CIS Confusion

[nixter]

Hmmm.. so much reading, so much confusion! I guess I'm the type that likes to have an idea of what might be going on before I get my hands dirty but just when I read something that makes sense, I'll read something contrary! So I'll list my symptoms and maybe you guys could help me out!

Failed emmisions, CO was like 3.5 times over the limit!

Idle is fine (around 900) and engine seems to run ok. I say "seems" because I don't know what I'm comparing it too. I kind of think the low end torque might be weak though.

My milage is awful (around 12-13 mpg) and I can sometimes smell fuel when running even with the windows and sunroof open.

It seems like I'm running rich but I don't have any of the idle issues usually associated with this! And if I was rich shouldn't I have better low end torque??

I though maybe I should try changing the spark plugs? The car is quite new to me so I'm not too sure when they were last changed. The car was in storage for 2 years before I got it though.

Thanks,

Nix

[nixter]

Yeah, that stuff is over my head. I'm a hard-core DIY'er but engines are new to me in that dept. I'll get the hang of it eventually but it seems like there are so many variables here that I better just get it checked out.

Nix

[aigel]

1980 has the 02 sensor, right? Idle mixture will have no influence on cruise, since the 02 sensor gives the brain feedback to adjust the mixture to optimal.

There can be many things leading to your condition. If the car sat that long and you have no service history, you need to start with a complete tuneup. Oil, fuel and air filter. Plugs, wires, cap and rotor. Valve adjust. Set timing.

Then you can start diagnosing the problem you have. Start by adjusting the idle mixture. You need an exhaust gas analyzer, e.g. the innovate meter that you can read about here and buy at pelican. http://www.innovatemotorsports.com

Once that is done, you plug in your O2 sensor and test it, as it is described in the bentley manual. If it does funny things, buy a new one.

My bet is that it's the 02 sensor. But do yourself a favor and go through the routine above, instead of blindly replacing parts...

I hope this helps. I am sure the gurus will chime in for more in depth info!

George

PS: These cars do not have much low end grunt. Generally a tad richer mixture (12.8-13.8 A/F ratio) will help with power in the entire band, but too rich will rob power. If you run way rich, you can ruin your catalytic convertor, so make sure you look into this soon. Your plugs may be able to tell you something too...

[Paulporsche]

If you were slightly rich I would suggest you set it yourself, but since you are so far off, I think either a gas analyzer or a trip to a mechanic with one is in your future. This setting is not expensive.

What is the CO limit where you live?

You can always reset it later to optimal for your car. Thjere are lots of threads on how to find the sweet spot.

[sammyg2]

It is running way too rich for the CO to be that high.
You can manually lean it out but that is prolly a band-aid in this case.
I suspect your O2 sensor is no good.
If your plugs or ignition were to blame you would have excess HC in addition to an elevated CO, but not that high.

Your fuel is getting burned but it doesn't have enough excess air to burn correctly so it makes CO instead of CO2.
Check the O2 sensor and replace it is necessary, have the CO adjusted correctly, and your car will thank you.

[MotoSook]

What was your HC number..just curious.

Your best bet is to find a shop that does EPA testing prep. Buddy up to the owner or manager and see if he'll let you tweek your own car (his wrenches won't know how to do it...likely). You will have to get the mixture, timing and idle bypass just right...

Also, are you running a cat?

[nixter]

I passed all other areas of the emissions test, I'd have to check the papers for exact HC numbers but they're in the car at the moment. Yeah, I'm running a cat.

Thanks for all the responces guys!

Nix

[mtelliott]

Mine is sitting at the mechanics right now getting adjusted. There are some things that I just don't want to mess with (and I rebuilt the engine). The mechanic has the right tools and equipment to get is straightened out in an hour or two. It will take you a lot of trial and error.

[RANDY P]

Hey Nik -

Yep. Time for a full check of everything, hot and cold CIS pressures and a CO adjustment..

Also, sorry, no joy on the wheel spacers. I think they got left in a car I sold. However I did find a used pair for $80 USD (I was told reg. $125 / Side ) from a local wrench. I'll bet he would install longer studs and the spacers for a few dollars more - I can ask for you. Just let me know if you want 'em. I can foward contact info to you if needed.

rjp

[sammyg2]

BTW, I had the exact same problem last year when it came time to smog my car.
Everything was within the limits except for CO, and it passed at idle but failed the two rolling tests.
I tinkered with it for a while, even paid a shop to set the CO at idle with their test equipment, no joy. Eventually i broke down and replaced the O2 sensor. That did it. It passed easily after replacing the sensor.
Hopefully yours will be as simple to fix.

[nixter]

Hey no worries Randy! Yeah I'd be interested in the used spacers for sure. I measured and it looks like 1.5 inch spacers would work nicely in the rear and 1 inch up front. How big were the used ones you saw?

Cheers,

Nik

[RANDY P]

Pm'd you Henry's contact info

[Doug Steinel]

An exhaust gas analyzer is really a fine piece of equipment when you work on these cars. I bought one on ebay for $150 and I finally have stuck a 3 MM allen down into that mixture screw and started to play. And I got my car running whole lot better. It was worth the $150 bucks.

[Superman]

Drive to Seattle, drop the thing off at John Walker's Workshop, and go have a corned beef sandwich at the 74th Street Ale House, along with the beverage of your choice. You'll go to sleep knowing you made at least two great decisions that day.