Broken muffler exit pipe and emissions issues

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TommyJ1980

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Hey folks- 1998 Chevy K2500 5.7L, 250,000 miles, very recent head, intake, and exhaust gasket changes. Had to do quite a bit of jacking on the exhaust pipes down below and had a rough time of it trying to get the manifold bolted back onto the block. I’m sure that was the last straw for the pipe as it exits the muffler on its way to the tailpipe. One of the last sensors that screw into the exhaust pipe was also loose in its fitting, but still plugged in. I have the symptoms you’d expect of louder than usual and exhaust smells, but I’m wondering, would these things also cause a propensity to die during initial acceleration from a stop? Thanks-
 

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someotherguy

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Hey folks- 1998 Chevy K2500 5.7L, 250,000 miles, very recent head, intake, and exhaust gasket changes. Had to do quite a bit of jacking on the exhaust pipes down below and had a rough time of it trying to get the manifold bolted back onto the block. I’m sure that was the last straw for the pipe as it exits the muffler on its way to the tailpipe. One of the last sensors that screw into the exhaust pipe was also loose in its fitting, but still plugged in. I have the symptoms you’d expect of louder than usual and exhaust smells, but I’m wondering, would these things also cause a propensity to die during initial acceleration from a stop? Thanks-
No, if you're referring to the rear O2 sensor that's just to give you a heads-up whether the catalytic converter is doing its job or not. Has no input to how the truck runs. I would be checking fuel pressure and cam retard angle to begin with. You did set it properly after re-installing the distributor since you had it out for all that work?

Richard
 

TommyJ1980

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No, if you're referring to the rear O2 sensor that's just to give you a heads-up whether the catalytic converter is doing its job or not. Has no input to how the truck runs. I would be checking fuel pressure and cam retard angle to begin with. You did set it properly after re-installing the distributor since you had it out for all that work?

Richard
It seems to be doing well now, there was the hesitation off the line and it seems to be pretty much gone now with the exhaust system intact. Last time I checked fuel pressure was probably three months ago and it was good, although I think I have a leak somewhere in the fuel system because I can smell raw gas frequently while I'm standing outside the truck :( As for the distributor, I know I'm either in the right spot, or "one tooth off" which I still haven't really gotten straight in my head because when I was still fooling with trying to put the distributor back in, it seemed like it would go in, or if I lifted it up and turned it, it would have to be turned quite a bit one way or the other before it would slide back into place, with the rotor pointing now a different direction. I didn't seem to have much luck adjusting it just a little bit one way or the other. Anyways, I just need to do a little more homework on it and get the anatomy of the part straight in my mind so I know what I'm looking at.
 

someotherguy

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If you didn't set the cam retard angle with a scan tool then the distributor is almost certainly not set correctly. It's not one you're likely to get lucky and stab it just right or a "tooth off" one way or another. It can be quite a bit out of whack and still not set an error code. Since it's been out of the engine, that would be my -very next step- is to borrow/rent/etc. a scan tool capable of reading that parameter, and ensure the distributor is set correctly. Warm it up, hold rpm's to at least 1,000 for a solid reading, and adjust distributor to within +/- 2° from zero. This is no longer timing light territory, and definitely no longer set it by ear territory.

Richard
 

TommyJ1980

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If you didn't set the cam retard angle with a scan tool then the distributor is almost certainly not set correctly. It's not one you're likely to get lucky and stab it just right or a "tooth off" one way or another. It can be quite a bit out of whack and still not set an error code. Since it's been out of the engine, that would be my -very next step- is to borrow/rent/etc. a scan tool capable of reading that parameter, and ensure the distributor is set correctly. Warm it up, hold rpm's to at least 1,000 for a solid reading, and adjust distributor to within +/- 2° from zero. This is no longer timing light territory, and definitely no longer set it by ear territory.

Richard
Will do, thanks.
 
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