Howdy Fellows, failed emissions last week with the "88 Pioneer" everything passed but the CO. Limit is 25.0000 GPM and I got 39.0926. Running rich it seems. I checked the air filter and it was pretty gummed up so replaced it with new, also added a can of CRC to clean up inner workings, then added new Champion RC12LYC spark plugs. Went for a retest today and it was worse. That doesn't make sense to me, restricted air = richer mixture.

Within the past 8-9 months I have replaced the IAC and the TPS and gut feeling leads me to the TPS, any thoughts on this? Should i try resetting the TPS. Also, didn't think much about this being a problem but the pioneer runs a bit cool. I put a new 180 thermostat in it last summer but the heater air never gets better than warm. Any connection there??? Thanks

forgot to include the new numbers which were CO 52.9400 and limit is 25.0000 It went just the opposite of what I was expecting.

That sucks.

Try adding some kind of alcohol to your gas tank........or some other combustible stuff. Look into it.

Thermostat should be 195°.

X2. It will run more lean with a 195 degree tstat, and yes your heat will blow hot.

Thanks XJlimitedx99. I sure didn't know that. What's the connection between the cooling system and the fuel injection system? Will get a new thermostat this evening and put her in tomorrow. What do u think caused those numbers to get worse on the test when they should have gotten better, I would have thought. The thermostat change was done back in the summer due to the housing being cracked and needing replaced so just grabbed a summer thermostat at the same time. (50's and 60's mentality LOL.)

Please see this link for any information you may need (especially numbers 5, 8, and 11): https://www.cherokeeforum.com/f51/cr...x-tips-153657/

How is your O2 sensor?

How is your catalytic converter?

How is your TPS?

How is your MAP sensor?

Update!!! Want a Renix Cherokee to pass emissions? Never deviate from the 195 degree thermostat. During the summer months I replaced the thermostat housing casting due to a crack and while I was at it replaced the thermostat with a 180 degree one since it was summer and hot weather......big mistake. Failed emissions 3 times after checking everything I could. Then one of the fellows from the forum mentioned that a cooler thermostat would make it run "rich". He was correct. I changed the thermostat to a 195 degree, took the pioneer back for a recheck and passed with flying colors. Thanks to the forums membership I'm good to go

A Renix is capable of almost unreal low numbers. I know it's expensive but after initially failing I replaced my cat (in 2012) and O2 sensor (in 2014) mine passed with flying colors.

Mine has been passing emissions, but if it hadn't - I would have been arguing the fact that it should be emissions exempt - it's pre-obd1 - some states will allow pre-obd 1 vehicles to be emissions exempt I think. If that didn't work, I'd just say screw it and register it as an antique/classic car. Emissions and inspection exempt lifetime plates, and many states have that.

I'll be doing this in a few months when inspection/emissions is due. I'm done with this Pennsylvanian yearly inspection racket.

Click on the link in my signature below and do tips 1 through 5.We'll go from there. Tip 27 wouldn't be a bad idea either.

Plugs, wires, cap and rotor done along with a throttle body cleaning and intake manifold bolt tightening done?

Vacuum harnesses in tact?

I'm in Denver, Colorado and they want every penny they can get u to **** for them but I do believe the Pioneer is ready for Antique Plates this year for a few bucks more and I won't have to worry about it for 5 years. Thanks again to the group for the helping hand.

I'm in Denver, Colorado and they want every penny they can get u to crap for them but I do believe the Pioneer is ready for Antique Plates this year for a few bucks more and I won't have to worry about it for 5 years. Thanks again to the group for the helping hand.

LOL, the jokes on me, these S. O. B's changed the eligibility for "collector plates" to 32 years, did it in 2013.

Ouch dude that SUCKS.

But at least you guys have legal weed... could be worse.

I'd trade 15 year classic/25 year antique plates for that any day =p

When was the last oil change? Old oil can have fuel in it from the small amount that gets past the piston rings over time and that can make the HC Higher as well.

Max