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MG MGF Technical - Handling Again!
Car is back from Dealers - wehayyyyyy :)
But when talking to the dealer he advised me that he still wasnt happy with the handling - although it is much better than before - They checked everything - geometry - bearings-track rod ends - bushes - camber - etc etc etc Anything to do with the suspension was checked and re checked
So as he cant book it into a mg specialist until next week he said i may as well drive it and see what i think!
Anyway - The only way i can describe the handling is that its fine up to 40 ish MPH
Drives straight - brakes straight - /accelerates straight etc etc
Under 40 you can chuck it round s bends no problems
But over 40-50mph the steering feels too oversensitive - so you oversteer - then correct and oversteer the other way - like a viscious cycle - the only way to be in control is to make very small adjustments to the steering - now I thought power steering was meant to vary the faster you went - hence needing more input? - mine doesnt feel like that at all - not fault lights on !
Mine feels like its getting lighter and lighter the faster you go
Any ideas would be welcome before it goes back next week!
|Drive it slower :0)|
I fitted a slick shift gear selector to my girlfriends car last week because she was complaining about the notchy gears. Any how that was a great success and she loves the new feel. But I thought I better test the new shift until, and as you say I was fine until I got on the main road and started to speed up. The car does not feel as sensitive as you have said, but when you come to a corner you have a definite lack of control. I drive a Lexus which I class as an old mans car that should not be driven fast at all, but the handling at the same speed is far far better. So I think the MGF needs to have the same treatment as yours.
Let me know the out come of your tests and this might give me some idea of what needs sorting. Any the girlfriend is happy as she only use’s in to get to work in (in the winter) and then she is sat in traffic most of the time.
Is it EPAS? (It is/was optional) If so get that checked - two possible places for faults in the PAS are the ECU playing up and the torque sensor faulty.
Do you have toe IN or OUT at the front (standard is OUT)
I (and some others here) find toe IN improves the handling at "high" speed and the feeling when cornering (at any speed)
|Tony, ive had the same problem as you mate ever since i got my car!! Everything suspension wise has been checked and ride highet and tracking, but still the same!.|
Ive got a 98 1.8 with no Powersteering or ABS. I was thinking it could be the steering rack being wobbly but no one can tell me that yet!!! I would love to know if you ever get yours sorted out what it was! Sorry I cant be any help.
|Not sure you mentioned it Tony, but the next thing to check is the chassis alignment- particularly of the subframes. If the driving angles are not in the same plane as the longitudinal axis of the car, then 'funny' handling can result.|
Other things to check are items like bump steer characteristics- but check the chassis alignment first.
Also, part of the speed related handling relates to aerodynamics- and here a splitter can help. The KH Assemblies item is widely thought as being best.
Lee, instability under braking is usually down to excess flexibility in the rear tie-bar bush. Remedy is easy either with spacers available from B&G or with poly bushes from B&G and Mike Satur.
|I have to say that this seems to be a front toe angle issue, related to ride height. The circumstances seem to be that as the speed rises a small degree of front end lift is occuring with the increased airflow. The effect will be to raise the suspension slightly and as the suspension moves in an arc up and down this impacts on the distance between the rigid body of the steering rack and the steering arm connection.|
The ride height issue is critical as it dictates the relative position of the rack to wheel centre and the influence this has. Things may well be within the tolerance range but what you find is that being at the end of one tolerance with another being at the other end can mean the cumulative effect is significant enough to create these conditions.
Caster, camber and KPI are non adjustable, and I would not be surprised if the right front caster is only just inside the acepted tolerance. (Production tolerance in the components!!) This leaves the toe settings and here the general feeling,and I subscribe to this too, is to set the front to about 5min toe in per side with 10min total. This is after the suspension ride height is checked and I suggest set to the lowest recomended position. (This will be 368mm which is measured at a nominal 17 degrees C ambient temp. 10mm either side of this setting is permitted to take into account normal temp variations. On this basis if ambient is 7 degrees then you should look at the ride height being 362mm)
Ideally a lower than standard ride height does offer some advantages in stability from reduscing the volume of air which is getting under the front of the car and lifting it.
