TPS sensor??!!

[crazymofo]

i was reading somewhere a while back that the 98+ kats have a TPS sensor on them, so im wondering what function it has since the kat runs carburetors.

is it tied into the ignition? for example, see's the enigine has X amount of throttle, imparts X degree's of ignition.

if this is the case, it looks like ive got some modifications to make to the gsxr1100 carbs i have floating round. i have found a set of bandit carbs, which i have picked up for a song, but i got them bare, meaining if there was a tps on it, i certanly cant tell. the gsxr carbs have a bogger thoat on them too (or so i can see)

cheers.joe.

[zerocool61]

TPS?? I haven't heard that the Kat has a TPS, but I could be wrong.

[Selby]

It's listed on the wiring schematic....

[ThAzKat]

It is part #3 on this schematic, it repositions it self when the bike is turned on and the same when bike is turned off, controled by the ECU.

[Junior]

THAZ....part #3 looks like a washer to me.

[ThAzKat]

OOOPPSS, typo, #23 is the part you should be looking for.

[The CyberPoet]

(A) yes, there is a TPS on the 98-05 models. They may also be present on the 96-97 model year, but I'm not sure.

(B) The sensor is a simple hall sensor that tells the system how far the butterflies are rotated, so the digital ignition system (DIS) can tell if the bike is idle (minimum throttle), steady-cruise or WOT. I've been trying to get Suzuki's tech people to give me a concrete answer on how this modifies the ignition timing, but haven't gotten an definitive answer yet. My research indicates that it should affect primarily low to mid-throttle openings and help provide crisp power with added torque in those zones over a non-TPS system (by changing the spark advance). I also suspect the combination of the TPS, the RPM sensor, speed sensor and the DIS mapping for advance change the spark timing at idle and around 4200 RPM to minimize sound levels for compliance with noise regulations at time of delivery. If you look at the wiring diagrams closely, the ignitor box gets feeds from all of those inputs (TPS, speedo, rpm).
Suzuki's own marketing press info states that the TPS improves drivability by increasing mid-range and just-off-idle power, resulting in a wider spread of torque.

(C) On bikes equipped with a secondary thottle valve system (such as the SV650), the TPS also feeds control info to the DC motor that moves the secondary throttle valve(s).

(D) On bikes equipped with injection (such as the 2003 GSX-R), the system uses dual fuel injection maps for each cylinder, with the first map being fed primarily by air pressure, and the second map being at mid to WOT based on TPS info. The '03 GSXR series also uses two sets of ignition mapping as well at the ECM based on which gear the bike is in (1-4 gets one map, 5&6 gets another). Since the Kat doesn't have a gear sensor as such, it may do the same thing by doing some simple math on the speed vs. RPM levels to come up with the gear.

KNOW THIS:
Because of the position of the TPS, it is a lot easier to take the readings for it at the other end of the short pigtail cable than it is to get probes up to the TPS sensor itself with the carbs in place.

Cheers
=-= The CyberPoet

[The CyberPoet]

A little bit more research has led me to conclude that there are different ignitor boxes on the market, meaning that there are probably different maps for the different advancer set-ups.

Example - for a '99 Kat 600:
Switzerland & Austria Ignitor 329000-08F30
Continental Europe Ignitor 329000-08F00
USA 49-state: 32900-08FB0 or 32900-08F20 (not sure which)
California: probably the other of the two above.

The factory service manual (pg 6-26) also shows the TPS info feeding directly into the main CPU within the ignitor as one of the input sources, and the presence of a seperate ROM within the ignitor box as well, meaning it could contain multiple ignition timing maps.

Cheers
=-= The CyberPoet

[crazymofo]

wow cyber, im impressed! thanks for that info.

it basicly affirmed what i originally thought. i thought i could be a cheap dodgy bastard and just fit the gixxer1100 carbs, but! i'll modify them to accept the tps at the end of the throttle shaft.

thanks again ppl.. problem solved.... er.. nearly LOL

cheers.joe.

[The CyberPoet]

wow cyber, im impressed! thanks for that info.

it basicly affirmed what i originally thought. i thought i could be a cheap dodgy bastage and just fit the gixxer1100 carbs, but! i'll modify them to accept the tps at the end of the throttle shaft.

If you're going with the turbo, I'd consider leaving the TPS disconnected. It would probably be far easier to tune the carbs if the TPS isn't modifying the ignition timing. The other thing is that I have no clue how you could modify a set of carbs not intended for TPS to take a TPS signal (the shaft isn't there for it to read off-of, right?).

Finally, why are you swapping carbs at all unless you are changing displacement? The smaller diameter 750 carbs should result in a higher intake charge velocity at the carb & intake valves, resulting in better cylinder loading at virtually all RPM's (or did I miss that you are going to an overbore or bigger engine?).

Cheers
=-= The CyberPoet

[crazymofo]

wow cyber, im impressed! thanks for that info.

it basicly affirmed what i originally thought. i thought i could be a cheap dodgy bastage and just fit the gixxer1100 carbs, but! i'll modify them to accept the tps at the end of the throttle shaft.

