Calmchaos

Sucks... but here is the info.
HC should be less than 100 my score was 364
CO% should be .5% or less mine was 6.72%

This was taken at 2470RPM.

What should I look at first? Or last. Whatever.

Thank you for any help
-Brett

Wipeout

O2 sensor?

Calmchaos

I replaced that within the past 3 years.
I thought that the O2 sensor didn't cause high HC and CO. I don't really know though.

J Berk

Wonder if someone fiddled with that screw on the DME? Think it richens the mixture....

Maybe check Clarks Garage?

Calmchaos

I know what you're talking about. I was wondering about that screw myself.
I was reading online and I think I'll be looking at the ignition system.
Also, would burning oil cause these readings?

vt951

I've heard if you play with the tire pressures, it can make a huge difference. There are certain RPM's that it will test horribly at, and a slight change in RPM it will pass with flying colors.

jsaindc

Mine failed for running too rich and it was all because of an aftermarket chip. Put the stock chip in and it passed fine.

bjd34

I back the screw out on the MAF which has some effect on the door in there. It makes me pass but the car runs a little more rough than usual. Then i just screw it back to where it was.

Calmchaos

vt951, are you messing with me?
I don't have an aftermarket chip.

And to bjd, how would I know how far to move this screw? Did you just take a shot at it then go back to inspection?

Calmchaos

My 1 and 4 spark plugs are pretty much black. I just checked them
Also, which injectors are paired in the DME. Is it 1 and 4, 2 and 3 or is it 1 and 3, 2 and 4?

Thanks

Update again.
I ran the car up to normal operating temperature and it idled at around 900 rpm. I then unplugged the O2 sensor, and noticed no change. Now what I need to do is find my freaking volt meter.....
I wouldn't say that the idle was "hunting" but it wasn't 100% steady. Every few seconds it would change by about 50rpm or so. I always thought hunting was more of a constant up and down.

bjd34

I ran it all the way out then threaded it in 2 turns. It it falls out and you lose it your car will not run. I havent tested that yet but a porsche mechanic told me so im not interested in finding out. I failed the first time i went through. Went to a mechanic who showed me the screw and i backed it completely out and passed. i have been through several more times and passed. I will take a picture of the screw tonight when i get home from work.

Calmchaos

Ok, I found my volt meter, but I am a bit confused about how to test the O2 sensor.
I read the information on Clarks Garage that is as follows:
Testing the O2 Sensor

1. Start the car and run until engine is at normal operating temperature.
2. Disconnect the O2 sensor and connect a voltmeter to the sensor plug.
3. Run the engine at approximately 2500 rpm.
4. Introduce propane into the intake to enrich the mixture until the engine rpm drops by 200 rpm. You may be able to create the same affect by disconnecting the vacuum line to the fuel pressure regulator. However, you'll have to plug the vacuum line to prevent a vacuum leak to the intake manifold.
5. If the voltmeter reading rapidly rises to greater than 0.9 VDC the O2 is correctly indicating a rich mixture. If the voltmeter response is sluggish or the voltage remains below 0.8 VDC, the sensor should be replaced.
6. Secure the propane addition.
7. While continuing to run the engine at 2500 rpm, disconnect a vacuum line from the intake to cause a lean mixture.
8. If the voltmeter indication rapidly drops to less than 0.2 VDC, the O2 sensor is properly reading a lean mixture. If the voltmeter indication responds sluggishly or remains above 0.2 VDC, replace the sensor.

What voltage am I testing? If the plug is not connected to anything where is it getting voltage from?
How do I go about connecting the volt meter properly? There are 3 pins on the connector.

I ran the car to temp, and had someone hold it at 2500 rpm for me. I connected that damn meter to everything on earth and read no voltage anywhere.

Please help

Mike C.

I thought that was a bit confusing too. I can only assume he (Clark) is saying hook the voltmeter + terminal to the disconnected O2 sensor wire and the - terminal to car ground. The sensor apparently creates its own current. I know there are devices used in some gas furnaces that when heated produce a small current (enough to run the house thermostat). I assume it must be the same principal.

vt951

Nope. But the guy that told me that may have been messing with me? He was talking about failing emissions in a 951 in NY, though, so maybe it's different. He said he went from failing by a long shot to passing at 1/3 the legal amount just by changing the tire pressures.

Mark944na86

I would think you are measuring voltage produced by the O2 sensor, so you connect you voltmeter to the two sensor terminals on the disconnected plug, rather than to the car ground. (It would only make sense connecting to the car ground if the sensor -ve was connected to the car.)

In any case, I suspect your O2 sensor isn't working, from what you've described.