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Old 05-15-2009, 07:19 AM   #1
mdfehrmann OP
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TPS Sensor Questions

I searched for this and I'm sure the answer is here but I couldn't find it.
What does the TPS actually do? Does it make adjustments to the timing based on the throttle position?
I have a 06 950 if it makes a difference.

Thanks dudes!
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Old 05-15-2009, 07:47 AM   #2
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deleted post due to uncertainty's still wheter it is actually used beyond emission stuff.
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Old 09-07-2010, 01:31 PM   #3
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950 CARBS, Surging and TPS

FOR 950 CARBS - the Throttle Position Sensor, TPS, sets the ignition advance. The ignition set the advance based on Engine RPM and Throttle Position. This is called a 3D Map, 1. RPM, 2. TPS, 3. Ign Advance.

When you turn on the ignition, the small computer in the ignition looks for a 'referance voltage' to determine if the TPS is in range. The voltage should be 0.5-0.6 volts when the throttle is shut. You should always have the throttle shut when turning on the ignition.

This referance voltage is set at the factory at engine idle. BUT, if the idle is turned down during the break-in period, then the referance voltage may be wrong! You may need to reset the TPS after the engine loosens up and the idle position is different. I've seen several 2006 950 Adventures with a too low voltage of 0.38 v. These had a bad surge around 3000 rpm. Reseting the TPS usually fixed it without re-jetting.

If the ignition doesn't see this voltage during start up, it may not set the advance correctly and you'll get a surge between 2000-3800 rpm. This acts just like a lean carb condition. It can be masked by richening up the carb low speed mixture screws or low speed jets, but you'll get poor mileage and a weak low rpm throttle response. If the TPS is dirty or worn, you can get the same erattic behavior.

The workshop manuals show how to set this. I'd recomend to try a resultant voltage very close to, but below 0.6 v. Check it several times by turning off the ignition and make sure you still have the same voltage when you turn it back on. Make sure it tracks voltage smoothly as you open/close the throttle. Any jumps, dead spots or other flaky action means you need a new TPS.

I did a search for this subject and only found fuel injection subjects. If anyone knows of a thread, please add the link.

(Edited on 2-20-11) .... Check this voltage between the Yellow and Black wire. Some early manuals have it different (blue/yellow) which is wrong. Just push the probes in past the rubber seals to touch the connectors. It is most critical to get the closing voltage between 0.5 and 0.6 v.
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Old 09-07-2010, 02:23 PM   #4
AdvGa
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Zuber,

Thanks for explaining the TPS in such great detail... I was wondering about this.

I found my this wire connection had slipped off the Carb (due to loosening copper connector) last week and wondered just how much it affected the bike without EFI.

Thanks again....
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Old 09-08-2010, 07:41 AM   #5
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This is very timely post for me. I pulled mine off after ridding the bike of the emissions crap and doing a valve adjustment and replacing the carb vents, etc. , and it's smoother but feels slower. That may be an illusion...gonna have to put it back on and set it up properly and see the difference...now that I know how.

Great post...Thanks!

*edit* This really should be added to Wisdom section.
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Old 09-09-2010, 09:18 AM   #6
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Follow up: Yeah, it's definitely slower...doggy. I guess it's not getting any ignition advance? If you give er a handful, it still goes though.

I just re-installed the wire and set it as per Zuber's excellent instructions, with help from the manual on CD. Easier than I thought it would be. One tip though: as the tanks are off the bike, when you turn the key on the pump starts and blows what gas is left in the lines straight up in the air. If you're standing on the left side of the bike like I was...well, it's laundry time anyhoo.

Stand on the right side of the bike when you do this!


Haven't had a chance to ride it yet as the weather sucks here today.
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Old 09-10-2010, 02:04 AM   #7
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Zuber you're a gosh darned life saver :)

I've been chasing a surging problem on my 950 for months now, fiddled with the carbs endlessly, I even checked the TPS.

BUT ...

The repair manual says the TPS should give .5-.6 volts when closed and 3.6 when fully open. Mine seems to have a slightly wider range, so I had guessed that the open voltage was the important one, and set it so that the range was about 0.4 - 3.6. How wrong I was! So now I've adjusted it to give 0.6 closed and about 3.8 open. What an improvement. The surging was not terrible but it was enough to make it very annoying when riding at low speed round town for example.

So thanks for that info :)

Also, the repair manual says measure the voltage between the blue and yellow wires, however on my bike it's the blue and black wires that give this voltage. Mine's an early bike (2004) maybe they were wired differently.
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Old 09-11-2010, 03:37 AM   #8
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Quote:
Originally Posted by Zuber
FOR 950 CARBS - the Throttle Position Sensor, TPS, sets the ignition advance. The ignition set the advance based on Engine RPM and Throttle Position. This is called a 3D Map, 1. RPM, 2. TPS, 3. Ign Advance.