If you're going with the turbo, I'd consider leaving the TPS disconnected. It would probably be far easier to tune the carbs if the TPS isn't modifying the ignition timing. The other thing is that I have no clue how you could modify a set of carbs not intended for TPS to take a TPS signal (the shaft isn't there for it to read off-of, right?).

Finally, why are you swapping carbs at all unless you are changing displacement? The smaller diameter 750 carbs should result in a higher intake charge velocity at the carb & intake valves, resulting in better cylinder loading at virtually all RPM's (or did I miss that you are going to an overbore or bigger engine?).

Cheers
=-= The CyberPoet

cyber-

the tps, is basicly a stepper motor, it has a series of notches inside each a certain degree past 0* (zero throttle) it has all moving and reading parts contained inside its body (part 23 on thaz's piccy) it attaches normally on a flat section on the throttle shaft (as you turn the throttle shaft the tps reads the angle of rotation.. the flat on the shaft turning against a flat in the tps body).

i basicly either can transpose the throttle shaft from the kat carbs or of needed, make a mount bracket and moddifly the original gixxer shaft... worst case scenario is to make a new shaft and mount for the tps.. all do-able!!

i was going to continue on with the tps, cos im worried it may cause the iggy ecu to go on the blink if the tps is diconected :S

adding a turbo is basicly another way of increasing the displacement. nothing encreases a engine's breathing capacity quite like extra psi.

a engine that breathes unassisted is actually consuming 14.7 psi of air (the atmosheric pressue) go adding 7.35psi on top (of positive boost) the engine then is actually ingesting a further 50% capacity (in theory) taking a 750cc to 1125cc. add another 7.35psi and you have in theory a engine thats double what you started off with. you need to match fuel to the increase in the amount of air ingested.

im adding 7psi for now, so a set of 1100cc gsxr carbs will be near bang on for the engines fuel needs. it will only be a matter of fine tuning to get it running sweet. when the engine junks, i'll rebuild it with a 1mm overbore and look into either jeting up the gixxer carbs or finding newies to go with the planned 14psi

cheers.joe.

[The CyberPoet]

the tps, is basicly a stepper motor, it has a series of notches inside each a certain degree past 0* (zero throttle) it has all moving and reading parts contained inside its body (part 23 on thaz's piccy) it attaches normally on a flat section on the throttle shaft (as you turn the throttle shaft the tps reads the angle of rotation.. the flat on the shaft turning against a flat in the tps body).

It's not stepped. At least when I actually tested mine with an ohm-meter, it wasn't, but instead put out a smooth transition in resistance amounts and doesn't mechanically bolt onto the shaft but merely surrounds it (thus the hall sensor comment; it could be a rheostat as well).

i basicly either can transpose the throttle shaft from the kat carbs or of needed, make a mount bracket and moddifly the original gixxer shaft... worst case scenario is to make a new shaft and mount for the tps.. all do-able!!

i was going to continue on with the tps, cos im worried it may cause the iggy ecu to go on the blink if the tps is diconected :S

When I said disconnected, I meant from the shaft, not the ECU. Most riders report no noticable change when they disconnect the TPS on the stock bike, but the difference may not be readily noticable in that sense (it might be noticable later as plug fouling though).

adding a turbo is basicly another way of increasing the displacement. nothing encreases a engine's breathing capacity quite like extra psi.

a engine that breathes unassisted is actually consuming 14.7 psi of air (the atmosheric pressue) go adding 7.35psi on top (of positive boost) the engine then is actually ingesting a further 50% capacity (in theory) taking a 750cc to 1125cc. add another 7.35psi and you have in theory a engine thats double what you started off with. you need to match fuel to the increase in the amount of air ingested.

While I agree that you will have to add additional fuel under boost, the compression ratios change depending on RPM and intake velocity (see the January '05 issue of TWO for a better explanation). Unless the turbo is waste-gated to provide that same pressure constantly, it too will affect the actual compression ratios, and I suspect the 1100 carbs will suffer at idle and low-rpm's due to reduced velocity affecting the fuel-air intake velocities. I would think using much larger jetting on the stock carbs would give you the best of both worlds.

From a similar thread
Carbs are not just carbs, even for the same cylinder count and displacement. The design of the carb takes into account such factors as intake valve-opening duration, the exhaust valve overlap and bore/stroke depth, which affects the vacuum levels and intake charge velocity. Example: The '90 GSXR has the same block and the same displacement, but uses a smaller bore and a longer stroke than the '88 - '05 Kat engines, thus the intake charge velocity changes, and the fueling equation at the carbs has to change to match.
In our case, both the '88 and '98 engines have the same bore & stroke, but I don't know about valve overlap -- rejetting to compensate may be required.

im adding 7psi for now, so a set of 1100cc gsxr carbs will be near bang on for the engines fuel needs. it will only be a matter of fine tuning to get it running sweet. when the engine junks, i'll rebuild it with a 1mm overbore and look into either jeting up the gixxer carbs or finding newies to go with the planned 14psi

I hope it all works out. Keep me posted

Cheers
=-= The CyberPoet

[The CyberPoet]

Oppsss.. double post