Ok, bought my 86 Iroc F code last year. Car ran real rough but was able to drive it home. In its current state I ran it thru emission thinking it would fail. It passed? One year later I replaced plugs wires and entire distributor. The car ran great. Turns out 2 cylinders were not even firing and it passed emissions. Car is bone stock no known mods. Smokes on start up valve guides. Also running it on 100% gas not a blend.

Emission time right now. Since it is running pretty well I thought I was good? Not - It just failed emissions? Ok it is running on all cylinders now go figure?

HC = 547 ppm/limit 220
CO = 5.55%/limit is 1.2
CO2= 9.6% ok I guess no limit

What to do first? Thanks.

 

Check the base timing. 6° with the connector disconnected.

Check the FPR for leaking by disconnecting the vacuum line and looking for a leak woth the engine running.

Finally is it still using the stock injectors? They could be bad.

Also how old is the 02 sensor? Put a fresh Delco sensor in it if it is more than a few years old.

 

Timing , as stated.

Poorly operating EGR can be a culprit for CO too.

 

CO2 is not a pollutant...

 

You are correct and thats prob why there isnt a limit on it, but CO is... Just out of curiosity, do you guys have to go through emissions testing every year? thats insanity!

 

We no longer have emissions testing in my county, but other counties still have it...

 

Ok. I never did check the timing when I replaced the distributor. It was running pretty well so I left it alone. I will do the timing and retest it.

It is still using stock injectors...I think. Not sure how to tell. I was thinking on doing the O2 sensors since they are pretty inexpensive. I’ll do the EGR valve too. I will let everyone know how it turns out. I might disconnect two plugs and retest it...lol.

 

If the car was running bad and burning oil it may have poisoned the cat. Cats don't like oil burning and misfires over time it degrades them. Also make sure the car is good and hot so the cat is operating at full efficiency, drive it hard before you take it in. Good luck.

 

One other thought that has helped many people over the years. Considering yours had a misfire it probably dumped a large amount of unburned gasoline into the crankcase which diluted the oil. Gasoline diluted oil will raise the HC readings as well.

 

MKM and Fast...Very good points. It does misfire at idle too. It smokes pretty hard at start up so the CAT may very well be spent. I need to change the oil too. The car smells of gas too. Seems too rich. I will run this fuel out and put in a blend too. It’s on 100 gas right now with no alcohol. The car runs really cool too. I always know these to run too hot to help the emissions. Not sure if that is a factor too.

I really need to rebuild it or throw a 350 in there.

Thanks for the advice. It is well appreciated.