Tips for passing emissions in my '88 Chrysler Fifth Avenue

-
MopaR&D

MopaR&D

Nerd Member
Joined
Jan 4, 2008
Messages
5,534
Reaction score
2,837
Location
Augusta, GA
I know it's not an A-body but it's close and it does have a 318 lol. The problem is the CO readings are too high. It still has the factory "Electronic Spark Control" (quasi-Lean-Burn) computer on it and the Holley 2-bbl with the weird solenoid valve inside. It runs perfectly so for now I just want it to pass so I can gut the exhaust and swap over my shorty headers and make some duals (with new dual cats of course). I'm pretty sure the reason it's failing is due to the cats being old but talking to the mechanic I bought it from he said it tends to run rich once it's warmed up and goes into "closed loop" mode... the second time I took it in after putting some ethanol treatment in the gas and topping it off with 1/3 tank premium (rest was regular in there) and the CO readings dropped drastically but it still failed by only 1.6xx ppm which annoyed the heck out of me but it's all automated so "tough beans". I had also disconnected a small ported vacuum line which I guess helped lean it out at cruise a bit too, just needs a bit more leaning-out I think...??
 
Add 2 gallons of methanol to a half tank of fuel. Drive it for 10 miles. Have it tested. Add a gallon until it passes.

Done it many times.
 
yellow rose said:
Add 2 gallons of methanol to a half tank of fuel. Drive it for 10 miles. Have it tested. Add a gallon until it passes.

Done it many times.
Click to expand...

Awesome that's the kind of underhanded che... I mean ingenious solution I was looking for. Where can I buy straight methanol?
 
Just googled it looks like I can get it at Home Depot, will that work?
 
New platinum plugs, pull the air filter use before you go in. Make sure you replace it afterwards.
 
So what were the other numbers CO2, HC, O2 etc... Are you just trying to pass, or make this thing run right? How old is the O2 sensor? Anybody who says these things run rich in closed loop mode is full of s**t.
 
Just did some more research apparently the enrichment solenoid in the carb is bad, gonna try cleaning it out see if I can get it to work again.
 
Move to a state that doesn't require an emission test on a 37 year old car. Frigging ridiculous.
 
kesteb said:
Move to a state that doesn't require an emission test on a 37 year old car. Frigging ridiculous.
Click to expand...

Well it's 29 years old but still I agree it's stupid. At least the requirements to pass aren't very strict and in a few years I can register it as a collector car so I can then wait 5 years till next renewal.
 
I have added a few gallon of e85 to the gas....drive it around until I know it is burning it....smog it...then add more gas to cut the e85 content...
 
Bad cooling thermostat?
Does the engine reach working temperature?
 
Tried the E-85 it worked like a charm... 3 gallons added to 14-15 of premium, cut HC, CO and NOx all by half and passed by about 50%. I'm definitely keeping that in mind for the future, thanks guys!
 
For real, E-85 is $1.99/gal at a station about 5 miles from my house. And it wasn't even that high of a concentration, if I had added that much to a half-tank or less it would have done even better. Probably would have started running funny though.

Now it's time to gut the exhaust and put on those headers and duals :D
 
You must log in or register to reply here.
-

Back
Top