Looks like I lost #7 piston
05-11-2008, 04:22 PM
#12
TECH Junkie
I am really sorry to hear this thunder...tragic.
05-11-2008, 05:52 PM
#20
Yeah I've run the engine a lot harder than that before. I'm not sure what happened. I know the lean #7 is a common problem with the stock style intake manifolds though. I'm probably going to look into a Vic Jr now. I'm hoping that the cylinder wall and head are in decent shape. Hopefully it's as simple as putting in a new piston and rings and honing the cylinder.
I think the tune may have had something to do with it, but I'm not 100% sure. I think the new location of the wideband sensor (about 4" or so after the turbo) is causing it to get too hot. I was logging during that run, but right as I got into boost the wideband flatlined at 11.12:1 AFR and stayed there until I shut the engine down later. It's possible that since I had been messing with the tune that I had inadvertently leaned out some of the higher RPM cells. I thought that they would be inline with everything else, but without a good AFR reading it's hard to say. This was the second WBO2 sensor that I had burned up in 2 days. Part of me thinks that since it was heating up too much that it was giving me inaccurate AFR readings, which could have contributed to a lean condition without my knowledge. When I put this back together the WBO2 sensor is going back where it used to be, in the exhaust under the cab about 3 feet after the turbo. I never had any problems with it there.
Also, I was due for an oil change, and like I've said in the past, the oil is easier to change with the engine out
This will also make the hydroboost conversion and thermostat swap a lot easier too
Anyway, she'll be back sooner than later hopefully, and back stronger than before
I'm bummed out, but it's like I tell everyone....you gotta pay to play. I've done more paying than playing lately, but the tables have got to turn in my favor at some point.
I think the tune may have had something to do with it, but I'm not 100% sure. I think the new location of the wideband sensor (about 4" or so after the turbo) is causing it to get too hot. I was logging during that run, but right as I got into boost the wideband flatlined at 11.12:1 AFR and stayed there until I shut the engine down later. It's possible that since I had been messing with the tune that I had inadvertently leaned out some of the higher RPM cells. I thought that they would be inline with everything else, but without a good AFR reading it's hard to say. This was the second WBO2 sensor that I had burned up in 2 days. Part of me thinks that since it was heating up too much that it was giving me inaccurate AFR readings, which could have contributed to a lean condition without my knowledge. When I put this back together the WBO2 sensor is going back where it used to be, in the exhaust under the cab about 3 feet after the turbo. I never had any problems with it there.
Also, I was due for an oil change, and like I've said in the past, the oil is easier to change with the engine out
This will also make the hydroboost conversion and thermostat swap a lot easier too Anyway, she'll be back sooner than later hopefully, and back stronger than before
I'm bummed out, but it's like I tell everyone....you gotta pay to play. I've done more paying than playing lately, but the tables have got to turn in my favor at some point.