AAN Camshaft position sensor

[johne]

The bit about it being used for 'cylinder sensitive knock control' just above.

I think what that is refering to is that Motronics needs this sensor to tell it where no.1 cylinder is, which is why the engine can't start without it, but once it has started Motronics knows where no. 1 is and will "remember" until you stop the engine. Likewise the knock sensing needs to "know" where the engine is so Motronics can relate the knock sound to which cylinder is firing - but - once it knows where no.1 is during startup I don't believe it goes back to the cam position sensor every time knock happens to then relate it to knock inputs as it already knows where the engine is.

John

[HMS-S6]

I think what that is refering to is that Motronics needs this sensor to tell it where no.1 cylinder is, which is why the engine can't start without it, but once it has started Motronics knows where no. 1 is and will "remember" until you stop the engine. Likewise the knock sensing needs to "know" where the engine is so Motronics can relate the knock sound to which cylinder is firing - but - once it knows where no.1 is during startup I don't believe it goes back to the cam position sensor every time knock happens to then relate it to knock inputs as it already knows where the engine is.

John

Right, well possibly its 'memory'' is wrong?? Its the one thing i've not changed yet. I bought it as a non runner and it was the sensot that failed then. Fitted a cheap one (before i intended to keep the car) paying little attention. The previous owner reported no problems, so it seems it's occoured since i fitted the sensor.

[johne]

Knowing where no.1 cylinder is fundamental to Motronics working, if that part has failed nothing would work. Motronics is very reliable in standard form. Has it been chipped?

John

[UrS4boy]

The bit about it being used for 'cylinder sensitive knock control' just above.

You are talking about the info in the first paragraph of this:

[HMS-S6]

Knowing where no.1 cylinder is fundamental to Motronics working, if that part has failed nothing would work. Motronics is very reliable in standard form. Has it been chipped?

John

Yes it does have a re-mapped ecu, however i also have the standard one which behaves the same, faultwise. When its intermittant you can feel the power come in and out like a switch!

[S2central.net]

IIRC the ecu retards timing if it detects absence of G40 signal after engine has started. Without a good g40 signal at the right time the ecu will prevent engine starting.

My tester gizmo visually shows presence of g40 pulses - plugs into loom inobtrusively.

I am working on some more advanced gizmos that provide more info but they haven't had much of my attention lately.

[Hammer786]

I went to my local stealer down here in Cardiff and asked about the hall sensor and they quoted £155 for a brand new one I was gob-smacked to be honest, genuinely. Any idea if they can be had brand new cheaper elsewhere? I've ordered the sensor separately and plan on splicing it into my current connector as it's a hell of a lot cheaper, hopefully fix my starting on 4 cylinders issue.

[madpugger]

Last one I bought came from Lucas via Bosch part number. It was around 65 quid. Theres a thread somewhere. I'd doubt it's causing 4 cylinder starting though. Either no starting or it starts. All it does along with pin on flywheel is allows engine to start on #1 cylinder.

[madpugger]

I have read on several sites that the camshaft sensor is used to govern knock reduction too. I was previously told also that it only was used for starting, but if this is the case, why does it turn boost down when unplugged!?!

Secondly, i do take on board re the valve timing, but i have checked it 3 times now and also the running fault is sort of intermittant

I have been chacing this for 5 years!

It's not so much checking the timing as making sure the timing isn't moving during running. Ie the crank or cam pulley key having broken allowing the pulley(s) to move slightly.

Also, the cam sensor is not used ONLY for starting. It's used by the ecu on WOT above 4k rpm. If the signal is not plausible, power is cut.

Hope some of this helps!