Electric power steering - centering

[Pugglt Auld Jock]

Can anyone confirm, or correct me, as to how the EPS on my 2010 Panda and my boy's 2012 is influenced by the power assistance?

My assumption is that as you start to turn the steering wheel the rack will be resisting the tendency to twist the pinion (because the tyres are gripping the road). So the top part of the steering column starts to turn whilst the lower part of the column lags very very slightly behind it. The torque sensor in the column detects this and commands the electric motor to assist turning in that direction. If you stop applying force to the steering wheel the upper and lower column parts will realign and the sensor knows this so cuts power to the motor. My assumption is that it's this "misalignment" which the sensor uses to decide whether to apply assistance or not?

The reason I'm dwelling on this thought is that I'm guessing the power steering has nothing to do with self centering of the steering when driving down the road? I assume that steering geometry, Camber, Castor and especially KPI are what will influence this? In other words, the power steering has no inherent ability to self centralize the rack? So, if the car tends to pull to one side when driving down a straight piece of road it can not be anything to do with the EPS itself which is likely to be the cause?

 

[Pugglt Auld Jock]

The reason I'm dwelling on this thought is that I'm guessing the power steering has nothing to do with self centering of the steering when driving down the road? I assume that steering geometry, Camber, Castor and especially KPI are what will influence this?

Sorry folks. I was being harassed when I wrote this. Of course I meant that it's the Castor - not KPI - which has most influence over self centering.

Anyway, no-one seem to have an opinion on this?

regards
Jock

 

[SemSu]

Guess You sorted this out, if not, yes the steering self centers by the geometry. If the car pulls to one side its due to the wheel alignment.
One thing to note is that in rare cases the servo sensor can give wrong signals and make the power steering motor pull to one side. That mostly is with variable force.
If it's a bad wheel alignment it will feel like a constant force to one side.

 

[Pugglt Auld Jock]

Guess You sorted this out, if not, yes the steering self centers by the geometry. If the car pulls to one side its due to the wheel alignment.
One thing to note is that in rare cases the servo sensor can give wrong signals and make the power steering motor pull to one side. That mostly is with variable force.
If it's a bad wheel alignment it will feel like a constant force to one side.

Thanks SemSu. As you guessed I found out for myself. I was asking because although things have got much better when I rebuilt the front suspension - new struts, springs, top mounts etc and tracking checked, I still have a very slight pull to the left when out on main roads. It's not really noticeable in town - it was before the rebuild - but out on open roads, cruising along at say 50 mph, you just have to keep a thumb crooked into the wheel spoke to stop this gentle drift to the left.

When the better weather comes back I'm going to check rear wheel geometry as I suspect it has a very very slight bias to the right. I'll do a post in the Panda section if I have anything to report, but don't hold your breath, I don't do this sort of thing when it's really cold unless it's really urgent.

 

[varesecrazy]

Thanks SemSu. As you guessed I found out for myself. I was asking because although things have got much better when I rebuilt the front suspension - new struts, springs, top mounts etc and tracking checked, I still have a very slight pull to the left when out on main roads. It's not really noticeable in town - it was before the rebuild - but out on open roads, cruising along at say 50 mph, you just have to keep a thumb crooked into the wheel spoke to stop this gentle drift to the left.

On a road quiet enough..
Cross the white line

It may well pull to the RIGHT
Just follwing the camber of the road.

I chased my tail with my tipo TD.. until a trip to France highlighted this

 

[portland_bill]

A lot of Pandas pull to the left. This seems to be poor jigging of the rear axle and a 4-wheel alignment printout should show this. Even a small thrust angle will cause the pull.

Later genuine axles seem to be better, but still not perfect. There's a thread somewhere with someone shimming it to align the hubs better, with some success.

Sadly, the aftermarket axles available have copied the axle so accurately that they have the same offset. Missed opportunity. I guess the sample used had also been damaged a little in transit, as the new ones also come with all the little brackets for hoses and cables bent incorrectly. All need resetting. My thoughts were that if they've copied it this exactly, the main part of the axle will be correct spec.

 

[Pugglt Auld Jock]

Hi PB. I remember reading that thread. Interestingly I got to follow Becky out to my son's house (hour's drive) the other day when I was taking his wife's Jazz back out after "attending" to it, as Mrs Jock very kindly came along to give me a run back into town.

