Bikesure_adrianflux

O2 Sensors walk through

Ron1000

Ron1000

Registered
Joined
Jun 16, 2015
Messages
951
Location
Livingston
Bike
M1100evo
Hi guys,
O2 Sensors. What’s the best way of checking if they’ve went bad?

I’ve read that if you plug into the OBD2 you can see the voltage reading fluctuate between 0.1v to 0.9v…anything out with that range or a static value is sign of a failing/failed sensor.

I Was also wondering if there’s a way you can test them with a multimeter?

I’m still trying to diagnose my continual misfire. Suspicions are starting to point to a bad o2.

Also I was looking at how much Ducati want for new ones 😰. What’s the general thoughts on just removing them and blanking them off.
 
You need to disable them in the ecu or get the plugs to fool the ecu into thinking they're still there. You can remove the cat then too.
 
Yeah was thinking about getting the bypass plugs also (certainly cheaper than the £240 Ducati want for a new o2). Only problem I’m running a power commander with auto-tune module and o2 piggyback. So unknown what the bypass plugs would do to the tune.

I done some research today and it’s very easy to test if the heater circuit has went bad, so I’ll get that done tonight. Little bit trickier to test the signal as I’d either need a vampire probe to get past the insulation or go over OBD2 which means buying a specific cable.

Could be the actual power commander has failed (shows a power on light at least). Anyway it needs a major service next year so if the problem is persists I’ll leave it for the mechanic to look at.
 
Afaik those bypass plugs are just a resistor so will probably do very little to adversly affect the pc since the value would be constant optimal value unlike the variable resistance of the sensor. If you"ve got aftermarket cans which most using those bypass plugs do then the sensor is redundant pretty much anyway. Getting the cables and jpdiag is worth doing anyway as its useful for other fault finding.
 
Ah that does make sense.

I’ll do this test tonight to see if the heating element is gone. Then I’ll use it this weekend see if it runs better (it won’t). Then I’ll have to dust off the streety while I source the cable, and a vampire probe to do a complete check on the o2 sensors.

If one or both are bad then o2 bypass it is, if both are good then that’s a head scratcher. Maybe have to completely disconnect the PCV to discount that.

The bypass connectors might get fitted just for the heck of it, another thing removed that can’t go wrong I suppose.
 
Hi James, as you know I run a similar set up with all the noise and emissions stuff removed, including the exhaust valve and the same Remus can…..I was devised on here by Vince (Luddite) that reprogramming the original ECU with a Rexxon (?) flash was the easiest answer…..I think it was Neale at Cornerspeed who did it?
 
o2 sensor heaters tested and good. 12.9ohms each one. The horizontal cylinder is significantly more ‘sooty’ than the vertical. So I’ll need to test the sensor next, then if they’re ok I’ll disconnect the PCV entirely and try that.

If it still misfires then maybe it’s a different issue, valves out of spec or something 🤷🏻‍♂️
 
Thought I might as well post up the photos of both sensors, see if anybody has the same conclusions as me
IMG_2963.webp
Vertical cylinder, metal poisoning from additives in fuel. Sensor probably failed.

IMG_2968.webp
Horizontal cylinder, running rich but not too much worry about. Sensor likely ok.
 
Found the issue…I think 😎

Can anybody explain how bypass plugs work? In my mind I can’t understand how a bypass plug, giving a constant value stops the bike running lean or rich.
 
Last edited:
I’d try bypassing the PC, My experience of piggyback ECUs is they’re often a bit if a bodge compared to a remap. If there’s an easy way to unplug it and test, that should be quick and free. Of course you may have tried this already on a previous thread, given your ongoing hunt for a solution.
 
The values recieved from the sensors are used to offset the base fuel map to make it leaner or richer. The upstream MAP (mass air pressure sensor) is required for normal running, the downstream Lamda O2 sensors just control emissions by maintaining catalytic convertor temperature and are usually bypassed for improve overlean poor low rpm running or exhaust tuning, cat removal etc.
 
Bypass plugs should be here tomorrow so I’ll be able find out very quickly if they cure this misfiring/extreme lean running situation.

After that I’ll put it in to get the tune looked at and tidied up.
 
Fitted both blanking plugs, bike seems to run better on idle at least…can’t get time to give it a proper run atm.

On idle I let it run for circa 20 minutes, got itself up to 2 bars in temp, no throttle input at anytime in the 20 minutes. Only really had the odd ‘hiccup’ and nothing you’d go as far as to say it was a backfire or misfiring. Looks like leaning running is the root cause.

I’ll take it out a proper run when time and weather permits. If the fuel range goes up (maybe circa 100/105 before light comes on) then I’d be comfortable it’s all good.

I’m putting my streety in for tune work next year so I’ll try to prioritise the monster and get the tune looked at ahead of the streety or at the same time, just to get a better understanding of the mapping and what adjustments might need made.
 
I agree three bars, but 20 mins in and it still was at 2 bars and it was after 8pm at night. Felt the neighbourly thing to do was turn it off. 😂😂😂😂😂
 
“Proper run” complete, better with bypass plugs but not “fixed”. Still hiccups and hesitates from time to time but not as bad as before and my mileage has crept up from 80/85 to 95ish before the light comes on.

It’s parked now anyway as my steering head bearing is a goner so I’ll fix that and slowly work through this hiccup issue.
 
Last edited:
You must log in or register to reply here.
Back
Top