Crank Relearn Explained (sort of)
07-12-2005, 04:56 PM
#21
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Originally Posted by 04BlackGmc
so what happens if you dont do the crank relearmn?
07-15-2005, 01:55 AM
#23
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It does all sorts of fun things. In some cases, you can't start the truck. Other cases it won't let you rev past certain rpms. Just reving alone is sluggish and painful.
This is common amoungst stroker engines. A grip of info can be had at our sister site www.ls1tech.com
Just type in crank relearn in the search menu.
This is common amoungst stroker engines. A grip of info can be had at our sister site www.ls1tech.com
Just type in crank relearn in the search menu.
07-18-2005, 12:52 AM
#25
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Originally Posted by CAMMIN03'
PCM relearn
Try to crank car.... leave key in on position for 11 mins(no shorter, but longer is ok)
after 11+ mins. turn the key to the off position... let sit for no less that 30sec..
Repeat this 3 mroe times is should crank on the 4th
Try to crank car.... leave key in on position for 11 mins(no shorter, but longer is ok)
after 11+ mins. turn the key to the off position... let sit for no less that 30sec..
Repeat this 3 mroe times is should crank on the 4th
02-24-2013, 09:08 AM
#26
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crankshaft variation relearn
In another thread (now closed) someone was asking about crank relearn. In a nutshell it is this: One of the requirements of OBDII is that the PCM must detect and report misfire conditions. So how do you detect misfire? Well, the way GM does it is to monitor the time between the crankshaft sensor pulses and the camshaft sensor pulses. Since there is always some slack in the camshaft drive train, the time spaces will be one value if the cylinders are firing and the piston is delivering power, and another value if there is misfire and the piston is just coasting along. However, as you can imagine, every engine has a different amount of slack, so these timing gaps have to be calibrated, or "learned", into the PCM. The PCM has a routine in its software to do this, and the routine can be triggered by a command from HPTuners or the GM TECH 2.
So what's up with the relearn? Well, certain parts changes, i.e. new cam, new timing chain or gears, etc., can change the amount of slack, and the PCM has to relearn the gap values. The thread in question was discussing a custom PCM tune. Not sure how that would monkey up the works, though. Maybe someone else can explain.
Anyway, hope this quick and dirty explanation helps.
So what's up with the relearn? Well, certain parts changes, i.e. new cam, new timing chain or gears, etc., can change the amount of slack, and the PCM has to relearn the gap values. The thread in question was discussing a custom PCM tune. Not sure how that would monkey up the works, though. Maybe someone else can explain.
Anyway, hope this quick and dirty explanation helps.
02-25-2013, 02:11 PM
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All GM relearns, CASE, security, trans and idle. Last page helps you identify your system based on your key.
http://www.bsecorp.com/files/techtips/ST9303l.pdf
peace
Hog
http://www.bsecorp.com/files/techtips/ST9303l.pdf
peace
Hog
08-20-2020, 10:29 AM
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i know its an old post !
hello i know this is an old post but i was wondering if you can help me out
i put in a new crankshaft position sensor 7,8 months ago on a 2000olds intrigue. i didnt do the relearn , cant find a mechanic that does it, and i dont have a scan tool .
aside from slight poor fuel economy , car starts up and runs normal . idle is a little bit rough but nothing to get excited about. anyhow is it possible that i can still do relearn manually without the scan tool? ? if i follow what you posted? please let me know . or should i even bother doing relearn at all at this point , ?it might screw up the cranksensor eventually anyway without doing relearn . thanks for your help!
i put in a new crankshaft position sensor 7,8 months ago on a 2000olds intrigue. i didnt do the relearn , cant find a mechanic that does it, and i dont have a scan tool .
aside from slight poor fuel economy , car starts up and runs normal . idle is a little bit rough but nothing to get excited about. anyhow is it possible that i can still do relearn manually without the scan tool? ? if i follow what you posted? please let me know . or should i even bother doing relearn at all at this point , ?it might screw up the cranksensor eventually anyway without doing relearn . thanks for your help!
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