Locating Tdc on my 1996 Audi Cab engine code AFC
 

Followed the bentley manual to the tee and I took out the plugs and it looks like the number 3 piston is at TDC not the number 1, Did I miss something

Firing order is 1-4-3-6-2-5, w/ the right bank being 1-2-3 & right bank 6-4-5 (front to back)...
 

per the ignition coil labels. Is your No. 3 the same as the right rear cylinder? In any case, if the crank pulley mark aligns with the TDC mark on the block, and your engine has been running normally, then you're at TDC. Unless someone incorrectly installed the crank pulley (aka the harmonic balancer), then the TDC is correct if the TDC marks are aligned.

You can't put the crank sprocket or pulley back on wrong, both are keyed.
 

Look down at the shield surrounding the rear of the crank pulley. Facing the pulley, at about 1 o'clock, you'll see a raised arrow pointing toward the radiator. If you can't see it, clean the plastic with a rag until you can.

Use a 15/16" socket, or a 24mm socket to rotate the crankshaft clockwise (that's clockwise facing the engine) until you see the scrib mark at the rear edge of the crank pulley line up with the raised arrow. That will be either TDC for #1, or TDC for another cylinder, #6 maybe? The only way tell what TDC you're on would be to pop off one of the upper timing belt covers and look at the metal bracket sitting at the end of the cam sprocket(s). You're at TDC for #1 when larger hole in the bracket is facing toward the center of the engine. You'll not when you look at the bracket that there are 2 holes drilled in it. One is smaller than the other. These are for the cam holding tool to engage.

Anyway, it's about a 5min job to pop one of the covers off and look at the cam sprocket end. Faster than pulling a valve cover and looking at cam lobes.

Re: You can't put the crank sprocket or pulley back on wrong, both are keyed.
 

With all the timing marks lined up.
I removed the plugs and the engine still has the #3 cylinder at TDC.
When I turned the #1 cylinder to the TDC the timing marks were 120 degrees advanced.
The #1 cylinder standing in front of the car is the left side first cylinder and the # 3 is the left side last cylinder.

Spend 5min and pop a t-belt cover off.

You are correct
 

This is going back 4-5 years but i recall when i installed my crank sensor for the TEC-II that with the engine locked at the factory position to do the timing belt and the crank pulley set at TDC it is NOT cylinder #1 that is at TDC. I remarked the TDC mark on the crank pulley 120? off to get TDC on CYL 1 to correctly do the timing for my EMS system. I would love to know the reason why this is done like this.

Rob

Re: You are correct
 

Rob K you are on the right track with me on this when you remarked the timing to set #1 at TDC did it work? Seems like the crank position sensor would be off.

Before we go too far with this - which side of the engine is this #3 cylinder of yours.
 

Brake master cylinder side or oil filler cap side?

Re: Before we go too far with this - which side of the engine is this #3 cylinder of yours.
 

passenger side USA rear cylinder next to the fire wall, standing in front of the car the left side to the rear.

Re: Before we go too far with this - which side of the engine is this #3 cylinder of yours.
 

oil filler side