My car wont start

[Red84Ttype]

My cars at the mechanics right now and we cant figure whats wrong. Theres no spark and intermittent fuel injector signal. So we checked the coil pack and spark plugs and both are. The mechanic thinks its the cam sensor or the crank sensor, but before he tares back into it I wanna get some input from yall.

[Shawn N]

May also be the cam sensor. Hopefully it's the cheaper crank sensor!

[Keller]

Cam sensor is easy to check if it is working. First think I would do if you have NO spark is remove the cam sensor cap and see if the trigger wheel inside spins when the engine cranks. If not, the sensor gear may be chewed up, or the sensor wheel might be damaged at the keyway on the shaft. Neither require changing the sensor to fix. The gear can be replaced (just like a distributor) and the trigger can be repaired with a device from RJC.

If it spins but shows no electrical activity while cranking (check with a meter), replace the cap with a Caspers one with an LED.

If its none of that, I would check the crank sensor.

[kenmosher]

... and if that all checks out, I'd suspect the ignition module or the wiring that goes to the ignition module.

[Red84Ttype]

Will the cam sensor spin if the crank sensor is done for? Or do I need the crank sensor to be working in order to test the cam sensor

[kenmosher]

Yes, it will spin. They are not mechanically connected.

Also, be sure the interrupter ring on the crank (which is used by the crank sensor) isn't tweaked/bent or dirty.

[Shawn N]

The cam sensor is supposed to set off the SES but I've seen several times were it did not do so. The crank sensor however will not set off the light.

[Keller]

While it will, it generates a "12", which is always present because the engine is never running when checking codes. That makes it harder to diagnose.

[Red84Ttype]

I ordered the 84/85 crank sensor from casper electronics for $101. My mechanic used this chart to help troubleshoot the problem. Here it is for you guys to use.
http://www.vortexbuicks-etc.com/1984...leshooting.htm

[Keller]

All of that is data also on this stie, or in the factory service manual. We prefer not to get hounded by GM legal folk, so we usually don't copy their pages here.

Hope it works!