On Wed, 5 Feb 2014 21:16:33 +0000 (UTC), Doug Miller
wrote:

dpb wrote in :

On 2/5/2014 1:39 PM, Doug Miller wrote:
...

Saturn S-series engines use timing chains, not belts. I suppose if
thetensioner broke, the
chain might have jumped... but that seems unlikely.


I've seen 'em get off a tooth (or break a tooth or the like) but as
somebody else noted, that you seem to have good compression means
mechanically it's in synch within enough it ought to fire lacking
something else. May be time for new for PM, but it ain't the present
problem.

I did the compression check before the engine began refusing to start at all. Haven't
rechecked it after.

Not sure about the sensors on that engine whether it's possible to get a
polarity problem or otherwise screw up the indicated position while the
mechanical is ok or not...

Saw pretty much the same behavior on our other Saturn S-series last summer when the
crankshaft position sensor failed. That tests good on this one, though.

Then the firing order is suspect

I've checked and rechecked the firing order maybe half a dozen times. It's correct.

or you put the cam back in 180 out or

Haven't had the cam out.

something similar to have the intake valves open when it fired. As
again somebody else noted, there's no back fire thru the throat if
intakes are closed when it fired so they weren't.

--

Have you checked the oil level??Smell the dipstick? Is there Gas in
the crankcase??
I've had engines backfire through the intake on ether before - and
even on gasoline - particularly if a valve is a little sticky - which
sometimes happens when an engine is badly flooded.
Pull the plugs, do a compression test, change the oil if required. If
the compression is low, squirt a bit of oil in the cyls and spin it
over - recheck. Then check timing

If the compression is good, and the plugs are clean and dry, and you
have fuel it WILL start