1989 240 starts then dies immediately!
 

I had to replace the crankshaft sensor and the mass airflow sensor. A buddy told me that was probably the only problems but it still won't idle worth sh*t. Has anyone had similar experiences or know what's wrong?

these are for 740/940 cars but your engine is the same B230F, with only minor differences (240 doesn't have the 'radio supression relay', and many components are in somewhat different places, especially electrical stuff like relays)... anyways, I'd go through these troubleshooting suggestions
Engine Tune and Performance

I *think* a 89 240 has LH 2.4 (my 87 has LH 2.2).... the LH 2.4 has a onboard diagnostic thing where you can read codes and execute diagnostics from a little blinky box thats under the hood. The earlier LH2.2 doesn't have this. see
Engine and OBD Diagnostic Codes for the OBD codes on a 740/940, the 240 are almost identical.

I figured out what's wrong with it. A rock flew in through a space into my flywheel and dented it all up. That's why my crankshaft sensor was destroyed. We turned it by hand and popped all the dents out, and it started right up. I don't think anyone could've seen that coming.

so it was the crankshaft sensor after all? Having the same issue that’s why I ask.

i thought flywheels were machined solid steel ??

edity: oops, 9 year old thread dredged up from the graveyard.

I always thought that too, would the crank sensor create the symptoms I described?

I bet it wasn't the flywheel that was dented but the tone ring which controls the CPS pulses! If the flywheel gets dented, the engine would be damaged-- good luck straightening it out!

its been too long since I saw a volvo flywheel.... I thought the CPS read holes drilled right into the side of the flywheel next to the gear teeth that the starter engages ??

My 89 740 is like that. Just blind holes drilled in the side of the FW. No way I think you can damage it so I would suspect the sensor itself.