Ford Focus speedo weirdness

Solitaire

Not enough variety around here (or maybe it's just the soul-destroying-boredom-field effect radiating from the Auris thread) so here's an issue: Focus Mk1.5 speedo problem.

But there's a thread about a dead Focus speedo at least once a week here, right? Well... I never said it was dead. In fact, mine likes to do the hokey-cokey every so often

This is quite disturbing. And the ECU is most certainly not enjoying it; when the speedo gets the wobbles the engine becomes rough, but when it starts flipping between 10kph and 110kph (when I'm doing 80kph!) the engine goes all over the place! :eek:

And to continue the originality of the thread, the odo is not randomly shutting down and starting up either, it seems to be largely unaffected by the fun and games. If only the ECU was so inclined! :rolleyes: Plus the engine is just a bit lumpy when gearing up. Might be a seperate issue but I only noticed it since my dial started dancing to the radio.

So... Speed sensor (known issue with Focus), instrument cluster PCB corrosion (known issue with Focus), cable corroded or coming loose somewhere (known issue blah blah) or something entirely different this time around (and hopefully not the entire gearbox or ECU!)? Anyone who actually has a clue want to have a guess?

Hal1

Trottle position sensor seen here. Woah image was too big. That pic is from a fiesta but should be near same place or at the rear.






I had to check with another forum to see if I'm right with my thinking with this. It could be this, but then again. I would check this first anyway. Clean with electrical contact spray, the spray can be used for cleaning MAF sensors too which can cause erratic idles.

Follow the air intake to the throttle. On the right hand side of the throttle housing is a little black plug bolted to the housing. It has a couple of wires connected to it. Held in by 2 hex screws. Unscrew and give it a good gentle clean. Put a flat head screw drive in the bit that connects to the butterfly spindle and give it a gentle twist from side to side.

Then put it back, be careful as if not lined up properly it could snap when you do up the bolts again.

junkyard

The back of the speedo clocks gets damp on some of them and corrosion builds up there and upsets things, take out the clocks, clean them up and spray them with contact cleaner, that should sort them out.

Plug

My speedo works when it feels like it, depends what mood she's in:rolleyes:
Loose connection or a cut wire. I don't think the tps has anything to do with it. Not 100% sure though.