However if the car is within dealer warranty then really you should remain within standard settings to avoid warranty conflicts.
|Roger, am I understanding correctly that the Rover specified ride height has no tolerance range?|
i.e. it has to be 368mm at 17deg +/- nothing, and the +10/-10mm variance is simply to accomodate changes in temperature?
This suggests that both dealers who pump cars up to 378mm at 17deg (most of them?), and owners (such as me) who depressurise them to 358mm at 17deg , are outside of the guidelines.
I am no mechanic, is it common for no tolerance range to be specified as in this case?
|Thanks to you all for your comments|
Listed below are what has been done so far
Subframe re aligned/checked after removal and refitting
Run on 5 DEG EACH toe IN setting - no difference
Run on Std setting - no difference
Bushes checked -- all suspension components removed - down to subframe - checked and re fitted - NO faults!
One wheel bearing was loose - replaced - no difference to problem but cured the "wild feel"
ride height - run at 330mm then 380mm - now 360mm - no difference felt at any level
Splitter fitted - more stable but no difference to the handling
This might sound daft but turning into a right hand bend feels slightly better than turning into a left hand bend -ITS NEARLY like never knowing quite how much the car is going to turn each time you turn the wheel = but worse on slight bends - slam it into a bend hard and put the car towards its limits and the car behaves well - UNTIL YOU NEED TO ALTER YOUR lime slightly - then your back to small adjustments which dont seem to be consistant with steering input!
Which sorta ties up with the car being better at slow speeds as more input is required to steer the car - or thats how mine feels
Anyway I am going to get diagnostics check Tuesday SO WILL point them at Power steering first!
|will post any results that make a difference!|
One thing i did discover is by reducing tyre pressures the handling improves - its not a cure - but helps
Downside is the tyres will wear on outer edges at lower pressures and braking grip may be compromised a little
I ran mine at 20f 22R which made the car feel much safer !
The ride height factory settings are
Front 368mm +/- 10mm @17 dec C
Rear 363mm +/- 10mm @17 deg C
These alter with temp at a rate of 0.6mm/deg C. Thus at 7 deg C, front is 362mm +/- 10mm and Rear 357mm +/- 10mm. Athough you could argue the tolerance also changes with temp but its probably negligable an I can't be bothered to guestimate it!
Plus the manual is not clear whether to measure to the metal or plastic bit of the wheel arch - a 2mm difference.
Just for info, on my car a Fr at 368mm equates to 400psi; some garages do it to pressure rather than height. Also the measuring process is quite precise; stand for 2hrs, bounce roll, no handbrake, bounce etc. Even then variations occur - average (temp corrected) readings over a few days.
However, as can be seen above, the bbs messages above and extensively in the archives it is an imprecise science with folk modifing height and geometry to preferences.
The whole HG system whilst giving handling advantages can also be a real pain - roll on mark 3 with real springs like most other cars on the planet.... Then the BBS will be full of spring rates, length and damper settings. Ho Hum..
Mine was 400mm all round on delivery and drove like a dog especially on the motorway. Now sorted out and at 359mm at 4000mls later it handles a lot better. But nowhere near as good as a 16" wheeled, decent tyred, lowered (knuckles) and tweaked geometry (camber and toe) car I have driven.
I've asked Santa for a handling kit but my wife says he doesn't exist....
|Ian, tell santa that Techspeed do a very very nice handling kit for about 675 quid...|
Well pleased with it on my car- usual disclaimers apply!!!
HO HO HO
Tony, do you have the figures for the thrust/ drive angles for each subframe and the other alignment data that you can post here? Unfortunately I think that you have a problem that may be a little more complex than the usual glitches we have dealt with here on the BBS.
|Try rear arb drop links,HTH.|
|Rob / all |
I am not entirely convinced it is a suspension problem so dont want to go paying out that sort of money (YET) :)
Considering that i have run the car with a toe in and then toe out setting - then 3 different ride heights and this has made NO difference at all - I can only assume that I am looking in the wrong place
In my opinion it has something to do with steering input being inconsistant with output to the wheels - but only at higher speeds (40mph+)
FOr instance - you are travelling along the motorway at 60mph - on a straight road - - you can take your hands off the wheel and accelerate/brake/coast and the car runs exactly true - no problems
But should you go to change lanes - and make a small input to the steering - the car either moves across the lane too fast or doesnt move enough - so you turn a little more and then it overeacts and turns to fast so you compensate by turning the wheel back and it over steers the other way - so you end up in a fishtail scenario
The only way to correct is to make very small steering inputs ie nudge the steering!
