Really high CO with emissions

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Joined
Mar 23, 2007
Threads
101
Messages
808
Location
Moab Utah
I just did my emissions today, and Everything looked good except the CO % it was 6.46% at 15 mph legal limit was 2.19% and 6.12% at 25 mph legal limit was 2.24%. I am pretty sure that I need to adjust the fuel air mixture. I read the FSM and was confused on how to do it. Do I just keep turning it out until the rpms stop going up? Also, if the EGR is not hooked up could this cause this high of a CO % when everything else is below the legal limits. I looked through all the posts that talk about too high of a CO with emissions and could not find the answer. n Thanks
 
In the 2F emissions factory service manual, page 4-5, it has 3 different scenarios:

1. High HC, Normal CO
2. High HC, Low CO
3. High HC, High CO.

It doesn't say anything about Normal HC, High CO.

Are you driving an FJ60 or 62? That's probably a good place to start- adding it to your signature line would be beneficial for help.
 
I just did my emissions today, and Everything looked good except the CO % it was 6.46% at 15 mph legal limit was 2.19% and 6.12% at 25 mph legal limit was 2.24%. I am pretty sure that I need to adjust the fuel air mixture. I read the FSM and was confused on how to do it. Do I just keep turning it out until the rpms stop going up? Also, if the EGR is not hooked up could this cause this high of a CO % when everything else is below the legal limits. I looked through all the posts that talk about too high of a CO with emissions and could not find the answer. n Thanks

Typicaly a non-functioanl EGR will cause your hydrocarbons to go up. Your high on CO which is unburned fuel. Yes, you're too rich, or your choke is malfunctioning or your timing is grossly off or a combination of the three. Some info would help. First, what is your vehicle, second, what modifications have been done. Do you have the ability to check the timing, adjust the carb, etc and what carb is it?
 
Typicaly a non-functioanl EGR will cause your hydrocarbons to go up. Your high on CO which is unburned fuel. Yes, you're too rich, or your choke is malfunctioning or your timing is grossly off or a combination of the three. Some info would help. First, what is your vehicle, second, what modifications have been done. Do you have the ability to check the timing, adjust the carb, etc and what carb is it?
Howdy! Adjusting the IDLE MIXTURE screw will not help, as your problem is not at idle speed. Gdood chance your choke is not striaght up when the engine is warmed up. If the top butterfly is leaning over, fix the choke. John
 
I just did my emissions today, and Everything looked good except the CO % it was 6.46% at 15 mph legal limit was 2.19% and 6.12% at 25 mph legal limit was 2.24%. I am pretty sure that I need to adjust the fuel air mixture. I read the FSM and was confused on how to do it. Do I just keep turning it out until the rpms stop going up? Also, if the EGR is not hooked up could this cause this high of a CO % when everything else is below the legal limits. I looked through all the posts that talk about too high of a CO with emissions and could not find the answer. n Thanks

mtnmort,

The cause of high CO is too much fuel. Carbon Monoxide is long chains of carbon that are formed from partially burnt fuel.

The problem will be in the carburetor: float level too high, leaking needle and seat, bad power valve circuit, things like that.

A few external factors must be eliminated: Plugged air filter, stuck choke, charcol canister flooded with fuel, for example.

The idle circuit is not at play while driving, so adjusting the idle mixture will not affect this problem.

The EGR controls Oxidies of Nitrogen (Nox) and it's non-action will not affect this problem.

You need proper diagnosis and a carburetor rebuild. I recommend rebuilding your carburetor if it's the origonal unit and not molested.

Good luck, let us know how your remedy goes,

Rick
 
Thanks for the advice. I just rebuilt the carb, though it consisted of putting it in carb cleaner over night cleaning it and putting it back together with the new parts and a factory service manual. It is a 1985 fj60. I was looking at the float glass and noticed that the bowl is full instead of the fuel coming up to the center line. I haven't adjusted the mixture screw since I put it back in, and I am sure that my mixture is off. I adjusted the timing to 7 degrees on the timing gun. Some one I talked to said that I needed to unhook the high altitude and the vacuum advance hoses before I do the timing, is this true? I adjusted the timing with the hoses on.
 
One other thing. I just pulled this motor out of a wrecked 60 and put it in this body. I rebuilt the carb because I had a rust problem in my old gas tank and the tank out of the wrecked one was good. I put all new emission hoses( the 3mm and 5mm ones) and I think that they are all where they are supposed to be( according to my interpretation of the FSM). And how do you add your vehicle to the sig line?
 
I am trying to adjust the idle to get the fuel to air mixture right and I can't tell any change when I adjust the mixture screw unless I put my hand over the top of the carb to restrict the air coming into the carb. I can unscrew the mixture screw all the way without a change in rpm. Am I doing it wrong. I tried to lean it like we do the helicopters. we start to pull the mixture knob that leans it until the rpms go up as far as they go, and then they come back down. once they go down we add a little more fuel. any suggestions I still need to pass emissions and they guy said that the CO was high because of the fuel to air mixture.
 
Dude,

You gotta get the float level set before trying other adjustments. Otherwise you are pissing in the wind....
With a high fuel level in the bowl, fuel will spill over easily from the other circuits and over-ride the idle circuit.
Look at the carb kit instructions. Every adjustment is a basis for correct, dependable operation. Do not ship any of the procedures or else you will waste your time!
Get the carb float to maintain the fuel level in the center of the sight glass. If you have trouble with that, check the needle and seat.

Rick
 
I have a new cat that i just bought with the rest of the exhaust system. I have finally decided to take it to the dealer. I was trying to adjust the float, and every time I got the carb back together it would either be all the way full or all the way empty. there might be some contaminants in the fuel that has caused a blockage in the carb. Also greg at the dealer said that the jets might be too small because I got a generic carb rebuild kit, and that is why it is not running properly. I am not sure if that is the case. It is a good thing that I am taking it to the dealer. I got to talking to the guy down there and I am getting a new gas tank while I am there. I have another parts rig that I am keeping for a build someday and it has not had the fuel tank recall done, so he is just ordering the tank and giving it to me. I will keep you posted as to what the mechanic said it was. He is also going through the vacuum hoses and making sure that they are all in the right place.
 
Did you pass the IM? I bought my FJ 60 in Colorado and have it tagged there but live in Davis Co and will need to tag it in Utah eventually. What did the dealer do?
 
I should be getting it back tomorrow. they said that there were a few miss placed vacuum hoses and they changed the jets in the carb. I guess that the generic ones that I got out of the rebuild kit were the wrong size, plus they changed the float because it was taking on fuel. I will try and get the emissions passed in the next day or so and I will post the results.
 

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