Aftermarket Temperature Gauge- Where to install?

[Krispy]

Hello all,

I am looking at installing a aftermarket temperature sensor somewhere near the head on my engine. I do understand my 96 XP does have an idiot light and beeper, but I would like to know whats going on before the beeper sounds.

I have already installed a Trail Tech TTO tach, and I was looking at their temp sensors.

http://www.trailtech.net/tto_temperature.html



They have 3 options, 2 of which I think would work well in our application.

The first mounts under the spark plug and gives the head temperature

The second mounts in a cooling line.

I feel the first method will yield much higher temps than the second method. But SeaDoo put their factory temp sensor in the cooling water (outlet?) so I think that is probably the most beneficial. Location.

What do you guys think?

 

[Dr Honda]

Under the spark plug will show very high temps. It will be looking at combustion temps.

Personally... I wouldn't worry about an aftermarket temp gauge since our skis run open-loop cooling. Basically... it will be all over the place. I would simply make sure that that sender, buzzer, and light are working properly. The reason is... when you are riding... you aren't watching a gauge. But, a buzzer will grab your attention.


With that said... if I was set on installing it... I would take the head shell off, and drill/tap a new hole in it, for the sender. It's the bast place to get the temp. And... if you ever want to remove it... all you do is put a plug in the hole.

 

[raider352]

I think if you put it under the sp you will change electrode reach into the chamber. If you put it on a cooling line you could restrict the flow, both of which might cause problems.

 

[SabrToothSqrl]

I wouldn't bother unless you've actually modified the engine as well. Open loop cooling is going to vary the temp widely. Also, these engines are pretty tough. I would remove your factory sensor, and using a heat gun? Flame? Test it. I think maybe you check the ohms across it cold and hot. See if that works, then using it or another method, lanyard off, press start to start the computer. And see if you can verify that the light/buzzer works.

I'd rather verify the OEM setup over installing that.

I think the FSM has the procedure to do all this. I've never bothered to test mine. Maybe I should, but then again I've never had an engine overheat in... 20 years of riding.

 

[Krispy]

I want to start by saying thanks to everyone for their feedback. Please keep the opinions coming and I encourage anyone with experience with temp sensors (stock or otherwise) to give their feedback as well.

I think if you put it under the sp you will change electrode reach into the chamber. If you put it on a cooling line you could restrict the flow, both of which might cause problems.

The under spark plug sensor is very thin, it would change the distance the plug went into the head but it would be exceeding minimal. The bigger issue as doc pointed out is the temps would be too high to give an accurate reading of what is actually going on with engine temps.

The inline restriction would also be fairly minimal, I mean they are made for this exact purpose surely they flow as much or more than the segment of hose they replace.

I wouldn't bother unless you've actually modified the engine as well. Open loop cooling is going to vary the temp widely. Also, these engines are pretty tough. I would remove your factory sensor, and using a heat gun? Flame? Test it. I think maybe you check the ohms across it cold and hot. See if that works, then using it or another method, lanyard off, press start to start the computer. And see if you can verify that the light/buzzer works.

I'd rather verify the OEM setup over installing that.

I think the FSM has the procedure to do all this. I've never bothered to test mine. Maybe I should, but then again I've never had an engine overheat in... 20 years of riding.

So I guess I should explain a bit the history of why I am looking into this option. I recently had a problem with my temperature sensor, it was working intermittently. Depending on the day it would constantly (faintly) beep, or it would beep loudly even just after the engine had started and was still quite cool to the touch.

I pulled the old sensor out and tested it in a pot of boiling water. I watched as the resistance between the pin on the top of the sensor and the body of the sensor went from very high (almost infinite) down to about 4-5 ohms. The problem was that the sensor wasn't acting as a "switch" , as in it wasn't "open" or "closed" circuit. So if the resistance was in the Kohm range I would get a faint beep from the buzzer, if the resistance was in the single digit range I would get a loud beep. The key here is that it wasn't acting in a consistent manner.

I now have a replacement sensor that arrived yesterday from Nick (Tonka). I will verify it's operation before I put it in my boat.

As for the temperature being all over the place I am not sure I agree. I think there will be day to day variations due to the lake water temp changing. But I think on a given afternoon the temps will be quite consistent. Seadoo has graciously give us an oh sh!t beeper that should alarm at 200F.

I like to compare it to the dummy light on my wife's VW. If her oil pressure is low, it will illuminate saying hey dummy stop what you are doing. It works great for her.

My car on the other hand will give me oil pressure down to the PSI (or kPA) if I prefer. This allows me to see a problem coming and head it off before it becomes an issue.

On the water this could mean noticing an overheat before I need to be towed off the water.

My engine is stock now, but may not be at a later date.

 

[Spimothy Leary]

squirell.. I think you can test it (OEM) in hot water vs an open flame...

I never installed it (TTO) in one of my personal ski's but I had a friend that loved to install gadgets (has since sold ski) put one under his spark plug, now of course he never overheated but he was basically able to establish a baseline (i'd have to ask him what that was) for a head temp, and kept an eye on it, I guess then he figured he would know if the temp went over his established baseline/comfort zone, there was no alarm that I'm aware of. From my discussions with him, it was partially because he had money to blow and partially because he thought it looked cool to have two tto's on his handlebar (pic below). and lastly because he really wanted to know the head temp...

now I can't say if the location under the plug was the ideal spot, but his ski ran just fine for months and months, so there was no reason to believe that it had a negative impact in anyway placed in that location.

now.. I will admit,,, it looked super cool on the handlebars, and when we were just sitting on the shore or the ski was on the trailer, we had an idea what the air temps were as well... which was kinda nifty... as you can see in the pic below, it was 80 outside when we took this pic I 'think' the mounting plate came from summit racing, thats just an educated guess since I swear summit racing was his home page on his browser

this was a pic after he fired it up and idled it for a few seconds... temp's jumped up quickly...

 

[manolocross]

So I guess the tto are waterproof?

 

[Krispy]

I think highly water resistant.



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