Freelander 1 Canbus question for Alibro

Yo @Alibro you're much more clued up on canbus than I am, did you ever look at the throttle position sensor in CAN before ripping out the dinoojuice burning bits from your EV project car? The reason I ask is that I'd like to find a way to "inject" a fake TPS signal to create a hand throttle like you used to get for vehicles with a PTO, penny for your thoughts on it?

The throttle isn't on the CAN. A simple duel rising and falling variable resistance is all you need.

Jayridium said:

Yo @Alibro you're much more clued up on canbus than I am, did you ever look at the throttle position sensor in CAN before ripping out the dinoojuice burning bits from your EV project car? The reason I ask is that I'd like to find a way to "inject" a fake TPS signal to create a hand throttle like you used to get for vehicles with a PTO, penny for your thoughts on it?

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The TPS is made up of two sensors. Not sure if they are POT's or Hall sensors but either way they both get 5V in and one gives out something like 0.4V to 1.4V and the other 0.8V to 2.8V.
The numbers I just quoted may not be correct but the idea is both halves of the sensor have to be in sync with each other or the car goes into limp mode.
Ebike throttles work in the same way but only have a single sensor. That's why I can use the Freelander throttle to drive an ebike controller to move the car around the driveway.
I can't think of an easy way to fake the two throttle signals required without using a proper TPS.

Cool, cheers for the input lads. As I understand it it's typically two sensors in opposition, one value increases, and the other decreases in unison, disparity in the signals engages limp mode. What I was wondering was is it possible to override the resultan value therein via a CANBUS command, and from what your saying,a nd what I've read else where, it looks like thats not an option, so back to the deawing board.

Cheers /Jay.

Jayridium said:

Cool, cheers for the input lads. As I understand it it's typically two sensors in opposition, one value increases, and the other decreases in unison, disparity in the signals engages limp mode. What I was wondering was is it possible to override the resultan value therein via a CANBUS command, and from what your saying,a nd what I've read else where, it looks like thats not an option, so back to the deawing board.

Cheers /Jay.

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Actually they both rise as you put your foot down but by different amounts. I measured them a while ago when testing. I guess as they rise the difference stays the same or is of a known quantity so the ECU knows if there is a fault or not.

I guess it may be possible to have a second TPS connected in parallel with the first, I have two throttles on my ebike, a thumb control on the left and a twist control on the right. and the controller seems happy to work with either. How you would operate a TPS by hand is a different question.

Gotta love modern vehicles, a job that could have been done with a repurposed choke cable looks like it's going to require an MCSE in C# and a masters degree in electronics... Actually, choke cable --> throttle pedal, #GhettoAF - but might work

The 2:1 ratio is quite common on throttle pedals. Was recently sorting a Corsa-C that used exactly the same values. You might be able to hack a hand control onto a spare pedal assembly (and remove the pedal), but the spring will need reducing !!

Jayridium said:

Gotta love modern vehicles, a job that could have been done with a repurposed choke cable looks like it's going to require an MCSE in C# and a masters degree in electronics..

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You could just connect an old fashioned choke cable to the pedal, so you can adjust the pedal position by the choke knob.

Think Mr Bean used a yard broom on the gas pedal!!