92 S-10 not passing emissions

[RyanbabZ71]

ok well my dads truck has been tested twice and it fails the hydrocarbon test bad.  The other 2 tests it does fine.

 

Any suggestions on how to help it pass? THings to fix or add?

[Zane]

ouch, not sure. We don't do emissions testing here in NH.

[CMNTMXR81]

Sounds to me as if something isn't working anymore.  Possibly the cat or the A.I.R. pump, EGR, etc, etc.

 

I know that in the past on 4.3's, I've been able to turn the timing back to get them to pass.  But that depends on whether or not it runs at 0 degrees BTDC normally.  if it does, I wouldn't turn it back any.  If it normally is supposed to run at 6-10 degrees advance, then I'd back it down to 4 or 5 degrees.

[RyanbabZ71]

Truck has new cat  EGR, and every other sensor there is since a few months ago.  

 

My dad suspects its the timing.  He needs to get it fixed before friday

:0

[CMNTMXR81]

It's an ancient chinese secret!  

 

Has he ever had it advanced?  We would always advance ours, go take the darn sniffer test, fail, go retard it, come back and pass.  Then go right back home and advance it again.