Colorado Emissions Woes... (1 Viewer)

[batthewmrown]

Well, I've just failed emissions (again) and I'm stumped. I'm passing on all measures except Carbon Monoxide. It's insanely high, 130 GPM (45 GPM is the limit). I assumed that it was an issue of the fuel mixture, so I seated the screw and backed it out the 2 turns specified in the FSM, but that didn't really help. Just looking for some advice on what should/could be checked before I saw screw it and take it somewhere.

 

[OSS]

Make sure the air injection system is working properly. There's not enough oxygen in the exhaust stream to allow the cat to convert CO to CO2. Either that, or it's running way too rich.

 

[cps432]

That's what I'm failing too. Do you have the graph they print out? Post a picture if you can. I think I've narrowed my problem down to the air pump. I'm replacing it this weekend along with a ton of other gaskets and seals. I'm going through the entire air injection system to clean all the crud out of the valves and whatnot. It'll be a few weeks before I'm driving her again because I've got to have my crank pulley rebuilt. Hopefully I'll pass after that.
Do you have the emissions manual? It's very helpful!

 

[augirthedude]

The officials that regulate the emissions testing are unyielding. Our 30+ year old emissions systems that were just a band aid are very inefficient . Here in NM / Bernalillo County just measure the exhaust and assure the catalyst is still installed. Trying to keep an old air injection system functional is ludicrous. I feel for you . I was having issues with mine a few years ago .. I switched to diesel. Exempt from testing .

 

[Infinity00]

If you fail multiple times you qualify for the emission tech place to look at it or something. Also, if you fail and have put a certain amount of qualified expenses into it they’ll exempt you. Call them up.

 

[cps432]

If you fail multiple times you qualify for the emission tech place to look at it or something. Also, if you fail and have put a certain amount of qualified expenses into it they’ll exempt you. Call them up.

Fail 4 times and you can schedule an appointment with a Colorado state mechanic who'll go through everything and help diagnose the problems. Spend more than $715 and you can try to qualify for an extension or temporary exemption. I meet both of those standards but I'm still sitting in the driveway trying to do it myself!

 

[SteveH]

Be sure your air pump is actually putting out air, and add several gallons of E-85 to your low-ish fuel tank. This adds lots of oxygen to the fuel and lowers CO. Much discussion on this, and I put a thread here: Using E85 to pass emissions - Rising Sun Member Forums

 

[batthewmrown]

That's what I'm failing too. Do you have the graph they print out? Post a picture if you can. I think I've narrowed my problem down to the air pump. I'm replacing it this weekend along with a ton of other gaskets and seals. I'm going through the entire air injection system to clean all the crud out of the valves and whatnot. It'll be a few weeks before I'm driving her again because I've got to have my crank pulley rebuilt. Hopefully I'll pass after that.
Do you have the emissions manual? It's very helpful!

Yeah, I'm gonna have a look at the air pump today and see if that's my problem. I do have a copy of the emissions manual that I'll look at 7692374 times before anything clicks and makes sense, haha.

 

[batthewmrown]

The officials that regulate the emissions testing are unyielding. Our 30+ year old emissions systems that were just a band aid are very inefficient . Here in NM / Bernalillo County just measure the exhaust and assure the catalyst is still installed. Trying to keep an old air injection system functional is ludicrous. I feel for you . I was having issues with mine a few years ago .. I switched to diesel. Exempt from testing .

Yeah, it's tough. I certainly appreciate clean air and a non-toxic environment but I also loathe the government. Such is life. Jealous of that diesel MPG!

 

[batthewmrown]

Make sure the air injection system is working properly. There's not enough oxygen in the exhaust stream to allow the cat to convert CO to CO2. Either that, or it's running way too rich.

Will do. I don't see how it could possibly be running too rich if the mix is at the factory specs. Carb has been recently rebuilt, so I'm definitely gonna look into the AI. Thanks!

 

[batthewmrown]

Be sure your air pump is actually putting out air, and add several gallons of E-85 to your low-ish fuel tank. This adds lots of oxygen to the fuel and lowers CO. Much discussion on this, and I put a thread here: Using E85 to pass emissions - Rising Sun Member Forums

Damn, that'd be awesome if that's all it takes. I'll give it a go and report back. Tank is fairly low right now, too! Score!

 

[SteveH]

A lot of air pumps put out a faint breeze. When I replaced the one in my FJ40 with one that wasn't missing vane pieces, my CO dropped in half. The quantity of air coming out was quite a bit more. It's subjective - there's no way to really test air pump output, unless you have a known good and a known bad pump to compare.

Every year in Denver, my brother loaded up his '94 80 series with E-85 and it would pass Denver emissions. CO was always the issue.

