Misfire cylinder 1

[radrodder04]

I have a 99 Saturn SL2/auto. Cylinder 1 will not fire. It has spark to the end of the plug. But the cylinder will not fire. No oil is getting on the plug it isn't fouling out. A brand new plug doesn't help at all. The cylinder is DEAD!

[Cat Fuzz]

Fuel injector maybe.

[radrodder04]

I'll check that 1st, because my next door neighbor says he thinks it's lost compression in cyl. 1 and I don't like his diagnosis.

[Cat Fuzz]

A compression test is easy. No compression, no fire.

[radrodder04]

So no compression means Rings or valves?

[Cat Fuzz]

Originally Posted by radrodder04

So no compression means Rings or valves?

Most likely. You could have burned piston. I've seen holes burned clear through a piston top before. A bent valve could cause no compression but valves don't just bend without something bending them, like, foreign matter getting in the cylinder or the engine being ran with the valve timing off, like when a timing chain breaks or is improperly installed.

[denisond3]

My first check would be to see if the connector to the injector for #1 cylinder is truly and fully seated onto the injector - and clicked in place. After that I would do a compression check.
If the engine still runs on the other 3 cylinders, I dont imagine it could be a problem of valve timing or a timing chain that has slipped. If it ever slipped enough to bend a valve - the engine surely would no longer run.

Your compression reading should be nicely above 110 psi, and not vary a lot from cyl #1 through #4.

[Cat Fuzz]

Make sure your ignition wires are in the correct order.

[drew300]

I had the intake manifold gasket leak, which caused a misfire on #1.
you can check it by spraying WD-40 or throttle body cleaner around the manifold / head.