So was interested in the EPAS theory which will be the next line of attack - As said before the car is warrantied - so It has to be right or it will have to go back - Shame though as the car is so clean I am going to struggle to find one in such good condition!
Not giving up on it yet though!
Ian - I think you out to buy your wife "the grinch" :)
I have sent my list to Santa but my wife says she doesnt think the Ferrari will fit in his sleigh :(
|Tony, try the rear ARB droplinks.|
|This probally wont help much but here i go anyway....|
My car felt awful to drive for about 6 months, its been in and out for tracking about 15 times, (still not correct)... 16" Alloys F1 directional tyres fitted, slightly better but still pitching and rolling...
the dealer finally did what I asked and reduced the suspension height, it was,
380 back (I understand that the back is dictated by the front so it probally equates to 375 all round.
when i picked the car it felt amazing, best drive i have ever had out of it.
The next day I mesured the tracking it was 350 all round.... from centre hub to metalwork.
Is this to low.... the drive does feel fantastic but will this put any stress on the car???
|Danny 370 is WAY TOO High 350 is about right!|
And as you say the front is what you measure tha back is linked via a pipe so the front dtermines the back.
|That is a big drop in height! Were the two readings taken in the same way; exactly to the book procedure, level surface, was it corrected for temp etc? I had a recurrent problem with me measuring lower than what the garage set it at. It turned out he was road testing the car to 'warm it up' then pressurising the system to correct height. Then when I got it home lo and behold it had dropped. |
Alternatively, you/they could have introduced air into the system.
I suggest you mesure strictly in accordance with the book several times, average the readings and if out of tolerance take it back and make sure they do it correctly!
|Oh and you're right the hydraulic interconnection determines back ride height but both front and Rear HG units can also be shimmed to correct one if the other is in tolerance.|
|I also found going to decent 195s on the front improved things no end. I found 205s on the front tended to tramline which meant you really had to hold on whenever the ground got slightly uneven. The standard 185 tend to understeer a little too much for me, it was not why I got a mid engined car. |
The need for overcorrection is not usually down to oversteer, this would suggest the effect of overcompensating for understeer to me.
Personally when it comes to height and tracking settings I have allways found it better to throw the Rover figures in the bin and experiment to find your own preference. Rover seem to put forward that this sort of problem can be simply be handled by pumping the car up.
Personally I find the handling and steering improves as the car gets lower providing you compensate by using a toe in setting for the front wheels. Tyre pressure can be varied without damaging the tyres providing you don't go too far either way and I found this can make quite a difference to how the car feels.
I assume after each height change the tracking was set each time, you must know the four wheel alignment gear pretty well by now.
Next on my list for the suspension is to lower it to 340mm by changing the knuckles and maybe get the front and rear hydragas seperated to make it fully independant (a four nipple job). Stick in the anti roll bar polly bushes just to finish it of and that should be it for the forseeable future. Ok, maybe a splitter when I get round to it, but if I'm going down to 340mm it may come off on the first curb I bump into.
I may one day go for 16" wheels but I would only do this so I could fit bigger brakes on the front. As far as I can see 16" wheels will make little difference to the handling, I would expect more change in the ride with the lower profile tyres.
|whats size 195 tyres do u have on your 15 inch wheels tony???|
195 55 15 fronts
205 50 15s rear
NCT3S - if i fit anything else warranty wont cover !
ride height is now just under 360mm
Splitter fitted and even i can feel it works - more stable at the front = less correction = less fishtails
tracking was reset - tried toe in out and shook it allabout :) well i got to laugh :)
So if your in wilts and pass a MGF looking like its totally out of control its one of two things
My fast red MGF with some handleing probs
Nick in his slow green MGF winding up his windows :)
|ok decided to go and re check ride height |
Temp is about 0c
front 347mm right
rear 353 right
so i guess thats about spot on!
