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Topic: Autobox Problem (Read 6197 times) |
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Highlander
Moderator
Expert
13 Scorpios, XR4x4, Suzuki SJ413 for off road :)
 
Posts: 8244
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Re: Autobox Problem
« Reply #20 on: Jun 7th, 2010, 3:38pm » |
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Traction control light would point to a problem at the rear rather than the front.
I'd have a very close look at the rear wheel bearings before you attempt 90mph again 
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on Oct 17th, 2011, 12:35pm, Simmo wrote:I give up !  Too much for an old boy!  |
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Tekno
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Tenho Ruohoranta
Posts: 599
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Re: Autobox Problem
« Reply #21 on: Jun 7th, 2010, 3:41pm » |
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Front abs sensor connectors can have massive amount of sand inside them. I removed them and soldered wires together. They are now also easy to measure and keep more clean.
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1998 Ford Scorpio Ultima Estate 2.3i 16V
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Cosray
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8th Scorpio, 2nd Cosworth: currently '95
Posts: 569
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Re: Autobox Problem
« Reply #22 on: Jun 7th, 2010, 7:58pm » |
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Yes Mike H, it does and it should. Each ABS-sensor generates a digital stream of one's and noughts when turning and when these do not match within say 10% ? of the others the ABS processor decides to sound the alarm and light the LED.
Therefore Highlanders suggestion to have a good look at the rear bearings is valubale. Once they start sqeaking or chirping it's too late.
Here's a bit of text on the subject:
http://www.fordscorpio.co.uk/abssystem.htm
Go to section FAULT --- SUGGESTED ACTION => ABS Light goes off etc. etc.
HTH,
Ray
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Mike H
Senior Member
Renault Clio
Posts: 2594
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Re: Autobox Problem
« Reply #23 on: Jun 8th, 2010, 6:26pm » |
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Fussy innit? 
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Mike H
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Cosray
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8th Scorpio, 2nd Cosworth: currently '95
Posts: 569
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Re: Autobox Problem
« Reply #24 on: Jun 8th, 2010, 6:43pm » |
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on Jun 8th, 2010, 6:26pm, Mike H wrote:Fussy innit?
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Which part , Mike H?
RAy
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Mike H
Senior Member
Renault Clio
Posts: 2594
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Re: Autobox Problem
« Reply #25 on: Jun 8th, 2010, 7:41pm » |
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ABS processor I presume
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Mike H
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Cosray
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8th Scorpio, 2nd Cosworth: currently '95
Posts: 569
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Re: Autobox Problem
« Reply #26 on: Jun 8th, 2010, 8:01pm » |
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on Jun 8th, 2010, 7:41pm, Mike H wrote:
Nothing fussy about that! Just an old tired processor comparing the timing of 4 signals... if one sensorsignal comes in slower than the other - meaning its wheel is slippin' an' slidin' - it will release the brakes on that wheel... and so on 4 times in a row, very quickly. So you won't have to pump your braking pedal... and dream on being safe.
HTH,
Ray
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faffi
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Two-wheeled cornering
Posts: 109
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Re: Autobox Problem
« Reply #27 on: Jun 8th, 2010, 9:41pm » |
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Still, you can really feel the ABS system on the Scorpio is of a very old generation. Regulation is very slow, which makes braking distances very long. And if it is really icy on the road, you actually risk the rear overtaking the front if you don't get off the brake soon enough.
The biggest let-down with the 2004 Mondeo I now have is that it's ABS is barely better than that of the Scorpio. Most modern cars will stop incredibly rapidly on dry road also with the ABS system working due to rapid cycling, but these Fords takes much longer to stop with the ABS than without, unfortunately.
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Cosray
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8th Scorpio, 2nd Cosworth: currently '95
Posts: 569
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Re: Autobox Problem
« Reply #28 on: Jun 8th, 2010, 10:02pm » |
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Dear faffi -- the longest and most disturbed and frantic reaction delay routing is between the situation - your eye - your poor paleontically old overworked brain busy visually processing, comparing, doing risk management and deciding - your spine - your right foot.
Everything else - hardware, software - is lightning fast, compared. Your ABS slow speed theory holds no water and is of no significance at all in the situation.
It will perform regardless if you are aware of it, which cannot be said of the brain.
Over to you, Ray
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faffi
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Two-wheeled cornering
Posts: 109
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Re: Autobox Problem
« Reply #29 on: Jun 8th, 2010, 10:37pm » |
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Not saying I would be without - I'm simply saying that compared to current systems, it's not very good. Back when Ford introduced this ABS system (1985?) there was a magazine doing tests with and without engaging the ABS. And the test driver beat the ABS even on ice (and by a lot in the dry) - although with practice and without experience anything panicking. So it is a safety enhancer for the odd situations where you mess up. I just wish it was better
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Tekno
Full Member
Tenho Ruohoranta
Posts: 599
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Re: Autobox Problem
« Reply #31 on: Jun 9th, 2010, 5:48pm » |
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I've tested scorpio with and without abs on dry tarmac. with abs it stops clearly quicker... on wet, gravel and ice its vice versa
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1998 Ford Scorpio Ultima Estate 2.3i 16V
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faffi
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Two-wheeled cornering
Posts: 109
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Re: Autobox Problem
« Reply #32 on: Jun 9th, 2010, 7:23pm » |
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Thanks for the links - although I was familiar with most of what was written, it was new to me that ABS would do so much worse on slippery surfaces. That's entirely opposite to motorcycles, where ABS outshines non-ABS by a significant margin when it's slippery, but only rarely does the ABS match the non-ABS in the dry.
