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Discussion Starter #1
Hi guys

I am guessing that maybe my temperature sensor sender unit is gone bad. This will be a bike shop job as my electrical skill is far less than my already minimal mechanical skills!
I can only do very basic maintenance stuff.

My battery is a near new grunty Yuasa lead-acid job with extra amp hours cold cranking, the battery is plugged into an Optimate 3 charger when not ridden. I have been running the "Julian" tune for years now and have a Trident stubbie can and stock air cleaner.
Normal operating temp on the open road is anywhere between 80C - 100C depending on circumstances.
In heavy traffic or idling on a hot day will get up to 103- 104 with fan kicking in till this drops several degrees
I live in a sub-tropical climate temp ranges from 0 C - 45 C with very high humidity.

Symptoms;
  • Bike starts quickly absolutely fine, no problems, a couple of cranks and she fires and idles immediately
  • Temp guage reads "Lo" as normal on a cold start idles around 2000rpm to start then drops down a bit
  • Normally idles around 1000rpm -800 rpm I think when warmed up a bit
  • Start riding and the gauge reads Lo then it reads 41 C - 57 C up and down when it should read at least 80 C
  • Over a 1 & 1/2 hour ride in the hills, it went up to 58 C but would then drop down and then read Lo again every now and then go back up to anywhere between 40 & 58 C?
  • The other gauges read fine, speedo, odo, etc all working normally
The engine seems to run fine but I am worried if the gauge is sending incorrect data to the ECU making the fuelling/air mixture changes associated with low temps and then running rich etc. as well as just being annoying for me reading the wrong temperature on the gauge.

Any ideas from your clever electrical types??

Thanks in advance
DaveM.................. the very non-electrical motorcyclist :rolleyes::unsure:
 

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The gauge isn't sending info to the ECU, the temp sendor is doing that. The sendor can be tested for resistance at cold and operating temps to see if within parameters. I believe a reference voltage goes to the sendor and then outgoing changed voltage goes back to the ECU and the ECU has mapping to use the info for fuel/air management. You may just need a new sendor if the engine seems to respond properly. I suppose the gauge could be at fault or maybe wiring/connectors to it. A service manual should provide the resistance values for the sendor at various ºC that you could check with a meter. Not too complicated.
 

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Discussion Starter #3
The gauge isn't sending info to the ECU, the temp sendor is doing that. The sendor can be tested for resistance at cold and operating temps to see if within parameters. I believe a reference voltage goes to the sendor and then outgoing changed voltage goes back to the ECU and the ECU has mapping to use the info for fuel/air management. You may just need a new sendor if the engine seems to respond properly. I suppose the gauge could be at fault or maybe wiring/connectors to it. A service manual should provide the resistance values for the sendor at various ºC that you could check with a meter. Not too complicated.
Thank you Felony

that sounds logical to me:)(y)
 

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Make sure the connection to the sender is secure. Easy to get to on the Daytona as it's just below the 'stat housing on LHS of the cyl head. Also worth checking you've not lost any coolant. If the temp sender isn't completely immersed at all times the temp won't read accurately. Oh, and a fresh radiator cap sometimes works wonders.
 

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Discussion Starter #5
Make sure the connection to the sender is secure. Easy to get to on the Daytona as it's just below the 'stat housing on LHS of the cyl head. Also worth checking you've not lost any coolant. If the temp sender isn't completely immersed at all times the temp won't read accurately. Oh, and a fresh radiator cap sometimes works wonders.
Thank you Terry

I'll have a squizz at that.
 

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Discussion Starter #6
Thank you Terry

I'll have a squizz at that.
Update...

Coolant level is normal (Motul blue stuff), wires to sender unit visually ok, booked into the shop to further investigate likely faulty sender unit or maybe like you suggest Terry a dodgy wire?

It's not spitting out coolant so unlikely to be a worn-out radiator cap in this instance I think. But I am no expert in these things.

Thank you all.
Cheers
DaveM:)

PS I am missing our good emojis :(
 

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Several years ago my Daytona 955i started idling fast, at about 2000rpm. I changed the idle control stepper valve, no change. This was before TuneECU was available, or I could have tested the valve, but I could hear it stepping when I turned the ignition on and off. The hoses to the valve were all OK, but have been known to split. I could not think of anything else that would cause fast idling. Then I glanced at the temperature on the instrument panel and saw it read 45 degrees C. I don't know why I didn't notice this earlier. As DaveM said, it normally runs (after warming up) anywhere between 88C (thermostat opening temp) to about 105C. The radiator fan is set in the ECU to start the fan at 103C and stop it at 101C.
So I replaced the coolant temperature sensor, 100% fix. The cause of the fast idling was then obvious, the ECU thought the engine hadn't warmed up to 50C or so, when the fast idle drops to normal.
IanB
 

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Discussion Starter #8
Several years ago my Daytona 955i started idling fast, at about 2000rpm. I changed the idle control stepper valve, no change. This was before TuneECU was available, or I could have tested the valve, but I could hear it stepping when I turned the ignition on and off. The hoses to the valve were all OK, but have been known to split. I could not think of anything else that would cause fast idling. Then I glanced at the temperature on the instrument panel and saw it read 45 degrees C. I don't know why I didn't notice this earlier. As DaveM said, it normally runs (after warming up) anywhere between 88C (thermostat opening temp) to about 105C. The radiator fan is set in the ECU to start the fan at 103C and stop it at 101C.
So I replaced the coolant temperature sensor, 100% fix. The cause of the fast idling was then obvious, the ECU thought the engine hadn't warmed up to 50C or so, when the fast idle drops to normal.
IanB
Thanks, Ian

I had those hoses replaced a few months ago due to a strange noise I posted about, the Triumph senior tech heard it and said straight away what it was!

