1986 Chevy 305 - failing emissions bad

LukeZ

G-Body Guru
Apr 24, 2015
525
63
Delaware
Hi all,

It’s time - I haven’t driven my El Camino much in the last year so I’m going to tag it as an antique with DMV. Went through inspection today, passed everything except emissions, which it failed miserably.

In Delaware, the high and low rpm hydrocarbon limits are 220ppm. My car got over 10 times that at both rpms. It failed for carbon monoxide as well, but not by much. I’m guess that is a secondary problem due to failing the hydrocarbons.

The motor is a 1986 305 sbc. Smog delete, a high flow cat, Eddy Intake with EGR delete, and an oil catch can between the PCV and intake manifold are the only things I’ve done to it that are related to this. It has passed emissions the last 5 years with all of these modifications, minus the catch can which was added a year ago.

Im thinking it’s related to ignition - sound right? Too much unburnt fuel? I guess my first steps are to check the spark plugs to see if they’re fouled up. I usually just adjust timing by ear - maybe that’s out of whack too.

Any advice on what else it may be? Thanks!
 

scoti

G-Body Guru
Supporting Member
Sep 5, 2019
806
93
Texas
Check & verify ignition basics. If any doubt @ all, change the plugs/cap/rotor.

When was the last oil change? If it's been a while, change it before re-testing.
 
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pontiac guy

G-Body Guru
Oct 28, 2016
551
93
Royse City, TX
How old is the fuel? Modern fuel doesn't last and it will come straight out the tailpipe if it's old
 
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ck80

Comic Book Super Hero
Feb 18, 2014
2,796
113
You could have carb issues. Nothing about junk ethanol gas is good for a carb, either coming out of the tank or sitting inside the carb while the car sat.

No idea what you're running for a carb. If it's stock then the CCC probably isn't managing it properly with all the smog and egr being knocked out.

If it and the dizzy were swapped then you could have an issue with the distributor being off, and again, who knows what common issues the unknown type and brand of carb may have.
 

CopperNick

G-Body Guru
Supporting Member
Feb 20, 2018
915
93
Canada
Okay. Five years straight, you passed the test. Last year you added the catch can. You did not say if you tested last year before or after you installed that can but I am thinking that you did not test at all given the limited amount of road time you suggest occurred.

This year you tested and El Flunko! Were it me I would be looking at the last item to be installed that could have an adverse affect on the emissions; in my mind that would be that oil catch can between the PCV and the manifold. The question in my mind is what happens to the oil mist that condenses in that can once it has filled up? Under normal conditions the PCV doesn't send liquids it sends a sort of light to heavy mist back to the manifold to be incorporated back into the air/fuel mixture. It sort of sounds to me like that can got full and then, during the test, dumped its entire contents into the manifold at once. Way too much oil for the engine to consume and expell. Contemporary two-strokes mix at around 40 to 1 or possibly leaner now. What your engine may have received would have been way richer in ratio by twice as much or worse.

At this point, I would be pulling the plugs to see what the tips look like. The tip off will be a plug tip that is absolutely black and oil fouled and stinking of burnt oil from attempted combustion. Instead of pulling #1 first, head to the firewall and pull #7 and #8. Sometimes they tend to foul out first and could show a good indication of what the rest look like.



Nick
 
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LukeZ

G-Body Guru
Thread starter
Apr 24, 2015
525
63
Delaware
Check & verify ignition basics. If any doubt @ all, change the plugs/cap/rotor.

When was the last oil change? If it's been a while, change it before re-testing.
I will for sure change the spark plugs and change the oil - doing that next week and getting it re-tested. If it still fails then I will investigate the distributor
 

LukeZ

G-Body Guru
Thread starter
Apr 24, 2015
525
63
Delaware
How old is the fuel? Modern fuel doesn't last and it will come straight out the tailpipe if it's old
Jeez, maybe that's it too. The gas is probably between 9 and 12 months old. Guess I should drive it to empty and then refill her. Thanks!
 

LukeZ

G-Body Guru
Thread starter
Apr 24, 2015
525
63
Delaware
You did an EGR delete and passed NOx? Nice.
haha yea I suppose Delaware is not too hard on emissions - this car definitely reeks of fumes and burnt oil and has still passed (barely, after a couple tries) in the past
 

LukeZ

G-Body Guru
Thread starter
Apr 24, 2015
525
63
Delaware
You could have carb issues. Nothing about junk ethanol gas is good for a carb, either coming out of the tank or sitting inside the carb while the car sat.

No idea what you're running for a carb. If it's stock then the CCC probably isn't managing it properly with all the smog and egr being knocked out.

If it and the dizzy were swapped then you could have an issue with the distributor being off, and again, who knows what common issues the unknown type and brand of carb may have.
Stock carb and distributor - maybe the old gas is hurting me more than I thought. I may siphon it out or just take it for a long drive. Thanks!
 
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