I am pretty certain that on motorcycles, the ABS reads how quickly each wheel is retarding (and frankly, I thought this was the case also with cars) and if it slows too quickly, it means it is about to lock up and pressure is released. The development between the BMW bike system of 1988 and today is massive, however, and today they are the best stoppers in the business. Honda has opted to go for slightly less than maximum braking in order to keep their bikes level and make absolutely sure they won't sommersault. Others, like Yamaha and Ducati, have the ability to topple over forward if there is enough grip, requiring a very alert and skilled rider to maintain control. For very experienced and good riders, the BMW has the best system. For 95% of the population, Honda's system is superior because it doesn't require the rider to think or react other than squeezing the brakes.
My main concern with the Ford system fitted to the Scorpio and the Mondeo is the slow cycling - you can hear it go thump-thump-thump. Another design fault is early onset - they ABS starts to regulate before the tyres are out of grip. At work, we have a 2005 Toyota Yaris, and I have driven it for nearly 3 years from time to time, and only this winter did I realise it was ABS equipped when it softly came in and assisted while braking on black ice.
One thing that I find hard to understand, is that people actually get startled enough to release the brakes in a panic situation when the ABS kicks in. I normally just keep the pedal to the floor and let the system do its job - although I have begun to release and reapply in slick conditions with my Ford because the ABS simply cannot get the car stopped effectively enough - just as stated by the article.
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Cosray
Full Member
8th Scorpio, 2nd Cosworth: currently '95
Posts: 569
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Re: Autobox Problem
« Reply #33 on: Jun 9th, 2010, 10:36pm » |
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Faffi, motorbikes' wheels + tyres may have a considerably less mass.
Also, the mass of the total vehicle to be stopped is probably... what half of that of a car? As I am sure the decelaration curve follows a square law these smaller masses may be a significant factor.
As a result, even a comparable system may respond much sharper on a bike than on a car, as the rotating mass has less inertia and subsequent forces are smaller.
What do you think?
Ray
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Mike H
Senior Member
Renault Clio
Posts: 2594
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Re: Autobox Problem
« Reply #34 on: Jun 11th, 2010, 7:07pm » |
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I dunno either of my Moto Guzzi's wheels are easily as heavy as a car wheel. Have carried a Scorp wheel up to the tyre place at top of our street but not sure I fancy carrying one on the MG's wheels any great distance. Mind you that's with the discs still bolted on as well.
Problee near enough right about overall weight, once you get two bods on and certainly with luggage as well.
on Jun 8th, 2010, 8:01pm, Cosray wrote:
Nothing fussy about that!
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Ahem, praps I should mention that was a joke.  Originally
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Mike H
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Mike H
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Renault Clio
Posts: 2594
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Re: Autobox Problem
« Reply #35 on: Jun 11th, 2010, 7:50pm » |
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Appendix ~ on average a motorcycle has only one eighth the rubber contact compared with an average modern car (wider tyres and all that), not a half as you might imagine cos it's only got half the number of wheels.
If either wheel locks you're usually thrown off straightaway (especially the front). So detecting onset of wheel lock suddenly becomes a very important consideration.
My Scorp handbook only says ABS allows you to steer around an obstacle while braking, not specifically that you'd be able to stop in a shorter distance than without ABS. Also it warns slippery conditions still require great respect.
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Mike H
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faffi
Full Member
Two-wheeled cornering
Posts: 109
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Re: Autobox Problem
« Reply #36 on: Jun 11th, 2010, 8:33pm » |
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In a straight line, locking up the front tyre on a motorcycle is no problem as long as you don't slide too long - I often lock up the front, especially in the wet, on purpose to to feel the limit and make sure I release as I should. While leaned over, however, locking up a wheel can quickly land you on your ear.
Motorcycles and cars stop in about the same distance, but messing up doesn't have the same negative impact in cars.
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tlundkvi
Full Member
Ex. Scorpio 2.9 24V -95
Posts: 909
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Re: Autobox Problem
« Reply #37 on: Jun 11th, 2010, 9:40pm » |
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on Jun 11th, 2010, 7:50pm, Mike H wrote:
My Scorp handbook only says ABS allows you to steer around an obstacle while braking, not specifically that you'd be able to stop in a shorter distance than without ABS. Also it warns slippery conditions still require great respect.
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I believe this is the right way to see ABS.
I think shorter breaking distance is one of the great misconceptions with ABS. ABS reduces breaking power to get better control of the car in these situations, locked wheel will always stop faster because of the friction, but the car will only steer when the wheels are rotating, simply speaking. Good tires will cut breaking distance quite remarkably too.
Regarding slippery condition, couldn't agree more. Everyone knows the pump-the-brakes theory from the driving academy (we steered around an imaginary elk on a track covered with ice and snow in Finland  ), but when in the real situation most are likely to panic anyway, hence the need for ESPs, ABS etc.
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faffi
Full Member
Two-wheeled cornering
Posts: 109
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Re: Autobox Problem
« Reply #38 on: Jun 11th, 2010, 11:03pm » |
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on Jun 11th, 2010, 9:40pm, tlundkvi wrote:
locked wheel will always stop faster because of the friction,
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Locked wheels will never stop the vehicle quicker on any form of firm surface. In deep snow or gravel, perhaps, but not on asphalt of slick ice etc.
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Mike H
Senior Member
Renault Clio
Posts: 2594
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Re: Autobox Problem
« Reply #39 on: Jun 12th, 2010, 1:44pm » |
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I am reminded of many years ago my driving instructor (was a long time ago!) was rammed in the side by a 4x4 failing to stop coming out of a side road on packed snow.
The driver was like "But I was in 4 wheel drive!"
My instructor was like "And that makes a difference because?"
LOL 
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Mike H
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