I think you guys are all confirming what I thought, sender unit buggered.
 

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I looked in the Triumph and Haynes Manuals, but don't see a resistance or voltage spec for the sensor. Part number T2100807. For less than the cost of an hour's workshop labour I'd just replace the sensor. You don't need to drain the coolant, but have the new one ready to insert when you withdraw the old one.
IanB
 

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Discussion Starter #10
Several years ago my Daytona 955i started idling fast, at about 2000rpm. I changed the idle control stepper valve, no change. This was before TuneECU was available, or I could have tested the valve, but I could hear it stepping when I turned the ignition on and off. The hoses to the valve were all OK, but have been known to split. I could not think of anything else that would cause fast idling. Then I glanced at the temperature on the instrument panel and saw it read 45 degrees C. I don't know why I didn't notice this earlier. As DaveM said, it normally runs (after warming up) anywhere between 88C (thermostat opening temp) to about 105C. The radiator fan is set in the ECU to start the fan at 103C and stop it at 101C.
So I replaced the coolant temperature sensor, 100% fix. The cause of the fast idling was then obvious, the ECU thought the engine hadn't warmed up to 50C or so, when the fast idle drops to normal.
IanB
Thanks, Ian

I had those hoses replaced a few months ago due to a strange noise I posted about, the Triumph senior tech heard it and said straight away what it was!

I think you guys are all confirming what I thought, sender unit buggered.
 

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Part number T2100807. For less than the cost of an hour's workshop labour, I'd just replace it. No need to drain the coolant, just do the swap quickly.
IanB
 

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Discussion Starter #13
Thanks Ken

I am not that electronically minded nor t=do I have the equipment but good information for future for other readers with more ability than I do (y)
 

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Multimeters that can measure voltage, amps and resistance are very inexpensive. The procedure is very simple if you want to dip your toe in the waters. Happy 2020.
 

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If you have a meter that measures resistance Dave, pull off the connector on the temp sender (on left side of Cyl head, just next to the thermostat housing/hose elbow) - measure with your probes between the two terminals on the sender - when engine is cold, it should read ~ 2.5K ohms
Plug it back in and warm up engine - repeat process and check again - it should now read ~ 200 ohms

You can also remove the sender from the head - measure the resistance across the terminals - again cold, it should be ~ 2.5K; then drop it into boiling water (100 C) - remove and measure again - you should now be in that 200 ohm range (maybe even slightly less)
That will tell you whether you have a sensor issue, or a problem that the coolant is not properly surrounding the sender and reflecting the temperature of it.
If you DO get those values, it says the sender itself is working properly
 

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Hi guys an old post I know but I'm having the same problem after a rebuilding the bike, not engine that stayed in one peice :)

I turn on the ignition and the fan is off as soon as I press the start button the fan kicks in. The temp gauge reads low all the time

I've swapped the sensor and tested both sensors they both read 2.5k cold and 300ish sat in boiled water from the kettle

Radiator gets hot on the left but is luke warm on the right, I've followed the bleed/burp procedure I found on here

How did you fix your issue DaveM

2000 Sprint rs

thanks
 

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So I've ran some tests and I have +12v going to the sensor and checked the yellow/red wire for continuity between the sensor and the ecu plug and I'm getting a reading so there's no breaks in the wire which is really what I was hoping for

TuneECU give me code p0118 which suggests a broken wire or something but all seems ok

Engine light is on all the time


It starts and runs fine although I've not been out on the road with it yet
 

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So I've ran some tests and I have +12v going to the sensor and checked the yellow/red wire for continuity between the sensor and the ecu plug
This one simple - the yellow/red wire does not go to the Temp sensor, it goes to the Purge Valve which is only utilized on California bikes with Fuel Vapour Emissions Control

The Temp Sensor has Pink/Black (sensor ground) and Pink/Green wires.
 

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so I've no idea where the plug is for the temp sensor then as no other plug reaches the temp sensor
 

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Should be in about the same location - on your 00 Sprint RS, the temp sensor is located in the cooling elbow coming on the Left Side of Cylinder head and that harness/connector should come from behind there (the one with the Yellow/Red wire comes from the same sub-harness that supplies the Injectors and is part of the main engine sub-harness that comes via the large connector - the temp sensor comes directly from the ECU, not through that engine harness connector
The other sensors that share common sensor-wiring with that harness are the TPS and Intake temp sensors (make sure you don't have the latter confused with the coolant temp sensor also - that one should have Pink/Black and Pink/Orange wires. All three of these (purge valve, IAT and coolant temp) use the same Junior Timer type connectors
 
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