Audi 80 ACE 16v: Good when hot - Poor when cold

Posted: Wed Jan 31, 2018 4:08 pm

sometimes the flywheel marks can be difficult to see.

I'd recommend removing the distributor cap so that the rotor arm is visible. Turn the engine by hand until you have the rotor arm almost pointing to #1 cylinder - now look for the mark on the flywheel. Move it tiny amounts and keep checking window in the bellhousing - an assistant helping is recommended.

If you find the mark - use some tipex to make it more visible.

Once you've got that mark, remove the front cover and check your cam marks

Posted: Sun Apr 22, 2018 12:03 pm

Ok, I did a fuel pressure test. Not exactly by the book - I used the test port on the lower half of the fuel distributor.

5.5 bar when the engine is running and
3.5 bar after 30 mins.
3.9 bar after 3 hours (it was a warm day)
3.0 bar after 24 hours

A great result and within guidelines. I think...

I am ready to give the fuel system a clean bill of health - I will repeat the differential pressure regulator voltage check which had some odd results in the last post.

I will also adjust the air flap mixture setting, with Vagcom running live data -> to get the smoothest idle. I may swap back my air flap to my old one which has not been adjusted.

Really, after that it is back to the ignition system and the associated sensors that the ECU uses.

...and it may be worth considering major failures like piston rings, leaking valves etc. The engine is emmiting a lot of dark grey sooty smoke - leaving deposits on the wheelie bin behind it. I believed it to be incorrect mixture burning that gave this but maybe something else.

I have done a number of compression tests with varying results ->Perhaps soot buildup is giving more favourable results at the moment. The plugs a get sooty but not oily FWIW.

I am looking for checks/tests to assess general engine health - any tips on the ACE or similar engine?