Whats the "rear knock sensor"

[alacol25]

Two weeks and 600 miles in and i've hit my first problem. Car has suddenly started running rough under acceleration but is fine on light throttle or tickover. Almost as if it is'nt firing on all cylinders. I've had a poke about and noticed a connector labelled rear knock sensor which isn't connected to anything. it runs along the top of the engine from the bulkhead along with the fuel injection cables. Could this be causing the problem and where does it go?

[GreenV8S]

Know nothing about that engine so I can't answer directly, but if there is a corresponding sensor near to the wire that it could plug in to then it might have dropped off, then again it might have been left off deliberately. Best way to find out for sure is to give your dealer a ring. Good on you for spotting it though, it's as well to familiarize yourself with little details like this so when it goes wrong in six months time you do know that this little pipe at the back is to bleed the clutch, the vac line to the fuel pressure regulator is supposed to be disconnected and so on.

One advantage of an older car is that all the exposed surfaces get dulled by dirt and corrosion - any time I see any shiny bits on my engine I know something's dropped off!

[hexhamhc]

It shouldn't be connected to anything. The wiring is there for when they fit knock sensors in the future I think I'm right in saying. Get along to your dealer and ask them to put it on their laptop to see if it has any fault codes stored. Hope that this helps. Best regards, Tony

[targarama]

I can confirm my car also has the spare cable/connector labelled 'knock sensor'.

[alacol25]

Thanks for the replys. Phoned H L Gorner and they think that the problem may be ECU not getting the correct signal from the water temp sensor (if I understood correctly). Unfortunately Tony I am up in Central Scotland and I think that you are my closest dealer so its a call to the RAC on Monday to take back down to Gorners. Still smiling though.

[hwassall]

Yep, my car has both front and rear knock sensor cables connected to nothing. I would suspct something else is amiss.

[Mr Freefall]

hwassall said:

Yep, my car has both front and rear knock sensor cables connected to nothing. I would suspct something else is amiss.

The Wiring Loom was borrowed from a Vauxhall, and the sensors were fitted to these cars. TVR when they borrowed the loom, didnt remove the little sleave with writting on

Mr F