Throttle Steering

[CaptainK 11]

Before I start, this is for a 1998 Ford Ka 1.3 Endura OHV engine with NO power steering (G/Fs car), but I'm guessing it could happen to any car.

 

The problem is that on applying throttle the car steers itself fractionally to the right (the amount it does it by depends on how hard you plant the throttle). It should be noted the steering wheel doesn't move, but the car seems to steer to the right. This only happens for about a second or two.

 

Likewise if you let off the throttle - e.g. cruising at 50mph and let foot of throttle - then the car will steer to the left in the manor described above.

 

Apart from that, it steers very well using the steering wheel and drives straight - doesn't wander when you let go of the wheel. Braking does not causing it to sway or move to either side either.

 

Its not a major issue, but if you are hammering it onto the bypass (full throttle) it means everytime you change gear you get a lurch to the right as you plant it and then to the left when you let off to change gear and then back to the right when you re-engage gear.

 

I'd *guess* its a change in weight as throttle on the weight shifts to the back, and throttle off the weight shifts to the front.

 

Its not:

1) Engine rev specific - i.e. if I'm cruising at 50 and already have the clutch down, changes in revs do not affect it.

2) Tyres and alignment are all good as got that done yesterday.

3) Front suspension bushes were changed also yesterday.

 

We've just bought the car and its always been like this. If anyone has any ideas on what to check I'd greatly appreciate it.

[welshpug 1,657]

I drove an escort that did this, bloody scary as I'd imagine it was a bit more vicious than yours!

 

Check that the balljoint pins are the right size, there were differences on the escort but I don't know about the fiesta, it wasn't the main cause of the problem on said escort but made it 100 times worse.

 

Apparently the gearbox was shot, or more specifically the diff, its the only thing that we didn't change on the car before the driver left us for another haulage company

(complete lower arms were changed, tre's brake calipers stripped and rebuilt in case they were dragging, one was a bit stiff)

[CaptainK 11]

Apparently the gearbox was shot, or more specifically the diff, its the only thing that we didn't change on the car before the driver left us for another haulage company

(complete lower arms were changed, tre's brake calipers stripped and rebuilt in case they were dragging, one was a bit stiff)

Oh dear.... that sounds expensive. I think I'll just put up with it if its that.

 

Thanks for reminding me - the drivers side lower suspension arm was also replaced yesterday as well as that had some play in it. None of the alignment, bushes or new lower arm cured the problem.

[Ahl 4]

It will most likely be something connecting the wheels. The typical cause is wishbone bushes on a 205GTI, but you say they are fine?

 

Wishbone balljoints/bushes/trackrod ends/Anti-roll bar links? etc etc

 

Steering rack too - the left side balljoint on the rack seems to go on 205's.

 

I'd give everything a good shake/lever and see if you can find something that moves when it shouldn't.

As Welshpug says, it could be the diff too, but its much much more likely to be something else first.

[M@tt 77]

i've just expereinced the exact same thing on my 205 this weekend on the Euro Trip the car would dive left and right coming on and off the gas. It's had new OE wishbones that have done less than a couple of thousand miles so i'm pretty confifent it's not the bushes but wouln't rule it out till i've had a look.

 

I'm thinking it might me ovalled ball joint hole in the hub. I'll let you know, the plan is to have the wheels of it this week and check it out

Edited May 13, 2008 by M@tt

[CaptainK 11]

I'm thinking it might me ovalled ball joint hole in the hub. I'll let you know, the plan is to have the wheels of it this week and check it out

That would be fab if you could let me know your findings. This Ka does dive left and right if you are hard on / off the throttle. But the way my G/F drives, its not noticeable (she's a learner). As its her car I don't see it much or have the opportunity to steal it to take to a garage.

 

Thanks.

[brianthemagical 1]

Do the brakes ahve any effect? I.e. off the accelerator on the brakes having the same effect as coming off the throttle, if that makes sense.

[KRISKARRERA 2 1 Cars]

My friend had this recently on his Escort - was wishbones.

[CaptainK 11]

Do the brakes ahve any effect? I.e. off the accelerator on the brakes having the same effect as coming off the throttle, if that makes sense.

It only happens just as I let off the throttle - literally just a quick jink to the left (throttle coming off). By the time my foot has moved onto the brake pedal its stopped doing it.

 

BUT, when my foot is on the brake I can brake as hard as I like and it brakes in a straight line and doesn't move around.

[CaptainK 11]

My friend had this recently on his Escort - was wishbones.

Sorry to sound a bit dense, but which bits exactly are the wishbones? The Ka just had a new lower suspension arm on the drivers side complete with bushes etc - made no difference.

 

Thanks again to all so far.

[Batfink 201]

when I was running completely knackered driveshafts it would steer when I came off the throttle - was pretty dangerous.

Easy to check though

[CaptainK 11]

when I was running completely knackered driveshafts it would steer when I came off the throttle - was pretty dangerous.

Easy to check though

How does one go about checking? I'm afraid to say this kind of thing is way out of my ballpark..... like most things on cars except the usual service stuff.

[Ahl 4]

There are probably other ways of checking, but I was always to told to stick the car on full lock (both ways) and drive round in a circle, with loud clicking noises indicating knackered driveshafts. (or certainly the outer CV joint I would imagine.)

[CaptainK 11]

Will do next time I drive it. But then thinking about it, my G/F has been learning in this Ka and I've been making her do lots of reverse parkings and haven't heard much. Still, will give it a go sometime. Thanks.

[stufarri 98 3 Cars]

Sorry if this is a numbnut post but could it not be worn engine mounts?

 

The reason I ask is that I replaced the inner wing mount on my 1.9 and this has reduced the on/off the throttle pulling to one side then the other. My bottom mount is shagged too so I am hoping replacing this cures it altogether?

 

Stu

[CaptainK 11]

Could be. Anything is possible at this moment. Still trying to find out myself.

 

I do know it jerks more to the side the faster the speed is, and more so if you are booting it before you change gear and thus let off the throttle as you change gear.