Emission system DP (dashpot) question

[Josh Sulsberger]

I'm trying to figure out an emission problem that I have, high HC on deceleration. I'm going through the TSRM and I've gotten as far as the DP system. The VSV and the filter test alright, but I wonder how far the dashpot should push that piston that the throttle linkage pushes on? Mine doesn't really move other than that the linkage piece pushes it in like a 1/16 of an inch when the throttle plate closes.

Thanks for the help!

Josh

 

[mrnickleye]

I believe it is there to 'cushion' the throttle when you let off suddenly. It only 'slightly' slows down the force of the return spring. I think your problem, like mine too seems to be, is in the computer system. Whether its the TPS, AFM, or O2, I'm not sure. For example...I was getting a very stinky rich smell when I stopped at a lite or sign. I had previously been running the AFM spring 3 clicks softer, so the door would open easier. I put it back to factory spot. I also replace what may have been the original O2 sensor (15 years old maybe ??). I don't have that rich smell anymore.

 

[Josh Sulsberger]

Emissions update: I adjusted the dashpot per the TSRM (it was off) and went to the emisson station earlier tonight. Passed all tests easily! I can finally put her back on the road!

A note to those with modified turbos who live in areas with emission testing: If you are failing, consider reinstalling your stock downpipe. That pre-cat can really help. It didn't solve my problem, but brought the offending levels in considerably.