3b misfires

[WidowmakerS2]

I'm having a weird issue with my 3b, and can't seem to sort it out.
The engine has been out for an overhaul, and has never been in this particular car before.

In runs 'okay' on idle (a tad low maybe), but on throttle you can hear it misfiring.
As long as the pedal isn't pushed down more than 1/3, it's okay (still hearing intermittant I think), but on load it almost jumps out of the road, shudders and the occational backfire with loads of black smoke.
Based on the smoke my first thought was a major boost leak. I found a leak near the IC, but that didn't help. Now im thinking ignition, but I didn't think the 3b fired unless the ignition was dead on.

This could be some basic problem, but im just baffled right now. I thought I was going slow enough to do things right the first time around.

If you feed me with a checklist, I'll check it out.

[filip.krticka]

Check following:
ignition distributor, ingnition cap, spark plugs ang ignition cables (that was my problem).
And be sure, that you don't have any boost leak at all, as usual IC o-ring, throttle body inlet hoses, vacume hoses etc.

[WidowmakerS2]

Spark plugs: A little black (fuel?)
Cables: OK
Cap: OK
Dizzy: A little loose!! Could easily turn it with a hand.

Air leaks: Nothing serious that I could find. Doing a more detailed search tomorrow.

A little vid that I took before I started today (sound is a bit low, and Ive got a faulty sensor that makes the oil light flash):http://www.widowmaker.org/Audi/forum/Video010.avi

[WidowmakerS2]

Okay, so I tightened the dizzy and looked around for any obvious leaks. Couldnt find any. Any other ideas?

[newsh]

You need to check the static timing of the dizzy, it has to be absolutely spot on. Roll car forward in gear onto the flywheel timing mark seen through the window in the bellhousing then check the marks in the dizzy. If its not correct you'll get a big misfire and a cloud of smoke out the back.

[dkw_dude]

Did you do a pressure test? Looking is not enough. If the hoses holds pressure, try to swap MAF with a known good one.

[WidowmakerS2]

I'll check the timing again, but I thought it had to be absolutely spot on to make it fire in the first place. A quick guide to how to do it would be appreciated, because my method obviously isnt accurate enough

I havent done a pressure test, but I'm still trying to get hold of a leak test kit.

[WidowmakerS2]

And just another thing: Will a major air leak explain the weird behaviour and the black smoke?

[newsh]

Theres actually a quick guide to the timing my last post ^^. You have to roll foward onto the marks as there's enough backlash in the system to make it wrong if you do it any other way. The timing mark on the flywheel is a zero. the one under the dizzy cap is obvious. The dizzy one will line up once every two revolutions of the flywheel.
If you have a major boost leak you will hear it as a whooshing noise and the car will cut out violently and kangaroo as the fuel pump gets switched off. You should definitely do a pressure test of the system anyway as you need to find any small leaks and check all the little vac hoses too.

[WidowmakerS2]

Okay. Will try it again with rolling it onto the marks. There isnt any timing marks relative to the block from the distributor housing, just the two marks inside it, right? So the rotor has to point to nr1 (ca towards the water rail) and the two marks inside has to line up?
Just making sure..

A pressure test seems like the best bet right now. I've forgotten stuff before, and probably will again.

[WidowmakerS2]

Did a boost test, found a leak in the IC O-ring. Fitted a silicone hose with two clamps instead, and the boost system holds pressure. Idle is now spot on. I still have misfires though, whenever i put the pedal down more than halfway, it misfires. I still have dark smoke that smells like petrol.

[newsh]

Check for a leak in the small pipe at the ECU. Clean the MAF connector.

[WidowmakerS2]

ECU vacuum OK. Cleaned MAF connectors.

Blinked codes and got: 2324

[newsh]

2324 is the MAF, maybe a wire is broken.. can you try another MAF?

There are 2 multi plgs at the back of the engine bay, it would be a good idea to inspect and clean the contacts in these. (I think the MAF wiring goes through one of them, not totally sure..)

[WidowmakerS2]

Yep, it's the Maf fault..
I'll have to try with a known good MAF when I can get hold of one.

I think I had this problem with the maf connector off too though..