[Narada]

So, if the oil temp sensor is enriching the air fuel mixture properly, what is causing the momentary hesitation, stumble, sputter, which occurs only for the first few miles, only during cold weather?  This while rpm are up but more throttle is applied.

Modern fuel injected automobiles run flawlessly when cold.  Why not my RE?  It doesn't seem like a fast idle alone could make this difference.

[Narada]

Oops, I'm a dumbsh#t!  I am running the PC-V with no O2 sensor! 

[SteveThackery]

So, if the oil temp sensor is enriching the air fuel mixture properly, what is causing the momentary hesitation, stumble, sputter, which occurs only for the first few miles, only during cold weather?  This while rpm are up but more throttle is applied.

Modern fuel injected automobiles run flawlessly when cold.  Why not my RE?  It doesn't seem like a fast idle alone could make this difference.

I don't know why yours has that hesitation, but be assured that this is not common to all our Bullets.  If they all did it, Keihin would never have signed off on the job.  I think there is something specific to your bike that is causing the problem (indeed, it may be common to several of our bikes, because Indian QA hasn't caught up with the West, yet).

Mine went through a phase of misfiring and generally misbehaving which seemed to be related to engine temperature, but it just disappeared one day before I got to the bottom of it.  It's been perfect since.

None of this has anything to do with the "bi-starter", though, which you're only supposed to use for 30 seconds and which is just a fast idle device.

[Rattlebattle]

In the end I refitted the O2 sensor to my C5. I've now tested it and found it runs better than with the eliminator fitted. I had a look at the spark plug. While still having a sooty rim the electrodes are a much lighter shade than they were. On balance I have decided to keep the O2 sensor; I feel it ran too rich with the eliminator fitted, though it's still too rich at tickover.

[malky]

So, if the oil temp sensor is enriching the air fuel mixture properly, what is causing the momentary hesitation, stumble, sputter, which occurs only for the first few miles, only during cold weather?  This while rpm are up but more throttle is applied.

Modern fuel injected automobiles run flawlessly when cold.  Why not my RE?  It doesn't seem like a fast idle alone could make this difference.

If it's any consolation, mine does exactly the same, three miles running from cold and it's gone so it doesn't bother me.

In the end I refitted the O2 sensor to my C5. I've now tested it and found it runs better than with the eliminator fitted. I had a look at the spark plug. While still having a sooty rim the electrodes are a much lighter shade than they were. On balance I have decided to keep the O2 sensor; I feel it ran too rich with the eliminator fitted, though it's still too rich at tickover.

Interesting outcome, and appreciated info.

[motorato]

In the end I refitted the O2 sensor to my C5. I've now tested it and found it runs better than with the eliminator fitted. I had a look at the spark plug. While still having a sooty rim the electrodes are a much lighter shade than they were. On balance I have decided to keep the O2 sensor; I feel it ran too rich with the eliminator fitted, though it's still too rich at tickover.

I'm very interested in this simple mod, but it seems the eliminator is making the mixture to rich, one reason I haven't bought the eliminator on ebay
until I read the explanation from Markku, that the resistor is to weak for the open loop intended with this eliminator.
I'm tempted to try and do one myself

Hello Sir´s
In the attachment i´ll try to explain the same as SteveThackery on April 12. Only difference is the sensor resistance when hot (<2 ohms). I have found no other source to confirm this.
The internal resistance of the sensor is about 10 k ohms, when hot, but it refers to voltage generator properties. This can be used as Freddy1 connecting 2 k ohms resistor parallel to the sensor. Voltage  will be about 1/5 times the measured. So it will vary between 0.02v and 0.2v.
I have connected 330 k ohms resistor to replace the sensor. The voltage is then constant 5v x 330k/(330k+500k) =2v. This value is low enough to turn the MIL bulb off, but also high enough to keep the system in open loop.
With small resistor value, for example Gremlins eliminator April 22, Reply #143, 46,3 k ohms, the voltage will be about 0,4v. The system will be in closed loop and ECU will try to turn the mixture as rich as possible.
Using zeners instead of resistors; the currents in the system are in micro amperes, maybe not enough for zener to behave ideally ("knee current").
I´ll hope that my information is usefull despite of maybe bad translation from finnish to english.

[Rattlebattle]

I get the impression that the eliminator is a generic one rather than one comprehensively tested for the EFI engine.

[Bmadd34]

The weather has turned for the better and I've racked up a few hundred miles running the eliminator. 

I have a 2014 C5 with factory air filter and EFI Classic Silencer from out host. 

I didn't have a "hunting" idle, but did have a weird flat/dead spot in the rev range, especially in the middle RPM range and a occasional stall when not up to operating temp.  Both of those are now gone. 

My butt dyno seems to think that my bike seems to have a more crisp and even throttle response throughout the rev range. 

