No spark? it cranks over but has no spark i replaced the coil but still no spark? on a 91 oldsmobile ninety Eight.

MANY possibilities! Assuming that your security light is not staying on--First, you must determine if it/s a no spark or a no fuel condition and take it from there.....

If you replaced only the coils, and not the module beneath, you wasted your time. Most times the module is what causes this.

Check fuel pressure,spark.If no spark possible crank sensor or ignition module.If no fuel pressure tap the bottom of the fuel tank with a mallet while someone is cranking the vehicle if it starts then you will need a fuel pump.Also if you have spark and fuel but the engine feels like it bucking while turning over,take a hair dryer and heat the coils up.you may have a bad coil pack.After they get warmed it night then start as the coil resistance changes.

Generally it is the Coils or the ignition control module that needs replacing. Hope that helps.

Have you replaced the oil pressure sending unit?

Check the crank position sensor.(CKP) just dont go replacing parts, check them and verfiy bad.

have you changed the fuel filter, air filter, and dod you put new spark plugs in it when you replaced the coil pack?

it is part of the ignition system. the ignition system provides spark to ignite the fuel/air mixture at precisely the right time in the correct cylinder. If you have a coil pack you dont have a distributor and the ignition gets its reference from the crank position sensor.

cam sensor is only half of the cam circuit, the other half of the cam circuit is the magnet on the timing chain. the cam sensor reads from the magnet every time the engine completes a revolution,
what happens is the magnet on the chain will break into smaller piece which makes the sensor harder to read every time the engine make a complete revolution.
most likely you'll need to replace the timing chain to fix this.

I had the same thing happen on a 91 Olds 88. Replaced crank shaft position sensor, coil, and ignition module. That solved the problem. I think the culprit was the CSP Sensor, but changed all three so can't say for sure.