I've had a P0336 (CKP sensor performance) code ever since I put the 427 in my car 2 years ago. I've replaced the sensor twice with the same results. Last weekend I went through the entire GN service manual troubleshooting guide with no smoking guns found. Anyone have any ideas what else could be causing this? The clearance between the sensor and reluctor ring is the same as the stock LS6 was (still have it sitting in a crate). The resistance between the CKP sensor connector and PCM connector was all good (0 ohms). I routed the wires as shown in the service manual (away from EMI sources). A visual inspection of the reluctor ring (using a boro scope) revealed no apparent damage.

The car runs well. The problems a fluctuating tachometer (about 3-400 rpm) and my data logs abviously show random 3-400 rpm fluctuations. And due to the p0336 code, I can't do the sensor relearn procedure (which sets the p1336 code). I'mm afraid I'm leaving a lot of ponies on the table due to fluctuating timing caused by this (does it affect actual timing).

A post in the C4 section mentions that a lope in the idle may cause this code (which I don't understand if that applies to the C5), but as listed in my sig, my car is VERY modified and this may be a cause (although there isn't a huge lope to the idle).

Any experts have any thoughts?? I'm looking to try anything at this point.

Derrick

 

I thought I'd post an update to this in case someone in the future does a search for a similiar problem. I tore the motor out because I thought I had a crankshaft endplay issue. upon tearing it down I noticed the reluctor ring was bent about 1/4 inch toward the front of the crank. After thinking hard I think I may have noticed that back when I built the motor but didn't think anything of it at the time. So I bent the ring straight again and changed the main bearing (endplay wasn't as bad as I thought, but was still .0010 when the spec is .0030 to .0070. It's now .0040.). I got it all back together and no more P0336 and runs much smoother. Now I have to undo all my tuning to try and "compensate" for the p0336 before... Back to work I go.

Derrick

 

Have you done the " crank position sensor re-learn " procedure ?--It is a must anytime the cam is replaced or taken out--I know it can be done with EFILIVE---not sure about HP---

 

Just got around to doing the CKP relearn today. Also drove the car for the first time today. WAYYYY smoother running. It's nice having a steady tach vice oscillating 400 RPM around the actual RPM.... Some things that I had problems with before and now don't that may be related to the P0336 are :

Tach smoothness
Running rough
Part throttle surging
Car now reeturns to a rock steady idle after revving it (vice hunting)
It no longer "hangs up" at 1200 RPM when the throttle cracker is activated (now returns to idle RPM when clutch is pushed and car moving)

The only downside, which I just need time to tune out, is that it's very "lopey" at idle and cold. It settles out as it warms up. I'll try playing with the timing at idle over the next few days to try and solve this problem (not really a problem, but gives away some of the stealth the car has otherwise).

Derrick