Waterproof TPS?

[Guest ratchethack]

After being caught out in a semi-serious rain with all the other happy Guzzisti on the way back from the Toy Ride (and again that night!) at last weekend's Rally at Dos Picos Park in Ramona, CA, I started thinking again about the scary-looking open space between the TPS and the throttle body on my Sport.

 

This little "feature" has always bothered me because it looks like such an obvious entry point for water, which it's not hard to imagine pooling up in there - not a happy thing for the wiper contacts in the TPS.

 

Though I don't have any "symptoms" from poor TPS performance (yet), I thought about doing some preventive maintenance by taking the TPS off and cleaning/drying the whole thing out with compressed air and shooting some ignition dryer and/or contact cleaner on the contacts. It looks like it would be easy to seal it from water and debris by putting it back on with a waterproof plate of some kind or even just electrical tape between the TPS and TB, which would provide some peace of mind down the road.

 

I've adjusted the TPS many times (fiddly as this is, it ain't too hard) but never had it off. It looks like it just sits there and would be easy to re-align with the TB shaft going back on (!?)

 

Anyone else have any experience and/or thoughts on this?

 

Thanks in advance!

[Baldini]

Mines full of silicone - still works ok.

[Guest ratchethack]

Mines full of silicone - still works ok.

38738[/snapback]

Baldini! Could you elaborate on this please? Did you take the TPS off and fill the entire hollow space below the TPS with silicone seal, or did you just put a fillet of silicone accross the open space?

[Baldini]

Sorry but I don't know. I had the shop do it on 6K service, not sure how they put it in there. KB.

[exwtk]

As you can notice there is a gap between the round boss on the injector and the

flat edge of the TPS.

I pressed it full of grease. Three years ago, no problems yet.

 

Greetings from Holland

Co.

[Guest ratchethack]

Thanks for the responses, Guys. As a quick follow-up, I just finished taking the TPS off. As I had suspected, water had indeed been pooling in the cup-shaped cavity below the TPS in the top of the throttle body. The cavity was full of 20 K mikes worth of powdery white corrosion that had evidently formed from repeat cycles of water getting in there and then cooking off with engine heat. Since the TPS sits above this cavity, the TPS itself appears to be relatively immune to any potential damage from this, but I cleaned the white stuff out of there, put a drop of oil on the TB shaft, and put a fillet of silicone seal accross the open space to seal it anyway.

[luhbo]

Actually I work for a factory that produces TPSes for several automotive customers. I can only strongly recommend not to put oil or silicone or something else like this into the potentiometer itself. The risk that you will loose the signal is high. Just leave it as it is, it seems to be quite quite waterproof.

Another thing is the throttle shaft. I have seen on one of the german speaking forums that this shaft can corrode so much that it will get stuck in the throttle body.

This year I tried to prevent this with the help of "gun-oil" what we have here, called "Ballistol". Next season I will try to improve this with some sort of cap put over the TPS.

 

Hubert

[Guest rotorhead]

FWIW, I blow the area under the TPS with compress air after wash or ride in the rain and always spray plenty of WD40 in the area to displace moisture and keep the corrosion at bay. In fact the entire engine and gearbox and such get a good coating of WD after every wash. I have been doing this with all my bikes for many years with no ill effects.

 

Keith

[Guest ratchethack]

Another thing is the throttle shaft. I have seen on one of the german speaking forums that this shaft can corrode so much that it will get stuck in the throttle body.

 

This year I tried to prevent this with the help of "gun-oil" what we have here, called "Ballistol". Next season I will try to improve this with some sort of cap put over the TPS.

 

Hubert

38765[/snapback]

 

Hmmmmmmm... The finding of corroded and seized TB shafts would be consistent with the mass of flaky white corrosion I found in there. It's no wonder. It seems that every time water gets in there, both the shaft and the TPS get a nearly enclosed steam bath of corrosion-inducing hot water vapor as soon as the engine warms up.

 

This makes me glad I both lubed the shaft with oil while I was in there, and sealed off the open space between the TPS and the TB to avert further corrosion.

