onebadmax Posted November 26, 2014 Report Share Posted November 26, 2014 Zippy, can you elaborate more on why it's neccesary after a cam only swap? I didn't perform this on my truck is why I'm asking? Thanks Quote Link to comment Share on other sites More sharing options...
ccgoodwrench Posted November 29, 2014 Author Report Share Posted November 29, 2014 I was going to reply to this a while back and simply forgot about it when I was on the last few times. If you don't know the proper answer... DO NOT REPLY... My biggest issue with post on here lately has been all of the people posting who have no actual knowledge about what it is they are actually posting about. Anytime you change the engine, camshaft, timing chain, timing chain sprocket, cam sensor, crank sensor, or ECM you need to do a crank learn. Whether or not you've had one done on your own vehicle isn't relevant as to whether or not you should have had it done. On the same point, even if you don't get a code for it you still need it done. When doing the job on HPT it won't tell you if you were successful. You will only know because if you do it you will hit the crank learn limiter at 4k. If you didn't do it correctly it will just rev. I will add that it doesn't mean to just lower the rev limiter to 4k, I once had a customer do that. and then told me he had to do that to get it to take. Do not do that.thanks for the info, is their a step by step how to for crank relearn?, I retuned the MAF and truck is running great, very smooth throttle response. And my trims are around -2 to +3, I just haven't turned the p0300 code back on yet to see i get the immature history for p0300, it was just annoying it would sometimes light the check engine light Quote Link to comment Share on other sites More sharing options...
zippy Posted December 4, 2014 Report Share Posted December 4, 2014 The reason it is required after a camshaft swap is simply that the cam sensor reads the camshaft itself for the cam reluctor. The crankshaft learn is to calibrate the crank and cam sensor together. If you don't do this after a camshaft swap you can end up with a faulse missfire condition (worse than even the lope itself causes) and also end up with knock due to inaccurate timing. Odd enough it can also cause a missfire at idle. The proper steps for crank learn... Get the engine to proper temp with an engine that will not die if you rev it. Set park brake. Sounds stupid, but pcm looks for this. Open HPT Logging software and connect laptop to the truck. Click File tab and then click Connect Click Displays tab and then click VCM Controls Go to Specials tab and if all is ok you will see a ready box to click on. Hold left foot on brake entire process from just before clicking ready to after done and don't let up until done for sure. Click Ready and stab throttle hard either to wide open or close to it. Do not follow HPT instructions to slowly rev it. Rev it like you mean it. GM actually calls for wide open with the Tech 2 when doing it. If you feel it hit the limiter at 4k rpm you will know it worked. Once it hits that limiter lift as fast as you can react. Let the engine return to idle and when ready comes back to the screen you are done. Exit scanner, shut off the truck, and leave engine off for 30 seconds or so. Fire it back up after and you should be done. There is no confirm mode with HPT. Quote Link to comment Share on other sites More sharing options...
ccgoodwrench Posted December 5, 2014 Author Report Share Posted December 5, 2014 The reason it is required after a camshaft swap is simply that the cam sensor reads the camshaft itself for the cam reluctor. The crankshaft learn is to calibrate the crank and cam sensor together. If you don't do this after a camshaft swap you can end up with a faulse missfire condition (worse than even the lope itself causes) and also end up with knock due to inaccurate timing. Odd enough it can also cause a missfire at idle. The proper steps for crank learn... Get the engine to proper temp with an engine that will not die if you rev it. Set park brake. Sounds stupid, but pcm looks for this. Open HPT Logging software and connect laptop to the truck. Click File tab and then click Connect Click Displays tab and then click VCM Controls Go to Specials tab and if all is ok you will see a ready box to click on. Hold left foot on brake entire process from just before clicking ready to after done and don't let up until done for sure. Click Ready and stab throttle hard either to wide open or close to it. Do not follow HPT instructions to slowly rev it. Rev it like you mean it. GM actually calls for wide open with the Tech 2 when doing it. If you feel it hit the limiter at 4k rpm you will know it worked. Once it hits that limiter lift as fast as you can react. Let the engine return to idle and when ready comes back to the screen you are done. Exit scanner, shut off the truck, and leave engine off for 30 seconds or so. Fire it back up after and you should be done. There is no confirm mode with HPT. thanks, I do sometimes get knock retard, will let you know how it turns out Quote Link to comment Share on other sites More sharing options...
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