Focus problem - Power loss / Speedo

Liam · 5 Mar 2010 at 22:53

Having a problem with my Focus, after about 5 minutes of driving it starts doing random things ;

- Speedo drops to 0
- When drops it loses power so if/when I have to stop (put the clutch down) it usually stalls

Anyone have any ideas?

Thanks

LEK-89 · 5 Mar 2010 at 23:04

Speedo - possibly the speed sensor on its way out?

Loss of power - spark plugs / HT leads or coil pack?

Liam

Liam · 5 Mar 2010 at 23:06

Forgot to mention that they happen at the same time. The speedo drops and I lose power. When the speedo comes back to life, the power comes back...

LEK-89 · 5 Mar 2010 at 23:08

Does the speedo literally go to 0 almost instantly? Or does it go down slowly with the revs?

Liam

Liam · 5 Mar 2010 at 23:10

Drops down instantly mate. Then, on occasion, it'll shoot up, down drop, shoot up ... kinda random.

daveydave · 5 Mar 2010 at 23:31

coil pack, map sensor, you need to start doing some trial and error.

Morba · 5 Mar 2010 at 23:33

im sure this is pretty common, head over to ffoc and do a search, bet you find a few threads!

Jotunkaiser · 5 Mar 2010 at 23:43

No engine management warning light?

sorn21 · 5 Mar 2010 at 23:47

JanseyB will probably know the answer to this.

It's happened a couple times to me, but not recently.

Think it's something to do with the ECU and most dealerships will update the firmware iirc.

LEK-89 · 6 Mar 2010 at 00:06

Thinking about it, it does sound ECU related. Have you tried disconnecting the battery for around half an hour? Let the ECU reset and this could possibly cure the problem?

Liam

Liam · 6 Mar 2010 at 07:58

LEK-89 said:
Thinking about it, it does sound ECU related. Have you tried disconnecting the battery for around half an hour? Let the ECU reset and this could possibly cure the problem?

Liam

No, but I will later on

Come to think of it, it did happen after I got a new battery a few months back.

Locky · 6 Mar 2010 at 07:58

my focus did this and it was the ECU, used to rev up on it's own as well.

Liam · 6 Mar 2010 at 08:18

Locky said:
my focus did this and it was the ECU, used to rev up on it's own as well.

Mine revs up too, usually when I change gear.

I'll rip the battery off later and update

dalin80 · 6 Mar 2010 at 08:26

Vehicle speed sensor, plugs into the top of the diff and is made from cheese.

Conscript · 6 Mar 2010 at 08:33

dalin80 said:
Vehicle speed sensor, plugs into the top of the diff and is made from cheese.

Yep. This is a definately a faulty VSS, common fault on the Mk1/.5 Focus. Part costs about £30 and can be replaced yourself, although it can be a pain to get to. Any good garage should be able to diagnose and fix it though.

iaind · 6 Mar 2010 at 08:51

The speed sensor will feed information to the ECU so could feasibly cause a stall - that would be my first guess

AtreuS · 6 Mar 2010 at 12:27

Same has happend to mine ( 2001 Y reg ) and its the speed sensor, getting it done on monday for £20 ( the mech owes me a favour as i fixed his pcs for nowt

)

AndyC · 6 Mar 2010 at 16:00

This will be the speed senser mine did the same, the loss of power I guess would be the ecu failing over into a fail safe mode, as the others said about a £70 garage fix.

markweatherill · 6 Mar 2010 at 19:17

Doesn't the standard Ford radio have a volume control that's linked to vehicle speed, from the same sensor? If the radio volume does odd things at the same time as the other odd things, that's the speed sensor for sure.

dalin80 · 7 Mar 2010 at 07:38

markweatherill said:
Doesn't the standard Ford radio have a volume control that's linked to vehicle speed, from the same sensor? If the radio volume does odd things at the same time as the other odd things, that's the speed sensor for sure.

nope, at least not all.