 Fist picture is my plug after installation and about 300 miles on it.  2nd picture is what the plug looked like prior to installation.

Is it just me, or does it appear the o2 eliminator plug actually LEANED the mixture? The plug is definitely lighter in color.
 

[longstrokeclassic]

Quite Possibly.  Have you checked your TPS output readings? Without the lambda sensor you have no means of electronic correction. Only manual.

[Bmadd34]

Quite Possibly.  Have you checked your TPS output readings? Without the lambda sensor you have no means of electronic correction. Only manual.

Manually?? you mean idle?

[Blairio]

If it's any consolation, mine does exactly the same, three miles running from cold and it's gone so it doesn't bother me.

Interesting outcome, and appreciated info.

My bike used to be like this - a bear with a sore head until it had warmed up.  Then my decompressor actuating pin broke and I had to replace it.  Following this, things improved somewhat, but what finally solved the problem (not intentionally!) was fitting the high level Hitchcock exhaust.  The bike now starts off the button or first kick, idles evenly, and pulls away smoothly after being left to tick over for a minute or so.

I can only imagine that the characteristics of the high level exhaust are a good match for whatever my EFI unit is doing when the engine is cold.

[longstrokeclassic]

Manually?? you mean idle?

Manually repositioning the TPS unit, then adjusting the bleed screw for a sensible idle  

I've set mine at the sweet spot in the fuel map located just at the point before the stall out changes occur - the map runs very rich at lower revs to prevent stalling, probably rich enough to wash oil off the cylinder wall. Not a good place to be   It's possible to detect an audible change just as you enter and leave this very very small sweet spot.

This is my current plug as it is now after remaining untouched in the bike for around 27,000 miles, it's actually done just over 27,500...


and this is how the stock plug looked with factory fueling - which reminds me I must treat the bike to a new plug soon!


The bike has recently been fitted with an 18 tooth front sprocket which is plus one over stock and whereas the bike used to hit the rev limiter as a GPS indicated 83mph (85 on the clock) it will now exceed that speed (on the standard exhaust system) but I have no intention to hold it at WOT long enough to see if it'll hit the limiter once again and Henstridge Runway certainly isn't long enough and I also have fears for the integrity of the standard exhaust valve 
 
When running with factory set fueling the bike required a long down hill stretch to even get close to reach its designed speed. Adjusting the fueling to see what could be achieved was just an exercise in inquisitiveness more than anything else. Minor no cost tweaks such as aligning the injector spray into the throat instead of at the inlet wall as well as indexing and side gapping the plug help a little as well as smoothing out the idle. The rest of the engine - decompressor removal aside - is just how it left the factory.
With different fueling the engine runs far better than stock - the increase in top speed is simply a byproduct of a far more satisfying bike to ride at normal speeds around country lanes. 

[Bmadd34]

Manually repositioning the TPS unit, then adjusting the bleed screw for a sensible idle  

I've set mine at the sweet spot in the fuel map located just at the point before the stall out changes occur - the map runs very rich at lower revs to prevent stalling, probably rich enough to wash oil off the cylinder wall. Not a good place to be   It's possible to detect an audible change just as you enter and leave this very very small sweet spot.

This is my current plug as it is now after remaining untouched in the bike for around 27,000 miles, it's actually done just over 27,500...


and this is how the stock plug looked with factory fueling - which reminds me I must treat the bike to a new plug soon!


The bike has recently been fitted with an 18 tooth front sprocket which is plus one over stock and whereas the bike used to hit the rev limiter as a GPS indicated 83mph (85 on the clock) it will now exceed that speed (on the standard exhaust system) but I have no intention to hold it at WOT long enough to see if it'll hit the limiter once again and Henstridge Runway certainly isn't long enough and I also have fears for the integrity of the standard exhaust valve 
 
When running with factory set fueling the bike required a long down hill stretch to even get close to reach its designed speed. Adjusting the fueling to see what could be achieved was just an exercise in inquisitiveness more than anything else. Minor no cost tweaks such as aligning the injector spray into the throat instead of at the inlet wall as well as indexing and side gapping the plug help a little as well as smoothing out the idle. The rest of the engine - decompressor removal aside - is just how it left the factory.
With different fueling the engine runs far better than stock - the increase in top speed is simply a byproduct of a far more satisfying bike to ride at normal speeds around country lanes.

Not really understanding. You manually reposition the TPS? Explain.

[Blairio]

Edit - Blair removed this post as it was intended for another thread. Doh!

[longstrokeclassic]

https://www.youtube.com/watch?v=TiX8oFtYZls

TPS output voltage is set at 0.6 +/- 0.2.

If you set the TPS voltage closer to 0.4V the bike runs weaker, closer to 0.8V and it runs richer.  IIRC  0.72V is the preferred powaaarh option,  with 0.61Volts being the optimal setting for the system itself.