I'm getting 3 codes, P0303, P0341, and P0340.


Po303 is a misfire on #3


P0340 Camshaft sensor Bank 1


P0341 Camshaft position sensor "A" circuit range/performance, bank 1


The engine has 230,000km and is on it's second timing chain. Any ideas out there? Does this sound like the chain has skipped a tooth on bank1 sprocket, or could it be a bad sensor? Sometimes the car will run flawlessly, and smooth, and then run rough a minute later. It sounds like it could be the sensor, but I don't have any troubleshooting information for that sensor to verify it.

 

I've experienced the same mix of cam codes on my 97 SC2 -- right as I lost all compression in cyl #4.....



The misfire code on #3 is in all likelihood the one to chase -- the
other cam codes will set in addition to P0303 b/c the car's PCM gets
confused when the camshaft is not where it is supposed to be in its
rotation.



Check for a bad plug wire on #3. Especially if the car runs
absolutely fine sometimes but runs rough at other times. Also
check coil pack resistance.



And of course, check the plug. If #3 is coated in oil and there
is a puddle of oil on the top of the cylinder, you may have a
valve issue on that cylinder....



Compression check should also help sort out fact from fiction.



This all sounds eerily familiar in a bad way....



Please post resolution



Derf



PS: The PCM apparently alters the timing once the cam codes set
to try to keep the engine running on the remaining three cylinders. So
once the cam codes set, the timing is shifted and the car runs roughly
in yet another way -- be sure to keep the codes cleared when
troubleshooting.














Edited by: derf

 

Derf


You made me laugh with your "eerily familiar" comment. I take it that you dropped a valve too!!


Number 3 cyl had a broken face on one exhaust valve. Aren't Saturn timing covers FUN to get back in when they are covered with fresh silicone!!


Anyway, I had a donor engine with a relatively new head. With a little valve compound, a few gaskets, and lots of hours in the garage......we are back on the road again.

 

Good call to check the miss-fire code first. s saturns don't have an actual cam sensor, so don't waste much time lookin for one. The 341 and 340 codes are set cuz of high resistance in the ignition circuit. the coil pack module measures resistance down the wires when it sends out spark to the plugs. It can tell by the resistance to fire the plugif the cyl is on a compression or exhaust stroke exc. It uses this calculation to put the injectors in to a sequential spray pattern. If it has a strange resistance value ie plug or wire miss-fire it can't calculate what cyl is on which stroke so it sets the code and goes into a base fuel injection program. Still runs ok but fuel economy suffers cus its spraying all the injectos at once instead of one at a time. Fixin the miss fire problem usually fixes all three codes. Good luck