
Thanks everyone!
Mark