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

__________________
-Marty

1986 300E 220,000 miles+ transmission impossible
(Now waiting under a bridge in order to become one)

Reading your M103 duty cycle:
http://www.peachparts.com/shopforum/831799-post13.html
http://www.peachparts.com/shopforum/831807-post14.html

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

-Anyone?

__________________
-Marty

1986 300E 220,000 miles+ transmission impossible
(Now waiting under a bridge in order to become one)

Reading your M103 duty cycle:
http://www.peachparts.com/shopforum/831799-post13.html
http://www.peachparts.com/shopforum/831807-post14.html

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.

__________________
1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra

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

Duke

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

__________________
-Marty

1986 300E 220,000 miles+ transmission impossible
(Now waiting under a bridge in order to become one)

Reading your M103 duty cycle:
http://www.peachparts.com/shopforum/831799-post13.html
http://www.peachparts.com/shopforum/831807-post14.html

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

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.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

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.

__________________
-Marty

1986 300E 220,000 miles+ transmission impossible
(Now waiting under a bridge in order to become one)

Reading your M103 duty cycle:
http://www.peachparts.com/shopforum/831799-post13.html
http://www.peachparts.com/shopforum/831807-post14.html

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?

__________________
-Marty

1986 300E 220,000 miles+ transmission impossible
(Now waiting under a bridge in order to become one)

Reading your M103 duty cycle:
http://www.peachparts.com/shopforum/831799-post13.html
http://www.peachparts.com/shopforum/831807-post14.html

Mode-----------CO%---------------HCppm-----------------RPM-------Dilution
2speed idle---Limit-Reading-P/F-----Limit-Reading-P/F---Read-Resu-Read-Resu
Idle----------1.2---0.26-----Pass-----220--191----Pass----703-Valid--15.0-Valid
2500 rmp----1.2---0.29----Pass------220---49----Pass---2580-Valid--15.0-Valid

Once again...Big thanks.

__________________
-Marty

1986 300E 220,000 miles+ transmission impossible
(Now waiting under a bridge in order to become one)

Reading your M103 duty cycle:
http://www.peachparts.com/shopforum/831799-post13.html
http://www.peachparts.com/shopforum/831807-post14.html

Your effort was exemplary and proves that following a systematic troubleshooting procedure will eventually get you to a solution, and this is certainly better than replacing parts willy-nilly or buying a bottle of "smog test in a can" based on guess work, which seems to be pretty common, both among DIYers and professional shops.

Since the service information for these engines is available on-line and can be downloaded for free, there's no reason not to follow this approach and educate yourself on the system operation and use the published troubleshooting and diagnostic procedures. Of course this takes time. Some expect a silver bullet from the Board, but there aren't any to pass out.

Your HC at idle is still high and would probably fail the CA two-speed no load test that is used in some areas of the state that don't have significant air quality problems. Before the loaded dyno test was phased in back in '99, we had the two-speed no load test. The 2500 RPM test was run first.

Do they run the 2500 RPM test first in PA?

This would help heat up the catalyst, but my car's idle HC count was always higher at idle and on the ragged edge of the limit a couple of times. There was probably still enough O2 in your car's exhaust to enable more oxidation if the catalyst was hotter, which is why "conditioning" is important, especially as the catalyst slowly degrades with operating time accumulation.

One way top keep the cat hotter is to understand the effect of ignition timing on both EGT and peak flame front temperature, which is the source of NOx.

http://www.peachparts.com/shopforum/tech-help/117048-successful-ca-asm-emission-test-ke-fuel-system-post833484.html#post833484

Duke

They run the idle test first... at least where I went they ran it first.
Unfortunately due to scheduling constraints this time, I left it for them.
I imagine it had been sitting for at least a half an hour... after listening to the engine, looking at the duty cycle, and sniffing the exhaust I was confident enough to leave it there for them to do their worst.
Besides which I had already exceeded the $150.00 emissions repairs amount to buy a waiver if it had failed.
It passed the first time through.
If you fail the first test here in PA they do a "preconditioning" (top off the oil if necessary, and rev it at 3000 for 3 minutes before doing a retest. If you fail the retest with "preconditioning" you have 30 days to get a repeat of the whole procedure at no additional cost.

__________________
-Marty

1986 300E 220,000 miles+ transmission impossible
(Now waiting under a bridge in order to become one)

Reading your M103 duty cycle:
http://www.peachparts.com/shopforum/831799-post13.html
http://www.peachparts.com/shopforum/831807-post14.html

Hey there,

Thought I would chime in in regards to your catalytic converter since I went through a similar situation with my non MB vehicle.

If you are running rich to the point that your mpg's and power have dropped considerably there is a strong likelyhood that you have cooked your catalytic converter.

__________________
1979 Thistle Green 300D 272,xxx miles
1984 Orient Red 300 D 4 spd Euro Import - 189,xxx miles
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Lofat Productions
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

I dispute this statement. If the engine is running rich there is no O2 in the exhaust to support oxidation, nor will reduction be supported, so the catalyst just doesn't do anything. The matrix may temporarily foul with hydrocarbons, but they should burn off and the catalyst's performance will return to normal with time once the correct stoichiometric mixture is restored.

Duke