I need some advice on adjusting or tuning my RV to pass emissions.
I'm now living in Colorado where i need to have my emissions tested.
My vehicle is a 86 Pace Arrow 27ft, 454, all of my smog or A.I.R.S equipment is still working,
approx 36k on the motor with no smoke at the tailpipe.
So for my vehicle, the test is done at Idle and at 2500 rpm.
The limits are :
HC PPM=300
CO% = 2.0
My results are :
HC PPM = 28.7 at 2500 RPM , 437.4 at Idle- Failed
CO% = .23 at 2500 RPM, 2.82 at Idle- Failed
Both failures appear to be in the idle circuit.
The vehicle previously resided at sea level and now I'm over 5000 feet.
I'm assuming it's jetted or tuned richer than it should be for my new location.
My plans are to replace the plugs, change the oil, and adjust the carb slightly, before retesting.
Am I going down the right path??
I'm guessing this is a rochester quadrajet?
Look here for help adjusting the idle air mixture screws, there are two screws. It's a simple adjustment to make and then retest it.
https://www.hemmings.com/blog/article/the-inner-workings-of-the-quadrajet-2/ (https://www.hemmings.com/blog/article/the-inner-workings-of-the-quadrajet-2/)
Normally when you fail like that, they will give you a list of items that cause those conditions. Is that on the report card? I would start surfin the net for ideas of what to look for instead of throwing money at something that you don't even know if it will fix the problem.
How warm was the engine and how long did it sit idling before the test was done? I've heard that if the motor sits and idles, the gases build up in the exhaust and give false readings on tests. Good Luck
I'm also in Colorado - but have passed no issue so far mechanically. Check into the info previously posted. You may want to order some new idle jets or something, I can't remember if that's a thing. It would need to be looked into. Wouldn't it be rich at idle if it's not passing?
Rebuilding the carburetor was one of the first things I did when I purchased mine. It wan't really that hard of a job, quite easy really. Order a rebuild kit, and clean that puppy up. That's a good time to check the jetting. You can then determine if you need something different that the normal sea level jetting.
Maybe it's dirty? Does it idle low or how is the performance otherwise? There's a couple other components that are air control related. Check the egr valve. I just ordered all of that stuff new because it's like 20 bucks. easy to swap too. I also replaced EVERY vacuum line as well because it was all cracked or removed, I'd say you need to check the diagram on the air cleaner where the filter resides, remove it entirely and replace those vacuum lines.
I just register all my vehicles at my mom's place in Florida. No emissions, no inspection, no property tax. LOL!
Kev
Quote from: Scootrader on July 01, 2019, 02:41 PM
I need some advice on adjusting or tuning my RV to pass emissions.
I'm now living in Colorado where i need to have my emissions tested.
My vehicle is a 86 Pace Arrow 27ft, 454, all of my smog or A.I.R.S equipment is still working,
approx 36k on the motor with no smoke at the tailpipe.
So for my vehicle, the test is done at Idle and at 2500 rpm.
The limits are :
HC PPM=300
CO% = 2.0
My results are :
HC PPM = 28.7 at 2500 RPM , 437.4 at Idle- Failed
CO% = .23 at 2500 RPM, 2.82 at Idle- Failed
Both failures appear to be in the idle circuit.
The vehicle previously resided at sea level and now I'm over 5000 feet.
I'm assuming it's jetted or tuned richer than it should be for my new location.
My plans are to replace the plugs, change the oil, and adjust the carb slightly, before retesting.
Am I going down the right path??
My 1985 fleetwood smokes when it's warm, so I just went into the test cold and it passed fine. I was kind of surprised actually. I'm in CO as well. Post a picture of your test sheet, that should help us figure out where the problem is.
If the carb still has the plugs over the idle mixture adjustment screws then I am sure it needs to be leaned out some. As TM Snyder said, look up the procedure for removing the plugs and you will probably need to get the special adjustment tool. Hint, It is not a fun job and if the tool slips out of your hand it will go right into the fan. Also make sure the A.I.R. pumps are both working if you have two pumps. Check all of the lines to and from the charcoal canister (may have one or two canisters) Your readings are both showing rich so I would say due to altitude you need to adjust the idle mixture. That is the cheapest and easiest thing to try first before throwing parts at it.
Here is the tool for adjusting the mixture.
https://www.amazon.com/Lisle-55250-Carburetor-Adjusting-Tool/dp/B0002SRDB4/ref=asc_df_B0002SRDB4/?tag=hyprod-20&linkCode=df0&hvadid=312094794461&hvpos=1o3&hvnetw=g&hvrand=3579268287403092199&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9052512&hvtargid=pla-491266386131&psc=1&tag=&ref=&adgrpid=62497261819&hvpone=&hvptwo=&hvadid=312094794461&hvpos=1o3&hvnetw=g&hvrand=3579268287403092199&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9052512&hvtargid=pla-491266386131 (https://www.amazon.com/Lisle-55250-Carburetor-Adjusting-Tool/dp/B0002SRDB4/ref=asc_df_B0002SRDB4/?tag=hyprod-20&linkCode=df0&hvadid=312094794461&hvpos=1o3&hvnetw=g&hvrand=3579268287403092199&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9052512&hvtargid=pla-491266386131&psc=1&tag=&ref=&adgrpid=62497261819&hvpone=&hvptwo=&hvadid=312094794461&hvpos=1o3&hvnetw=g&hvrand=3579268287403092199&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9052512&hvtargid=pla-491266386131)
I agree with rick, lean it out ...
Thanks guys, working on it this weekend, changing wires,plugs,oil checking vacuum lines, air pumps are working. Need to dial down the idle adjustment just a little. Will let you know how it goes in a few days.