 

Thanks again for the input, Guys :!:

[windchill]

TPS?? Sorry to be thick, but honest(!) what is it?

[Martin Barrett]

TPS?? Sorry to be thick, but honest(!) what is it?

 

Throtle Position Sensor - I hope - My understanding is that its is a variable reostat

and indicates to the ECU a variable value, and depending on the resistance level that you set as a base figure . The Gods of Electrickery will accept the sacrifice of Ron 95 with the sound of thunder and allow you forward motion.

 

I can understand , jets, needles and slides - for anything else I can subscribe to a omnipotent being

[Keith Foster]

TPS?? Sorry to be thick, but honest(!) what is it?

38910[/snapback]

T - throttle

P - position

S - sensor

 

It tells the ECU how much you have the throttle yanked open, so it can tell how much fuel to squirt, what the ignition advance should be, etc.

 

They are located on top of the throttle bodies. Black gizmo's.

[windchill]

Aha!! Need to be very carefull with these sneaky little TLAs!!

 

Thanks.

 

And are they a problem waiting to happen?

[Guest ratchethack]

are they a problem waiting to happen?

38922[/snapback]

 

To answer your question, in all liklihood, no, per lack of readily identifiable history of problems therewith. Far be it from me to blow a whistle here, when as far as anybody knows, there ain't no train a-comin'!

 

Possibly better stated, there seems to be low probability of a problem - at least near-term. But this begs the maintenance effort/tradeoff question - How long do you plan to own your bike?

 

I have no way to know for sure, but there may actually be no known cases of TPS *throttle position sensor* failure whatsoever on these bikes due to contamination through the open space described above. I do know for certain that potentiometers, rheostats and in general, all devices with mechanical electrical contacts don't like water and other contaminants, including lubricants (with the exception of contact cleaners specifically formulated for the purpose), of which many are for the most part known to cause failure as mentioned above by Hubert.

 

Having had the TPS out for a good look, it appears NOT to be a sealed device, having open areas on it's lower surface, which look more or less like open invitations for disaster (evidently often residing directly below ) to me.

 

The TB *throttle body* shaft is another matter.

 

HOWEVER, if you plan on a long partnership with your Sport/LeMans variant Guzzi (the models with the TPS on top) AND you're semi-seriously anal retentive about preventive maintenance like me , and/or consider that there's just no good reason to continue to expose the TPS (and now that there seems to be at least some evidence of corrosion-induced seizure of the TB shaft as well) to risk, even in the absence of known case history - Why not clean the stupid thing out, lube it, and seal it - especially since it's so easily done (assuming you can re-adjust the TPS properly yourself or have it done for you), then just forget about it?

 

At least that was my reasoning on what was, for me, a 10-minute project, tops. Just being anal again, maybe, but I get a little queasy whenever I discover any malignant-looking, obviously growing, festering mass of corrosio-puke anywhere on my machine, let alone in the top of my TB, directly under the TPS!

 

My opinion (worth exactly what you pay for it) at this point is that if you ride in the rain &/or snow, dust, etc., or are apt to get water in there while cleaning your bike, or suspect water or other cleaning solutions or road contaminants may be pooling/piling up in there - I'd say taking care of this per above just might be a pretty good thing to tack on to your "to do" list. But then as always, YMMV

 

Best Regards,

 

Ratchethack

[al_roethlisberger]

I agree.... of all the things people have complained about prematurely failing with regularity, the TPS isn't one of them.

 

I think we've heard of a handful of TPS issues over time, but few and far between, and they seemed to be defective, not failed units

 

I also wouldn't worry too much about a "seized shaft" either, because... if you are riding the bike regularly, the throttle action should keep the shaft "broken free" and moving regardless of a little corrosion.

 

If you have a big concern about it though, a drop of strategically placed oil with a needle dropper should do the job, as an ongoing maintenance procedure.

 

Again though, I've personally never heard of any real issues with either the TPS or shaft in general however.

 

al