Can you tell me if I'm missing something.

[my1st911]

You are running to rich. Look at a clearer chart

[oregonmon]

If it were that simple than why couldn't the local shop fix that when they had it? Could there be a running problem that is not properly burning the fuel?

[my1st911]

Originally Posted by oregonmon

If it were that simple than why couldn't the local shop fix that when they had it? Could there be a running problem that is not properly burning the fuel?

I'm in the automotive repair world. Many many many shops are just not very good. I take pride in my work, and I am a car nut as well. Alot of techs are just not that way. I'm willing to bet most "shops" dont even know that your car has a "CO adjustment", where it is, or even how to adjust it. The air pump might help a tiny bit, but not enough to pass. Print out the adjustment instructions, and bring it with you to a shop with a gas analyzer. They should be able to get it within passing specs for you

[my1st911]

Originally Posted by oregonmon

If it were that simple than why couldn't the local shop fix that when they had it? Could there be a running problem that is not properly burning the fuel?

It "could" be a running problem, but your HC tells me your rich. A dead miss would be much higher, like 2000 ppm. 600 is a running rich issue which will affect your CO. I;m willing to bet you NOx is quite low. You didnt post that number, but would assume they test that gas as well. You also never mentioned that the car wasnt running well, or shaking or any drivablity problems, so I assume she is running fine, but you cant get the numbers in an acceptable range

[kidrock]

The air pump should definitely help. I also agree with leaning your mixture. Also, for whatever reason, these cars often need a spirited drive for at least 20 minutes before testing.

[my1st911]

Originally Posted by kidrock

The air pump should definitely help. I also agree with leaning your mixture. Also, for whatever reason, these cars often need a spirited drive for at least 20 minutes before testing.

Most people, unless they live in CA remove the airpump. As much as I have to admit it serves a purpose, installing it will not magically get him through inspection. The only thing that will is leaning it out. I'm curious to see the NOx readings.

[oregonmon]

I appreciate everyones input. Hi Harry! Thanks 1st.

Here's what was going on with the two shops I was going to. One guy who went through fuel system and replace injectors didn't have gas analyzer.
The other shop diagnosed a stumble in high rpms (injectors solved it) as a transmission/clutch issue and wanted to drop the engine and tranny. That completely stumped me.
Went back to that shop after new injectors to get it tuned/adjusted with analyzer and couldn't get it low enough. Proposed new cat, plug wires because they weren't sheilded, oil change with a bill over $800!

This shop supposedly has a great rep but part of me wonders what they were trying to do?

[my1st911]

Originally Posted by oregonmon

I appreciate everyones input. Hi Harry! Thanks 1st.

Here's what was going on with the two shops I was going to. One guy who went through fuel system and replace injectors didn't have gas analyzer.
The other shop diagnosed a stumble in high rpms (injectors solved it) as a transmission/clutch issue and wanted to drop the engine and tranny. That completely stumped me.
Went back to that shop after new injectors to get it tuned/adjusted with analyzer and couldn't get it low enough. Proposed new cat, plug wires because they weren't sheilded, oil change with a bill over $800!

This shop supposedly has a great rep but part of me wonders what they were trying to do?

Ok, so you have a 3.0, a cat, and no o2 sensor. You are running cis though, correct.

[my1st911]

Also, please post your NOx readings. I agree that a cat helps, but there are plenty of guys who's cars didnt have cats that run cleaner than that. The problem may stem a little deeper into the CIS system, but I believe you have an adjustment for how rich or lean your car runs. I am confident that leaning it a little would solve it all. Your NOx readings will help determine that, but not always. Running too rich could cause carbon build up, and make your NOx high anyway. The shop with a gas analyzer already wanted to sell you work you didn't need, whether it was deliberate, or unintentional, but I still wonder if they know what to look for. If you have a VW shop, I would swing by, and just ask if they could lean out your mixture a little. Many old german cars had this setup. If you go to a "good" shop that knows nothing about CIS, They may have also looked for the engine in the front

[oregonmon]

Originally Posted by my1st911

Ok, so you have a 3.0, a cat, and no o2 sensor. You are running cis though, correct.

