96 SL2 cranks but won't start

Since my last posting (March 2), the engine did finally start up, and run normal for several days after removing the plugs, testing compression, (fuel relay, ignition module connector removed) and putting all back together. This is a 1.9L DOHC engine.

The findings then were: cylinders wet with fuel, plugs in 1 and 2 look good, 3 and 4 fouled. Tops of cylinders 1,2 looked normal, 3,4 have nasty deposit of grainy oily looking "black stuff" on top. Compression in 1 and 4 came slowy (11 cranks) up to 155PSI, but 2,3 both had low compression 50-60 PSI. The fuel pressure at the fuel test port is 45 PSI, with a little "wiggle" (maybe 2 PSI) while cranking.

After running OK for several days, it then died slowly over the course of half a minute, losing power on the freeway, acting much like a dirty fuel filter.

So, I know I at least need to do head work (maybe an engine swap) but want to find out why it won't start before making any more changes. Hopefully some of your experiences will help.

1. Since both the 3 and 4 cylinders fire from the same "side" of different coil packs, is there a fault mode where one side of a coil becomes "weak"? This may account for the 3,4 cylinders fouled plugs.

2. The low compression in both 2 and 3 cylinders would indicate gasketing leaks between the two, but the oily residue and fouled plugs are in the 3,4 cylinders. Any ideas?

3. How do I test the fuel injectors without the motor running? I'm thinking maybe sticking injectors in the 3 or 4 cylinder.

4. Am I correct in assuming that if the ECU fires the plugs, it has no terminal (won't start engine) faults, so it is not the problem?

5. Can I use 91-95 ignition coil packs on a 96 SL2 DOHC engine?

Finally, sorry for the long posting, but any suggestions would be appreciated.

Thanks,

1. first, they shouldn't be on the same side, the order on the coils should be 4-1-2-3. second, the DIS system uses a waste spark method, so one coil fires two plugs at the same time(1/4 and 2/3). if one plug of the pair fires stronger then the other then ether the plugs, wires, or cylinder compression is at fault.

2. perform a cylinder leakdown test to find where you are losing compression

3. there is, i'm not exactly sure how, i think its called a spray test, and probilly requires some special machine

4. not exactly sure what your asking, but with that low of compression, i would be more surprize if it did start.

5.module -no, coil packs - unlikey, 96+(OBD2) are a little more picky about the firing voltage.

Thanks, guess I wasn't too clear, what I meant was the 2 and 4 cylinder are connected to the same "polarity" of thier respective coil. Still not much clearer than mud...
Anyway, I finally pulled the valve cover off today to find out why there was now NO compression, and found either the intake and exhaust cam slipped, and are now timed exactly the same! Looks like the problem has been the camshaft chain or the tensioner. Since the chain slacks up half an inch or so at certain spots on the crankshaft cycle, I'm now betting on replaceing the whole cam chain system.
Also found about six bolts missing from various spots... oil pan, PS pump bracket, cam cover... guess this "new project" car is gonna be a whole lot of fun....
Thanks for your info and help,
Terry



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good luck, lots of the info you will need can be found on Saturnfans.com

be forewarned, if the timing jumps enough, the pistons may hit the valves and bend them.