91 Sunbird died--won't start

My son's 91 Sunbird SE (4 cylinder) died yesterday as he was driving it. I had it towed home. I've not done a lot of troubleshooting, but did find that it's getting gas, but no spark. I have 12volts going to the coil, but no spark at the coil. Is it a bad coil or am I on the wrong track?

Mark

There are several possibilities. First, change the coil as it may be bad. 2. The crank position sensor may be bad and not referencing the crank. 3. If you change the coil then make sure that the plug wires are good. A bad wire will cause the coil to go bad. 4. It is possible but doubtful that there is a problem with the computer of the car. 5. Make sure the timing belt didn't break. This could account for the car not starting although you should have power to the coil. Good Luck!

Thanks for the fast reply. I did replace the spark plugs, wires, dist. cap & rotor about 6 months ago with good quality parts. The timing belt is okay as the distributor is turning when I crank the engine, just no spark. I guess I'll start by replacing the coil. Where is the crank position sensor located?

Thanks!

Mark

There are several possibilities. First, change the coil as it may be bad. 2. The crank position sensor may be bad and not referencing the crank. 3. If you change the coil then make sure that the plug wires are good. A bad wire will cause the coil to go bad. 4. It is possible but doubtful that there is a problem with the computer of the car. 5. Make sure the timing belt didn't break. This could account for the car not starting although you should have power to the coil. Good Luck!

Mark, If you have a distributer you don't have a CPS. Check the module inside the distributer. That may have gone bad. That is what usually triggers the spark from the coil. The coil is not that expensive to replace anyway so it may be good insurance to replace it too. Also I would check the ground to the coil. I had a tach short out once when the ground wire broke and shorted out the ignition also. Don't know if this helps but it is a place to look.

Okay, what a day. Today, I replaced the coil, distributor module and pickup. Also, I found that the wiring harness for the distributor was shot, so I replaced the wiring harness. Everything is new now and still the car won't start. Still, no spark.

Any ideas on what to test at this point? The car cranks over fine, lights, everthing works, it's getting fuel, just no spark. Now, I've replaced almost the entire ignition system. Does this thing have a computer somewhere that could be bad?

Mark

Mark, If you have a distributer you don't have a CPS. Check the module inside the distributer. That may have gone bad. That is what usually triggers the spark from the coil. The coil is not that expensive to replace anyway so it may be good insurance to replace it too. Also I would check the ground to the coil. I had a tach short out once when the ground wire broke and shorted out the ignition also. Don't know if this helps but it is a place to look.

The only other thing I can think of is the primary ignition wire leading from the ignition switch to the car. I once worked on an ambulance that had this problem, there is a connection at the firewall and it is usually a red wire, check the wiring diagram first. It this is not making contact then you can crank forever and it won't start. Also check the wires leading to the starter. there may be a problem with one of them that is not sending voltage to the ignition system. That is about all I can think of. Keep posting results as someone else may have other ideas.

You mentioned a crank sensor in a previous post. Where is that located?

Mark
The only other thing I can think of is the primary ignition wire leading from the ignition switch to the car. I once worked on an ambulance that had this problem, there is a connection at the firewall and it is usually a red wire, check the wiring diagram first. It this is not making contact then you can crank forever and it won't start. Also check the wires leading to the starter. there may be a problem with one of them that is not sending voltage to the ignition system. That is about all I can think of. Keep posting results as someone else may have other ideas.

If the car has a distributer there is no crank sensor. The distributer takes the place of a CPS due to the fact that it spins in relation to the crankshaft and that is what fires the plugs. If you are not getting fire from the coil there is a problem in the primary ignition circuit and that is where you need to look. It could be a bad wire or a short that is causing the coil not to produce spark. Check the ignition switch too as it has to work properly before the car will run.

look for a fuse called ecm fuse i think thats right and see if its burned out thats what happened to my friends sunbird