It's a little difficult to say - so the effect is very slight, if at all - but I fancy her (Becky's) rear end may have been crabbing very very slightly to the right. When the good weather comes back I'm going to investigate this more fully and I'm already construction a rig to do it. I feel another in depth post coming on!

Regarding Charlie's suggestion. I have noticed that the leftward pull almost disappears when I'm driving down the single track road near the crematorium. I guess there's no camber effect here? I'm intrigued to try your idea of driving on the right a go too.

 

[Pugglt Auld Jock]

So here's an interesting observation. My oldest boy (2012 Punto 1.4 8 valve) called in just by chance on his way past the house and Mrs J asked him if he'd go to the shop for milk and bread to save her going. Ok, you drive Dad just to see if you notice anything.

I serviced this car - and rectified a few things (Harrisons did a clutch too) - not so long ago during the good weather so wasn't expecting anything. Well, with my mind being "tuned" to supersensitivity regarding steering feel, I found that down the single track crematorium road she drove nicely straight. However out on the main road heading to the supermarket she had just a touch of pull to the left. Just like the Panda but perhaps a little less noticeable. I was longing to try her on the "wrong" side of the road but the opportunity never safely arose.

My Ibiza, which has very strongly assisted steering doesn't feel like this. Maybe it's a "Fiat thing"?

 

[chris3234]

So here's an interesting observation. My oldest boy (2012 Punto 1.4 8 valve) called in just by chance on his way past the house and Mrs J asked him if he'd go to the shop for milk and bread to save her going. Ok, you drive Dad just to see if you notice anything.

I serviced this car - and rectified a few things (Harrisons did a clutch too) - not so long ago during the good weather so wasn't expecting anything. Well, with my mind being "tuned" to supersensitivity regarding steering feel, I found that down the single track crematorium road she drove nicely straight. However out on the main road heading to the supermarket she had just a touch of pull to the left. Just like the Panda but perhaps a little less noticeable. I was longing to try her on the "wrong" side of the road but the opportunity never safely arose.

My Ibiza, which has very strongly assisted steering doesn't feel like this. Maybe it's a "Fiat thing"?

Does the senate have hydraulic steering or electric like the Fiat's?

 

[Pugglt Auld Jock]

Does the senate have hydraulic steering or electric like the Fiat's?

Hi chris. senate?

The Ibiza's steering is pure electric as far as I know - haven't really worked on her yet as the warranty expired with the last service and the next one isn't due till March. I'll be looking after her from then on, even bought the Haynes manual which they've conveniently just published.

The steering is also speed sensitive although it's rather too light and insensitive for my liking. I'm going to explore whether my VCDS program will allow it to be altered.

regards
Jock

 

[chris3234]

Hi chris. senate?

The Ibiza's steering is pure electric as far as I know - haven't really worked on her yet as the warranty expired with the last service and the next one isn't due till March. I'll be looking after her from then on, even bought the Haynes manual which they've conveniently just published.

The steering is also speed sensitive although it's rather too light and insensitive for my liking. I'm going to explore whether my VCDS program will allow it to be altered.

regards
Jock

Seat that should have said guess my phone didn't like the word lol

 

[Pugglt Auld Jock]

Up until I bought this Ibiza - nearly 4 years ago now - I was really quite impressed with the Skoda and SEAT brands (never having owned one of their more prestigious brands). We have had several in the family with the old VE and PD diesel engines, all estates except for one hatchback, and they have been very good. OK, silly niggly problems but never anything serious and they've all gone on to in excess of 100,000 miles.

Now thinking about the Ibiza I have to say I think it's a step backwards. I must admit it's handling is more sprightly and sharp but the ride is hard and joggly yet it pitches horrendously over speed bumps. You have to go really really slowly to avoid burying her nose in the tarmac. Out in the countryside she drives very nicely with enough power from that little 3 cylinder turboed petrol engine for my needs but in town the turbo lag is a real pest. I liked the old hydraulic power steering more too - Not so "airy fairy" with a better feel for what was going on under the front tyres.

