Can a bad CPS not throw a code

My cars that are OBD1 will not throw a code if the CPS (crank position sensor) is bad. On the forums the first notice is usually a no start situation but can present itself in other ways.

 

One of the online parts suppliers had this about the CPS -

 

"You will know that you have a bad crank position sensor by how your engine idles, how your pistons fire, or how you accelerate. It will usually be more noticeable as you raise the RPM's. With a bad or faulty sensor, you engine may misfire causing motor vibration or backfires. You may also experience hesitation while accelerating or shaking during engine idle. In the worst case scenario, you won't be able to start your car"

 

I have these -- "motor vibration, shaking during engine idle and a general misfire when accelerating."

 

 

1. Would a bad CPS throw a code in OBDII
   
2. Would a misfiring wire throw a code in OBDII
   

I did an internet search using bad CPS but no CEL and there are hits where people had a bad CPS but no CEL. I thought OBDII was supposed to monitor all this stuff?

 

 

The CPS was just something that came to mind while I was trying to find ways to not have to change the spark plug wires.

A bad crank position sensor should show on all on board diagnostics, on obd2 it will come up right away and the vehicle won't start at all. During the motor replacement in my 95 legacy I had a bad crank sensor and it took me about an hour to figure that out because its not a very common failure, the cps is only a magnet and really only fails if it gets too hot or the wires get cut or nicked.

Im sure it could be on its way out with no cel yet. Sometimes you have to make a best guess based on the symptoms and replace that part. Most of the time if you do a lot of research and have good instincts it pays off. I do know if it goes totally out you will have no spark so when it starts to go im sure it would start sometimes and other times not. Probably not run as smooth either.

Why not change the plugs and wires first though? The Crank sensor can be a pita to replace on our cars cause they can corrode and get stuck.

I was looking at the CPS and yes I could guess it may be a PITA. The rear bolt doesn't look easy to get to and if it is corroded?!?!?!

 

Plugs were changed by the PO and I would have paid him for new wires, if only he would have asked before doing the plugs and using old wires.

 

Im sure it could be on its way out with no cel yet. Sometimes you have to make a best guess based on the symptoms and replace that part. Most of the time if you do a lot of research and have good instincts it pays off. I do know if it goes totally out you will have no spark so when it starts to go im sure it would start sometimes and other times not. Probably not run as smooth either.

Why not change the plugs and wires first though? The Crank sensor can be a pita to replace on our cars cause they can corrode and get stuck.