Throttle pot wiring Megasquirt

[Belle427]

I'm just finishing up a megasquirt conversion and when initially setting up the throttle pot calibration it's working in reverse, ie no throttle is reading 70 % and full throttle 0%.
Could anyone tell me which wires I need to switch at the throttle pot to correct this ? (I'm assuming that's the problem).
I thought it might be the 2 outer wires.
Thanks

[Steve_D]

If it is the standard wiring then
Blue is common ground
Brown is +5V
green is signal

Steve

[Penelope Stopit]

http://www.megamanual.com/mtabcon.htm

[Sardonicus]

Dont guess the wiring double check if you fk up and ground that 5v + you will damage the ECU

[Penelope Stopit]

I wonder if the TPS is not suitable for the job, perhaps if it was turned around by 180 degrees it would work
Yes I know you can't simply turn it and fit it but..........

[blitzracing]

Its just a normal potentiometer- so you simply swap the blue to +5 and brown to ground. The pot is insulated from ground, so no worries there.

[Belle427]

Thanks all, just wanted to double check.

[Dougal9887]

I found the hotwire TPS, when used with Megasquirt, to have poor resolution and erratic readings when viewed on the MS TPS gauge.
I changed to the Emerald supplied Colvern TPS which has wide resolution and super smooth action when viewed in MS.
it does however require that you make up a small adapter spindle and I also decided to mount it on an aluminium plate incorporating a small bearing to support the shaft as the Colvern TPS looks a bit fragile if used to support the shaft.

Dougal.

[Belle427]

Looks a good solution.
Can i ask did you use the existing cts and need to calibrate it in Tunerstudio?
Edited to add I found the information online and calibrated the existing rover item.

Edited by Belle427 on Friday 2nd August 16:26

[Sardonicus]

No its a Colvern unit and it will calibrate in TS no problem in fact any sensor that sweeps from 0-5v TS will accept

[Belle427]

I see racetech sell a nice conversion kit but money I don't want to spend at the moment.

[Sardonicus]

An healthy Lucas Hotwire TPS will scale just fine

[Dougal9887]

Have you had a shot at calibrating the Rover TPS in Tuner Studio yet?

[Belle427]

Yes I've done that, test fired the engine and although it runs I can only keep it going by feathering the throttle.
Afr goes off the scale @ 19:1 so I'm getting Shaun of Ms2 tuning to remotely connect later to see if he can adjust it for me.
Looks a very good piece of software Tunerstudio.

[Dougal9887]

It would be interesting to see your .msq

[Belle427]

I can mail it to you if you pm me an address.

[Belle427]

Dougal9887 said:

I found the hotwire TPS, when used with Megasquirt, to have poor resolution and erratic readings when viewed on the MS TPS gauge.
I changed to the Emerald supplied Colvern TPS which has wide resolution and super smooth action when viewed in MS.
it does however require that you make up a small adapter spindle and I also decided to mount it on an aluminium plate incorporating a small bearing to support the shaft as the Colvern TPS looks a bit fragile if used to support the shaft.

Dougal.

Be interested to know how this has worked for you, I had a slight issue with the original Lucas Tps not returning to zero even after multiple calibrations. I assumed it was worn at the closed end.
I purchased a replacement upgraded Tps kit from act performance at great expense and it’s exactly the same.
The throttle is returning and not binding at all so I’m a little frustrated.

[Sardonicus]

Why do you want to see zero? it calibrates from the lower to upper figure the MS just needs to see a linear movement and does the rest , mine sweeps from 70 something to around 900+

[Belle427]

My idle seems to hang when it sticks, sometimes as high as 1% even though I’ve verified the throttle plate is closed.

[spitfire4v8]

Update your min tps setting in MS with the value shown when the engine is ticking over.
I'm guessing what's happening is that the throttle spindle is moving due to play in the shaft/plenum. You've presumably set the min value with engine off, but that changes when there is vacuum against the back side of the butterfly.