So I rebuilt my engine a couple weeks ago and these last few days my check engine light has been on. The code is P1391. I put a NAPA CKS in during the rebuild, although the original was working fine. The light came on after a few days of driving and I thought to change out the NAPA to the original thinking that maybe I got a bad sensor, however that didn't to anything. I always had a hard time dealing with the timing of the distributor, so I thought it could be something to do with that. I plugged in a OBDII reader and found that the engine was putting in 18 degrees of timing. I thought that seemed high, and maybe causing my light, so I repositioned my distributor. It ran fine for a little but the light came back on, same code. I can't think of what else it could be. Could timing be off and cause that code, and if so could my timing chain be off? Thanks for any help.

 

If the code didn't come on during your first few drives your chain timing and distributor position is probably ok. I would leave the stock Crank sensor in for now,You might have something going on with the cam sensor though. If i'm not mistaken there are distributor bushings that can go bad causing a false reading from the CMP. Hopefully someone more experienced in tracking down this specific fault will chime in.

 

So today i tore into the timing of the motor to find that it was off one tooth. I also bought a new distributor. The new distributor feels much better than the old, the old one's shaft rattled around a lot. It runs much better now

 

Glad to hear it.