Emissions help

[moranda]

I live in Nashville and for some stupid reason they make us have emissions testing in this county. Motor is a AMC 258 i6 / 4.2l , rebuilt with maybe 5k. It has also been nuttered and team rushed. The CAT is fairly new been on there for a year maybe a year and a half. The jeep had sat from Oct to March because the ECM went out and I didn't have the time to get it working. I took it through testing center which requires a tail pipe sniffer cause the vehicle is older. The first time I went through my readings were 760 ppm on HC and 3.6% on CO. The passing limit is 220 and 1.2 respectively. I have been driving the jeep around as much as I can to get the CAT hot and burn off anything settled in it. I bought 2 bottles of iso heet (methyl alcohol) and put them in and took it through the testing center again. My hydrocarbons remand high at 780 ppm but my CO dropped to .04%. Anyone know how to get my hydrocarbons down? I have heard things like using seafoam can help also adjusting the timing to make it run funny can lower your HC. I also heard that running to lean can raise HC. Any insight is greatly appreciated thanks.

 

[Torxhead]

Is this something new? I didn't think there was emissions testing in Tennessee. My first suggestion would be to hook up the computer again to operate the carb and ignition. The next and most expensive option would be to have one of the fuel injection kits for the AMC 258 i6 / 4.2l .

 

[mtnwhlr]

High HC readings are a result of unburned or partially burned fuel.
High CO readings occur when the air/fuel mixture is to rich.
So you need to see if you can lean it out and make sure your EGR is working like it should.

 

[moranda]

We have had emission testing in Davidson county for at least 2 decades. Every other surrounding county does not have emission testing. The problem with hooking the computer back up is that it is completely dead. I will eventually go fuel injection just not in the budget right now. Also I swear I just read that a lean mixture increases HC but I might have read it wrong and will double check on that.

Sent from my SPH-L720 using Tapatalk

 

[Torxhead]

Thanks for the info, good luck with whatever you decide to do with the countys emissions testing.

 

[Saddle Tramp]

Is the EGR valve gone? For some reason I thought that a Nutter could be done with or without the EGR but I’ve never done one myself. The EGR lowers the combustion temps in the cylinders during ignition by squirting a little bit of exhaust back into the cylinder. The exhaust is an inert gas that does not burn and lowers combustion temps; lower combustion temps = lower HCs. The EGR cost little to nothing power wise to run and the added benefit of lower temps is less wear and tear on the engine.

 

[moranda]

The egr valve is in place it just doesn't have the vacuum line on it. I am not really sure where that is supposed to go either.

Sent from my SPH-L720 using Tapatalk

 

[Bent]

You need to hook it back up for emissions testing. The vacuum line should "T" off the ported vacuum line that runs to your vacuum advance and go to the thermal switch in the drivers side of the block just behind the power steering pump bracket. from there it will run to the EGR valve. If your thermal switch has more than two nipples, check google images for a diagram for vacuum line placement.

 

[Fastatv]

High HC readings are a result of unburned or partially burned fuel.
High CO readings occur when the air/fuel mixture is to rich.
So you need to see if you can lean it out and make sure your EGR is working like it should.

^^^^^^^^Here is where you really need to have a look. To assist in getting thru the emissions testing, you might consider leaning the a/f mixtures screws until the idle begins to get slightly rough....take it back thru, hopefully pass, then re-adjust the screws for a smooth idle.

 

[Torxhead]

The egr valve is in place it just doesn't have the vacuum line on it. I am not really sure where that is supposed to go either.

Sent from my SPH-L720 using Tapatalk

The egr is hooked into ported vacumn. I once passed smog with my '86 after doing a Nutter By-Pass and couldn't believe it.

 

[WHATROAD]

Is there a possability that your charcoal canister has gone on permanent vacation? Some say change it and there are those that don't even know it exists. Might have some influence on your readings and is not an expensive replace. Just another thought to munch on

 

[Neuner]

Is there a possability that your charcoal canister has gone on permanent vacation? Some say change it and there are those that don't even know it exists. Might have some influence on your readings and is not an expensive replace. Just another thought to munch on

PO removed my mud packed canister from the loop. I bought a new one for a Grand Cherokee and made all of the line connections. I was surprised at how it improved. For the little cost, I'd give it a try if yours is not connected.

 

[moranda]

Yeah I ripped out most of those vacuum lines. I think it still might be down there just chillin. That might be a last ditch effort for me.

Sent from my SPH-L720 using Tapatalk