Was experimenting with the cam timing on the mr2 yesterday, and gave the exhaust camshaft a whack of retard - and I knocked the inlet back to what I thought was zero adjustment.

A mile up the road I plant the foot and I get the biggest, and I mean the biggest, most badass backfire you have ever seen - flames shot out of the engine cover vents about 2 feet in the air! She started revving up like crazy then and the vacuum gauge went crazy - a vacuum leak. Also had a MAP level warning on my in car pc display monitoring the ECU - obviously a pretty hardcore backfire (A backfire remember happens in the inlet tract, an afterfire happens in the exhaust)

So back to the house, engine cover up and immediately obvious that 3 vacuum pipes have been blown off with the force of the explosion - put them back on and the revs dropped from 3000rpm to 1500rpm at idle - still far too high. Arse I thought (Since there were no obvious leaks), there could be a crack in the inlet manifold or the gasket - but the gasket seemed highly unlikely as it is a sheet of thin steel. Buggerations - so I started to strip the inlet tract off to get at the manifold. While I was doing so I stuck a mirror up the back of the manifold to check out the injectors - bingo! O-rings blew off number 1 and 2 injectors - hence the loud ticking noise (Injector noise) and the vacuum leak causing unmetered air to enter the engine and throw the AFRs all to hell and over 16:1 at idle.

Have to try and get a set of o-rings tomorrow to fix that and going to re-degree the camshafts while Im at it. Pissy o-rings that were supplied probably saved my manifold as they were so bad -

Lesson learned = ALWAYS write down your initial cam settings when you have a set of verniers! Dont assume they were at zero !

lol, dont you just love tinkering with cam timings!
sounds like you took the exhaust back a tad to far and the inlet to early.

got it accurately degreed this morning, and fired it up - runs like a stocker now, yeooooo

Now, on to the mid-boost road tests!!

Need to weld on a nut to the sump to use as oil temp probe mount, and make myself a right angled adapter for the oil pressure sender now as well.

Also noticeably quieter at idle - the o-rings must never have been sealing properly against the block.