Its slightly better lower rather than higher on settings - but bear in mind i was on 330mm at its lowest and this still didnt improve things - maybe very slightly!
While on 330mm i had tracking rechecked at 5mins toe in each side - no difference - then set toe out rover spec - no difference
Another thing - on tugging and pulling at all four wheels - everything feels very stiff - now wheel bearing has been sorted:) but thats was the only problem we found
Standard bounce test gives good result - maybe a little out on rebound - seems a little slow to rise!
car sits perfectly flat - no body roll - even with a couple of us trying to rock it !
I would still call it dangerous to drive
O well 2 days and it goes to the chimps tea party
So rear roll bar drop links
That reminds me - is there any way of running the car without the power steering - ie like a non assisted car - with the engine off the steering doesnt feel too bad - just wondered if i could test drive it without to see if this may be a problem !
I assume the power steering works on ecu anD input from servo ?? could there be a leak ? in a hose i mean ? Anyone know how the power steering functions on the F or have details ?
i CHECKED FLUID - NO LOSS
I am flicking through my manual and it mentions the EPAS system electronic power assisted steering..
it says the EPAS ECU is located above the glovebox behind the dash and incorporates a fail safe mechanism which will make it revert to manual steering should it fail. Fault codes are stored in the ECU memory for identification by textbook.
The EPAS has a torque sensor on the column and an electric motor to add assistance. The assistance calculated by the ECU varies with steering input (torque) and road speed; i.e. mutes assistance at speed. From what you described my money is on the speed sensor being duff and not muting the EPAS at speed. The sensor is located at the rear of the car - somewhere... I guess a testbook/MGR could check it out for you.
There's a big 40A fuse under the bonnet near the main fuse box that supplies permanant 12v to the ECU. I have read on either this BBS or the MGOC BBS of people that have removed this fuse to disable the EPAS and revert to manual but I wouldn't do it or recommend it...
I assume the rack and column is not loose...
On another tack altogether, if everything checks out OK. :-
I did take a while to get used to the EPAS on my MGF - to me it feels over sensitive. Holding the wheel lighter/smoother seems to improve things - just a thought. Sudden torque inputs and car response dynamics might create the situation you described. But this should have been tuned out by MGR.
Aircraft pilots can induce similar instability called Pilot Induced Oscillation. With apologies to all you pilots / control engineers out there, a simplistic outline...
PIO is where there is a lag from contol input to an aircraft reponse. For example the pilot pulls the stick up, nothing happens for a moment so he pulls it up more and the aircraft pulls up sharply.. oops! So he pushes the stick down to correct it and nothing happens so he pushes it down further and the aircraft goes down sharply.. oops again, and so on, up and down, ever increasing and at some point he stops, crashes, throws up or all three. The job of a control engineer is to dial this characteristic out using joined up sums!
Why tell you all this? Think about it next time you're driving. Change the way you steer and see if it helps. In fact change anything in the system from driver to suspension bushes to play to stiffness to tyres and the response changes.
think you may be onto something
I am going to get it checked - and if that doesnt work rip out the EPAS fuse hehe - it really isnt consistant steering - especially high speed low input = so seems the obvious choice that the sensor may be duff! REALLY feels heavier at lower speed than higher speed - which is backwards! Especially with the splitter fitted!
No movement in rack - totally solid all the way to the wheels - although thats kinda how it feels except instead of getting lag - you get more steering than you expected way to light and sensitive for the speed !
I did find holding the wheel lightly and very sensitive input helps - but thats not the way the car should be - no way - people with less experience and road time would die in BIG motorway pile ups!
One big problem is if overtaking lorries and trying to correct the buffeting - beacause its tiny inputs you have to be very careful as the car tries to rush under the truck wheels :)
OR - perhaps i have a little japanese ghost in my car ???
