Timing a 2.9 - an impossible quest..??

[Ralph S3]

I’m struggling to set the timning on my 2.9 S3 since I rebuilt the engine. I have set it as it was previously by using a mark I drew on it but now I want to do an accurate check using a timing light. Its running a little hot and the spark plugs look like they are too hot so I think it is out. Problem is I am struggling to put it in service mode so I can use the timing light.

I have tried disconnecting the throttle pot but I’m not convinced this actually drops it in service mode.

I have a gunsons diagnostic meter which I have plugged into the correct (based on the wiring) plug under the dash. However it is not doing anything. It looks like it is not connected. I assume this is because I haven’t been able to disconnect the earth from octane plug. On my car all the leads are wrapped together and short of unravelling everything I can’t find the t junction where the octane adjust runs to ground.

I am now thinking of cutting the sprout connector near where it connects to the ignition module on the distributor. This seems to be the favoured method in the US when tuning the 2.9. Before I cut the Sprout cable has anyone got any better ideas?

I assume TVR did the bloody timing when they originally built the thing but I’m buggered if I can see how.

[lewdon]

I had the same problem, I posted details on here last year, (search "resetting the distributor"). The spout lead is screened so rather than cutting it i unclipped it from the plug going into the distributor and pulled it out while i set the timing and put it back afterwards. If search doesnt find the post I may be able to find some photos.

[phillpot]

This is Lewdon's old post?


Rather than mess with any wires at the dizzy end or try removing the "sprout" wire from the multiplug I cut it and fitted a switch, timing now as easy as flicking a switch


Prior to my little switch mod I would set it with the TPS disconnected then "fine tune" out on the road, a gnats clockwise or anti-clock, till it felt right

[lewdon]

Hi Phillpot. I was worried that the spout wire was screened, but as you know I tend to overthink things. I assume that, as your switch works fine, the screen doesnt actually do anything on the S.

[phillpot]

Maybe the screening is more important at the dizzy end with all sorts of voltages "flying around" ...

[lewdon]

That was lucky then, thats the end I would have cut, as easiest to get to.

[Ralph S3]

Thanks Guys,

Lot's of great ideas. I think I'll try Lewdon's soln first and then fit Phillpot's over the winter.

R