Does anyone know what this unused plug is? There doesn’t seem to be a mate. Also, the thing wrapped in tape seems to be some kind of sensor that used to attach to something.

 

That thing wrapped in tape is a knock sensor, follow the wire and check if the plug is part of it.

 

And look down with a torch below the inlet manifold (near the mid point on both banks) to check that there are knock sensors actually fitted.
I guess it would be possible to re-map the ECU so that it would not flag a missing sensor/s.

Richard

 

I knew that the 4.0 ECU isn't remappable..

 

I'm afraid that you've lost me now.

Richard

 

I thought I'd seen some weird stuff on my car. What would possess someone to zip tie a knock sensor to a vent hose??

 

If still plugged in to prevent knock codes and restricted performance. The knock sensors are plugged in by the water tower.

 

Please excuse my limited knowledge of English, but I didn't understand what this sentence meant.. ??

 

He doesn't understand what you meant when you said the ECU isn't programmable - I agree, as far as I know it isn't possible to remap the ECU.

 

It’s still hooked up. I just need to find where it attached and find out why it was removed. It almost looks like it was glued on.

 

I do apologise. I didn't realise that English isn't your first language.

Rather than "I knew that .......", I now appreciate that you meant "I thought that ......"

In fact, the X100 ECU can be re-mapped but not by simple software programming. That might not have happened but, if the knock sensors are not connected, on most cars this would result in the car either not starting or going into limp home mode so something would have to have been done to bypass the missing sensor.

Richard

 

By "still hooked up" I guess you mean that there is a knock sensor mounted under the middle of both inlet manifolds?

The knock sensors are fixed into their outer casing with a liquid epoxy which is often shiny and black so it does look like solidified glue. This could well be what you are seeing.

The knock sensor on each side has a captive cable which goes to the main loom connector which is held on a mount on either side of the black plastic thermostat tower at the front of the engine which you can just see the edge of in your photo on the extreme right-hand side. If you look carefully you should be able to look down and see the connectors on either side with the cable going to sensor.

If the two complete connectors are present on both sides and the cable runs to the sensor then your open connector cannot be for a knock sensor and I've no idea what that 3rd sensor cable-tied to the breather hose is all about.

Richard

 

After further investigation, I found a new knock sensor installed but not plugged into the plug in the photo. The one wrapped with tape is not plugged into anything. I plugged the new one in and removed the old one.

 

That's very surprising. Does the engine run properly with no faults showing with only one knock sensor connected? I don't understand how that is possible with the ECU being re-mapped but that would be far more expensive than simply fitting a new sensor if one had failed.

Richard

 

Thanks for the clarification; now I understand what you meant. Sometimes I use a translator and sometimes I don't, so I might make mistakes. What I meant was that I thought the ECU on the 4.0 couldn't be remapped, whereas the 4.2 could.

 

The car seems to be running just fine.