 

[cps432]

Yeah, I'm gonna have a look at the air pump today and see if that's my problem. I do have a copy of the emissions manual that I'll look at 7692374 times before anything clicks and makes sense, haha.

View attachment 1748552

That's more or less what mine is reading too. It seems that when you're at idle everything is fine and you're passing. It jumps as the technician climbs to the top of the gear. You see it plummet as he shifts from 1-2 2-3 and then when he gets around 30 mph it skyrockets. Then it drops down at highway speeds. It seems that somehow either fuel is being dumped into the engine at the top end of the gear or there's a lack of air when the throttle is open wide. The air pump is a secondary air injection source. Someone correct me if I'm wrong here, but as the throttle opens more air is injected into the mix through the air pump. If the air isn't making it back into the mix then it's running extremely rich at the top end of the gear. Or the exhaust isn't being cycled back through for a second combustion and is being dumped out the tail pipe. This is why I'm going through that whole system to clean it out.

 

[augirthedude]

Yeah, it's tough. I certainly appreciate clean air and a non-toxic environment but I also loathe the government. Such is life. Jealous of that diesel MPG!

22 mpg on an extended highway trip. Normally 18mpg

 

[Infinity00]

Common Reasons for Failure | EnviroTest

Scroll down to the CO paragraph. Read the part where it talks about low vacuum can cause an overly rich condition. Your other thread sort of ended around the time you checked your vacuum and it was giving you a reading of 11”. Have you solved that issue yet? I think that needs to be resolved before you can pass. But I also agree checking all the AI, and get a rebuilt smog pump from O’reillys and check your check valves - mine were bad.

I’m not an expert but your CO levels are higher then 180, to my untrained eye, it looks like you’ve satuatated their data analysis tool on the vertical axis. I think the low octane or E85 will halp but you’ve got a more significant problem. Sorry to be the buzz kill but fix that vacuum leak and then try that.


Here’s an excerpt from the link:

“Rich Air-Fuel Mixture
There are many aspects of the engine’s fuel delivery system that may need to be checked when diagnosing a rich air/fuel mixture. That is the main reason that this is listed behind crankcase vapor and evaporative emission control systems-even though they are less likely causes of the problem, they are much easier and quicker to check.

When diagnosing a rich air-fuel mixture, it is important to keep in mind the possibility of a defect in an entirely different area affecting the operation of the fuel delivery system. For example, certain mechanical engine defects may cause abnormally low engine vacuum and result in the fuel system delivering more fuel than is actually needed by the engine. The symptom of excess CO may lead one to think that the defect lies with the fuel system but the problem actually lies elsewhere.”

 

[cps432]

I’m not an expert but your CO levels are higher then 180, to my untrained eye, it looks like you’ve satuatated their data analysis tool on the vertical axis. I think the low octane or E85 will halp but you’ve got a more significant problem. Sorry to be the buzz kill but fix that vacuum leak and then try that.

You may be reading that correctly. The limit is 30 I believe. There's another page that gives actual numbers. Mine has been hitting the mid 90's. I suppose his are close. Either way it's grossly over the limit. Using low octane makes a negligible difference when you're spiking like this. It's gotta be something with air delivery. His vacuum does seem low and may indicate a problem that is manifesting as high CO. I'm pulling right around 16 inches which is pretty spot on for my altitude and I'm still having the same issues.

 

[Infinity00]

Yeah 16” is good for our elevation.

Eh maybe this will help

 

[cps432]

Gotta be in the AI system. I rebuilt my carb after two failed tests and it improved marginally on the test and significantly in actual performance. I'm fairly certain that I nailed the float levels and got everything installed correctly. I'm tearing into it in a little while... we'll see what I find.

 

[Infinity00]

When my smog pump was on, I could feel a significant amount of air when it was bypassed to the air cleaner. It was noticeable, so if you don’t get that, it probably needs to be replaced. Sucks because the one I got from O’Reillys was expensive and I’m fairly certain it’s broken again. They’ll replace it, but I got lucky to get one in a Toyota case, after returning two that broke right away. I don’t want to swap it and get one from a ford again. The belts get way too close to those. If you get around to welding a bung (that always sounds so funny) onto your exhaust, I could set you up with my O2 and AFR meter to see what your fuel to air mixture looks like at the different RPMs. It still isn’t easy to get it working right - ultimately you still have to go through all the systems and understand them. Also, I’ve read about people who have put their 60 on the dyno and tuned them that way.

 

[cps432]

Thats not a terrible idea. I need to fix my harmonic balancer before I can do any more testing though. The valve connected to the air rail is disgusting. So is the pump. I pulled the carbon wipers because they're all intact but everything else in the pump was rusted. I'll replace the pump tomorrow and clean this valve and air rail tonight.