PA Emissions -Failed
 

Failed Hydro Carbons big(?) and CO please help gurus.


Mode-----------CO%---------------HCppm-----------------RPM-------Dilution
2speed idle---Limit-Reading-P/F-----Limit-Reading-P/F---Read-Resu-Read-Resu
Idle----------1.2---8.74----Fail-----220--577----Fail----703-Valid--18.1-Valid
2500 rmp----1.2---8.34-----Fail-----220--336----Fail-----2548-Valid--18.0-Valid


I am thinking O2 sensor.
Any Ideas where I should start?

Edit: this would be on my 86' M103 300E -as per my sig. BTW

Also- have had increased gas consumption from 17-20 mpg down to 13-16 mpg.

-Anyone? :confused:

I think O2 sensor is a good guess. My 86 Supra, which is L-jetronic based, had the same exact symptoms (except for my mileage was still OK as far as I know). I checked, changed and adjusted EVERYTHING to no avail, until finally my friendly local mechanic said "It is the O2 sensor" (he diagnosed it over the phone for no charge - can't complain about that). Anyway, $35.00 later I had perfect (near zero) emissions scores. So if the O2 sensor is not too expensive, I would try it. On the other hand I have no specific knowledge of your car so maybe someone else has a more likely answer.

Test the O2 sensor. Do a search - many discussions of the subject.

Duke

Thanks mpoli,
I went out and picked up a 1990 mustang 302 o2 sensor as per this article:
http://business.baylor.edu/Richard_Easley/autofaqs/o2sensor.htm
for $41.00 after tax, I will spilce it up tonight and install it tomorrow.
This seems to be a likley candidate for all my symptoms from what I have read. Hopefully it cures me.
I also noticed in my reading here that ideal conditions for an older cat like mine are well heated up and run hard right up to the actual test, which I did not do. (The plugs & wires are from this last summer and I always use 93 octane by mfg recomendation.) So I will do this and keep my fingers crossed.

Anyone out there know if there is a way to test an o2 sensor, out of the car?
And or in the car an running?

Tried that, searched "oxygen sensor testing" but guess I didn't look hard enough.
Will try again.
Thanks

You are almost off the chart on both HC and CO - I think you have something more basic than the O2 sensor wrong, like the fuel distributor, EHA, start valve, or the warm-up system. Something would appear to be dumping a lot of unneeded fuel into the cylinders, which is consistent with your note about fuel economy. If you don't deal with this promptly, you will foul your converter.

I have taken off the air cleaner and browsed around a little but this is pretty new stuff to me. I have read about my fuel injection system so I am roughly familiar with how the system works but I am not really familiar with testing procedures and where to start. So I guess I have more reading to do.
As I am off to that now I will moniter this thread for any sugestions.
Multi-Meter is fired up and ready. Just got to figure out where to stick it.

Have you done just a exhaust sniff test?

I did that a few months ago and my eyes were teary with richness. Not horrible, but not right. I checked the easiest first- The temp sensor which read about 4.8k ohms. I R&R it today and remeasured at 70 F, 5.6k ohms.

Seems much better- last time through emission testing it was only NOX that was very close. I'm hoping it was out of range last year... New plugs and an oil change before we pay the test station.

Michael

rookie hits the driveway
 

did 3 tests
1) at X11 (ignition on engine off)
pin 3 red banana to V/F/C/Ώ/mA/uA
pin 2 black banana to COM
Dial set to % duty
reading 30.1

2) at X11 (engine running)
pin 3 red banana to V/F/C/Ώ/mA/uA
pin 2 black banana to COM
Dial set to % duty
reading 50.6

3) in passenger footwell
black wire lead from O² Sensor to red banana to V/F/C/Ώ/mA/uA
aligator clip to front right fender inside engine compartment to black banana to COM
Dial set to % duty
reading 0.0

Am I doing this wrong?

Use the following single words in separate searches - emission, emissons, sensor, O2, test, failed, failure.

Also search posts under my user name. I've made many, many posts on emission test issues.

Duke

I am pretty sure it is rich.
I had a center muffler failier around Halloween, when I replaced It (both it and rear muffler had been off for 1½ months) I expected to see a big improvement in mpg that never appeared. It has been a little slugish as well.

Was that temp sensor on your 86'? If so where is it exactly (side of the block?) and any tips on the test?

Think I found a lot of what your talking about Duke:
http://www.peachparts.com/shopforum/tech-help/88269-87-300e-power-loss.html?highlight=EHA+testing
http://www.peachparts.com/shopforum/tech-help/108163-oxygen-sensor-voltage-question.html?highlight=oxygen+sensor+test
http://www.landiss.com/mixture.htm
and more like em.

what do you think of my test results?
I would have rather seen a low reading than no reading as I am new to this and think I am maybe doing something wrong.

Out of curiosity, have you noticed a drop in the full throttle power to go along with the drop in fuel economy? If so, your cat could be at fault (partially plugged).
I once had a Honda that melted it's cat, giving me a lack of highway power and 15mpg. 2 dealers gave me idiotic diagnoses of 1) failed ignitor in the distributor and 2) plugged fuel filter. It finally got so bad that I was sick of dealers doubting my plugged exhaust theory that I pulled out one of my ice axes for the next service manager and bashed some holes in my muffler. The car remained silent and the service manager believed me.
What was remarkable though was just how far the fuel mileage dropped before the lack of power was felt. If you're playing underneath with the O2 sensor anyway, it couldn't hurt to take a peek at the cat internals.

I have noticed a drop in power as per post #12 " It has been a little sluggish as well."
Of course I am hopping the cat is not dead. If it is I will try to achieve a $150.00 spent on emissions waiver before going that route. Having just replaced everything behind the cat already I suppose its time may have come. What should I look for if I can see in there?