Warning - may be out fuseless tommorow - so watch out :)
Thanks for all your replies :)
Very helpfull -
Nick Can i have a look at your manual/handbook sometime !
I've only recently come across this thread. My '96 F has EPAS and has always been very stable at high speed (well 95mph anyway) and a joy to drive fast.
Then came the day I replaced the rear tyres (with same as original equipment), wheels balanced, no other changes. I drove the car home, and at the first bit of dual carriageway, put my foot down, but at 65+ mph, WOW was the car unstable !!
In many ways the handling is similar to your original posting but at a higher speed - it is fine up to 65 ish MPH; the car is stable & reponsive, everything happening as it should.
But over 65mph the steering is way oversensitive - and with out trying, it oversteers - then a correction and oversteers the other way - I really thought it would be easy to loose the car on more than one occassion. This was very scary and it felt really unsafe.
ok, there may have been some newness in the tread surface or initial stiffness in the tyre walls, but it's way past that now, and the problem persists. It also has nothing to do with wind speed or direction.
Yes I have checked the tyre pressures, and there is plenty of tread left on the front tyres.
It is a test of nerves, and very gentle steering is required to go near the 70 mark now.
As much of my driving (for pleasure) is along the coast which is often beseiged with traffic, this has not been a problem, and I have tolerated it. But I am very concerned that the performance has seemingly changed quite dramatically, and I don't know why.
The tyre change may be pure coincidence, as no height / tracking changes were touched (I was there), and they were rear tyres anyway; but it is the only obvious change. btw I've only done 26k miles.
So, I will be most interested in the outcome of your EPAS test and whether the sensor or other factor can make a difference. The MGF has been a great car but this does spoil it.
|Tony, taking out the fuse will certainly determine whether the EPAS is contributing to the problem or not!|
Re the speed sensor and I dont know whether it is the same speed sensor I referred to above. When I first had my car I complained about engine/MEMS 3 control smoothness; another topic for a BBS. Anyway MGR put it on testbook and the fault code P0500 came up - speed sensor fault. On ABS cars it is the ABS ECU that generates the signal from the wheel sensors. On non ABS cars it is a sensor fitted to the NSR hub (note where it is Rob! - could it have been damaged?). A toothed wheel on the back of the hub generates pulses in the sensor and mutes the MEMS 3 missfire detection system on a rough road.... Predictably they had to order a new sensor and it took about a week and 30 mins to fit. I didn't have any of your symptoms though - in fact no symptoms at all and it didn't fix the engine either.
Rob/Tony I would definately get both cars checked by MGF experienced folk at a MGR dealer, neither sound safe to me nor should they drive like that. Better to be safe than sorry...
|Thanks Ian |
Will give it a go just for sciences benefit :)
Should I hedge it I will endevour to replace fuse before ambulance arrives :)
This is interesting !
I had my rear tyres changed as soon as i got the car to standard NCT3s ! - From memory the car was a little wandery before the tyre change but i did do over 100mph here n there so wasnt that bad! (without a splitter)
Wouldnt get near 100mph now with a splitter!
Now the rears i changed were like for like but the old nct3s were nearly bald - unless the new tyres are duff uns - what tyres did you have before ??
More info for the garage!
ARE MG still spec ing NCT3s?
Wonder if its worth swapping over some wheels to F1s JUST TO SEE IF THERE IS ANY DIFFERENCE
Nick - what tyres u got ??? :) heehe
|If I was a betting man I wouldn't put money on the tyres being at fault providing they are the correct size. The effect you described is symptomatic of steering induced instability. |
You also mentioned several times about a splitter I assume this redirects air flow around/over the car and thus reducing lift and increasing down force. Or at least it does on the front. Do you have a matching rear spoiler? I'm a bit rusty (cr*p!) on aerodynamics but is the back end a bit light at speed and thus contribute to the effect you described. Was it OK before this was fitted? You could try a weight in the boot to see if its that; a concrete slab etc... But I guess this isn't it as the splitter manufacturers would have found this out anyway.
So back to MGR for testbook inquisition on the EPAS for me!