The gearbox on all previous cars has been absolutely fine. People complain about the "notchy" feel to VAG 'boxes but I rather like it and find it makes for a very "positive" positioning of the lever. Previous 'boxes have been smooth and quiet in operation but this new one is like a barrel of loose nuts and bolts. It behaves like a box with too much backlash everywhere. There is sometimes a clunk when selecting 1st gear form standstill (I would guess it's backlash being taken up by the action of the synchros causing the input side shaft to take up the slack) There also tends to be a clunk when letting in the clutch and taking up drive and if you are going on and off the throttle in heavy slow traffic. Although not a noisy box there is a slight whine in intermediate gears which was not there in the diesels. I've mentioned this every time she went for service and was told "it's normal, they're all like that". I think the test drive I took behaved the same but there were many other aspects I was more interested in so wasn't paying particular attention to the 'box.

I've tried to get a test drive in a demonstrator but here's never one available when I ask. It puts me in mind of a box which has been built up far too loosely shimmed between the gears with too much backlash on the final drive. I can just picture the transmission shop instructor, back in the '60's, who, if I'd presented him with a rebuild to this quality, would have put his hands on his hips and said "that'll never do laddy, strip it down and do it again - right this time mind!"

I may be lucky in that my neighbour across the road has just bought a Fabia with the same engine - so I assume the same 'box? - I will ask if he'd let me take it round the block just to see if it's the same. I have to say that in the nearly 4 years of ownership these characteristics have never changed so it doesn't particularly worry me that it will fail prematurely - it just annoys me that it's not, in my eyes, perfect. I dare say the modern propensity for filling gearboxes with lubricant of roughly the same viscosity as water is not helping either.

As a final general reflection on the situation in general, Who thinks "things" have taken a backward step with the introduction of these new small turbo petrol engines? Complexity has increased, everyday reliability seems to have decreased and driveability is definitely poorer on the few I've tried so far. Now we have inlet carbon fouling and LSPI to contend with as well! - Really quite wish I'd bought that 1.8 i-VTEC tourer instead.

 

[Pugglt Auld Jock]

On a road quiet enough..
Cross the white line

It may well pull to the RIGHT
Just follwing the camber of the road.

I chased my tail with my tipo TD.. until a trip to France highlighted this

Merry Christmas everyone.

Just a wee update on this before we set off for my oldest boy's house where we are all (15 of us) having our Christmas meal. I've been using the Panda a lot over this festive period because it's just so handy for doing drop offs up in town - Mrs J going shopping and all the females going to the ballet (Snow Queen) etc - I got the chance to try out Charlie's suggestion (driving on the "wrong" side of the road) on one of my solo return trips and it's been very interesting.

Driving on the left there is a detectable and obvious slight pull to the left. Straddling the white line you are not immediately aware of any pull to the left but if you let the wheel find it's own way (ie take your hands off it) she will drift off to the left very very slightly. Driving on the right, if you take your hands off, she goes, as near as makes no difference, straight. I turned round and took a careful look at the road camber and it was normally cambered. By which I mean there was a small camber to both left and right of the centre line.

So it would seem I do have a small problem and after following the car with the Seat a few days ago and seeing what I think is a very slight "crab" of the rear wheels to the right (particularly the N/S wheel I think) I just can't wait to do more in depth investigations when some better weather prevails.

So, in addition to the Christmas wishes, have a very "guid" new year.
Kindest regards to all
Jock

 

[Popitinpete]

Merry Christmas everyone.

Just a wee update on this before we set off for my oldest boy's house where we are all (15 of us) having our Christmas meal. I've been using the Panda a lot over this festive period because it's just so handy for doing drop offs up in town - Mrs J going shopping and all the females going to the ballet (Snow Queen) etc - I got the chance to try out Charlie's suggestion (driving on the "wrong" side of the road) on one of my solo return trips and it's been very interesting.

Driving on the left there is a detectable and obvious slight pull to the left. Straddling the white line you are not immediately aware of any pull to the left but if you let the wheel find it's own way (ie take your hands off it) she will drift off to the left very very slightly. Driving on the right, if you take your hands off, she goes, as near as makes no difference, straight. I turned round and took a careful look at the road camber and it was normally cambered. By which I mean there was a small camber to both left and right of the centre line.

So it would seem I do have a small problem and after following the car with the Seat a few days ago and seeing what I think is a very slight "crab" of the rear wheels to the right (particularly the N/S wheel I think) I just can't wait to do more in depth investigations when some better weather prevails.

