Audi s2 3b won't start PLEASE HELP

[Stealthacq]

I did notice every time I moved the dizzy slightly off the correct timing it did not open the injectors but as I got closer it opened them all for the one cycle so it must be bang on time. I think Al check the dizzy tomorrow but it did come off a running car

[twoqu]

Did you notice whether it was a plastic or metal gear on the dizzy? The latter is more durable. Would be bad luck if a plastic broke as soon as you swopped it but who knows!

[Stealthacq]

It is plastic but it is in good condition. At least I tries to start so we must be getting a no closer!
It looks like it had an old immobiliser in but it has been taken out.
I have checked the crank. Speed for any alterations on the wiring for an immobiliser but they all bell out correctly.
Do you knoe what other sensors or circuits thay can tap in to inhibit it to start?

[twoqu]

Not really, although I would have thought it was easier to cut power to something essential.
The only thing that puzzles me is that 4V with ign on the G28 speed sensor. I would like to know if its from the ecu out as I can't understand how the sensor would generate any signal without the engine being cranked/running. There are sensors that use 5V referenced from the ecu but the G28 is not one of them. The G40 is.
I have read elsewhere on here that the G28 fault code gets wiped when the ecu sees a 0.5V amplitude from the sensor, i.e. the car cranks, so that does not fit my earlier theory!

[Stealthacq]

This may not be the case now I will have to check tomorrow as it's got the new ecu now. It mayhave a short it's all I can think

[Stealthacq]

I have just Checked for a signal from the crank sensors and at a guess I should be getting about 4v when the pin goes past. I don't get anything. I have done this with the plug disconnected so if there was any shorts it does not interfere with it.

[Stealthacq]

The pin is there is does look slightly bent tho. Al have a look tomorrow but I did not get a signal when it was cranking. I manually checked both the new and old g4 crank sensors and they seam to work with the same reading.
Does anyone know what sort of voltage I should be getting when it passes the pin?

[twoqu]

You can see the scale on that other thread. The output depends on the speed of rotation. Its looks like just over 2V when cranking and over 10V when running. Others have said the range is -/+ 15V.
If you can get the G28 out without damage you could substitute any of the other sensors and see if they produce the expected waveform to double check they function. If they do, then the only other variable is the pin. There is a specified dimension between the pin and sensor and I think the closer it is the better within reason.
Other than measuring the wrong pins which can be checked with a MM, I am out of ideas.

[twoqu]

Some more info here but you will have to read through it!

http://www.s2forum.com/forum/showthread.php?t=74058&highlight=g4

[twoqu]

There is a couple on here:

http://www.sjmautotechnik.com/trouble_shooting/audi_waveform.html

They are from the 10V turbo but thats going to be closer to the 3B. The idle one looks close to 10V which supports the other one.

[Stealthacq]

Hiya I have put it all back together and I don't get a flick when the pin goes past but it looks absolutely fine!!
It does try to start on the first crank on the key but dies as so as it seems to look for the next tdc.
It must be bent.
All I get when the g40 is unplugged is a bit of interference and the odd flick nothing uniformed to se that is a timing pin!!
All I can think is to update the pin to the more substantial aby pin!?
Am soo bloody close and keep saying it starting tonight. And the next night and the night after that haha
Dam thing!!

[twoqu]

You would have thought it would throw up the G4 code 00514 if it had no signal.
When you say bent, do you mean downwards away from the sensor?

[twoqu]

Also if it ran on easy start you must have sparks and you only get sparks when the ecu sees the G4 and G40!

[Stealthacq]

Hiya am so confused lol
It doesn't look bent but looks like it may have had a nock on the top but it's not really anything even major!
The boss for the sensors are they all the same across the aby. Ann. 7a and 3b.
Could it be a different hight to alter it?
So if i have a spark the timing is OK? 10000%??

[twoqu]

Well thats my understanding. If the blip from the G4 is in the gate of the G40 you get spark, if not, no spark as per that link. If the pin goes AWOL no G4 blip, no spark. Clearly there is a distance that the sensor has to be within @1.25/0.5mm the closer the better for the signal. I would have to check the pn but I expect that block is a carry over from 10V engines so would be the same on any 5Cyl with 2 sensors.
That pin is pretty hard so I would have thought it would shear off rather than bend.
Should be easy to check for a spark.