Throttle Position Sensor

All the time I have had my SV, the throttle response from closed throttle has always been somewhat "lumpy" and its sometimes a bugger to start.
It occaisionally coughs and misfires, once in a while it will even stall.
I've tried many things (balancing the carbs etc) but nothing seemed to work, I just learnt to live with it.

Anyway talking to a friend of mine the other day and I mention my SV's little problem, and he replies "Has it got a throttle position sensor ?"

So, two minutes with Haynes manual and I realise it does, another ten minutes with the manual and a multimeter and I realise that its actually knackered.

A phone call to Mr Suzuki dealer this morning £58 for a new one !!!
Just hope that this solves the problem.

Well if nothing else, at least it has improved my fine throttle control

[johnnyrod]

Totally knackered? The two ones I checked just needed moving right to the end of their adjustment. What mileage?

Just coming up on 10K, although I have had it a year (done 5k) and its always been a bit crap from a closed throttle.

"A" reading is about 5K and doesn't change regardless of throttle position.
"B" reading is about 900 on a closed throttle.

[embee]

Originally Posted by tricky

Just coming up on 10K, although I have had it a year (done 5k) and its always been a bit crap from a closed throttle.

"A" reading is about 5K and doesn't change regardless of throttle position.
"B" reading is about 900 on a closed throttle.

the TPS is a resistive track with a wiper, so the resistance you measure between 2 of the pins is the track and that stays at a fixed value (around 5K, manual says 3.5K-6.5K).


The value you set it to is 78% of that (78% of 5K = 3.9K) at full throttle on the pin which goes to the wiper. (If you measure at the wrong reference pin you'll get the other end of the track from the wiper, in other words 22% (or 1.1K in your case)).
The value at closed throttle isn't actually given, but I'd guess it's going to be in the region of what you say (circa 1K)

[BillyC]

The problem with the Throttle Position Sensor is that they're rarely adjusted correctly.

The Suzuki workshop manual does detail how to adjust it, and it has been covered on this forum in days gone by.

However... beware! Firstly the bolts that hold it from place are made from the cheesiest material that Suzuki could possibly find - if you think you've cheesed a bolt easily before, you've not seen anything yet! Secondly, they're very difficult to get to, positioned just inside the frame on the throttle body. Finally, they're use a security torx bit to get to them.

You might just save yourself £60

[Viney]

I take it that this is only on the FI bikes?

Originally Posted by embee

the TPS is a resistive track with a wiper, so the resistance you measure between 2 of the pins is the track and that stays at a fixed value (around 5K, manual says 3.5K-6.5K).


The value you set it to is 78% of that (78% of 5K = 3.9K) at full throttle on the pin which goes to the wiper. (If you measure at the wrong reference pin you'll get the other end of the track from the wiper, in other words 22% (or 1.1K in your case)).
The value at closed throttle isn't actually given, but I'd guess it's going to be in the region of what you say (circa 1K)

Oh dear I'm getting confused now.

Right, firstly I am definaetly measuring across the right pins.
The way I read the manual, I understood that B should be 78% of A whatever the position of the throttle. (is this not correct ??)

What I have is:

A: 5.35K regardless of throttle opening
B: about 1k on a close throttle increasing to about 5K fully open.

[embee]

no, the 78% is the percentage of the full track resistance as measured on the wiper pin relative to one end of the track at full throttle (in your case A=5.35K so 78%=4.17K).

The wiper slides up and down the track as you open/close the throttle, so the resistance you measure between it and either end of the track varies.


(Don't know if this diagram will work?)



track

0%--------------------------------------------------------------------------100%
.................^.................................................. ...................^
........closed throttle.................................................. ..open throttle = 78%

.................................^
.........................<----- wiper ------>

Not happy with this, best I can achieve is about 83% with the twistgrip on the stop.
Sensor at the maximum range of it adjustment.
Theres something not right here

Originally Posted by Viney

I take it that this is only on the FI bikes?

Nope, there's a TPS on the carb body of your curvy.