technical question

[V3 NGS]

Hi everyone
Can anyone out there tell me what the voltage output should be on the o2 senser after the cat when the fuel mixture of 14.7 parts of air to 1 part of fuel {ideal mixture of course}. Also what voltage should you have on the heater circuit as i have had to get a o2 simulator installed as i the ecu will not learn the new set up i have but my fault code reader says it is out with exceptable perameters.... so if i knew what the ideal voltages should be i can stop the trial and error ....
i hope you can help

sorry what a bam i have a 03 mini cooper S

cheers

[stoney]

have you an aftermarket system or just the standard system on ??


if its aftermarket then i know of a few that have done this but dose not make any difrence to the car also know some pepes have a wee thing you plug in and it tricks the ecu in to thinking it is fine

[V3 NGS]

hi stoney thanks for the reply it is a full race manifold with decat with a full race stainless twin silencer.. the fault codes i am getting are .... P0420 catalyst system efficiency below threshold and P0036 heater control circuit
cheers
Nigel

[stoney]

hi stoney thanks for the reply it is a full race manifold with decat with a full race stainless twin silencer.. the fault codes i am getting are .... P0420 catalyst system efficiency below threshold and P0036 heater control circuit
cheers
Nigel


ok sounds like kind of the same set up as i have it dose not mater about the light as said before some get a plug in to take it off but mine just went off bye its self after a while

i know a bmw tec who fitted my manifold and de cat he told me the light would come on but no to worry about it till mot time :thumbs up: but it just went off after a while mabie 2/3month tho

[stoney]

also post some pics of it sounds nice

[C.Noble]

Hi everyone
Can anyone out there tell me what the voltage output should be on the o2 senser after the cat when the fuel mixture of 14.7 parts of air to 1 part of fuel {ideal mixture of course}. Also what voltage should you have on the heater circuit as i have had to get a o2 simulator installed as i the ecu will not learn the new set up i have but my fault code reader says it is out with exceptable perameters.... so if i knew what the ideal voltages should be i can stop the trial and error ....
i hope you can help

sorry what a bam i have a 03 mini cooper S

cheers


It should just be a normal Zirconia type sensor and should therefore produce around 500mV at the stoichiometric value (14.7:1) 500-1000mV is "rich" and 0 to 500mV is "lean" but if the ECU just sees 500mV all the time, it may produce a inactivity code (P0139 or P0140).
As for your P0036 code, to replicate the heater circuit, you need the correct resistance in the circuit as the ECU monitors the current, the supply voltage to the sensor should remain relatively constant (system voltage 13.5-14.5 volts) but the earth control side will depend on the duty (Hz) of the heater control.

What exactly have you done to your car, and when did the codes appear? If you have "de-catted" the exhaust system or fitted a "sports cat", there are easier ways of tricking the ECU into not putting up these codes.

I would also check fuses, P0036 is a general failure in the O2 sensor heater circuits (upstream and/or downstream) whereas P0141 is specific to the downstream heater circuit only.

[V3 NGS]

thanks for the reply... all i have done is fitted a manifold with a decat pipe and a full flow exhaust system.. then the light came on while i was on my way to knockhill and has been on ever since.... I was told to get a o2 sensor simulator, to get rid of the light. the instructions stated that i should cut the wires to the cat sensor and hooked the simulator in to the wires, and tune the pots till the light goes out.... however the light will not go out so i needed the values in order to set up the simulator correctly to eliminate the light... you say there is an other way that would be great as this can be removed very easily... or should i persevere..... thanks in advance Nigel

have added some photos and the instructions for the simulator if they will help!!!!

here is the link for the simulator .... http://www.magnumtuning.com/index.phtml?op=termek_elmelet&termek_id=661

http://i407.photobucket.com/albums/pp152/hirobosuddo/HD-MINI-MEGAN.jpg


http://i407.photobucket.com/albums/pp152/hirobosuddo/exhaust.jpg

thanks again

[C.Noble]

The P0420 (cat. efficiency fault) code is generated when the ECU sees the upstream and down stream oxy sensor reading as too similar. Without going into too much detail of how the cat works, it will use the oxygen in the exhuast gasses and merge it with other gasses within the honeycomb inside the cat itself, so theoretically, the oxygen content of the gasses going into the cat should be different (usually less, but not always) than that of the gasses leaving the cat, if it is operating correctly.

In your case, the two sensors are measuring the same oxygen content as there is no cat to change the composition of the exhaust gasses.

you can continue on with your simulator, but the hardest bit to simulate will be the current drain of the heater element inside the sensor, this element is about 6mm long and capable of heating the internal of the sensor (the cell) to at least 4-600 deg. celcius. The current drain has to be accurate to within around 20mA (tiny) or the ECU will see it as faulty (this is why everyone finds the use of these so called "universal sensors" often ends in having to remove them for OE ones after a few days, the sensor works fine, the heater works fine, it just draws too much or too little current)

I havent tried it on a MINI...yet, but on previous occasions where I have "de-cated" for people, I have either bought or manufactured myself an extended sensor boss. This will pull the downstream sensor out of the direct air (exhaust) flow, this will cause the air to circulate around the sensor rather than pass over it, this results in the sensor reacting slower to changes in the O2 content of the exhaust gas, and hopfully fool the ECU into believing this delay/differance is the work of the catalyst, while still using the original heater element, thus avoiding heater fault codes.

Hope this helps.

I really need to cut these posts down...:yawn:...gonna bore the a&$e off everyone!

[V3 NGS]

yes it does help a lot thank you very much ... where can i get an extension piece from and will it fit as it is very tight in the tunnel ...... cheers

[C.Noble]

yes it does help a lot thank you very much ... where can i get an extension piece from and will it fit as it is very tight in the tunnel ...... cheers

Hmmmm. I cant find any specific ones for a MINI, give me a couple of days and I will investigate making one up, or maybe even a few of them, I am sure you are not the only person suffering this problem.

[V3 NGS]

thanks very much .. looking forward to hearing from you ...... cheers