[W126 Coupe] Emissions question

Dick Spellman spell.yy at verizon.net
Sat Feb 24 17:15:09 EST 2007


Hi Rich:

I've got a gray market 86 300SE with the 2 cats fitted and immediately
followed by the O2 sensor. I'm pretty sure you have one on there in
order for the Lambda to work. If it's installed it should be just
behind the cat and up top near the floor boards. Not a mechanic just a
DIY'r so perhaps Jonathan can chime in on this subject where he is a pro
wrench among other things and knows the 500euro motor. I retained all
of the other euro characteristics similar no doubt to your 85 SEC
including the variable ignition resistor that allows for different
octane grades on the fuel. I'm dialed up for premium US which is 93
figuring on running this one 500k miles with a bit of luck.

Dick

richard jaffe wrote:

> Dick,

>

> I don't believe I've ever seen an O2 sensor anywhere in the exhaust

> stream on my car. Also, the cats were never OE on this car. They were

> added when the car came over during the heyday of the gray market.

>

> Rich

>

> ----- Original Message -----

> *From:* Dick Spellman <mailto:spell.yy at verizon.net>

> *To:* Mercedes Coupes Mailing Lists <mailto:mbcoupes at mbcoupes.com>

> *Sent:* Friday, February 23, 2007 9:40 PM

> *Subject:* Re: [W126 Coupe] Emissions question

>

> Hi Rich:

>

> When was the O2 sensor last replaced? Assuming the O2 has <100K

> miles, check the lambda and make a note of the value then lean the

> lambda down till she just runs poorly and add a can of Emissions

> Pass followed by a 30 minute 'easy' highway run just before going

> to the test center. Leave engine running the entire time from

> highway run to emissions test and see if she passes. Assuming you

> pass, rich up the lambda until you are back to the original values

> for best performance.

>

> More than 100K on the O2, time to replace it. DO the Mustang O2

> sensor (see archives) for $37 and you should be good to go.

>

> No rattle on the cats? If you can move the exhaust so as to hear

> the cats rattle then you may have fouled out the cats (typically

> from too much oil hitting them over time) where the heat is

> trapped and they turn more solid then porous leaving you with a

> rattle and poor cleaning of the exhaust gasses. Poor cats will

> usually result in an exhaust restriction giving your poor running

> which you are not having! So, I'd probably lean her up as

> mentioned and then restore best performance when emissions are passed.

>

> Also check to see at what point your state has any cut-off on

> emissions values due to vehicle age. That's how I get a pass on

> my 83.

>

> Dick

>

> richard jaffe wrote:

>> Hello All:

>>

>> The following are the test results of the emissions test

>> performed this afternoon on my 85 Euro 500 SEC:

>>

>> 25/25

>> test

>> 50/25 test

>>

>> reading allowed

>> result reading allowed result

>> HC ppm 212 137

>> Fail 216 140 Fail

>> CO % 1.86 0.87

>> Fail 1.85 0.79 Fail

>> NOx ppm 1028 956

>> Fail 1036 1046 Pass

>> RPM 1302 2500

>> max 1357 2500 max

>> CO+CO2 % 15.5 6.0

>> min 15.5 6.0 min

>>

>> The following items are new: 8 fuel injectors w/ air tubes, Beru

>> spark plugs, Beru ignition wires, Distributor cap and rotor

>> button, ICM and various vacuum hoses and vacuum connector, 1 can

>> BG 44 intake system cleaner.

>>

>> The car now runs great. Just can't seem to satisfy the clean air

>> nazis in this state. Is the mixture too rich?

>> Any ideas how to rectify this situation? Oh yeah, the car does

>> have catalytic converters.

>>

>> Rich Jaffe

>> 85 Euro 500 SEC 259K

>> 83 300 SD 192K

>> ------------------------------------------------------------------------

>>

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>

> The MB Coupes Website!

> W126 SEC Mailing List

> Postings remain property of MB Coupes, L.L.C.

>

> ------------------------------------------------------------------------

>

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> W126 SEC Mailing List

> Postings remain property of MB Coupes, L.L.C.





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