1100GS oil temp sender - where is it fitted?

(RIP) Yamaha1

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In an effort to cure the seemingly common rich mixture syndrome on my '99 import cat-equipped 1100, I have replaced the oxygen sensor on the exhaust box - but the CO mixture is still high at about 5.0.

I saw that others have said that the oil temp sensor could be the fault, so I have ordered one from Motorworks - but where on the bike is it fitted, please?
Despite searching the fiches and workshop manual, I can't see where on the engine it's fitted!!

Any help most appreciated, folks.

Mike
 
I replaced mine last week, its on the top of the engine right hand side, the connector is dead centre, I used a 19mm flare nut spanner, its easy to see but hard to get a spanner on, its the brass one :thumb2
Stewart
 
If its like the 1150,its at the top of the offside of the motor near where the pipe to the oil cooler goes.
Do you have the RID with the oil temp indicator in it and does it show about halfway up when the motor is warm?.
If the sensor is telling the ECU that the oil,therefore engine temperature is low,the ECU may be telling the fuel injection to pump extra fuel into the motor all the time;hence higher fuel consumption.
May be worth checking the basics though.Air filter,plugs,TPS voltage all OK?.
I guess you cant adjust a mixture control pot(fitted to earlier 1100s) to set the CO2.If you have an O2 sensor fitted-it should do it automatically.
 
If the sensor is telling the ECU that the oil,therefore engine temperature is low,the ECU may be telling the fuel injection to pump extra fuel into the motor all the time;hence higher fuel consumption.

Wouldn't the "choke" lever do that? Just asking as my 1100 doesn't idle at the same speed as when the "choke" is applied, and sometimes the engine stalls when cold.
 
Wouldn't the "choke" lever do that? Just asking as my 1100 doesn't idle at the same speed as when the "choke" is applied, and sometimes the engine stalls when cold.

What you call the 'choke' is just a fast idle control - all it does is raise the idle speed a bit to help the engine when it's cold. It has no effect on the mixture at all. Mixture is controlled by the ECU taking into account readings from various sensors including the oil temperature sensor. When the engine's cold the mixture will be made a bit richer than normal but of course the ECU can't control the idle speed on such a basic system, hence the provision of a fast idle control for the rider to do that him/herself.
 
It doesn't matter what you call it - you were saying that using it tells the ECU to pump in more fuel which isn't right. :rob

It causes more fuel to be added ....

So you have the "choke" and the oil temp sensor causing more fuel to be added? Why doesn't it just need the oil temp sensor input? Or doesn't the oil temp sensor input give enough extra fuel for stone cold engines, only partly cold ones IYSWIM/
 
It causes more fuel to be added ....

No it doesn't - it causes the throttle to be open slightly more. Exactly the same as if you held it open slightly with your right hand. It has no effect on the fuelling at all. Oh, OK, if you want to be pedantic opening the throttle slightly does allow more fuel to be injected but only along with more air being drawn in. Put it another way - the fast idle control has absolutely no effect on the mixture (a/f ratio).

So you have the "choke" and the oil temp sensor causing more fuel to be added? Why doesn't it just need the oil temp sensor input? Or doesn't the oil temp sensor input give enough extra fuel for stone cold engines, only partly cold ones IYSWIM/

The 'choke' (fast idle control) opens the throttle a bit to help the engine run when it's cold and the signal from the temperature sensor causes the ECU to make the mixture richer when the engine's cold. There is no overlap between their functions.

On a more sophisticated injection setup (e.g. on the 1200GS and just about any other injected car/bike) the ECU has control over the idle speed too so it performs both functions - makes the mixture richer and increases the idle when you first start the engine from cold. But the 1100/1150 system is very basic and doesn't have idle control, which is why they gave you the fast idle lever to do it yourself.

The reason why you will be corrected if you call it a choke is that on a carb'd engine the choke performs both functions - makes the mixture richer and increases the idle speed - but on 'our' bikes the lever increases idle speed only.
 
:nenau Maybe they called it 'choke' so people knew what to do with it?

But the choke/fast idle lever pulls on the throttle mechanism and nothing else - it can't affect the mixture.
 
Thanks for that info, guys - will have a butchers for it tomorrow.

I thought replacing the exhaust oxygen sensor would cure the problem - it does seem slightly better, ie, not so much soot on the silencer outlet - but maybe this oil temp sender will do the trick.

Its starting to get to the stage where it would be cheaper to pay the extra on the fuel, rather than the cost of changing much more trying to cure it...........!!!

Mike
 
Yes, Drosselklappe doesn't quite have the same ring to it, does it? :D

PS Before any German speakers say that Drosselklappe isn't a direct translation for choke, that's the best that Babelfish could come up with!
 
Common usage - everyone knows what to do with a 'choke'. Even if it doesn't do what traditional chokes do (i.e. restrict the air intake to richen the mixture on carb engines) the effect / when to use it are the same.

Because our engines use batch injection, the first injection 'shot' which happens at TDC compression has to hang around in the inlet tract and wait for the next shot and the intake stroke. Most of this first shot plates onto the inlet tract walls and doesn't 'unstick' as effectively on a cold engine (most of it is vapourised on a hot engine). This is why cold engine running can be a bit fluffy until the head has warmed and why raising the idle speed (which is effectively what our choke does) helps.
 
I thought they called it a 'choke' just to start interminable threads about how it works :D

To get back to the original point, changing the oil temperature sensor on my bike (albeit an 850GS) helped cure the rich running. In my case though, I also ended up changing the potentiometer (adjusting the original one had no effect) and re-setting the TPS. By the way, I believe that there are two sorts of oil temperature sensors; one is secured by a large gland nut, the other by two small allen screw, if I recall correctly. I have one of each type; I believe it depends on the year of the bike, the earlier bikes having the gland nut, but I might be wrong.

Regards
 
I thought they called it a 'choke' just to start interminable threads about how it works :D

To get back to the original point, changing the oil temperature sensor on my bike (albeit an 850GS) helped cure the rich running. In my case though, I also ended up changing the potentiometer (adjusting the original one had no effect) and re-setting the TPS. By the way, I believe that there are two sorts of oil temperature sensors; one is secured by a large gland nut, the other by two small allen screw, if I recall correctly. I have one of each type; I believe it depends on the year of the bike, the earlier bikes having the gland nut, but I might be wrong.

Regards

the helpful chap at Motorworks told me that the oil temp sensor is common with some of the other K series bikes too where its a water temp sensor, still feeding its info to the Motronic though, on my 97 1100 it was a brass hex nut. I am not sure whether this sensor makes the oil temp on the RID work as well, because that always worked fine.
Stewart
 


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