Crank and cam position sensors required ASAP.

[S2central.net]

I'd also go with flywheel pin but has the fuel pump relay been ruled out ?

It's in position #10 in the main fusebox... You can pop it out and gently tease it's lid off to expose the contacts... Gently refit it and see if the contacts close on cranking. If it doesnt then you can use insul tape to close it manually for a test.

Also - with the ignition on... Check you get 12V on side of the fuel injectors. That proves your ecu holding relay and wiring is good. Think you tried a spare ecu but is good to check.

[Si Blythe]

Thanks for that Paul I will try it. If the pin has dropped off I take it it means a gearbox off job?

[AndyP]

Thanks for that Paul I will try it. If the pin has dropped off I take it it means a gearbox off job?

I've heard you can weld a new one on by removing the starter motor, not sure it's something that every garage would take on though!

[AndyP]

Brain Tonks came up with a good method for checking the flywheel pin. Remove the 2 sensors on the passenger side and stick a cable tie through the hole, spin the engine over on the starter and feel for the cable tie tapping against the pin.

No tapping = no pin

[UrS4boy]

I've heard you can weld a new one on by removing the starter motor, not sure it's something that every garage would take on though!

I for one have suggested that it is possible to weld a newly fabricated cranks sensor pin to the back of the flywheel through the starter hole. One of our local UrS club members had to do this. It worked. There are other people who have successfully done this without having to remove the transmission and flywheel. Here are details (again) on this size and location of this pin:

http://forums.quattroworld.com/s4s6/msgs/51259.phtml

[Si Blythe]

I would like to locate the original pin to be honest as I don't like the idea of it rattling around in the housing. It maybe be an opportunity to take the car off the road to do the cambelt and a few other jobs. I will need to find a cheap runaround for a while

[UrS4boy]

I would like to locate the original pin to be honest as I don't like the idea of it rattling around in the housing.

I *thnk* you first need to find out IF this is your problem before thinking that far ahead.

[Si Blythe]

Totally agree and that is good advice. I will get her running first, I don't think it is something I have disconnected in the dash when I changed the matrix but you never know. As I say I did drive it after putting it all back together.

[S2central.net]

Check fuel pump relay first of all.

Meantime I will try to speed up my efforts to make a lil G4 and G28 tester that won't cost the earth.

[Si Blythe]

Paul, the pin has dropped off of the flywheel - did the test this morning that's all I need!

[S2central.net]

Good stuff. At least you know now.

If you getting it welded on electrically - unplug battery, ecu and abs controllers first of all.

[Si Blythe]

I thought the gbox needs to come off to get the pin out of the housing.

[UrS4boy]

G4 Crank Position Pin Info - with rewelding suggestion

Paul, the pin has dropped off of the flywheel - did the test this morning that's all I need!

I think that we ALL might want to think about pre-emptively adding extra weld(s) to the G4 crank position pin BEFORE it decides to take early retirement. How many miles/kilometres are on your car?

G4 Crank Position Pin info:

http://forums.quattroworld.com/s4s6/msgs/51259.phtml

[Si Blythe]

Forgot to mention, I did the fuel pump relay and when you close it together it does fire up the fuel pump however, the car still didn't start! At least it is one less thing to change.

[S2central.net]

Well yes of course on fuel pump. If ecu doesnt get good G4 then it will not spark or squirt.