What's wrong with my 2010 Ford Focus - does it sound like the differential?

Forums › Transport (cars, bikes and boats) › What's wrong with my 2010 Ford Focus - does it sound like the differential?

1 | 2 | 3 | 4 | 5 | 6

Mad Scientist
29827 posts

Uber Geek
+1 received by user: 6089

Trusted

Lifetime subscriber

#1375333 27-Aug-2015 17:27

DOes the traction control decouple the transmission and give the engine surge described?

Fred99

13684 posts

Uber Geek
+1 received by user: 10018

#1375336 27-Aug-2015 17:36

joker97: DOes the traction control decouple the transmission and give the engine surge described?

No to "decouple the trans" (although that's how it may "feel") but yes to "surge". If it's a conventional A/T with torque converter (or CVT), then if brakes applied (by ESC) without decreasing throttle, revs will increase - even if it doesn't drop down a gear.
A conventional AT may drop down a gear (or torque converter lock-up clutch disengage) also with a corresponding rev increase. A DSG may drop down a gear (it shouldn't "slip").

I doubt it's a DSG in a 2010 Ford - but could be wrong. VW introduced DSG in diesels before they brought them into equivalent petrol models like Golfs etc.
Ford has used some hideous CVTs in some Euro/UK models which were sold in NZ.

Batman

Mad Scientist
29827 posts

Uber Geek
+1 received by user: 6089

Trusted

Lifetime subscriber

#1375341 27-Aug-2015 17:53

I thought when traction control kick in it cuts engine power? [that's purely my primitive understanding]

[But yes if you are right about how TC works then faulty slip sensor explains everything]

Batman

Mad Scientist
29827 posts

Uber Geek
+1 received by user: 6089

Trusted

Lifetime subscriber

#1375343 27-Aug-2015 17:55

Unless you were explaining active vehicle dynamics control ...in which case yes that makes sense

Fred99

13684 posts

Uber Geek
+1 received by user: 10018

#1375345 27-Aug-2015 17:58

joker97: I thought when traction control kick in it cuts engine power? [that's purely my primitive understanding]

[But yes if you are right about how TC works then faulty slip sensor explains everything]

Some may do that (reduce engine power) but as for the Focus - perhaps not. I'm out of my depth here, but expect that if it's tied to the ECU to reduce power, then that feature's perhaps more likely to be in a high performance car. With a diesel, if it cut power immediately on ESC actuation, due to compression braking it might cause the driver more problems than it was trying to fix.

ETA after reading your post - it's a Focus with ESC - not "traction control" like some launch mode on a supercar. Related but not the same.

Batman

Mad Scientist
29827 posts

Uber Geek
+1 received by user: 6089

Trusted

Lifetime subscriber

#1375348 27-Aug-2015 18:02

whoever is right (and i am pretty sure TC alone will always cut power when wheel slip is detected, VSC cuts power and applies brake, active VSC does heaps of weird things inc steer for you as well as apply power to certain wheels)

the easiest way to test your theory is disable TC/VSC and see if it happens. if not then bingo. if still happens then it's not the TC/VSC

Fred99

13684 posts

Uber Geek
+1 received by user: 10018

#1375350 27-Aug-2015 18:08

joker97: whoever is right (and i am pretty sure TC alone will always cut power when wheel slip is detected, VSC cuts power and applies brake, active VSC does heaps of weird things inc steer for you as well as apply power to certain wheels)

the easiest way to test your theory is disable TC/VSC and see if it happens. if not then bingo. if still happens then it's not the TC/VSC

It's not TC on a Focus - but yes, disabling it to check may confirm, though of course especially if it's intermittent, it might be hard to reach a conclusion on that.
ESC may on some cars reduce power.

I'd say take it to a franchise dealership workshop and explain. However, I've found Ford franchise workshops to be useless at diagnosis of their own product, so wouldn't count on them finding the answer.

Samsung

Shop now on Samsung phones, tablets, TVs and more (affiliate link).

