Failed emissions, CO too high

[Draekon]

I just moved down to Colorado last week, and just got my emissions testing done today with bad news, it failed.  I still have all the emissions equipment hooked up and a strong running motor.  It has had a recent tune up too.  Its acted like its running rich, especially up here at this elevation, and I guess this test confirms it.

Here are the results I got:

HC PPM:
155.7 @Idle
228.4 @2500
220.0 Limit

CO %:
0.69 @Idle
5.05 @2500
1.20 Limit

The HC barely failed, and Im assuming that if I can get it leaned out, the HC will drop enough to be passing.

Is there any quick cheap way to get it leaned out to a better A/F mixture?  Or something I can do to get it to pass?
It is an 81, so its a non-feedback carb, and I have the hotter coil upgrade, other than that it is mostly stock.

I have 10 days to get a free retest, and less time before it is legally supposed to be passed and registered.  And I am on a college budget, so cheap is best.  Worst case I could upgrade to a MC2150, but my first paycheck wont be coming for awhile, so Id rather find a cheaper option.  Thanks in advance.

[vangremlin]

Draekon,

Where are you located in Colorado?  I know a shop that will get it set up to pass in Aurora, and then do some fine tuning after you pass to get it running well again lol.  They worked on my 78 Gremlin and got it to pass.  PM me for futher info.  Thanks

[Eagleearl]

There should be an Altitude Jumper connector that is near the MCU, under the passenger kick panel,  that needs to be jumped across at high altitudes (over 4000 feet) to tell the computer to adjust for thinner air.

[El Matador]

There should be an Altitude Jumper connector that is near the MCU, under the passenger kick panel,  that needs to be jumped across at high altitudes (over 4000 feet) to tell the computer to adjust for thinner air.

He mentioned a non-feedback carb, so assuming that's original, there will be no MCU in this car.

[eaglefreek]

When I lived in CO I my Eagle failed bad but I needed to pass emissions to get my tag and wanted to do the Motorcraft swap, but not right away. I put in 5 gallons of E85 to about 5 gallons of regular and it passed with flying colors. No guarantee, but it worked for me.

[Draekon]

I'm out in Boulder, Aurora isnt too far away, although if there was something I could try first it would be nice to utilize my free retest.

When I lived in CO I my Eagle failed bad but I needed to pass emissions to get my tag and wanted to do the Motorcraft swap, but not right away. I put in 5 gallons of E85 to about 5 gallons of regular and it passed with flying colors. No guarantee, but it worked for me.

While that might make it pass, I'd be worried about the E85 eating the fuel lines.

[eaglefreek]

I don't think a one time thing will cause problems. Heck, all gas in CO has 10% ethanol.

[Eagleearl]

Sorry I guess I should pay attention. A 50-50 mix of gas and E85 for 1 tank will not hurt your gaslines.

[Draekon]

Well I went to a shop today to ask about my emissions failure, and am now pretty ticked off.  The guy was very rude and treated me like I knew nothing, and everything I said was wrong.  I should mention, this is NOT the place vangremlin referred me to, I had decided to take it somewhere a little closer first.  He told me if I was going to spend limited money, replacing the catalytic converter would be a better way to spend the money than working on the carb.  This just seems like bullshit to me.  Sure, the cat may be bad, but there is more of a problem than just the cat.  I KNOW the car is running rich.  Replacing the cat would just be a bandaid fix and it would end up getting burned out quick if I dont touch anything else.

I also mentioned to him that I was considering a motorcraft 2150 upgrade, and he said that he had never seen a 258 with a 2150 pass emissions.  This shop is supposed to specialize in jeeps, and he claims to never have seen a 2150 pass emissions, yet GRONK has sold tons of the kits, and never heard of a car failing emissions because of it?  Doesn't quite add up.

Anyways, I have been doing more research on the whole emissions issue and haven't quite decided what to do.  I know the car is running rich, and the timing is probably a little off (I set the timing down at sea level, probably need to adjust it for high altitude).  I don't really want to spend the money on a carb at this point, but I also don't want to just bandaid fix it.  Since the real failure happened at 2500rpms, the only way to adjust the carter carb to maybe pass would be messing with metering rods and such, which I know nothing about.  I also don't think e85 would be able to drop my CO levels down enough to pass.  5% down to 1.2% is a pretty big drop.

[GRONK]

You need to downsize your jets 7% for elevation assuming you came from lower elevation and you need to advance your timing 1degree for every 1000' above sea level.  The E85 trick works well too AFTER the jets and timing are correct.  Block off your PCV valve from entering the fuel mix for the test and find what your max idle RPM's are and max them out.  Faster running means cleaner burning.

F the cat converter.  Unless you have reason to believe it has failed elements, leave it alone.

[brownbear]

I have a gronk kit and mine failed........

[Draekon]

I bought a junkyard MC2150, rebuilt it, and installed it and passed easily passed emissions.  I have to admit, its not the cleanest install, but I was on a limited budget (sorry GRONK, couldn't afford your kit).

[GRONK]

No worries Draekon.  If you need any info for your install let me know.  I will provide.  I have passed emissions at just about every elevation in every state that tests.  These carbs run amazingly clean and atonomize the fuel better than most aftermarket TBI setups.  They will definitely not compensate for other running components that are off.  The 2100/2150 series will run amazing but you still need to have a decent platform for them to perform their best.

[JayRamb]

I'm fortunate that MN doesn't have emissions testing.

[carnuck]

I found that dirty oil makes these motors fail almost every time I tested.