So, in addition to the Christmas wishes, have a very "guid" new year.
Kindest regards to all
Jock

Hi , sorry to reply to an old okd old thread, I've no doubt you've sorted it now but I've just gone down this route myself , cut a long story short , both my 169 pandas over the years have pulled to the left ever so slightly , and I'm always adjusting my tracking to make sure I wear all of my tyres out evenly , if not they will scrub and wear outer the outers or just the inner tread. Had the tracking done , twice , a lot better but still a pull and the wheel not exactly in the straight ahead position even though I made sure the wheel was dead straight before the guy checked anything. Always the same , got home and the pull was there and wheel just off kilter.....finally had enough today so I used my tried and trusted string method , a method I've used for a long long time with fantastic results. Now , I used the string method and it was out , but not just towing in or just towing out , with the steering wheel straight both front wheels were pointing about 2mm to the right....if I then put the steering wheel to its default position , ie just off kilter, the tracking was bang on !....as you know this is EPS ( electronic power steering) , I did some research and after some alignments, or a battery disconnect or someone messing about with other stuff , the EPS can actually lose its ability to find the centre again or it's ability to self centre!
You can with the right software actually tell the EPS where dead centre is and re-calibrate it or if your lucky , turn it from lock to lock and it performs a self centre recalibration . I tried that but no luck so as I'm sick and tired of the car pulling to the left I did the cheat of taking the airbag off , taking the wheel off it's spline and moving it one spline to the right , bingo! Dead straight tracking and dead straight wheel. No pulling . So with engine off, the tracking can be set dead straight but when you start the engine then EPS will actually think the self centering position is where it thinks it is , ie slightly to the left , and actually pull the steering wheel to the left , so it starts pulling and the wheel goes crooked , that's why when you have the alignment checked it's always bang on , but drive it and the centre is just to the left.I will look into getting my EPS position sensor calibrated but for the time being it's fine , also the back axles on the 169 have a very limited adjustment :
The four bolts that hold the rear beam on are a smaller diameter to the actual holes in the beam so with both sides slackened off the beam can ' float' around and actually can be out of track simply by one side being bolted up with that end forward on its bolts and the other side could be bolted up with the that side of the beam biased to the rear, the result is a rear beam either trying to steer the rear of the car slightly right OR slightly left. At the factory the beams are just put on with no attempt at getting the beam perfectly straight , hence why a lot of 169 models scrub the rear tyres....
I checked mine and guess what , the beam was out of true , biased in favour of trying to steer the car to the left...ie , more gap between the wheel and wheelarch on the o/s ( the wheel arch rear seat side) than the gap on the n/s by about 3mm.
I slackened all 8 bolts, applied the handbrake, drove forward about a foot and tightened up the bolts. This then settles the apex of the holes in the rear beam to the same place on all bolts , ie , a ' straight ' back axle. Both sides then measured the same , I'm sure this out of alignment rear beam was not helping with the car pulling to the left.
How did you sort yours?

 

[Pugglt Auld Jock]

Hi , sorry to reply to an old okd old thread, I've no doubt you've sorted it now but I've just gone down this route myself , cut a long story short , both my 169 pandas over the years have pulled to the left ever so slightly , and I'm always adjusting my tracking to make sure I wear all of my tyres out evenly , if not they will scrub and wear outer the outers or just the inner tread. Had the tracking done , twice , a lot better but still a pull and the wheel not exactly in the straight ahead position even though I made sure the wheel was dead straight before the guy checked anything. Always the same , got home and the pull was there and wheel just off kilter.....finally had enough today so I used my tried and trusted string method , a method I've used for a long long time with fantastic results. Now , I used the string method and it was out , but not just towing in or just towing out , with the steering wheel straight both front wheels were pointing about 2mm to the right....if I then put the steering wheel to its default position , ie just off kilter, the tracking was bang on !....as you know this is EPS ( electronic power steering) , I did some research and after some alignments, or a battery disconnect or someone messing about with other stuff , the EPS can actually lose its ability to find the centre again or it's ability to self centre!
You can with the right software actually tell the EPS where dead centre is and re-calibrate it or if your lucky , turn it from lock to lock and it performs a self centre recalibration . I tried that but no luck so as I'm sick and tired of the car pulling to the left I did the cheat of taking the airbag off , taking the wheel off it's spline and moving it one spline to the right , bingo! Dead straight tracking and dead straight wheel. No pulling . So with engine off, the tracking can be set dead straight but when you start the engine then EPS will actually think the self centering position is where it thinks it is , ie slightly to the left , and actually pull the steering wheel to the left , so it starts pulling and the wheel goes crooked , that's why when you have the alignment checked it's always bang on , but drive it and the centre is just to the left.I will look into getting my EPS position sensor calibrated but for the time being it's fine , also the back axles on the 169 have a very limited adjustment :
The four bolts that hold the rear beam on are a smaller diameter to the actual holes in the beam so with both sides slackened off the beam can ' float' around and actually can be out of track simply by one side being bolted up with that end forward on its bolts and the other side could be bolted up with the that side of the beam biased to the rear, the result is a rear beam either trying to steer the rear of the car slightly right OR slightly left. At the factory the beams are just put on with no attempt at getting the beam perfectly straight , hence why a lot of 169 models scrub the rear tyres....
I checked mine and guess what , the beam was out of true , biased in favour of trying to steer the car to the left...ie , more gap between the wheel and wheelarch on the o/s ( the wheel arch rear seat side) than the gap on the n/s by about 3mm.
I slackened all 8 bolts, applied the handbrake, drove forward about a foot and tightened up the bolts. This then settles the apex of the holes in the rear beam to the same place on all bolts , ie , a ' straight ' back axle. Both sides then measured the same , I'm sure this out of alignment rear beam was not helping with the car pulling to the left.
How did you sort yours?