Batman

Mad Scientist
29827 posts

Uber Geek
+1 received by user: 6089

Trusted

Lifetime subscriber

#1375359 27-Aug-2015 18:27

OP what transmission does your car have? What kind of vehicle dynamics control does your car have - TC/VSC/Active VSC?

Just re-reading everything it sounds like the transmission is disengaging when it happens.

sxz

761 posts

Ultimate Geek
+1 received by user: 194

#1375360 27-Aug-2015 18:30

Fred99:
sxz: Hi - OP here.

The traction control light comes on but I suspect this is more symptom than cause

I don't - see the last part of my post above. Copy the relevant part and put it under your mechanic's nose if he doesn't believe it.

OK excellent idea. Thank you

Fred99

13684 posts

Uber Geek
+1 received by user: 10018

#1375625 28-Aug-2015 12:26

joker97: OP what transmission does your car have? What kind of vehicle dynamics control does your car have - TC/VSC/Active VSC?

Just re-reading everything it sounds like the transmission is disengaging when it happens.

Reading back, it sounds like the OP's car is actually MT - somewhere back in the thread I did read comments about dual clutch and got sidetracked.

So there's nothing possible there in the entire drivetrain (excluding the clutch - which has been checked) capable of "slip" but would not also cause some almost immediate and catastrophic failure, rather than a somewhat repeatable but intermittent issue. But that doesn't explain the reported increase in revs/surge. I'd ask is that actually happening or not - does it just seem that way (because of changed engine sound)?

Of course there's another possibility - the front wheels actually are losing traction and the ESC is kicking-in exactly as it's supposed to do. Uphill (thus more weight on the back wheels), a little bit too much right foot, slippery or bumpy road and/or tyres or shocks perhaps not as good as they could be, and sure, especially in a front wheel drive car. Chuck a couple of passengers in the back or something heavy in the boot, and it's very easy to inadvertently drive a FWD car beyond it's safe limits even on good flat roads. If that actually was the reason, then the solution is very simple - even if less evident with ESC than without.

Batman

Mad Scientist
29827 posts

Uber Geek
+1 received by user: 6089

Trusted

Lifetime subscriber

#1375692 28-Aug-2015 14:00

In fact that surge is more likely to happen WIHTOUT ESC, esp with manual (more torque transmitted).

If ONE tyre loses traction the engine will surge without traction control due to an open differential pushing all the torque to the slipping wheel. This is known as a burnout in boy racer terms.

Batman

Mad Scientist
29827 posts

Uber Geek
+1 received by user: 6089

Trusted

Lifetime subscriber

#1375706 28-Aug-2015 14:26

best way to demonstrate loss of traction (wheel slippage) in a front wheel drive would be to do a hill start on a wet day (doesn't have to be very wet), best if the hill has loose gravel. put in first gear and floor it.

do NOT do that on a RWD unless you want to fall off the cliff or kill someone

sneaka

3 posts

Wannabe Geek

#1375766 28-Aug-2015 15:39

So ours is a manual transmission, as is the original car in this thread. And when the problem occurs, the revs DO increase (as displayed on the rev counter) and the traction control light comes on. It's going in to get checked out Monday coming, we'll be taking the technician for a drive up some nearby windy hills to hopefully replicate the problem. So will keep you posted if anything comes to light.

Batman

Mad Scientist
29827 posts

Uber Geek
+1 received by user: 6089

Trusted

Lifetime subscriber

#1375794 28-Aug-2015 15:48

can you stop on a slope with loose gravel (or on a wet day) and put into first gear, and as soon as you manage to fully let go of the clutch, put your foot down, report what happens. repeat with turning off traction control. report.

MikeAqua

7787 posts

Uber Geek
+1 received by user: 3623

#1375799 28-Aug-2015 15:55

My guess is that the OP's problem may relate to a malfunctioning/sticky clutch plate spring.

Mike

1 | 2 | 3 | 4 | 5 | 6