PAS installed, steering wheel does not self center

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   Hello,just took my van for a ride after having installed a corsa C electric steering column. What a difference! It's almost too light now, but definitely worth it.
The only issue I have with it is that the steering wheel does not return to center by itself, you have to guide it after bends: I don't know how it was before, as I didn't really drive it much since I bought it, and have changed a lot of stuff along with the PAS (bushings, brakes, dampers...).
I hope it's an alignment issue, I have it booked for proper alignment next week, from what I understand I should increase caster, giving it even more angle than what's prescribed for non PAS t3s, right? Is caster even adjustable in the t3?

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mastakilla Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: 15 Jul 16 Location: Italy Status: Offline Points: 42	Post Options Post Reply Quote mastakilla Report Post Thanks(0) Quote Reply Topic: PAS installed, steering wheel does not self center Posted: 19 Jul 18 at 12:38
	Hello, just took my van for a ride after having installed a corsa C electric steering column. What a difference! It's almost too light now, but definitely worth it. The only issue I have with it is that the steering wheel does not return to center by itself, you have to guide it after bends: I don't know how it was before, as I didn't really drive it much since I bought it, and have changed a lot of stuff along with the PAS (bushings, brakes, dampers...). I hope it's an alignment issue, I have it booked for proper alignment next week, from what I understand I should increase caster, giving it even more angle than what's prescribed for non PAS t3s, right? Is caster even adjustable in the t3?

nicq Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: 13 Jan 13 Location: Surrey Status: Offline Points: 163	Post Options Post Reply Quote nicq Report Post Thanks(0) Quote Reply Posted: 19 Jul 18 at 20:03
	What system do you have, speed related, torque, or just pas. Speed related only gives assistance up to 20 mph the its as if you had no assistance.

mastakilla Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: 15 Jul 16 Location: Italy Status: Offline Points: 42	Post Options Post Reply Quote mastakilla Report Post Thanks(0) Quote Reply Posted: 20 Jul 18 at 08:36
	I have the supposedly "automatic" one, which should sense the driver's input torque and adjust assistance accordingly. I say supposedly as it doesn't seem to vary much if at all, assistance is always pretty high: there's a jumper in the control box which selects high or low assistance, and mine is on low. I have a vague plan to eventually add some hall sensor to a driveshaft and make it into a speed sensitive unit using a microcontroller, but for now it'll do.

nicq Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: 13 Jan 13 Location: Surrey Status: Offline Points: 163	Post Options Post Reply Quote nicq Report Post Thanks(0) Quote Reply Posted: 20 Jul 18 at 08:45
	I have speed related and I must say its very good. As you know you don't need any assistance over say 20mph perhaps you can put a meter on the motor wires and see what you have when you dive it.

mastakilla Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: 15 Jul 16 Location: Italy Status: Offline Points: 42	Post Options Post Reply Quote mastakilla Report Post Thanks(0) Quote Reply Posted: 22 Jul 18 at 20:26
	Yes, speed related is definitely better, but it requires adding a speed sensor (hence my idea of adding a hall sensor on a driveshaft). How is yours wired? Where does it take the speed signal from?

nicq Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: 13 Jan 13 Location: Surrey Status: Offline Points: 163	Post Options Post Reply Quote nicq Report Post Thanks(0) Quote Reply Posted: 22 Jul 18 at 21:54
	I fitted an Ultimate Engineering kit. Phone Tim I am sure he will supply a speed ring, sensor and bracket for the rear drive shaft.

mastakilla Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: 15 Jul 16 Location: Italy Status: Offline Points: 42	Post Options Post Reply Quote mastakilla Report Post Thanks(0) Quote Reply Posted: 23 Jul 18 at 08:50
	I have found online a guy that had my exact issue with corsa EPAS, on its lotus 7. The issue is due to the crappy control boxes faking the speed and engine signals, so you get too high assistance at driving speeds and that makes it impossible for the steering wheel to self center after turns. The signals the corsa ecu expects are simple 12v square waves, so what I'll do is use the VSS speed sensor that clips on the rear of the speedo (https://www.brickwerks.co.uk/vehicle-speed-sensor-t3-late.html) and a simple voltage sensing circuit and use an arduino to digitally generate the correct signals. Thanks for the help!

mastakilla Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: 15 Jul 16 Location: Italy Status: Offline Points: 42	Post Options Post Reply Quote mastakilla Report Post Thanks(0) Quote Reply Posted: 26 Jul 19 at 11:09
	Update for posterity: the self centering issue turned out to be mechanical in nature, removing the PAS and driving it as manual it's clear that something is binding in the steering mechanism, it is fine around center but gets progressively stiffer as the wheels turn, on either side. I have investigated it further and the problem lies in the steering rack, which I'll get changed next week. About the PAS, I did what I wanted to do from the beginning, got rid of the crappy control box (which I analyzed with the oscilloscope finding out that it produced a fixed speed signal even if it was advertised as "torque sensitive" - what a scam) and made a new programmable ecu with an arduino nano, a darlington transistor array and some passives. Now it only turns on the PAS after the engine has been started (I use a voltmeter >13.8V to check that), reads the gowesty VSS signal and produces an accurate speed signal for the PAS ecu. For anyone considering the "torque sensing" controllers for corsa b/c columns, my advice is don't. If you can't rig up a speed sensitive controller, which is the way to go, stick to the pot controlled units as at least you can set them to permanent low assistance, as having 100% assistance at speed is scary and dangerous.