Converting Temp Gauge to Analog

[giarcg]

I cant stand the look of the digital display on my '01 ST4 so I'm planning on removing it and installing an analog water temp gauge a'la 996. I can live without the clock, fuel gauge and I know I'll loose the reserve light as well. I got the gauge and the foam surround now I just need to figure out where to install the sending unit. The 996 had a different style coolant hose "T" with a hole for the sending unit, the ST's does not have the hole and drilling one is not a solution.

Do any of the resident experts have any ideas regarding a possible solution? I've examined using different part number "T"s from different models but haven't found one that I think will work.

[wwahl]

Just stick it on top with a little Play Dough.

[Stick]

Is the 996 sender similar (threads) to our ST machines? If so, just undo the FRONT sender, and replace it with your 996 one. or maybe there's a simple adapter to be had?

Makes sense to me, since you're not planning to use the one on the machine.

Also, is the 996 sender got the same 2-prong plug? Maybe they're the same in the first place!

[giarcg]

Stick,
Both models have one thermo switch for the fan and one temp sensor for the ECU. The 996 has a an additional sender for the gauge. The ST does not and that's what I need to add. All have different P/Ns.

[Stick]

What I'm wondering is, is if the 916 temp sender and ST temp senders are similar or same? They're obviously both analog type devices. The ST uses a NTC (negative temp. coefficient) device. hi resistance when cold, and lower resistance as temps rise.

I can give you this one point that's easy to replicate on the ST: Plug a 220 Ohm resistor into the connector (in place of the un-plugged temp sender). This will give you a readout of 207 Deg. F.

If this resistor shows something "close to boiling water(212)" on the 916 gauge, then they're probably using the same element.

If you find the Bosch replacent info in here, (p/n), and then play on the web, you can see the Temp./resistance curve that the ST uses.

Hopefully some of this info helps.

[giarcg]

I have verified that indeed the sensors are different. I wired the analog gauge to the ST sensor, ran the engine to temp and the indicator moved only slightly.

Your reply did cause me to question my understanding of the system however and I went back to the wiring diagram. As it turns out the two ST sensors are the same p/n after all, one feeds the ECU and the ECU signals the fan. The other feeds the digital temp display. This is great news! I just need to remove this sensor and find a reducer that will allow me to install the smaller diameter sending unit in its place. Problem solved.

Thanks for your input!

[Stick]

Shoot, I thought you already knew that the front sender did just the read-out, and the one on the Vertical head did the ECU... And yes, the ECU commands the fan relay.

Point of interest: The Ducati factory senders (OEM) are crappy "Jaeger" brand. Both of mine were F'd up on the ST2. I finally realized/verified that the intermittent readings on the readout was, indeed the sender (and not the connector!!)

And the fauly one for the ECU was "off" so far, that it was turning my fan on at maybe 250 F or higher... The Bosch or NAPA replacements are a cheap cure for this problem.

Approx. $100 for one OEM. Maybe $40 for TWO of the aftermarket ones.

[giarcg]

Update -

Finally finished this little project and I'm pretty happy with the result. Biggest problem turned out to be finding a place to install the correct sending unit for the analog gauge. Simply replacing the stock temp sensor wouldn't work due to hole diameter differences and machining an adapter wasn't the answer. I ended up finding the correct size in-line adapter and spliced it into the coolant hose adjacent to the original sensor. Had to solder a ground to the sensor body to complete the circuit. Works great and gives me the instrument package look I prefer. Spent a little more than I cared to but hey...its a Ducati.

[MarkST]

Nice work giacg, that's a great looking job you've done there.

[blue44]

wow that came out great giacg, nice work... Donn