Our forum is really a great stable for ZMR owners and almost anything related to ZMR are found here. Thanks to everyone for building such a strong database.

Now coming to my issue, I had a trip from Chennai to Bangalore on this weekend, while returning and when I was half a kilometre away from my home, noticed the PGM Fi started blinking. (2long 1 short), the light stayed on continously when throttle input was given, and blinked when kept idle. Though, engine was running without issues and so I reached my home safely. Next day after surfing in our beloved forum, got to know that there is an issue with Lambda Sensor. On observing my ZMR, I noticed that the wire was cut and was dangling there. I stilled used the bike in the same condition today and thought of fixing it in the evening.
Here comes the twist of the tale, with lambda sensor disconnected, I have observed the following changes in my ride.

1. RTMI figures went up by minimum of 10-15 kmpl for every RPM - gear relations than the normal observation. Ex. @65kmph, RTMI was 70 kmpl
2. Throttle response at low end was better and smoother idling.
3. No change in engine heat dissipation level (remains same as when lambda was connected)

Note: Rimula R3 is currently doing the duty and these above changes are observed after 1800 kms with Rimula R3, a long ride (780kms) and lambda sensor got disconnected.

Now I am wondering whether I need to connect back the sensor or to keep it as such.
@Divya Sharan, @psr sir, @rreneav1987 any suggestions?

From my understanding, the lambda sensor is the O2 sensor and it helps to measure the concentration of oxygen remaining in the exhaust gas to allow an Power Control Module to control the efficiency of the combustion process in the chambers... which definitely mean it could be the reason for the low FE.

Now that said, I might have to see how the condition of my bike's O2 sensor is. i am getting less FE than how it used to give 6 months back..

I guess you have conceived my issue the other way. I am observing way more efficiency than what I used to see earlier.

When the lambda sensor not on its role, the system would run richer which should only bring down my vehicle's efficiency level. But it's happening inversely.

I guess you have conceived my issue the other way. I am observing way more efficiency than what I used to see earlier.

When the lambda sensor not on its role, the system would run richer which should only bring down my vehicle's efficiency level. But it's happening inversely.

I guess you have conceived my issue the other way. I am observing way more efficiency than what I used to see earlier.

When the lambda sensor not on its role, the system would run richer which should only bring down my vehicle's efficiency level. But it's happening inversely.

With the O2 sensor not in the ECM's sensing, ECM will automatically go into open loop mode....The ECM had already learned your driving habit, and so it will be present inside the ECM memory...so using that the ECM is calculating the AFR for a given throttle position and RPM...Since the wire seems to have got cut while returning on a long journey, ECM has That run in it's memory and using it....
If the battery gets disconnected, then all of this memory will be lost and ECM will start using the Standard OE preset settings....hope this is helpful..

But what about the increase in mileage? He claims almost 12 kmpl increase!!

RTMI increase is irrelevant as it just shows the average FE on the last 8 seconds of riding pattern and it keeps on cycling every 8 seconds. I sometimes see 199 kmpl (yes you read it right!). [emoji14]
RTMI = real world mileage only on the highways with a steady riding pattern.

Real world mileage if increasing drastically might sadly link to a fuel pump failure about to happen soon. I've seen everyone reporting an increased FE by 7-10 kmpl a few months before the pumps died.

RTMI increase is irrelevant as it just shows the average FE on the last 8 seconds of riding pattern and it keeps on cycling every 8 seconds. I sometimes see 199 kmpl (yes you read it right!).
RTMI = real world mileage only on the highways with a steady riding pattern.

Real world mileage if increasing drastically might sadly link to a fuel pump failure about to happen soon. I've seen everyone reporting an increased FE by 7-10 kmpl a few months before the pumps died.

Thanks @psr sir & @Divya Sharan for your inputs.

@psr sir: But, how is that even possible that the ride has become a lot more smoother? Is it due richer fuel mixture as the vehicle is always in open loop mode? Will it be a problem in the long run if this O2 sensor is not connected to system?
Any problem to fuel pump?

I assume that ZMR is always on closed loop since, the current behavior of the bike, be its fuel efficiency or engine smoothness, it all got changed at any given level of throttle inputs. Is my observation correct?

@Divya Sharan: I have observed this increased KMPL during my daily office commute for the past three days which itself is on highways. So, the given figures are found during steady throttle inputs only. Even I have observed the 199KMPL stuff so many times and I have an understanding of how this RTMI figure fluctuates, but I am sure that is not the current case here.

Guys, is the ZMR BS-IV compliant?
I'm made to believe that all FI engines are BS-IV. Is that correct?

So ZMR is not BS-IV compliant?

So ZMR is not BS-IV compliant?