That's all correct and according to the sheet, I don't see any NOx numbers.
Actual numbers.
HC 640
CO 2.0774
CO2 11.6

[my1st911]

Originally Posted by oregonmon

Actual numbers.
HC 640
CO 2.0774
CO2 11.6

With seeing the CO2 numbers, it gives me a better idea. If they included O2 and NOx, it would be help as well. Basically with these numbers, you could be either a little rich or lean Its very hard to tell, but with an adjustment of the "CO adjustment", I would think it wouldn't be difficult to get it in the sweet spot. I got some info off the internet to help you understand what the gases tell me, and maybe will help you fix it

High Carbon Monoxide (CO) readings usually indicate a fuel mixture richer than ideal (rich mixture - air fuel ratio below 14.7). In general CO is an indicator of combustion efficiency. The amount of CO in a vehicle’s exhaust is directly related to its air-fuel ratio. High CO levels result from inadequate O2 supply needed for complete combustion. This is caused by a too rich mixture - too much fuel or not enough air (AFR readings below the optimal 14.7

High hydrocarbon (HC) readings usually indicate excessive unburned fuel caused by a lack of ignition or by incomplete combustion. Concentrations are measured in parts per million (PPM). Common causes include a faulty ignition system, vacuum leaks, and fuel mixture problems. Circumstances that can lead to a high HC emissions are:

* Incomplete combustion due to fouled spark plugs.

* Improper timing or dwell

* Damaged ignition wires

* Poor compression

* Vacuum leak

BTW, I believe they mean high HC in the 2-3000 area. I believe that 600 ppm is more of an indication that there is to much fuel, not enough O2, and thus leaving some unburned fuel

Low carbon dioxide (CO2) readings indicate a fuel mixture either too rich or too lean, exhaust system leaks, or sample dilution


With High CO, Low CO2, and moderately high HC, I believe you are running rich. Hope someone near you, or even you can get you with a good sticker soon. If I were you, I would aquire the proper adjustment tool, and try to adjust yourself. Its very easy. Very small turns is all it takes. It doesnt take much for the cis to get a little out of whack, so I would start there before buying cas etc. Good luck, and let me know

[HarryD]

Ryan,

Mike knows how to do this. If you already paid for the service once, I would press him a bit.

[javadog]

Just for reference, the spec for CO on a US '79 is 1.5-3.5%, with the air pump disconnected.

JR

[oregonmon]

Good to know javadog, the CO gotta be 1 and under. So even if the mix is rich, which I'm sure it is, it seems the pump is probably going to help.

[dfk911sc]

Originally Posted by kidrock

The air pump should definitely help. I also agree with leaning your mixture. Also, for whatever reason, these cars often need a spirited drive for at least 20 minutes before testing.

+1 on the spirited drive. My last two smog tests were done without the airpump "vanes" in the pump (had to keep the pump and belt in place for completeness). After no joy finding a pump that didn't sound like a cat in a fan belt, my mech adjusted the mixture and insructed me to make sure the care was fully warmed up. passed with flying colors.

[oregonmon]

I drove around in 1-2 gears lower than i normally would. it was hot. I don't know what else, would be the problem unless it goes deeper. It runs good, especially now, with new injectors and fuel system clean through. The only running problem is that it does buck some at light to no thottle and I'm not sure that is related or what is causing it. Could that be a symptom of a rich mix?

[kidrock]

bucking is an indication of a lean mixture, IIRC.

"Spirited" drive...just drive it normally, but push it a bit (watch for cops!)...no need to run in lower gears.

[87 930]

Oregonmon:

my1st911 is right on the money. Exactly! High CO is an indicator of too much fuel or too little air. The O2 reading will help point out if you're rich or lean. If your HCs are high also, you're way too rich. Fix the CO problem first. Often, the HCs will come into line. Your mixture screw should get the air/fuel mixture in range and below 1% for CO. If your HCs are still high, you need a tuneup or your compression is down. These are the simple things to start with.
Good Luck,

[john walker's workshop]

you can lean it out but the HC will stay up there or get worse. fix the wasted fuel issue first. it can be anything that causes incomplete combustion. remember, CO is a byproduct of combustion, so what shows as rich now would be even richer if it all was burned. check the brake booster vacuum hose down by the trans and torsion tube for cracks, OHM the plug connectors, check for air leaks, leakdown and compression, etc.

[oregonmon]

Yeah John, I hate to say it, but wondering if there is a low lying issue that neither shop has found. Which is very frustrating.