Checked my TPS need help understanding data

Jeff Williams · 05-27-2005, 12:44 PM

Hi all,
the new bike has alway felt different from the last bike.
I know every bike feels different but it just doesn't feel....you know... right.
In my search I just checked my TPS voltage.
It measured 333mV.
From all the articles I have it should be between 370-400mV.
I'm not very good at understanding electrons, voltage, current, etc.

The question I have is what does it mean in practical terms.
I'm not going to move the two TPS screws because the bike is still under warranty.
So I'll have to adjust the left throttle stop and bring the voltage up between 370-400mV, but what should it do when I increase it.
Put another way what should I expect the bike to to.

thanks from a electrical neophyte

jeff

JonyRR · 05-27-2005, 02:00 PM

DONT MESS WITH THE THROTTLE STOP SCREW! wait until you feel comfortable moving the tps body itself.
Obtain, if you already haven't done so, the rob lentini '0=0' article; read it until you understand it and then follow the procedure exactly. 330MV is pretty 'lean'. You COULD try disconnecting the 02 sensor and pulling the CCP to richen 'er up some (just pulling the CCP OR disconnecting the 02 sensor at the harness plug under the tank should do the trick).
Muck about with the physical throttle body reference stop screw on the LH throttle body at your peril.
I just did this again as a check in my driveway last evening. TPS=390MV at rest, BBS's synched at roughly 1.5 turns and a mechanical synch at 3K RPM hot, and she runs sweet with no backfire, hesitation or stalling at idle and pulls cleanly with no untoward foolishness regardless of rpm. If you did the measurement correctly, 330MV is tooo friggin' lean, man, specially w/ a pipe, filter and induct.
Does your scoot ever stall at idle when you let the clutch out with little throttle?

Jeff Williams · 05-27-2005, 06:48 PM

Jony,
thanks that why I like you guys, a wealth of knowledge.
No it doesn't stall at idle.
As soon as I got the bike I felt it was out of sync.
I adjusted the throttle bodies without messing with the TPS,(neophyte), and it run well to a point.
But it felt lean when I put the mods into it.
To be honest the other bike felt lean as well until I put the k regulator into the bike.
The other bike was set at 385mV.

Ok here is my thoughts jony.
Look at the 12 steps to Throttle Set Screw and TPS adjustment in the article Throttle Screw TPS Adjustment by Stephen Karlan,(reviewed by Rob Lentini).
If you assume that the TPS is 0=0,(which when I did the 12 steps on my other bike was the case), Do step 1, then go directly to step 6 and complete to step 12.
Warranty will not be voided and the voltage will still be 370-400mV.
Please tell me what is wrong with what I would like to do, I don't know.
It seems like it would work.
thanks for your patience

cya
jeff

Jeff Williams · 05-28-2005, 04:15 PM

Jony,
Thanks for your help it worked just as you suggested.
better your way than mine.
jeff

brad black · 05-30-2005, 07:10 PM

the idle switch range when read by the gt1 is from around 325 to 390mv from memory. so anywhere in that range will activate the idle switch. that's the only setting procedure from bmw, so if it's within that range it's considered ok.

if you change the idle stop screw setting you should check the balance with the air bleeds wound in on both sides as you'll probably have unbalanced idle stop settings. most of them are out from the factory anyway.

when you do a zero = zero this idle stop balancing is important as the rh one will be open quite a bit more than the lh one - which is now open less due to the tps baseline being higher with the same / similar idle voltage setting. this is also why the zero = zero makes them a little richer - the throttle is open less for the same tps reading.

doing the 'air bleed in' idle stop balance can often make them that little bit nicer at idle and low throttle openings.

JonyRR · 05-30-2005, 09:54 PM

Brad Black:
'if you change the idle stop screw setting you should check the balance with the air bleeds wound in on both sides as you'll probably have unbalanced idle stop settings. most of them are out from the factory anyway.

when you do a zero = zero this idle stop balancing is important as the rh one will be open quite a bit more than the lh one - which is now open less due to the tps baseline being higher with the same / similar idle voltage setting. this is also why the zero = zero makes them a little richer - the throttle is open less for the same tps reading.'

Mine was surprisingly off when I did this originally..I thought it was just me, but that's a great explanation and I might revisit this adjustment once more..though I like the way it runs so well now I should just leave well enough alone....