I'm running standard NCT3s as previously fitted. I don't see how the tyres alone would make a difference, particularly as they are at the back.
Ian, I do not have ABS, so your comment is very interesting, as indeed changing the rear roads wheels could be one of the few times the rear hubs are exposed.
I did speak to my garage about this previously, but they sounded very clueless. Now there may be something here that can be tested / substituted, so it is worth re-approaching them.
the car was slightly worse without the splitter - all this has done is create more downforce for the entire car
ROB - Do you have power steering ?
The rear tyres/suspension can really affect steering feel - ie if the rear wheels flex too much under load they can tend to add rear wheel steer making the car feel like its on ice - so all four wheels and suspension settings are very important
I am going to mail Goodyear and see what response i get - ie - complaints about nct3s
Yes I do have power steering. However the car has been well treated and 'sits' correctly so I have no reason to think anything should be badly amiss there.
The Service Engineer is away this week so I will not be able to get any decent response from my garage until next week, but I will certainly be enquiring about the speed sensor.
I am taking mine to MG tommorow
Will be driving it with the power steering fuse out to see what affect that has other than building muscles :)
Will let you know!
Note Mike's simple little comment about rear ARB links. He doesn't often say much but when he does it's worth listening!!
In respect of disabling the EPAS you can run the engine whilst stationary at about 2500 rpm for a couple of minutes and watch the EPAS warning lamp come on. This is because the system is programmed to expect engine rpm way above idle to be accompanied by a speed signal. Because it doesn't get that road speed signal the system assumes a sensor breakdown and shuts off EPAS. Now what should happen is that this will shut the EPAS until you switch the ignition off, and the system shuts down. (about 10secs after the ignition is switched off)
When you restart the engine the EPAS warning lamp will be illuminated until you start to drive and then when the EPAS ECU receives both engine speed and road speed signals it will reinstate EPAS. There will be a fault code entered in the ECU memory, but this will be automatically erased after a set number of ignition on and off cycles.
It's worth trying this as you do not have to 'remove' or 'disconnect' anything.
Going back to your now distant question. The setting is specific at 368mm at 17 degrees C. It is assumed that dealer workshops will operate at an average of this temp, and that before any car is worked upon a 2 hour rest time will be present for the whole car to equalise temps. It does however allow the plus or minus 10mm to account for alternative temps. There is a little more flexibility with the systems than this indicates and this is often tested by delaer and owner variations.
|Thanks for the reply Roger. So basically the idea is the car should be at 368 at 17deg but a little higher or lower is allowable.|
Ian, interesting that some dealers set ride height by pressure - would be more reliable than measuring on a possibly uneven surface I would have thought.
Interestingly, when I lowered my car from c375 to c360 although the handling improved, to me the ride quality suffered noticably. If only my insurance would let me fit knuckles...
|Thanks Roger - all !|
I am certain I have run the car on idle before for a long time before driving off - say 10 minutes and have not had the EPAS shut down - maybe this is linked to my feeling that the steering is not "tuned" to the speed !
Anyway - awaiting call from Rover!
Guess what car they gave me as a courtesy car
Mazda MX5 :) LOL
|if its got epas either the epas ecu or steering column- both should show epas light intermitently - sounds silly but also check tyre pressures are not too high|
|Thanks John - My feeling is its the power steering !|
definately agree about tyre pressure - mine runs better with 4 psi less than standard and was dead scary with 3-4 psi too much in !
|>Guess what car they gave me as a courtesy car|
How did you sleep in the MIXy ? ;)
Take care that you don't getta puncture if on a ride together with a co-driver.
No space for the replaced wheel then !!
|The MX5 is quite a nice little car - although its not as "street cred" as the F |
In saying that I had a great drive back through Cheddar Gorge in it and really enjoyed it
Must say its not as comfortable as the F seat wise
Engine is good when you thrash it - but i miss being able to slide the rear end out off the throttle - no torque!
All the fun in the MX is to be had at 6000 rpm which is good except you keep breaking the speed limits to enjoy it
All in all the F is better by a long way - it has character!
