As a followup to my "cracking the Harmonic Balancer" post I thought for those searching for answers I'd post the fix for the no start problem.

So here's the story: I needed to replace the cam belt tensioner, as it rattled badly at startup.

(Short version of the answer- the timing was 3 teeth advanced by previous mechanic - we had assumed it was correct - car drove well and it was 30,000km since it was done - and the cam belt didn't slip with our work - but a bee's D*&k adjustment on belt tension made the timing too far out to start - Apparently)

Long version:

Removed belts Harmonic Balancer (eventually) & covers.

I had a friend lever up the tensioner pulley - whipped the old tensioner out and whacked the new one in . Turned the motor by hand 2 revs - and made a cup of coffee, came back - tensioner collapsed again - belt must be too tight - used a home made tool to release some tension by turning the offset/cam pulley the tensioner pushes on maybe 10 degrees?, turned the engine over by hand 2x times and waited 10 minutes - perfect!

Reassemble - turn key and NO START - turns over (badly) and almost diesels backward as it stalls. WTF! checked everything and still no go, Noid light shows injector pulse, spark good, The only thing we touched was crank angle sensor connection, recheck - nothing wrong.

A week later armed with a used crank angle sensor and the workshop manual - fit new sensor - no go. now knew how to read the diagnostic engine light flashes - reports no errors Huh?

My friend suggested we check the timing - we had wet spark plugs ie: fuel, we had brilliant spark, we had compression so it had to be timing - but we knew it hadn't changed right? WRONG!

We used a screwdriver in #4 plug hole to find TDC - and the cam marks were 3 Teeth past the TDC marks - I don't understand how it ever ran!

So after some considerable faffing around (it's hard to skip 3 teeth in one go) the timing was back and Vroom Vroom runs like a bought one and 1L/100Km better economy.

So Assumption - Kills me!

I don't think there's any chance it would have run if it was originally three teeth out. Something else has happened while you've been working on it IMHO.

1000% sure nothing moved - if you've ever heard a cam skip a tooth it makes a noise - there were none, and I got my mate to lever the tensioner assembly away from the hydraulic unit - quickly swapped it and re installed ie: the belt didn't move. Also BOTh cams were exactly the same amount out, not likely unless the crank skipped - and you can see that while working on the tensioner.

As the harmonic balancer in this car (TJ December 2001) doesn't seem to have any definitive marks for TDC we had to use a screwdriver down #4 plug hole to find TDC - possibly we ended up 1 tooth retarded (yeah put a joke in here) so at most it is 2 teeth out - whatever - the car starts and runs MUCH better than before - getting better than 1L/100Km economy, better idle and if anything it goes even harder, Traction control light has been on a bit....

As the harmonic balancer in this car (TJ December 2001) doesn't seem to have any definitive marks for TDC we had to use a screwdriver down #4 plug hole to find TDC.

This statement is a bit of a worry.
There is a mark on the inner pulley of the harmonic balancer that lines up with marks on the timing cover.
Once these are off, there is another mark on the crank gear that lines up with a mark on the oil pump case. Bit hard to see, you need to know what you are looking for (manual helps) and a torch to find them.

A bit of a dead thread but hey life moves slowly sometimes... I had to replace the power steer belt, so decided to check the timing, and found the mark on the inner side of the balancer (nice one Mitsi - put the mark where you can't see it and the timing mark jammed next to the chassis rail) - anyway turned the engine and pointed the mark at 0 degrees and popped the top cam belt cover - and 100% right timing so I can confirm it was 3 teeth out on the cam - and at the same time I pulled #2 plug and it was nice and white - unlike the black sooty version before fixing the timing.

So I can assume you can *just* barely get the engine to run 3 teeth advanced - it must be a fine line though as a tiny tweak to the idle pulley screwed the engine...