MIL light O2 sensor

[stansnuts]

Hi, has anyone experienced the MIL light indicating an O2 sensor issue?

MIL gives two long and four short flashes when ignition is switched on with the side stand in the lowered position. I’ve tried clearing the fault using the diagnostic plug and shorting tool but it won’t clear. I’ve also tried the ecu reset by disconnecting and reconnecting the battery then starting the bike and letting it run until the radiator fan kicks in and switches off, all to no avail.

Has anyone replaced an 02 sensor or installed an O2 sensor eliminator device?

 

[Grum]

Sounds like your ECM has detected a genuine fault. Code 24 is for your cylinders 2 and 3 O2 sensor.

 

Sections 6-32 and 6-33 of the Service Manual shows how to check the O2 sensors.

 

The fact that you have two identical O2 sensors means you can do some good comparisons both Ohmically and Voltage wise between them. Any difference between them could point to the 2-3 one being at fault, OR its associated wiring.

 

Code 24 does refer to the Heater circuit of the Sensor so do a resistance check for the O2 heaters, between the two White wires, if you don't get a similar reading between the two O2 sensors then the 2 - 3 sensor is likely to be faulty. Refer 6-32 Heaters should read 10 to 40 Ohms.

 

Failing that do a continuity check of the wiring especially of the 2-3 one back to the ECM as well as no shorts to Ground. Again you have the 1 - 4 O2 Sensor to compare with. Check and compare the Heater Voltage between the two sensors (white wires)

Having a known good O2 sensor to compare with should help greatly in finding the fault.

 

You might even find that a good check of the Black 4P Plug for the Sensor might be dirty and having poor contact resistance, perhaps a spray of WD-40 or similar into the pins and sockets might help.

 

Sorry, can't comment on the O2 Eliminators!

 

Good Luck.

[DannoXYZ]

Don’t use O2-bypass/eliminators by themselves! Base fuel-maps are on rich side and ECU uses O2-sensor feedback to lean out mixtures to optimal stoich mixtures.

 

O2-eliminators are only to be used with fuel piggybacks like PowerCommander or Bazzaz. These will adjust injector’s duty-cycle away from stock maps to account for upgrades.
 

If O2-sensors are left in place, ECU will use them to re-adjust mixtures back to stoich 14.7:1 AFR, thus undoing all adjustments you did with PC or Bazzaz. To prevent that, O2-sensor is removed and PC/Bazzaz has full control.

 

ECU will detect missing O2-sensor heater and throw MIL. So O2 bypass/eliminator is just a resistor of same resistance as O2-sensor’s heater. This tricks ECU into thinking O2-sensor is still there and it won’t throw MIL.

 

so again, don’t bypass/remove O2-sensors unless you’ve got PC/Bazzaz to adjust fuel away from factory rich maps. Especially if you don’t have any major upgrades.

[stansnuts]

On 10/8/2020 at 9:17 AM, DannoXYZ said:

Don’t use O2-bypass/eliminators by themselves! Base fuel-maps are on rich side and ECU uses O2-sensor feedback to lean out mixtures to optimal stoich mixtures.

 

O2-eliminators are only to be used with fuel piggybacks like PowerCommander or Bazzaz. These will adjust injector’s duty-cycle away from stock maps to account for upgrades.
 

If O2-sensors are left in place, ECU will use them to re-adjust mixtures back to stoich 14.7:1 AFR, thus undoing all adjustments you did with PC or Bazzaz. To prevent that, O2-sensor is removed and PC/Bazzaz has full control.

 

ECU will detect missing O2-sensor heater and throw MIL. So O2 bypass/eliminator is just a resistor of same resistance as O2-sensor’s heater. This tricks ECU into thinking O2-sensor is still there and it won’t throw MIL.

 

so again, don’t bypass/remove O2-sensors unless you’ve got PC/Bazzaz to adjust fuel away from factory rich maps. Especially if you don’t have any major upgrades.

Bike has allegedly been remapped by a company called Hilltop here in the UK to smooth out throttle response in the lower Rev range, so will the eliminators be OK?

[Egg on Leggs]

2 hours ago, stansnuts said:

Bike has allegedly been remapped by a company called Hilltop here in the UK to smooth out throttle response in the lower Rev range, so will the eliminators be OK?

 

Google Treetop and weep.

 

 

[DannoXYZ]

12 hours ago, stansnuts said:

Bike has allegedly been remapped by a company called Hilltop here in the UK to smooth out throttle response in the lower Rev range, so will the eliminators be OK?

There's two maps to adjust in low/mid-range, ignition and fuel. Since O2-sensor is in place and being used by ECU, there's absolutely zero, zip, zilch, nada adjustments you can make to fuel-map that will change anything because ECU will use O2-sensor feedback to dial fuel to precisely and exactly 14.7:1 AFR. That leaves ignition, and some advance in ignition in partial-throttle/mid-range area can make bike more responsive and lively. But.. there's limit to how much you can advance ignition before requiring higher-octane petrol full-time. Sounds like Hilltop is selling lots of snake-oil to unsuspecting bike-owners.

 

Don't try to game the ECU. It's very well designed and robust and O2-sensor really makes for more reliable and durable engine in long run. Grum's given you some helpful tips, with procedures right out of manual. Do tests and figure out if O2-sensor is bad, or wiring is bad. Then replace/repair wiring or O2-sensor.  Don't shoot messenger, fix actual problem.