So thats scuppered the idea of getting a MX5 - lets hope they find the Fs handling probs or I may end up with a westfield!
Well I rang my MGR Service Manager this morning. I explained the fact that another person(you)had worse handling problems than me but of a similar nature, and that checking your suspension geometry, springs etc. had made no difference. In my case the handling changed seemingly as a direct result of fitting new (original spec NCT3) rear tyres.
I got the point across of a possible speed related problem in the EPAS, it being wildly oversensitive at higher speeds, then went on to suggest the potential sensor problem, based on Ian's suggestion. They have no experience of this nature of problem affecting the steering, and were perhaps unaware (put on the spot) that the sensor was in the NSR hub. They have asked me to fax in details of the problem I have got, and they will then approach MGR for info on the sensor.
Unlike you my car is well out of warranty, and I am not willing to fork out mega pounds for no improvement, plus I also cannot just drop into my dealer and leave the car with them on a work day. However, now that there is a worthwhile lead to follow up I will try to get this resolved.
Tony, did you drive your car with the EPAS fuse out ? Did it make a difference / improve it ?
Have just picked up on this thread.
Over sensitive EPAS at speed was I believe experienced by Dirk with his F. AFter changing the speed sensor, it was partly cured by changing the torque sensor in the column.
I had problems with my EPAS last year (different to yours), and Rover told me that it was not possible for EPAS to cause such a problem as faults always cause the system to fail safe - it doesn't!
Anyway I found and cured my problem by systematically changing the whole system - Dirk then tried my spare parts to cure his EPAS woes!
Driving the car with disabled EPAS is not a problem - much the same as a non EPAS car, and good exercise, not to mention stopping my wife borrowing the F!
If you need any advice on the EPAS system let me know.
|Rob, take a Workshop Manual or get MGR to look up steering section page 1! There is a picture of the component location and '5' is the 'Road speed transducer' at the RNS close to where my u/s speed sensor was. Can't see MGR fitting more than one. If you look under the car at the back of the RNS hub you can see the toothed ring on the hub. I think the transducer is mounted above it. On page 7 of the above manual section is a picture of the 'Road speed transducer' The description section doesn't explain the speed sensor well at all; could explain why MGR are a bit vague.|
However, if you look at the suspension section and on page 2 'Front suspension components' (I think MGR have transposed the F & R diagrams in the manual....) you can see the toothed ring clearly on the back of the stub axle. Sorry I can't fax or scan pages from home.
Anyway Testbook will detect u/s sensor and you could look for damage to wiring/sensor etc too.
|Thanks Jason Ian and Rob|
More n more info leading to this conclusion - EPAS!!!
I didnt run it with the fuse out - decided it wasnt my problem to sort out - the joys of warranty !:)
I will however send this info on to the Rover dealer as I expect I will get the standard response - It cant be EPAS blah blah blah - (This is where i ask the mechanic if a F outhandles an MX5 and challenge him to beat me on a 2 mile trip down the lanes - assuming the garage is well insured it wont be too long until a brand new F is sitting in my garage and there will be one less monkey in the dealers to argue with :) )
Whatever happens I will let you all know what the outcome is - hope to hear in the next few days what is found if anything!
May be worth trying the EPAS OFF - Someone mentioned that starting and idleing the car for a number of minutes disables the EPAS ?
|Roger said above - run the engine whilst stationary at about 2500 rpm for a couple of minutes and watch the EPAS warning lamp come on... system assumes a sensor breakdown and shuts off EPAS. I must try it for a bit of fun!|
|Hi Tony, Ian, Rog & Jason,|
Thanks for your comments and advise.
I emailed my Dealership today with relevant info and they contacted MGR. My Service Managr just phoned me back with an update:-
MGR say that the ABS sensor ring is common to all models as a standard rear hub assembly, even if not fitted with ABS. There is NO sensor associated with the EPAS here, but is runs off a signal from the speedo transducer in the gearbox which feeds the ECU and thence to the EPAS.
You will understand that that is not the answer I was anticipating, and a step back is required. It seemed very neat to tie the event of changing the rear tyres to the change in handling, but this just may be coincidence. The gearbox sensor is obviously working o.k. as the speedo is still working o.k.
