Throttle position sensor

Araitim · Sep 13, 2018

krolinked said:
What's needed to remove the sensor leads? I have rapidbike Evo. Would like to disconnect the sensors but what else do I need to do?

Rapidbike said to disconnect the actual plug that gos from the sensor to the rapidbike wiring(not the plug that connects from the rapidbike into the main wiring harness) and the bike will default into 'open loop'. In the instructions it talks about doing this too but you need to turn off autotune. The bike will be folded into thinking the target air fuel ratio is on point but the bike will no longer detect a sensor. It runs great now with the sensor unplugged, the Kul map uploaded and the autotune off. When doing the Kul map he even says to disable the autotune(if I remember correctly) but leave on "rbo2" to trick the sensors into thinking the target is good. There are many threads where ducati riders solder a resistor across the sensor leads to turn off the dash light but those threads are not for the hyper, so it is a common thing to just unplug and run. You can do what you want to do but eventually I'll replace the sensors. I only have resistance across 2 of the sensor leads and the value changes as I heat the sensor with a heat gun. Both sensors had the same values while testing. This made me think that the sensor were good so I started emailing CA Cycleworks (a common supplier for TPS sensors for the other ducatis) and they say that the likelyhood of the TPS on the hyper being bad is highly unlikely. I explained what all I have done and they concur that the lambda sensors, their wiring or the leads from the sensors through the wiring harness might be the issue (apparently sometimes the sensor wires dont just go strait to the ECU. Sometimes they go up to the display too(I havnt been through that part of the wiring harness yet.

Don't let disconnecting the o2 sensors scare you. The bike will be running a known tune that has had alot of research done to make it ideal(even though that changes slightly from bike to bike it wouldn't be enough if a change to cause catastrophic failure). The original EFI bikes like the honda 929 and early R1 only ran open loop and numerous tuners prefer open loop to get the most power. There are many threads about having rexxer and other stock ECU tuners program them to turn the O2 sensors off just so the dash light gos away and so the maps they upload are uninterrupted.

ferdi · Sep 13, 2018

if it's an 821 and you disconnect o2sensors, bike automatically is in open loop and runs much better because its only running with its internal maps. only thing is that the yellow engine light is on.

Araitim · Sep 13, 2018

ferdi said:
if it's an 821 and you disconnect o2sensors, bike automatically is in open loop and runs much better because its only running with its internal maps. only thing is that the yellow engine light is on.

That's what I'm saying. I have a tendency over explain.

appliance821 · Sep 13, 2018

So your saying the internal maps operate in a vacuum. How does the bike know if it starting at sea level on a warm day, or high on a cold mountain. It no longer has air/fuel info to adjust, based on the map, what it's pumping into the cylinders. What happens over time to the cylinder walls, what kind of stress is being placed on the motor?

ferdi · Sep 13, 2018

appliance821 said:
So your saying the internal maps operate in a vacuum. How does the bike know if it starting at sea level on a warm day, or high on a cold mountain. It no longer has air/fuel info to adjust, based on the map, what it's pumping into the cylinders. What happens over time to the cylinder walls, what kind of stress is being placed on the motor?

all other sensors are still active, only regulatiuon in closed loop to (nearly) lambda 1 is off.
o2sensors do not messure airpressure, temp or whatever else.
internal maps have corrections to airpressure, temperature, enginetemp ....
the only reason for o2sensors is "clean" exhaustfumes, which are not good for a good and healthy running bike.

appliance821 · Sep 13, 2018

ferdi said:
all other sensors are still active, only regulatiuon in closed loop to (nearly) lambda 1 is off.
o2sensors do not messure airpressure, temp or whatever else.
internal maps have corrections to airpressure, temperature, enginetemp ....
the only reason for o2sensors is "clean" exhaustfumes, which are not good for a good and healthy running bike.

Airpressure etc. affects O2 levels and the bike adjusts the fueling based on those levels. Much of riding is done in the closed loop mode - idle and cruising - and the efi reacts to and adjusts based on the sensor readings. Do what you like etc.., but in my book the starting and warming of an engine is a critical stress time for the motor, and I'd want the correct AFM, and if it helps with clean emissions too- I'm all for it.

ferdi · Sep 13, 2018

appliance821 said:
Airpressure etc. affects O2 levels and the bike adjusts the fueling based on those levels. Much of riding is done in the closed loop mode - idle and cruising - and the efi reacts to and adjusts based on the sensor readings. Do what you like etc.., but in my book the starting and warming of an engine is a critical stress time for the motor, and I'd want the correct AFM, and if it helps with clean emissions too- I'm all for it.

you are right, but its more healthy for an engine to run rich than lean. and o2 regulations leans out air/fuel ratio to lambda1, which is not really healthy, for any engine.
cars and bikes do not have wideband o2sensors, but only narrowband, which are only able to read air ratios richer or leaner than lambda1. so it always changes ratio leaner leaner leaner - ok - richer -ok - leaner .... so that ratio always is in the near of lambda 1.
if you use a wideband sensor, than you exactly can manage air/fuel ratio for load and rpm, but that's not the case with our bikes. They only have very simple narrowband o2sensors.

but, if you do not know about it und do not believe it - do what you feel is right in your opinion, but please do not tell technicians how engines and fuel injections work and whats good for them.

