Jag that won't start

Well, it takes air, gasoline and a spark to fire. If you are getting air and gasoline, I would check out the spark. Pull a plug lead and see if you are getting a spark at the end of the lead.

We have a spark but gas doesn't seem to be getting past the injectors that are working.

Not to offend your mechanic's abilities but I'd suggest you confirm the camshaft vs. crankshaft synchronization - it may be off - even by 180 degrees.

My two cents (or pence).

Hmm,

Ok. You have spark, but that does not mean that the distributor is correctly lined up.

Ok. If the cams were installed 180 off then I would assume bent valves. Perform a compression test.

Ok. Your injectors seem to be operating yet no fuel is spraying out. Pull the injectors and clean the inlet screens or have them cleaned and tested at an injection shop.

Ok your mechanic is stumped; it happens.

DieInterim

If your 180 out, your probably putting fuel into cylinders which are on the exhaust stroke. A compression gauge is what you need to see the compression stroke while "bumping" the engine. On max compression, stop, and look at what cylinder the rotor is on. (trace the plug wire of that location) It all should match the cylinder that just compressed. Then check the firing order just in case and make sure your not one hole off all the way around.