The Service Manager says that these EPAS units are very reliable, and would normally fail completely if there was a problem. He has suggested, (as has been suggested to Tony on this board) that I disconnect the EPAS, either by removing the fuse, or by disconnecting the EPAS connector to the left of the driver footwell. I think this is my next move, at least that will determine whether it is over-assisted, or a problem elsewhere. If it is an EPAS problem I guess it is a case of substitution in the steering colomn or EPAS unit, and I can see big bills looming as various parts are changed. Bad news.
That's it for now.
|>EPAS units are very reliable, and would normally fail completely if there was a problem.|
Surely a contradiction in terms here? Some would say this about the whole car...:-)
nobody surfed for information in the archives or technical web sides ?
Anyway, the speed sensor is a small Reed Switch inside the instruments.
See the thread due to Navi Sensor, GAL.
Dunno whether a faulty switch is the case for the above written failures, but it can stick and result in 'no speed signal'. IMO no intermittant trouble. It works, or it gets broken.
Wiring of the EPAS system is another case. Loads of contacts in multiplugs which can have bad contact.
Torque sensor at the column was also once mentioned as failure.
|Well car was back today and still no joy - felt a little better but no obvious faults from the diagnoses found|
I think they tweaked the geometry - copy of report on its way as to what was done BUT all in all no real improvement!
Anyway - As it felt a little better I thought I would treat myself to a new set of front tyres - Rover also said that as the fronts were worn on inner edges they would prefer to reset geometry with new rubber fitted on Monday
So I had a new pair of NCT3s fitted - chose Ncts soley to avoid any arguments with Rover !
Now I drove out on the new rubber and REVELATION the car goes where its meant to - NO wobbly feel - No oversensitive steering - 90mph on the motorway without heart in mouth etc etc !!!!!!!
Being wet tonight the car doesnt feel great - but then I can accept that given the reputation of the NCTs(they feel wooden - no feedback at all) but I could actually drive without fear of wiping out on a bend - hooorahhhhhh !!!
So just for your info - The rears are brand new NCT3s 205s(done approx 500 miles)
The fronts Brand new NCT3s 195s
The old fronts were worn on the inner edges - so anyone with the same problems - I urge them to get the tread gauge out and check the fronts for even tread depth as this really affected my car badly !
Tracking is now set to parrallel - will be reset to toe in on monday!
I find it amazing that there can be such a difference between one set of tyres and another of the same make - there was just a few mm between the depth of tread on the outer compared to the inner old tyres
I saw other threads tonight about worn rear tyres causing a problem - but believe me - worn fronts are just as bad
Now all I need to do is get some decent rubber fitted -SO2/3s or RE720S - unfortunately I had to go for NCTs to accomadate rovers request and the feedback they give is non existant - however I actually enjoyed driving the car tonight - so things can only improve from here !!!
Thank you all for your help and advice - I think I have cracked it! Never would have believed it was worn front tyres causing such awful handling!
And all set about by replacing the rears!!!
Maybe these cars just need all four tyres replaced at once?
Cor! Just imagine your reaction if you'd taken the plunge and gone for a proper tyre instead of the NCT3s ??? ;o)
Into a different league of handling (and wear).
|Excellent! All's well that ends well!|
I Enjoyed the debate trying to solve the problem too!
I guess the moral of the story with the benefit of hindsight is to borrow some wheels/tyres to eliminate effect of tyre/wear combinations to aid diagnostics.
Enjoy your 'F' again!
|Tony, Uneven wear on the front tyres seems very common. I had this problem with the Rover tracking settings. I have not had this problem since I changed to a toe in setting at the front. I still believe the Rover toe out setting at the front is simply wrong.|
If yours is under warranty see if Rover will pay half for the new tyres. I won't buy tyres from Rover dealers because they charge nearly twice what other tyre dealers will charge you. So even with Rover paying half you are getting NCT3 for the same price as you can get them elsewhere.
This thread was discussed between 29/11/2001 and 15/12/2001
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