[s-cars] Pre-emptive rewelding of the G4 crank position timing pin.

[David Forgie]

Yet another AAN lost its G4 crank sensor pin. 
http://12v.org/urs/MushashosMissingG4CrankPositionPin.jpg

Here is the story:

"On Friday evening something happened while pulling away normally from a standing start. I think I 
heard something as if something had fallen off which may or may not be significant but the S4 
instantly ran horridly. The engine wouldn't rev, was popping and I couldn't get passed about 30 
MPH. I could smell the exhaust fumes from I suspect rich running. I nursed it to the roundabout at 
the top of the hill where it stalled and wouldn't restart. It appeared to turn over normally and I 
couldn't see anything obviously wrong or missing so I got it towed back home."

If an AAN won't restart after previously running, it is one of four things: Fuel pump, G40 cam sensor, 
G4 crank position sensor or the G28 engine speed sensor.  You need all three of the G4, G28 and 
G40 working to get the engine started.  The fact that the owner heard a noise made me think it was
 the G4 pin taking early retirement (we have heard this story before here, e.g. Skollie, Mushasho,
 etc). 

I suggested that he look to see if the G4 timing pin  was still there.  I also suggested that he check the
 condition of the G4 and G28 sensors. To be complete, I also suggested he check the condition of
 the G40 cam sensor. (I gave him links to info on all of these).  Several others also suggested that he
 look at the G4 pin. 

Today he came back with the answer: the G4 pin is missing. Now the trick is to weld a new one in
 place.  Based on this, I think we (AAN, ABY and ADU owners) need to start thinking about a pre-
emptive rewelding of that timing pin - before it comes off. I am strongly suggesting that we consider
 adding additional tack welds on both sides of the G4 pin to help prevent this fatal (flat bed time)
 problem.
 
It can be welded through the starter hole (I know Skollie did it and probably Mushasho and others).
 Needs two people to start, one to press the pin into position with a wooden dowel and the other to
do an initial tack weld and then the final welds. 

More info here: http://forums.quattroworld.com/s4s6/msgs/51259.phtml