Araitim · Sep 13, 2018

Like Ferdi said. Look at all the sensors that are still in play. Many tuners and race teams opt to remove the o2 sensors and tune based off of a wide band sensor as opposed to an on/off narrow sensor. Here is a nice diagram of the wiring and the sensors

Sent from my SM-G955U using Tapatalk

mentalist · Sep 14, 2018

if the engine doesn't detect the sensors when the sensors are disconnected, it defaults to running in safe mode, not necessarily optimum running mode. That's why the bike runs better.
Same as a mass air flow meter, if they are faulty, cars tend to run like a bag of *****, but disconnected puts them in default safe mode, so the engine does run better, but it again not at its best.
In simple terms, if disconnecting your lambda sensors makes your bike run better, you know one or both need replacing. Don't just rely on the safe running mode by leaving them off.
If the Rapid Bike didn't need these O2 signals then it would have come with blanking plugs like a power commander 5.

gatdammit · Sep 14, 2018

I know from initial research that the Auto Tune function definitely uses O2 input.

Araitim · Sep 14, 2018

mentalist said:
if the engine doesn't detect the sensors when the sensors are disconnected, it defaults to running in safe mode, not necessarily optimum running mode. That's why the bike runs better.
Same as a mass air flow meter, if they are faulty, cars tend to run like a bag of *****, but disconnected puts them in default safe mode, so the engine does run better, but it again not at its best.
In simple terms, if disconnecting your lambda sensors makes your bike run better, you know one or both need replacing. Don't just rely on the safe running mode by leaving them off.
If the Rapid Bike didn't need these O2 signals then it would have come with blanking plugs like a power commander 5.

Instead of a blanking plug the just have a button to check when uploading the map. It recommends having the ecu reprogrammed to disable the o2 sensor though. I know that I should replace them and I will but I am running the bike with them unplugged till then

Sent from my SM-G955U using Tapatalk

mentalist · Sep 14, 2018

So have I solved your problem then from your original post. You where under the impression that the throttle position sensor was at fault???

Araitim · Sep 14, 2018

mentalist said:
So have I solved your problem then from your original post. You where under the impression that the throttle position sensor was at fault???

Gotham cycle has ruled out the TPS on the throttle bodies as well. What would you say the issue is then? My thought is that the o2 sensors are the defective pieces causing my problems and that is why the bike runs good with them un plugged. Gotham cycle(the main trouble shooting and supplier of most ducati sensors fir the other bikes) also suggested that it could be a faulty connector elsewhere in the wiring but the only connector that is between the rapidbike wiring harness and the sensor is the sensor itsself.

Sent from my SM-G955U using Tapatalk

mentalist · Sep 14, 2018

Have you checked the resistance? also check the wiring back to the rapid bike evo module.

Araitim · Sep 14, 2018

mentalist said:
Have you checked the resistance? also check the wiring back to the rapid bike evo module.

I have. The resistance between pin 1 and 2 (out of the 4 pin connector) is 17ohm and when heated up jumps to 21ohm. The rest of the pins have no continuity between them. Both sensors have the same reading. I swapped them front to back to see if it made a difference but it didnt. I went through every connector on the bike when I cut the wiring harness open. I cut a razor blade down to fit into each of the female connectors. I also thinned the blade using my cut off wheel. It made a cross hatch pattern on both surface. The idea was to make something that would clean the female connector without over extending the connector past the point that the Male portion would do but still be able to feel the resistance of the blade and clean the contact. I did this with every female connector including the ecu plugs. I have been very through with this. Rapidbike and gotham cycle said to make sure there is continuity through each pin of the connector while its plugged in. I soldered needles onto my fluke meter and slightly penetrated the sheath of each wire to assure there was continuity on both lambda o2 sensors.

What did you think solved my problem from the original post? I mentioned that I had it (potentially narrowed down) to the o2 sensors through extensive test, cleaning and rewiring.

mentalist · Sep 14, 2018

I think it would be unusual for both to fail at the same time.
I'm offshore at the moment for another two weeks or i'd measure mine to see what the resistance and voltage changes are so you could compare, its about 14 months since I checked and replaced my front sensor and I can't remember what I had for lunch yesterday ;-), so I don't remember the values.
Have you checked the voltage and that it fluctuates rapidly when lean or rich between 0.1 and 0.9V ?

Araitim · Sep 14, 2018

mentalist said:
I think it would be unusual for both to fail at the same time.
I'm offshore at the moment for another two weeks or i'd measure mine to see what the resistance and voltage changes are so you could compare, its about 14 months since I checked and replaced my front sensor and I can't remember what I had for lunch yesterday ;-), so I don't remember the values.
Have you checked the voltage and that it fluctuates rapidly when lean or rich between 0.1 and 0.9V ?

I have not. I will have to check that. I have not done any tests to the o2 sensors when the bike is running, only bench testing.

mentalist · Sep 14, 2018

I think mine had open circuit on the heating element
Even when hot

fredgilb · Sep 15, 2018

I had intermittent check engine light. I replaced the rear O2 with one from a 821 monster. It's a totally different design but has the same bung size. Upshot is with the Eldor coils & used o2, the bike runs stronger than ever.

Sent from my SM-G930U using Tapatalk

appliance821 · Sep 15, 2018

ferdi said:
you are right, but its more healthy for an engine to run rich than lean. and o2 regulations leans out air/fuel ratio to lambda1, which is not really healthy, for any engine.
cars and bikes do not have wideband o2sensors, but only narrowband, which are only able to read air ratios richer or leaner than lambda1. so it always changes ratio leaner leaner leaner - ok - richer -ok - leaner .... so that ratio always is in the near of lambda 1.
if you use a wideband sensor, than you exactly can manage air/fuel ratio for load and rpm, but that's not the case with our bikes. They only have very simple narrowband o2sensors.

but, if you do not know about it und do not believe it - do what you feel is right in your opinion, but please do not tell technicians how engines and fuel injections work and whats good for them.

Ducati engineers and technicians, or after market part technicians?

Throttle position sensor

Similar threads