Gramm

Hi guys, Im' from Moscow, this is my first post here on mbworld. I call in for your help as i can't find solution among our service society on our forums. I drive C230K sport sedan imported from California.

So I've got a problem with mixture, as a result I have heavy on fuel and errors 201C P0172 - rich fuel mixture. I've spent too much time muself and in services to find the reason and have alredy replaced all possible things which could cause the problem.
I prepared to this post and made huge service work in advance (stop oil leakage to the harness, cam shaft magnets replacement, first O2 sensor replacement on new one, air flow sendor replacement on original new one, checked all connections in intake for some kinds of air leaks, system of recycling crankcase gases replaced: houses, valves, vacuum houses of cat heating system replaced)

For your information catalisators deleted from the system and O2 sensor after catalisator turned off electronically.

So what i have as of today:

-Low voltage on first O2 sensor 1000 mV istead 1500 mV (means rich mixture)
-big fuel consumption especially on idle and low speeds in traffic jams especially.
-self adaptations on idle and partial loads in plus
-fuel pressure 3,75 stable on idle rev
-idle rev is stable 750 rpm +-5


So the most hard for understanding is unlogical behaviour of ECM. We have as given by O2 sensor data - rich mixture and at the same time we see that ECM (ECU) trying to rich misture more

I have conducted some experiment where i arranged air leak inside the system and got high voltage of O2 sensor, and arranged air leak out and got low voltage o2 senser


Below some screenshots form StarDiag and my ELM327 of current data






Did anybody faced with such behaviour? What else i should check in your opinion?


P.S. sorry for mistakes in text and big pictures is it possible to make spoilers for pictures here?

lghikas

Have you solved your problem ?

Bo Er

Did u solve the problem? I meet the same one, code coming out p0172 p201-001

Russell Ormerod

Firstly how did you delete the o2 sensors electronically?
Secondly if you have in fact switched off closed loop. Why are you bothering to read o2 sensor values?

fenyovari

Hi! A solution? I have a similar problem with the m271 engine. No power, a little jerk and a lot of consumption.

sajo1973

Seems a common problem, got it aswell. I think it might be the 12$ hose beneath the airbox, going to change it and see if it makes a difference. Doesn't look like it has any cracks or tears in it.

fenyovari

In the meantime, a solution has been found. The failure was with the second catalyst. He collapsed and clogged the exhaust.

sajo1973

Thanks buddy will check out the catalyst

artim808

I have exact same problem. Can someone confirm it was the catalyst?

Besbenz

Same problem, did u fix it? Can you help me with this

Besbenz

can you confrim it, wich is the second catalyst

Geri-go

these codes also appear to me. who solved the problem? I have all the vacuum lines in order! Thanks whoever answers

Geri-go

these codes also appear to me. who solved the problem? I have all the vacuum lines in order! Thanks whoever answers