When you turn on the ignition, the small computer in the ignition looks for a 'referance voltage' to determine if the TPS is in range. The voltage should be 0.5-0.6 volts when the throttle is shut. You should always have the throttle shut when turning on the ignition.

This referance voltage is set at the factory at engine idle. BUT, if the idle is turned down during the break-in period, then the referance voltage may be wrong! You may need to reset the TPS after the engine loosens up and the idle position is different. I've seen several 2006 950 Adventures with a too low voltage of 0.38 v. These had a bad surge around 3000 rpm. Reseting the TPS usually fixed it without re-jetting.

If the ignition doesn't see this voltage during start up, it may not set the advance correctly and you'll get a surge between 2000-3800 rpm. This acts just like a lean carb condition. It can be masked by richening up the carb low speed mixture screws or low speed jets, but you'll get poor mileage and a weak low rpm throttle response. If the TPS is dirty or worn, you can get the same erattic behavior.

The workshop manuals show how to set this. I'd recomend to try a resultant voltage very close to, but below 0.6 v. Check it several times by turning off the ignition and make sure you still have the same voltage when you turn it back on. Make sure it tracks voltage smoothly as you open/close the throttle. Any jumps, dead spots or other flaky action means you need a new TPS.

I did a search for this subject and only found fuel injection subjects. If anyone knows of a thread, please add the link.
Nice find!

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Old 09-12-2010, 12:45 AM   #9
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So the conclusion is that carb bikes DO need the TPS after all. Mine is broken, just sits there and give way false readings in voltage, but i cant really tell if the bike runs as it should, all i know is that it runs ok. I can however feel that its not that crisp in the range of 3000 - 4000 rpm. Maybe time to get a new TPS after all....
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Old 09-12-2010, 08:43 PM   #10
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I think so. I ran mine without one at all and it was kinda doggy at lower RPM's, but very smooth - NO throttle jerkiness what so ever. That tells me it was mis-adjusted before...well, I'm sure it was cause I was messing with the idle setting constantly.

Valve adjustment, carb sync, fuel screw adjustment and replacing the vent lines and it's never run better. The idle is consistant now. I put the TPS back on after seeing this post and set it up, and got the low RPM response back without the snatchiness.
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Old 09-23-2010, 12:53 AM   #11
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Quote:
Originally Posted by Zpider
So the conclusion is that carb bikes DO need the TPS after all. Mine is broken, just sits there and give way false readings in voltage, but i cant really tell if the bike runs as it should, all i know is that it runs ok. I can however feel that its not that crisp in the range of 3000 - 4000 rpm. Maybe time to get a new TPS after all....
Please post on here if you notice any fuel economy differences when the TPS is back workign again, I'm interested in this.
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Old 12-04-2010, 05:27 PM   #12
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Quote:
Originally Posted by uk_mouse View Post
Zuber you're a gosh darned life saver :)

I've been chasing a surging problem on my 950 for months now, fiddled with the carbs endlessly, I even checked the TPS.

BUT ...

The repair manual says the TPS should give .5-.6 volts when closed and 3.6 when fully open. Mine seems to have a slightly wider range, so I had guessed that the open voltage was the important one, and set it so that the range was about 0.4 - 3.6. How wrong I was! So now I've adjusted it to give 0.6 closed and about 3.8 open. What an improvement. The surging was not terrible but it was enough to make it very annoying when riding at low speed round town for example.

So thanks for that info :)

Also, the repair manual says measure the voltage between the blue and yellow wires, however on my bike it's the blue and black wires that give this voltage. Mine's an early bike (2004) maybe they were wired differently.

Mine bike is an 06. The blue and yellow wire voltage was 4.3v closed and 1.3v fully open. I checked the blue and black and the voltage is .6v to 3.6v. Thanks for the tip!
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Old 02-15-2011, 07:11 AM   #13
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Quote:
Originally Posted by tejaspuke View Post
Mine bike is an 06. The blue and yellow wire voltage was 4.3v closed and 1.3v fully open. I checked the blue and black and the voltage is .6v to 3.6v. Thanks for the tip!
same on my 04 I thought the sensor was busted initialy but I guess not.
black and blue it is
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Old 02-16-2011, 05:17 AM   #14
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Cry Caution

Just a word of caution - When you set the TPS up in a cold garage, make sure the carb heaters are disconnected, as they suck a bit of voltage and could leave you with a flat battery: or if you have no fuel in the carbs they could damage the seals leading to a fuel leak when reconnected and then catch fire when you try and balance the Carbs.

please don't ask me how I know.....
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Old 02-16-2011, 07:06 PM   #15
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Quote:
Originally Posted by adiablolex View Post
same on my 04 I thought the sensor was busted initialy but I guess not.
black and blue it is
*correction*
black and yellow WTF?
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