Well I just couldn't resist and I installed some racing headers on my Z4. It sounds great, runs faster than ever, but the damn Check Engine Soon light eventually came on after about 50 miles! Does anyone out there have any experience with MIL Eliminators, and can you provide me with a source? Thanks!
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MIL Eliminator
- Thread starter bvcg1
- Start date
I'm on the lookout for them too. My check light comes on occasionally since I fitted the 100 cell cats. Not surprisingly the code is for poor cat efficiency. I've found adjustable MIL eliminators on ebay but I would prefer to have something more BMW specific. You can just splice a resistor into the lambda sensor wiring but knowing what rate of resistor to use is the tricky part!
Is the MIL/CEL on because of the after-cat sensor?
If that's the case, there's 2 ways to do it:
Method 1: Something like this. All it does is moving the O2 sensor away form the direct flow of the gasses. In close loop condition, the way the ECU adjust the fuel trim when a narrow band O2 sensor is by switchig back and forth from rich to lean around the stechiometric value of 14.7... This is due to the low reaction time of the narrow band O2 sensor. It also facilitate the job of the catalitic converter by switching for oxydation to reduction. Therefore the pre-cat sensor senses the increase & decrese in O2, while the post-cat shouldn't (therefore the voltage should be more constant). If it does, the low efficiency code is recorded. By moving the O2 sensor away from the direct flow, you don't expose it to changes in O2 concentration... At least that's what I figured...
Method 2: use a resistor and some stuff like that: this is what you basically buy on the internet. If interested, here's the schematic on how to make it... Narrow band O2 sensors all have the same voltage range so there's not really a BMW specific O2 simulator.
If I would have to pick between the two, I would personally go with the Method 1 as it's totally reversible and you're not messing with the car electronic... If end up not working for you, you can always investigate it further and get an actual electronic simulator.
PS: wide band O2 sensor are used mostly in direct injection cars beacause of the ultra lean operation, or when tuning the trim and you need to know the actaul A/F ratio.
If that's the case, there's 2 ways to do it:
Method 1: Something like this. All it does is moving the O2 sensor away form the direct flow of the gasses. In close loop condition, the way the ECU adjust the fuel trim when a narrow band O2 sensor is by switchig back and forth from rich to lean around the stechiometric value of 14.7... This is due to the low reaction time of the narrow band O2 sensor. It also facilitate the job of the catalitic converter by switching for oxydation to reduction. Therefore the pre-cat sensor senses the increase & decrese in O2, while the post-cat shouldn't (therefore the voltage should be more constant). If it does, the low efficiency code is recorded. By moving the O2 sensor away from the direct flow, you don't expose it to changes in O2 concentration... At least that's what I figured...
Method 2: use a resistor and some stuff like that: this is what you basically buy on the internet. If interested, here's the schematic on how to make it... Narrow band O2 sensors all have the same voltage range so there's not really a BMW specific O2 simulator.
If I would have to pick between the two, I would personally go with the Method 1 as it's totally reversible and you're not messing with the car electronic... If end up not working for you, you can always investigate it further and get an actual electronic simulator.
PS: wide band O2 sensor are used mostly in direct injection cars beacause of the ultra lean operation, or when tuning the trim and you need to know the actaul A/F ratio.
ZetaTre said:Is the MIL/CEL on because of the after-cat sensor?
If that's the case, there's 2 ways to do it:
Method 1: Something like this. All it does is moving the O2 sensor away form the direct flow of the gasses. In close loop condition, the way the ECU adjust the fuel trim when a narrow band O2 sensor is by switchig back and forth from rich to lean around the stechiometric value of 14.7... This is due to the low reaction time of the narrow band O2 sensor. It also facilitate the job of the catalitic converter by switching for oxydation to reduction. Therefore the pre-cat sensor senses the increase & decrese in O2, while the post-cat shouldn't (therefore the voltage should be more constant). If it does, the low efficiency code is recorded. By moving the O2 sensor away from the direct flow, you don't expose it to changes in O2 concentration... At least that's what I figured...
Method 2: use a resistor and some stuff like that: this is what you basically buy on the internet. If interested, here's the schematic on how to make it... Narrow band O2 sensors all have the same voltage range so there's not really a BMW specific O2 simulator.
If I would have to pick between the two, I would personally go with the Method 1 as it's totally reversible and you're not messing with the car electronic... If end up not working for you, you can always investigate it further and get an actual electronic simulator.
PS: wide band O2 sensor are used mostly in direct injection cars beacause of the ultra lean operation, or when tuning the trim and you need to know the actaul A/F ratio.
Thanks ZetaTre,
Yeh, it's the secondary sensors that trigger the fault.
I've looked into method 1 already but the problem is that my sensors are already so close to the transmission tunnel that I can't fit a further extension piece although I could build something at a right angle so that the sensor sits parallel to the pipes just like the system Supersprint use but it's a pain to do.
Method 2 is fine and I've found some on ebay which use a variable resistor so you can play around with the settings until you get what you want but what I really wanted is something that fits inline between the O2 sensor plug and the engine wiring harness. I've found them online for Ford fittings but I wondered whether anyone knew of one designed specifically to fit the BMW wiring harness. The Ford ones might even fit if they use the same multiplugs as BMW but I don't know and I can't get a response from the suppliers when I email them. Link below shows you the kind of thing I'm looking for.
http://www.teamtorquesteer.co.uk/fiesta-engine/mil-eliminator.html
I've just found some right angled adapters on ebay US but I would still prefer the inline resistor type if possible.
http://cgi.ebay.com/ebaymotors/UNIVERSAL-O2-SENSOR-ANGLE-Header-ADAPTOR-02-Extension_W0QQcmdZViewItemQQ_trkparmsZ72Q3a1301Q7c39Q3a1Q7c66Q3a2Q7c65Q3a12Q7c240Q3a1318QQ_trksidZp3286Q2ec0Q2em14QQhashZitem250310539937QQitemZ250310539937#ht_1516wt_0
http://cgi.ebay.com/ebaymotors/UNIVERSAL-O2-SENSOR-ANGLE-Header-ADAPTOR-02-Extension_W0QQcmdZViewItemQQ_trkparmsZ72Q3a1301Q7c39Q3a1Q7c66Q3a2Q7c65Q3a12Q7c240Q3a1318QQ_trksidZp3286Q2ec0Q2em14QQhashZitem250310539937QQitemZ250310539937#ht_1516wt_0