I read this on another site....and no it wasnt vxon
It was about a Vectra tho.....mk1 i believe and dont know if its is the same on Omegas but dont see why not.

It was about a non starting problem.

The guy was advised to unplug the crank sensor.....if it then started the fault was the crank sensor and the cam sensor must be ok.
Same with the cam sensor.......if it starts with the cam sensor unplugged then cam sensor is faulty and crank sensor must be ok.

Just thought if this to be the case.....then if Omegas fail to start due to crank sensor fault.....unplugging it could be a temp fix to get you 'home'.

What do peeps reckon....

If this should be in general chat please feel free to move

Cheers

If someone can start their car with the crank sensor unplugged I will be seriously impressed! 

A dead cam sensor will not prevent it starting, will make it run like a dog though!

The key thing to understanding this is to think what each sensor does.

Cam Sensor, this gives the ECU information on which cylinder is firing next, it needs this to support sequential fuel injection and to know which coil to trigger on coil per plug setups (i.e. 2.2,  2.6, 3.2). This information can not be obtained from the crank sensor as its a 4 stroke engine. Some may remember the early fuel injection systems which didnt utilise sequential injection and didn't have a cam sensor.

Most ECU setups can overcome failure of this by firing two spark plugs (true of a DIS pack anyway) and two injectors (or even all four injectors) simultaneously and limit the revs to 4K rpm as part of a limp home mode of operation. Its not the most efficient way of running though.

Crank Position Sensor (or crank angle sensor) -  this gives the ECU information on the crank position, this is key to getting the timing of the injection pulse and spark ignition correct (these are referenced to the crank and hence piston position), without crank position the ECU would only now which cylinder was firing next as the cam sensor cannot give accurate positional info to back it up.

As a result no crank signal results in no engine running and thanks to the critical nature of the signal the ECU wont operate spark, injection or fuel pump with it missing.

As a further point to consider on the crank signal, a few lost pulses can be accommodated as the ECU can actually guess pretty accurately where the next one should be, this it can cope with  for quite a few pulses.....hence a failing crank sensor often can get you home.

An the subject of this, it is very rarely the cam sensor that fails, as a rule its the cable that connects to it that breaks down so if your stuck and good with a soldering iron, you could splice a new length of cable to it. This is also born out by the fact that the V6 cam sensor pretty much never causes problems (never ever seen one needing changing) but, the cable is routed in a much nicer and cooler environment.

i think he's getting confused, and doesn't really know what he's doing...

I would if knew where it was lol......i could find it on a V6 
But i dont think anyones said before where it is on a 2.2, if they have i missed it 

Marks DTM Calib wrote on 03. Aug 2006 at 17:37:


Just been to have a look....

My aircon pump is on the right below the power steering pump......the only wire i can see that runs across the front then drops down (right or left) is on the right, drops behind the aircon pump then disapears between the dipstick and an engine mount and couldnt see/feel a connector....if this is the correct wire/s (as its in a plastic shroud) the connector must be well buried.

The end thats buried is the sensor end.....follow it up and over the engine to the connector