ST220 cam position sensor

Measuring its resistance would only give a conclusive result if it was reading infinity or close to zero. (In either case it wouldn't be working at all, of course.)

The reading you are getting may be low enough to indicate some shorted turns; a replacement sensor is only around 20UKP, so if it were mine, I would change it anyway.

Chris

Peter Spikings expressed precisely :

Might the quoted 430 be impedance, rather than resistance, as it is a coil?

If it is a VR sensor - basically just a coil - I'd expect it to work or not. If a hall effect - they have internal electronics - more likely to go intermittent. But if you're losing the cam signal I'd expect the performance to be down too, as it would go into limp home mode. You can't have sequential injection (and ignition) without the cam signal. Only batch injection and wasted spark.

Hi,

Yes performance is OK, just that occasional stalling which might be IACV. It's an inductive sensor with two pins.

As per the code the engine definitely points at the sensor or the wiring so I guess I'll replace the sensor anyway as it could be intermittent - in fact thinking about it the MIL hasn't lit up since I checked it.

I bet it's the wiring which will be annoying to sort :)

Thanks all,

Peter.

Cam sensors failing intermittently are a well-known Mondeo fault; Google it and you will get lots of hits. Wiring faults are much less likely.

As I said up-thread, a new sensor is only about 20 quid. An ST220 isn't the cheapest car to run, so the cost of replacing 'just in case' would be insignificant.

The Idle Air Control Valve on Fords of this era doesn't really control the idle, oddly enough. It's done by the ECU changing ignition timing and injector bandwidth. Apart from when cold, they will usually idle perfectly well with the IACV disconnected. The thing you would notice most if the IACV failed would be some driveability issues, mostly on the over-run.

Chris

OK, thanks.

Yep, got one on order though it's £36.74 (Ford part) from fordpartsuk.com.

LPG for the win on ST220 running costs though the LPG ECU being placed right next to the cam sensor makes this job trickier than it needs to be :)

I won't pretend to fully understand that ;) The times it stalls most often is when warm and I depress the clutch during overrun.

Thanks,

Peter.

Ah, OK. In your original post, you describe the fault as stalling when idling.

Chris

I'm not quite sure how that could be caused by the cam position sensor with no other symptoms? But I'm not familiar with the ST220.

Ordinarily, first check clutch switch operation, but with lpg conversions, even factory ones, there is a whole new world of pain to suffer when faults present.

Nedavno Peter Spikings napisa:

Air intake pipe facing front can cause week mixture during overrun.

Does the same happen on both LPG and petrol? Above can be true for LPG.

Pass, I don't think it's happened on petrol but I run it on petrol so rarely for obvious reasons that doesn't mean anything.

Ta. will do if new cam sensor doesn't cure it.

Oops :)