EF base timing cannot be physically adjusted - it has to be done electronically thru the ECU - ie. with a plug in module.

That gizmo that sits on the EF engine where a distributor normally would be is just a cam phase angle sensor - the ECU looks at the sensor on the crank at the front of the engine to work out what degrees of rotation the crank is at, but any given reading there could be on either intake/compression rotation or power/exhaust rotatation for any given cylinder - ie. such as no. 1 - so that gizmo on the side lets the ECU know which cam phase it's all at -

If you like, you can think of it as telling the ECU which cylinder is actually coming up to TDC compression - and with that info plus a rotational angle on the crank then the ECU knows exactly where the whole engine is at.

Actually I think it's all aimed at determining where no 1 cylinder is.

Thanks for the explanation Greenmachine.
The cheep gregories manual i have is a*** in detail

The issue i am trying to solve is that my EF I6 pings on unleaded low octain petrol but doesn't on the high octain juice.
In an older car i would just retard the timing but seems that's not possible with the EF.

Would not surprise me that the dealer machined too much off the head when fixing a blown gasket.

Cheers.

Have a real good look at your knock sensor wiring and the connector at the sensor - unplug it and give it a good clean if it looks undamaged - and replug it in (clean out the socket on the sensor too) - next would be to look at replacing the Knock Sensor. The Knock Sensor feedback system should stop pinging under virtually any circumstance (which is why they essentially did away with the ability to manually alter timing) - so it really sounds like a problem there to me.

In short, the EF ignition system is a dynamic real time feedback/sensing setup - the Knock Sensor is integral to the system so if you're getting pinging then it really sounds like a problem there somewhere.

Ive got my EB XR6 running at 18 degrees advanced, doesnt seem to ping, and i run it on BP Ultimate, its only got extractors and exhaust and shes pullin 15.1's with a lazy 60 foot time of 2.3 so it should be puliing bout 14.7's so the advanced timing has effected me greatly in performace.

Thanks again Greenmachine, your explanation makes sence.
That's one more thing on my list - change fuel filter, flush auto oil, change engine oil, install cruise control, and now check knock sensor

In practice, can one test the knock sensor by attaching a timing light and tapping near the sensor with a spanner?
The timing should show the white mark on the front pully retard when tapping and return to normal when not.

In theory this should be possible but the knock sensor seems to be placed in a real awkward place to try such a test.
Is there an accessable and workable location to tap ?
What do you think ?

Cheers.

Hmm - very tricky - it's worth a try I guess. The other thing I'd consider doing is unplug the connector from the sensor - secure the cable so it won't get damaged while driving the car - then go for a drive and see if the engine behaves any different. Sort of similar to the old unplug one ignition lead at a time test - ie. if the engine behaves the same then it's pretty certain that knock sensor is doing squat.

Yeh that's probably the easiest to start with, unplug and drive.
Then when it seems to ping more, hit it with something bigger than a spanner

You previously mentioned that the EF timing is controlled by the ECU using both a cam and crank angle sensor. In theory you should be able to adjust the cam or crank sensor which should have some effect on the timing, but which one would have the overriding effect ?
I would suspect it would be the crank sensor as the cam limits can be made greater since it just needs to tell the ECU when the piston is near TDC.
But it could be a little hard to move the crank sensor when the engine is running
Anyway the crank sensor may not have enought meat in the support to make some radial slots to allow adjustment.
What do you think ?

Cheers.

hmmm wat is timing? i think i dot an idea of wat it is