OT '96 Saturn DOHC won't start

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

Your firing order could be correct but the timing could still be off. All this means is that the proper plug may fire the proper cylinder but that it doesn't fire when both valves are closed. I don't know how many degrees it would need to be off for the intake valve to be open whin the plug fires. Eric

============= Lots of good suggestions.

You didn't get a batch of contaminated gas did you? Did wife fill up just before trouble started? Is fuel filter clogged/restricted?

Backfire with starter fluid seems to rule out no-spark electrical. Any chance of damage if you try this again?

also try

google on {saturn DOC "starting problems"} 615k results

VIRTUALLY impossible with a direct fire lost spark system

Semantics....4 cycles go through 720 degrees of crank rotation for each compression stroke, whether there's multiple pistons or a wasted spark is irelevant.

That said, it sounds like it's getting fuel, but for some reason the spark is going off when the intake valve is open....(which may well be perfectedly expected, IF you have a flooded cylinder and the wasted spark normally occurs at valve overlap)

Hopefully you've also checked to make sure that the LOW VOLTAGE wiring TO the coils are attached to the correct coil.

Correctamundo!

I have never followed GM products, period, so you're right. I do vaguely recall hearing about it but didn't pay much attention.

GM dealers would still be handling parts and repairs of the beasts and have the database on repair methods, so there would be the place to go, should someone need it. Don't tell the milmac mutt. ;)

With the rest of the corn. ;-)

Ditto, and I shunned them then, too. Damned used car salesmen...

Amen. I wonder what passes for training nowadays. Are they simply training board-replacers, or what? As teachers go the way of the buffalo, so do intelligent students and the populace as a whole.

When the SHTF, the true cost will be told.

And what volatile oil that is! I've seen fires from a stuck float in a carb. The rubber oil cap on a chebby 350 dented the hell out of the hood when the crankcase ignited.

High on the list of "what shotgunning doesn't fix".

From Wiki

The biggest changes for 1996 were the OBDII PCM, an all new sequential fuel injection setup that utilized a first ever "compress sense" cam sensor setup (cam sensor input was achieved by the ignition module sensing the amount of amperage it took to fire cylinder number 4. More amperage meant TDC compression, less meant TDC exhaust) in lieu of a conventional camshaft position sensor. Also full spark control (timing and firing of the ignition coils) was achieved solely in the engine control module as opposed to the ignition module.

So if the plugs can't fire (voltage same on both cyls) due to flooding, it shuts off the spark - or throws a "shower" of spsrts to start the engine?

Regardless, the plugs need to be clean and dry - or replaced. Use AC Delco plugs. - it IS a GM.

Greetings Doug, Didja figger it out yet? I would really like to know what the problem turned out to be. I'm sure others here would like to know if you got the engine running properly. Our egos are waiting. Cheers, Eric

snipped-for-privacy@whidbey.com wrote in news: snipped-for-privacy@4ax.com:

No, not yet. I haven't had as much time to work on it as I had hoped -- it's funny how your job can sometimes get in the way of doing what you really want to do... and it doesn't help things that my garage is not heated, and it's 8 degrees right now, headed to a low of -3.

I did verify that the valve timing, at least, is dead nuts perfect: rotated the engine manually, with a wrench on the crankshaft, until #1 piston was at TDC of the compression stroke

-- and the timing marks on the cam sprockets were exactly where they should be. (Saturn S-series engines have alignment holes in the cam sprockets and the head; when the timing is right, a 3/16" pin slips through the hole in the sprocket and into the hole in the head. It does.)

Ex-mechanic working at the parts counter of my local Advance Auto suggested that maybe, just maybe, a faulty knock sensor could do this. I have most of the afternoon off work tomorrow, so hopefully I'll have time to check on that. Should be easy to test: service manual says that a functional knock sensor should have about

Knock sensor will NOT cause a no start. It will not affect cranking timing.

snipped-for-privacy@snyder.on.ca wrote in news: snipped-for-privacy@4ax.com:

I didn't think so either, but it's easy enough to check while I'm under there.