TPS voltage settings

[Lord Snooty]

I'm doing my 30k service today.

Started with the valve and end float clearances - no probs.

I then checked the TPS voltage and it was over 0.5v so I have reset it to 0.36v

The bike was running ok prior to discovering the voltage was out of tolerance so what exactly happens when the TPS setting is out It was running with a bit of a rough spot around 4k rpm but I think "they all do that sir".

When I started the bike after setting it correctly I noticed that the idle speed had dropped so other than that what difference will it make

 

[Steptoe]

The bike was running ok prior to discovering the voltage was out of tolerance

Then you should have left it alone.

 

[sockpuppet]

Then you should have left it alone.

You mean if it ain't broke don't fix it.

That has bitten me in the ass so many times that I now do leave it instead of trying to fix something that works

 

[Butchersdog]

I thought about checking this TPS thingy then I discovered Steptoes comments about balancing etc etc and left it alone! My rough running was down to an old fuel filter

 

[Timolgra]

Then you should have left it alone.

Class

371mv

 

[Lord Snooty]

Then you should have left it alone.

A pithy answer oh GS guru but it doesn't really answer the question does it?

Whilst the bike was running ok there may well have been a gradual drop off of performance/operating efficiency due to the settings being out of tolerance that, due to the gradualness of the change, were imperceptible. BMW employ highly qualified and presumably well paid engineers who determine these tolerances, and as German engineer are probably not noted for their frivolity, then there must be a reason for them. I am merely trying to determine what that reason is and what happens to the throttle/fuelling system when the voltage is not what those clever teutonic chappies have calculated with their sophisticated computers.

Neil, if a customer of yours asked for a bike to be serviced would you leave the valve clearances as they are even if you found them to be out and the customer told you the bike was running ok? I doubt it; because you know that there is a very good reason for them to set as per the service manual.

I have not said that the bike is running worse since I adjusted the settings, merely that there is a slight drop in the idling speed.

So if anybody out there does know the answer to the original question I'd be grateful if you could share it with me.

I.E what effect does the TPS have on the bike when the voltage is not set within tolerance....thanks in advance for any informative and enlightening responses.

If somebody does know the answer then if you share it we might all benefit from the knowledge.

 

[Geno]

Would like to know how to set TPS ,and what to use and how to set it . I to would like my bike running at its best . Any pics would be great ,
Thankyou . Geno .

 

[Steptoe]

A pithy answer oh GS guru but it doesn't really answer the question does it?

Whilst the bike was running ok there may well have been a gradual drop off of performance/operating efficiency due to the settings being out of tolerance that, due to the gradualness of the change, were imperceptible. BMW employ highly qualified and presumably well paid engineers who determine these tolerances,

Where have you got this "tolerance" measurement from ??

There isn't a tolerence on a TPS. Do you know how the TPS is set at a main dealers ?? It doesn't give a voltage measurement, it just gives a "0" when it's set to the factory spec.

You decided to touch and adjust the TPS, and THEN ask what it does and what the effect will be -

because you know that there is a very good reason for them to set as per the service manual.

Show me the BMW service manual that tells you what voltage you set the TPS at.

Are you mistaking something you've read on the internet as a BMW service schedule.

I'm not saying you can't adjust it, but just because it reads differently to what might be posted on the internet doesn't mean it's wrongly set.

 

[Timolgra]

A pithy answer oh GS guru but it doesn't really answer the question does it?

Whilst the bike was running ok there may well have been a gradual drop off of performance/operating efficiency due to the settings being out of tolerance that, due to the gradualness of the change, were imperceptible. BMW employ highly qualified and presumably well paid engineers who determine these tolerances, and as German engineer are probably not noted for their frivolity, then there must be a reason for them. I am merely trying to determine what that reason is and what happens to the throttle/fuelling system when the voltage is not what those clever teutonic chappies have calculated with their sophisticated computers.

Neil, if a customer of yours asked for a bike to be serviced would you leave the valve clearances as they are even if you found them to be out and the customer told you the bike was running ok? I doubt it; because you know that there is a very good reason for them to set as per the service manual.

I have not said that the bike is running worse since I adjusted the settings, merely that there is a slight drop in the idling speed.

So if anybody out there does know the answer to the original question I'd be grateful if you could share it with me.

I.E what effect does the TPS have on the bike when the voltage is not set within tolerance....thanks in advance for any informative and enlightening responses.

If somebody does know the answer then if you share it we might all benefit from the knowledge.

Calm matey, I put the answer in the post above yours.. 371mv

 

[ELIMINATOR]

Opinion alert!

Isn't it a potentiometer that informs the ECU of the position of the throttle opening? If it's not reading as it should at a given setting, then the ECU wont react accordingly.......... higher or lower idle speed? amongst other throttle related "errors".

 

[cookie]

i've been told (by a US BMW "Master Tech") that if the ECU sees more than 0.4v from the TPS then it regards it as out of spec and stops using it.

personally, i have had best results with 0.385v


more volts is richer BTW.

 

[fundura]

Please will someone post a 'how to' on the TPS setting,As i've never done this Would be good to know. Thanks

 

[Stewart H]

Its all here,under the Zero Zero procedure, dont be surprised if the earths magnetic poles reverse and plunge us all into nuclear winter though
Stewart
http://www.ibmwr.org/r-tech/oilheads/index.shtml

 

[cookie]

Its all here,under the Zero Zero procedure, dont be surprised if the earths magnetic poles reverse and plunge us all into nuclear winter though
Stewart
http://www.ibmwr.org/r-tech/oilheads/index.shtml

don't get dragged into doing the whole "zero zero" thing where you reset the throttle stops. these are set at the factory using a flow bench and are best left alone.

just check the voltage from the TPS to earth and rotate the TPS unit to adjust. it's a five minute job.

 

[billyt53]

TPS adjustment

http://advwisdom.hogranch.com/Wisdom/tps3.1.pdf

Billy

 

[Steptoe]

Its all here,under the Zero Zero procedure,

Nooooooooooo, as cookie has said, zero zero is something completely different to TPS adjustment.

 

[Colban]

Opinion alert!

Isn't it a potentiometer that informs the ECU of the position of the throttle opening?

Thats the way i've understood it.Its one of the parameters the ECU uses when it works out how much fuel it needs to gob into the cylinder.
The higher the TPS voltage,the richer the mixture.

 

[BrianR]

+1 for Steptoe. I tried it, all that zero zero stuff. after a full rebuild of TB's and cables....... unless your a rocket scientist with the patients of a saint, it aint gonna work.

Mine ran well enough when I had finished but used so much fuel i thought I had a leak.

Took it to the man eventually (dealer.... no flames please)...... and all is well now. runs perfect and back to better than my pre rebuild consumption.

If it runs and your happy LEAVE IT ALONE


BrianR

 

[Superhypo]

BrianR ,I did too the TBs rebuild (with the Bing repair kit from the german guy Ralph ) but without zero=zero procedure, I just put the TPS to the value measured before striping down. I am curious why you did mess up with the throttle stop screws? By the way the TPS voltage value was/is 324 mV (very low from what I've read in various posts here) but seems to be ok.

 

[Lord Snooty]

Calm matey, I put the answer in the post above yours.. 371mv

Thanks Tim, so there is an optimum setting for it, I'll leave mine at 360mV rather than tinker with it again.

Thanks Trev (Eliminator) for the additional info - that's what I was after.