Thank you, what an interesting post. I've mucked about endlessly with Becky's but never improved it much. As it's quite a minor annoyance I'm not all that strongly motivated to spend a lot more time on it. I'd wondered about trying repositioning the steering wheel as, I'm guessing, that might have an effect if the self centering abnormality is due to the electronics rather than the mechanical self centering effect due to KPI angles etc. However what with all the problems around the passing of my brother and other family stuff to say nothing of the normal daily problems that come with just being old and still alive I never got round to it. Thanks for your post though, I greatly enjoyed reading it. If Becky passes her MOT in February then I might get up enough enthusiasm to have another concerted effort to sort it out next spring.

 

[portland_bill]

Somewhere there's a post where someone spent a lot of time measuring everything. They found that the left rear hub mounting plate was slightly out of true, jigged incorrectly when the axle was made. They fixed it with shims behind the hub mounting bolts.
Sadly, the aftermarket axles have copied the original so exactly, that they pull just the same. An opportunity to make the aftermarket one better was missed.

 

[irc]

Somewhere there's a post where someone spent a lot of time measuring everything. They found that the left rear hub mounting plate was slightly out of true, jigged incorrectly when the axle was made. They fixed it with shims behind the hub mounting bolts.
Sadly, the aftermarket axles have copied the original so exactly, that they pull just the same. An opportunity to make the aftermarket one better was missed.

Some of the early ones also had bent brackets for the brake lines except... they were all bent exactly the same. Maybe copied TOO closely?

 

[portland_bill]

Some of the early ones also had bent brackets for the brake lines except... they were all bent exactly the same. Maybe copied TOO closely?

Yep. When I collected my axle, there was a pile, all brackets bent exactly the same on every one. Gave me confidence that the rest of the spec, materials, etc., would be correct.

 

[irc]

First 4 or 5 I had were like this. Then they seem to have realised and tweaked them.
Made me smile at the time.
I did take some measurements to compare against a 2004 almost rust-free original and they were dimensionally spot on, so whatever beam they got their measurements from seems to have been one of the better ones. Or at least not one that had been used to jack the car up.

 

[Popitinpete]

Thank you, what an interesting post. I've mucked about endlessly with Becky's but never improved it much. As it's quite a minor annoyance I'm not all that strongly motivated to spend a lot more time on it. I'd wondered about trying repositioning the steering wheel as, I'm guessing, that might have an effect if the self centering abnormality is due to the electronics rather than the mechanical self centering effect due to KPI angles etc. However what with all the problems around the passing of my brother and other family stuff to say nothing of the normal daily problems that come with just being old and still alive I never got round to it. Thanks for your post though, I greatly enjoyed reading it. If Becky passes her MOT in February then I might get up enough enthusiasm to have another concerted effort to sort it out next spring.

My condolences to you in regards to your brother. Yes if yours is not too bad as you say ' live with it' . Hope the MOT goes ok. All the best to you.