Modern Vespa

Like other HPE Supertech owners (2019 APAC version for me), i am frustrated by the dashboard temperature readout being so far above ambient temperature.

Can someone tell me where the sensor is located, so i can try moving it to a location that isnt influenced by engine or radiator heat.

Also - if anyone knows - is this a single sensor that is also feeding data into the engine management, or is there a separate inlet manifold sensor for that purpose?

I heard Robot mention that the latest Supertech's (2021 i think) had relocated the ambient temp sensor for more accurate readings, but (unfortunately) he didn't mention the old location

there's at least 3 temp sensors that I know of in a supertech.

1. coolant temp (suspect near/in the engine rather than near the radiator)

2. air intake temp (believe it's in the throttle body)

3. 'external'/'ambient' air temp. This is what's displayed on the top right of dash and is generally wrong enough to be essentially useless. This is the one that Robot said moved. The parts diagram for the 2019/2020 editions of the supertech show it in the lower right of the legshield. This sensor has nothing to do with the ecu or engine (else it would also be on a hpe gts not just supertech)


air temp sensor location

Hi Steelbytes,

Well its 7 months since you replied, and until now i hadn't realized that you had replied. Now i see it, i will have a poke around on the scooter to try find the sensor.

Curiously the diagram makes it look like the same shape as the sensor that would be screwed into an engine manifold. I wonder if that's what they have used, but just screwed somewhere on the frame in free air. We will see.

Ken

FWIW, I'm comparing the ambient temperature sensors of my '22 SuperTech with Le Wife's 2013 Honda CR-V; neither vehicle's sensor has an absolute lock on reality, but I'm curious as to what the "spread" is. so to speak.

after riding a supertech for 2 & 1/2 years I suggest sticking a bit of tape over the ambient temp sensor display on the dashboard. It gets further and further above reality the long your ride as the whole front of the bike can get pretty warm

Robot said that the ambient temperature sensor moved to the very front of the front fender in the newest SuperTech models, and that it was previously in the floorboards where it would get heat-soaked by the radiator causing the temperature reading to be way off.

See 6:40 in this video:

here's the part

https://www.scooter-center.com/en/temperature-sensor-environment-air-piaggio-vespa-gts-125-zapmd3200-zapmd3201-vespa-gts-250-zapm45100-zapm45101-vespa-gts-super-125-zapma3700-zapmd3200-vespa-gts-super-hpe-300-zapma360-vespa-lx-125-zapm44100-zapm44300-vespa-lx-1-gp581142

found it on my Australian* 2019 Supertech. I confirmed this by using a hair dryer then an ice pack to change the temp. note: the temp on the dash is pretty slow to respond, turning the ignition on/off helped my testing.

this is under the right floorboard, half way along. right near the tilt switch. and the return hose from the radiators back to the engine runs right above this so ...


* I mention Australia as a reminder that our bikes here come from the Vietnamese factory unlike the European and North American models.

Have you looked on yours? I'm curious

I have found the sensor in the same place as you , steelbytes.
Today I have stuck insulation on the metal and sensor cables inside to battery/footwell (see photos to follow) to see if lowering the internal convective heat might help enough to improve the readings. Seemed like the easiest first step. Yet to do a test run.

Sounds somewhat promising!! Let us know what you find out 😁

Robert, sounded promising…but wasn't. Initially the onscreen temperature perfectly matched a thermometer that I carried. (Ambient temp was 17degC). But after riding for 10km it has risen to 4.5degC above the ambient.

So, I feel the only solution is to relocate the sensor to a place that is not effected by either radiator or motor heat. Since the wiring runs through body channels to the scooter floor - that didn't look to be easy. I have not made any more progress

Thanks for the update, tech!

Could the old sensor just be unplugged and plug a new one in and place it where you want?

Mankite, the sensor is quite accurate, so the issue is just extending the cable back to a 'clean air' location to reuse the existing sensor. The difficulty is that it's routed through a cable duct in the floor of the scooter from somewhere in the leg shield , which appears difficult to access and thread a cable back through. The cable itself is simple, and could be lengthened with joiners or solder.
The other difficulty is finding that 'clean air' location which isn't influenced by Sun heat or radiator or engine heat. I Haven't experimented with locations (yet).