Technical Anti-knock sensor

[well-dweller]

My son has an early Fiat Uno Turbo 1.3ie. The anti-knock sensor fitted to the front of the engine is not connected. It terminates in a two pin plug. Can anyone tell me where this plug should be conected. A picture or diagram would be good.
Cheers, Andy

 

[SteveNZ]

It plugs into the loom off the microplex unit. It should be easy to see unless someone has chopped it or somehting

 

[well-dweller]

Thanks mate
The lead and connector doesn't reach as far as the Microplex unit. Should there be a connector off the loom? Could it be that a later engine with a sensor has been fitted into an early car without a sensor, or should they all have sensors?

 

[alexGS]

OK, sorry I've been a bit slow with this one.

Here are a couple of pics: the knock sensor (circled) and its wire where it runs behind the battery earth lead and joins with some purple wires (arrowed).

All Uno Turbo i.e. Mk1 versions, early and late, have this knock sensor.

I don't have my Haynes manual handy (which is why I didn't reply before) so I can't tell you which ECU pins the sensor should connect to. But perhaps now you know which wire it would have attached to, hopefully you can find it (the Uno Turbo engine bay is a mess of pipes and wires everywhere...)

Cheers,
-Alex

 

[well-dweller]

Cheers Alex, I'll show my son Alex the photos. I think we were looking in the wrong place for the conector, at the back of the engine.

 

[Biz]

To test if its working properly, run the engine and kinda hit the head or block with a copper head/plastic hammer and listen for the engine sounding a bit "duller"

 

[well-dweller]

Thanks mate. Will give it a try.

 

[alexGS]

Interesting check Biz! Thanks, I hadn't thought of testing it that way... didn't realise the knock sensor would be functional with the engine only idling with no boost.

Perhaps it's possible to use a timing light to see the ignition timing retarding?

-Alex