Originally Posted by 97lt1camaro

I have a code thrown instantly even with engine not running, P1336 which appears to be crank variation bla bla not learned. From what ive read i can fix this issue in hptuners, which i have. More info on this would be appreciated.

Originally Posted by GM Service Manual

The Crankshaft Position (CKP) sensor sends pulses to the PCM as the reluctor wheel teeth rotate past the CKP sensor. The PCM uses the CKP pulses to synchronize the ignition and fuel injector operation, and to time the interval between each CKP pulse. The PCM determines when an excessive change in crankshaft speed occurs by comparing each new time interval with the previous interval. A misfire causes an unexpected change in the crankshaft speed. A certain amount of acceleration/deceleration is expected between each firing stroke, but if the crankshaft speed changes more than an expected amount, the PCM interprets this as a misfire. The interval between CKP sensor pulses is extremely small. At high engine speeds, slight variations in the following components make misfire detection difficult:

•Crankshaft.
•Reluctor wheel.
•CKP sensor.

The PCM learns variations during the Crankshaft Position System Variation Learning Procedure. The PCM compensates for these variations when performing detect misfire calculations. Only a scan tool can command the PCM to perform the Crankshaft Position System Variation Learning Procedure again.

Originally Posted by 97lt1camaro

I also have another issue however, my rpm guage is way off, I can be wound out in 2nd gear and only be reading 3000rpm, when clearly im near redline. Is this a sensor issue or more likely a pcm thing that needs to be adjusted?

Originally Posted by S10Wildside

These two issues are not problems. They are both unfinished work for your conversion.

Regarding the P1336 DTC, you will find the following information in the GM service manual.



In short, the crank learn data in your PCM has been lost (through a full flash of a new operating system). So the PCM is telling you, "Hey, there is something I'd like to know about your engine and I'm going to set this P1336 DTC until you allow me to look at the crank and cam signals through a testing procedure." And by the way, a "misfire" is defined by the misfire tables in the calibration. Assuming your calibration is based on an LS1 engine, those misfire table values are only appropriate for a stock LS1 engine. If you have the original misfire settings in those tables and have a nasty cam, at idle the PCM may interpret a misfire. I doubt there are many tuners who take the time to properly rework the misfire tables.


pulse counts to 3. Then enable the tach pullup (if that's what HP Tuners calls it?). Then let us know how the tach looks.

Originally Posted by 97lt1camaro

Would the crank learn variation be something i should wait till the car is running near optimum for. Cause the tune is pretty rough on it seems at the moment and i heard there might be issues getting it to do its "learn" if the car isnt running quite right.

Originally Posted by S10Wildside

If, in park/neutral, your air/fuel ratio is somewhat close to 14.7 from idle to about 4500 rpm, then yes you can do a crank learn. If not, make the few changes in the calibration and do the learn. It's not much work to change the fuel calibration while in park/neutral. If for some reason you cannot make the calibration changes at this time, then I would wait to do the learn procedure.

Regardless of crank learn status (learned or unlearned with a P1336 DTC set), the engine is always going to fire injectors and coils based on the crank signal. Unless there is something I am unaware of, you are not hurting anything to postpone the crank learn procedure.

Originally Posted by 97lt1camaro

I also appear to be throwing a code for the knock sensor, so im hoping its the sensor and not the wiring as i dont really want to have to dink around with it.

Originally Posted by S10Wildside

From the PCM's point of view, there are two knock sensors...and "a code for the knock sensor" can mean many different things. A 4th gen F-Body does not have clearance near the motor mount for a second knock sensor.

Without any additional information, I'm going to guess that you are using one knock sensor and the calibration is set to use two. If this is the case, you simply have to change the calibration settings to indicate that you are using one knock sensor. Problem solved.