appatula

Being lazy and have not done extensive searching before posting but.....

I'm hoping there are some OBDII code experts that can give me a definitive answer.

CEL came on, recieved generic code P0141 "02 Heater Circuit" (Bank 1, Sensor 2)

Freeze Frame Data:
Fuel Sys 1: CL
Fuel Sys 2: NA
Calc Load(%): 18.43
ECT(celcius): 86 degrees
MAP(kPa): 27.00
Eng RPM: 2688
Veh Speed(km/h): 18


I'm guessing o2 sensor. How many are there on a 95' C36 (Have not looked underneath her yet) Pre cat and how many after cat if any? Please "learn" me guys!

johnhef

technically, theres only one "O2 sensor" although there is a second one that looks identical to it, but MB calls it a "diagnostic probe." Its been awhile and I can't quite recall which one is which.

KJI3jflarryfe93

Does every US version of c36 and c43 have 4 o2 sensors?
2 fronts and 2 rear?

On euro cars there are only 2 o2 sensors and they are the front ones!
rear sockets are plugged on my car!

appatula

I'm uessing there is most likley only two, one precat and another after. Either way would 'Bank1 Sensor2" lead me to believe that if there are in fact two, it would be the one furthest down the exhaust stream (after cat?). o2's aren't very expensive anyhow, I just don't want to start throwing parts at it whilist not doing my detective work first. I'll end up going the Bosch splicing method as I'm purrty good with my dandy soldering iron and heatshrink wrap (I think these are the 4 wire sensors?)

Thanks for the help so far guys!

jayrasheed

is the one before the cat a narrow band or wide band one like VW group use on their cars?
btw my car now only has one since i have no cats, and on a scan it throws no errors, guess cause i dont have the CEL and its systems check.

i did install a wide band for a test un the other day, the car on WOT ras as follows:

below 2800 to 3000 rpm AFR is abt 14.
above 3000 till red line its at 12.8 steady, but at 3600 rpm (the famous flatspot) the afr rises slightly to 13.1 to 13.2 then by 4000 its back to 12.8.
so at 3600 it seems the resonance flap change over disrupts airflow for a fraction of a second. what do u think guys??

So below 3000 rpm we can benefit if we drop afr to abt 12.8, guess that’s y a superchips is said to improve low rpm pickup.

MarcusF

If you're going with Bosch universal 4-wire O2 sensor replacements, they use stainless steel wire and almost impossible to solder. Because of that, the kit comes with crimp connectors. They crimp connectors make them very easy to attach. Some other details can be found at www.marcusfitzhugh.com/CLK/DIY/o2univ.html

appatula

Marcus your just too much! Super awesome write-up man, that will help a lot!

To be honest with you the problem with soldering stainless steel is the problem of how fast it oxidizes and the type of solder you use. Acid based flux and silver-cadmium solder will do it with no problems whatsoever with a pencil iron. Even simple 60/40 tin lead solder will work flawlessly with proper fluxing procedures. Basically, while your applying the solder, put a drop of muriatic acid. If one can't get such a dangerous acid apply tons of generic acid based flux before and during your soldering procedure and you will be amazed! Any acid based flux should be sufficient. Just don't breathe the fumes in or get it in your eyes (it stings...badly).

FLUX is the absolute key when soldering SS. However, after all that I will most likley just crimp the connectors on and then solder, just because I'm a soldering junkie. Hope this info may help some others in the future when they run into problems with SS soldering to steel or copper wiring....Flux, Flux, Flux....or muriatic acid

appatula

Jay, very interesting you mentioned this! I'm pretty sure all OEM cars have narrowband o2's. I've crawled into the wideband arena and have almost bit the bullet and bought a Innovate LC-1 for my MSII setup. Is it possible to wire in a wideband sensor into a car that came stock with a narrowband without upsetting the ECU and such? It would be great to know what AFR's I'm running ect. and post along with your's jay (a definite future thread for sure) PM me details on this Jay I'm very very interested as I am planning to run a stock 2-4psi turbo setup. I feel with such modest boost and a additional injector (pulsewidths controlled by a piggyback ecu ( my MSII sitting on the shelf) I could avoid knock or pre-det easily keeping the whole car system stock and adding a few HP without having to deal with the ASR electronics, ECU electronics, throttlebody ect. The car will think it is all stock. When under boost the MSII will keep AFR ratios perfect with the wideband and additional injector somehow mounted in the throttlebody boot. So modest a setup that ignition timing can be ignored...I HOPE. Just as long as my AFR's remain stable through the small boost range I feel 3-4psi would not be a problem at all and if knock does occur the ECU will retard timing anyhow, right? Then I lower boost...(reply in a PM Jay as to keep the thread on topic)

KJI3jflarryfe93

[QUOTE=jayrasheed;3940185]is the one before the cat a narrow band or wide band one like VW group use on their cars?
[COLOR=black][FONT=Verdana]btw my car now only has one since i have no cats, and on a scan it throws no errors, guess cause i dont have the CEL and its systems check.

