Hope you guys can help . I bought an '88 IROC from a dealer that swapped the engine from a 305 TPI to a 350 TPI. Thing runs great. One HUGE problem. I live in Texas in one of the high pollution counties so starting June 1st, any car between '67 and '96 has to pass a dynamometer emissions test to get an annual inspection sticker.

Well, this car failed CO and HC tests for both 25mph and 15mph the first and second time it was inspected. The third time (after the dealer adjusted the MAF sensor and replaced the temp control sensors and adjusted the timing) it failed ONLY the CO at 15mph. (Yeah I know it's highly unlikely the car will ever be driven at 15mph other than passing thru it)

I was told that if I put a bottle of RPG additive in the tank (think that's the right name...a little orange bottle), it will pass. I've heard conflicting stories on how to use it. One guy said run a tank thru with it then get it tested. Another guy said there is a spike in 'cleansing' about 15 mintes of run time after adding then a drop and gradual increase.

Anyone here have any ideas/comments. Gotta get it past the inspection. No way around it unless I sell it...don't want to do that.

TIA for any help

 

CO is carbon monoxide...
Carbon monoxide doesn't want to be CO, It would rather
be CO2 but can't find a partner ...

The implication is that the mixture is rich or that it doesn't
have time to find enough partners (timming)

An unusually aggressive cam can do this but those are usually
in purpose built race cars....

Sooo....
What to do ...
you need to be a bit leaner

the usual suspects
Air cleaner...
O2 sensor... (change em every 30K)
fouled plug... (plug, wire etc )
timing

BTW "how do you adjust a MAF"
The bottle trick can work but it remains your car is broken
or at least in a very sad state of tune not to pass emmisions

 

I have lived in both California and Colorado, and in both states, the seller is responsible for the vehicle passing emissions.

I'd check the Texas law before spending a dime on it. You may find that the dealer is on the hook for it.

FWIW, the last vehicle that I had difficulty getting to pass HC and CO, my full-size '84 Chevy van, passed with flying colors with a new cat. It had just barely passed the two previous times. I did so many things to try to get the mixture leaned, I finally figured the only thing left was the original converter. Actually, that's what it was all along (the thing was empty).