1991 olds 98.3800 motor. Where is the cam sensor?

did you try cranking with throttle open 100%
this clears flooding this cuts the injector(s) dead.
does it/
try fresh spark plugs, are the 10 years old?
try test fuel (spray)? run for 3 seconds,
if not, you lost spark check fuses.
if you have spark and it wants flood is the cam belt 10 years old too, if it slips it will not run again, ever.
until that is cured.

as it is the basic 305 block the differences may be fuel injection over carburettor which may require sensor attachments but basically the engine should just slot in place.

The link below will give some images showing the cam position sensor:
1991 pontiac cam position sensor Google Search
You're probably better reading what other Pontiac owners have written:
1991 pontiac grand prix will not tickover Google Search

Did you replace engine with one of the same year? I'm not sure about this motor but i had the same problem when i swapped a 00 with a02 in a concorde. T hat motor had a cranksensor that read off the flywheel and a cam sensor that read from a pickup on the end of the cam. The problem i had was the sensor rings on the cam and flywheel were different from the engine i removed.The answer for me was to swap the old flywheel and drill out rivets on cam sensor pickup ring and rivet in old one. The slots were different in the rings so sensors were sending incorrect signals to the pcm.The first thing i would try is unhook just the cam sensor and see if it will fire up.Hope this works for you.

try unpluging your torque converter

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.

Please get a brand new sensor.

New parts are better than used/ old parts.

Visit www.repairpal.com (for estimates)

Visit http://www.autopartswarehouse.com/ (for genuine parts)

Good luck and remember to rate.

i think you mean a crank shaft position sensor witch is located on the back of the motor towards the bottom. good luck

41 is cam sensor code. are you sure the magnet is still in the cam gear? use only quality parts. if the magnet is missing, you need to replace the timing gears/chain.

if the emissions control didnt check the egr valve check that. otherwise the idle air control motor/servo. also look for vacuum leaks.