Lak shu dude!
Now that you removed your cats, you're drivin' freeflow!
The car runs much better I guess?
Which octane do you use for pumping gas?
The higher octane gives more feedback in combustion when driving fast, your car feels stronger and faster!
The higher octane is good for turbos and special tuned cars that needs 100 octane!
Or Shell's V-Power 99.
You have this in Lebanon?

Do you have any government regulations for annual vehicle inspection?
Complete check ups for safety and enviromental issues?
Is it legal to remove the complete cats?
Maybe you can mod your car what ever you like to do?

jayrasheed

[QUOTE=kowalski;3940429]hey, yeah the car runs much better at the top end and it sounds really nice, not loud but u hear the engine note changes as the RPM goes up.
We do have a yearly strict check up on saftey and emissions but as long as my car is well tuned and i can pass emissions with no cats.
Yes we can mod cars alot here but it need to be safe and with good emission control on idle at least.
As for fuel we have 98 octane at the pumps but some places even sell Avation gas and race gas, but 98
is good enough for the AMG for now.

KJI3jflarryfe93

Voila, siara super!
I've sen your videos on jutub!
you drive like you stole the car!
inner roof lining is bouncing around when you drive on these rugged roads in Beirut!
Now that you don't have any cats car feels faster and it gains a few extra hansirs!

well if your car runs perfect with that set up then continue with it!
It's a winner!
shukram habibi
jalla bye

appatula

I run the highest that we have in the states here which is 93 octane. Beefore this starts to roam off which sensor do you think it could be guys pre or after cat? Do you even need both or will CEL be thrown if both are not installed and functioning properly?

jayrasheed

If the pre cat one is going out u should feel that something is out of tune with the car. Like trouble picking up when floored on low rpms. And u should smell raw fuel on idle.
The rear will throw a cel as its there to confirm that the cats are doing the job..

And your 93 octane is the same as our 98. marcusF prolly can explain better.

KJI3jflarryfe93

Now that you have removed your cats on your c36!
You can fill up your car with any type of gas you want without killing your cats?
In Lebanon do you have leaded gas or only unleaded but in various octane?
Do you always pump 98 octane, if pumping lower octane does your engine pinking?
I think this was the correct word for low premium gas? (pinking)

Does any country have leaded gas for cars nowadays?

jayrasheed

Well i always use 98 octane, i think on the AMG any lower will cause it to ping and thus the ecu will retard timing and power will be less.

we only have unleaded in either 95oct or 98 oct. as i said some special pumps sell AVGaz, and some sell race fuel.
98 sells at USD1.1/liter today, but every week the price is adjusted according to oil prices.

KJI3jflarryfe93

Shlomo habibi!
Yeah for $1.1/liter US D. is about 8 swedish kroner!
That's ok liter/price.
In sweden 1 liter is about $1,65-1,70.

Gas is not cheap in western europe!
cheap gas only in old Russia!

Pumping race fuel or AVGaz is cool but I guess it's a very costly expense?
But your car will run like shajtan/haiwan!

johnhef

ok front one is the o2, rear one is the diag probe.

appatula

Thanks John! I know the workings of an o2 sensor but what exactly does this "diag probe" do?

johnhef

It's an O2 sensor...

For reference G3/2 is the front sensor (sensor 1), and G3/1 is the rear sensor (sensor 2). Confused yet?

jayrasheed

The rear one confirms to the ECU that the cat is still doing its Job. Howw exactly it knows i dunno :$

So the rear one even if its dead will only throw a CEL but wont affect the idle, running of the engine.

MarcusF

This is “how” the ECU uses the two O2 sensors. The catalyst material stores oxygen. Being O2 sensors, the sensors supply the ECU with readings as to how much oxygen is in the exhaust stream. By comparing the precat and post cat oxygen levels, the ECU can determine how effective the cat is. The less oxygen sensed by the secondary O2 sensor, the less effective the catalyst material is. There is a downside. There are catalyst materials that may be more efficient than the OEM materials. Some of those materials don't store oxygen, which makes them incompatible with OBD-II.

appatula

THANK YOU EVERYONE! This will without a doubt help others understand and diagnose this problem in the future. With that being said my response has been somewhat laggy...going for the first sensor first. eBay here I come! Keep everyone posted with a quick DIY with pics.

BTW after clearing codes it has yet to come back.....? who knows, still montoring cycles though....

johnhef

It may take some time to come back. I replaced my cam sensor tonight so I go to erase that Check Engine light and damned if there wasn't a fault for the air injection system that has popped up since I last scanned it. Sure enough the valve isn't holding vacuum so it seems I'm in the market for one of them too :/