crank relearn
09-19-2004, 02:39 PM
#1
crank relearn well guys getting closer and closer, my new shortblock is in and now i just have to hook everything back up..question is: the shortblock is out of an 02 model, i have a 98.. will i have to tow it to the dealership to have the crank relearn done on it or will it run, but just like crap? the dealerhip is aprrox 5 miles from my house.. i really dont want to pay to have it towed, but i guess i might have to...any help
thanks
matt
thanks
matt
09-19-2004, 02:49 PM
#2
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After a PCM swap I had it beefing about crank relearn not
done, it ran a little funny / weak but it ran. As long as the
crank and cam sensors are in there, it should run. Also, I
believe it's supposed to try and relearn on its own at some
interval but various sensor codes etc inhibit it. Unless there's
something funny about '98s I think you can get it to the
dealership. Another option is to find someone with EFILive
Pro version, that will do the force relearn (as long as there
are no codes problems).
done, it ran a little funny / weak but it ran. As long as the
crank and cam sensors are in there, it should run. Also, I
believe it's supposed to try and relearn on its own at some
interval but various sensor codes etc inhibit it. Unless there's
something funny about '98s I think you can get it to the
dealership. Another option is to find someone with EFILive
Pro version, that will do the force relearn (as long as there
are no codes problems).
09-25-2004, 05:43 AM
#3
hey, i still got the car on the ramps, but i started it up..i had no SES lights... 
shouldnt it be throwing a code stating it needs the relearn done on it or will i have to actually drive it for a little while or what? seemed to idle alright, still have to get my tb hole the right size but other than that ran smooth..on the ramps that is... 
shouldnt it be throwing a code stating it needs the relearn done on it or will i have to actually drive it for a little while or what? seemed to idle alright, still have to get my tb hole the right size but other than that ran smooth..on the ramps that is... 
09-26-2004, 11:58 PM
#6
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Originally Posted by Viper
Do a search on crank relearn and my name; mine didn't throw a code for months. $78.00 visit to the dealership for a relearn.
do i still NEED a relearn??
09-27-2004, 06:11 AM
#7
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When you perform a CASE (Crank Angle Sensor Error) learn the PCM records the *exact* relationship between the crank teeth and the crank angle sensor - for the current crank/sensor configuration.
It uses that information to detect the small acceleration of the crankshaft at the instant of each firing event. If a firing event does not occur the PCM will not detect the small crank acceleration and will log a misfire.
Note: large cams, rough roads and rough idle can cause false misfire detection.
When the PCM "learns" the crank position sensor error, it writes the learned information to non-volatile memory.
In a new PCM, that memory is blank and it will throw a code immediately indicating that a crank relearn is required.
If you swap your PCM for a PCM that is not new, i.e. one that has already had a relearn done - probably for a different engine, then the PCM does not "know" that the learned information is incorrect for the current engine. Hence it will not log a code to indicate that a relearn is needed.
If you change any part of your engine that effects the relative positioning of the crank to the crank sensor then the learned information will probably no longer be correct. And still the PCM will not know that a relearn is needed.
If the learned information is not correct, the PCM may not be able to detect valid misfires and/or may detect false misfires. P0300 codes
Regards
Paul
It uses that information to detect the small acceleration of the crankshaft at the instant of each firing event. If a firing event does not occur the PCM will not detect the small crank acceleration and will log a misfire.
Note: large cams, rough roads and rough idle can cause false misfire detection.
When the PCM "learns" the crank position sensor error, it writes the learned information to non-volatile memory.
In a new PCM, that memory is blank and it will throw a code immediately indicating that a crank relearn is required.
If you swap your PCM for a PCM that is not new, i.e. one that has already had a relearn done - probably for a different engine, then the PCM does not "know" that the learned information is incorrect for the current engine. Hence it will not log a code to indicate that a relearn is needed.
If you change any part of your engine that effects the relative positioning of the crank to the crank sensor then the learned information will probably no longer be correct. And still the PCM will not know that a relearn is needed.
If the learned information is not correct, the PCM may not be able to detect valid misfires and/or may detect false misfires. P0300 codes
Regards
Paul
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09-27-2004, 06:25 AM
#8
thanks, just wasnt for sure if it would set a ses light or not..ill schedule an appointment.. quick question, i have the hotcam.. . i have yet to get my car to idle, i drilled the hole out two sizes bigger but when it gets hot, it still will start surging badly and die..will they be able to do a crank relearn with it doing this? if it requires the car to idle for like 2 minutes or something i am hosed i guess becuase it wont idle for me unless i keep my foot on the gas,,then again i havent drove it yet, just on the stands, hope to get it out tomorrow..
thanks
matt
. i have yet to get my car to idle, i drilled the hole out two sizes bigger but when it gets hot, it still will start surging badly and die..will they be able to do a crank relearn with it doing this? if it requires the car to idle for like 2 minutes or something i am hosed i guess becuase it wont idle for me unless i keep my foot on the gas,,then again i havent drove it yet, just on the stands, hope to get it out tomorrow.. thanks
matt
Last edited by redbandit98; 09-27-2004 at 07:04 AM.
09-27-2004, 09:09 AM
#9
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To do the crank relearn, the engine has to be at 159* or higher.
To add to EFIliveV5's post, the crank relearn is also intended to detect minute variations in crank conditions due to mass production inconsistancies, and set the PCM up for one engine and its nuances.
To add to EFIliveV5's post, the crank relearn is also intended to detect minute variations in crank conditions due to mass production inconsistancies, and set the PCM up for one engine and its nuances.
09-27-2004, 04:45 PM
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Originally Posted by EFIliveV5
When you perform a CASE (Crank Angle Sensor Error) learn the PCM records the *exact* relationship between the crank teeth and the crank angle sensor - for the current crank/sensor configuration.
It uses that information to detect the small acceleration of the crankshaft at the instant of each firing event. If a firing event does not occur the PCM will not detect the small crank acceleration and will log a misfire.
Note: large cams, rough roads and rough idle can cause false misfire detection.
When the PCM "learns" the crank position sensor error, it writes the learned information to non-volatile memory.
In a new PCM, that memory is blank and it will throw a code immediately indicating that a crank relearn is required.
If you swap your PCM for a PCM that is not new, i.e. one that has already had a relearn done - probably for a different engine, then the PCM does not "know" that the learned information is incorrect for the current engine. Hence it will not log a code to indicate that a relearn is needed.
If you change any part of your engine that effects the relative positioning of the crank to the crank sensor then the learned information will probably no longer be correct. And still the PCM will not know that a relearn is needed.
If the learned information is not correct, the PCM may not be able to detect valid misfires and/or may detect false misfires. P0300 codes
Regards
Paul
It uses that information to detect the small acceleration of the crankshaft at the instant of each firing event. If a firing event does not occur the PCM will not detect the small crank acceleration and will log a misfire.
Note: large cams, rough roads and rough idle can cause false misfire detection.
When the PCM "learns" the crank position sensor error, it writes the learned information to non-volatile memory.
In a new PCM, that memory is blank and it will throw a code immediately indicating that a crank relearn is required.
If you swap your PCM for a PCM that is not new, i.e. one that has already had a relearn done - probably for a different engine, then the PCM does not "know" that the learned information is incorrect for the current engine. Hence it will not log a code to indicate that a relearn is needed.
If you change any part of your engine that effects the relative positioning of the crank to the crank sensor then the learned information will probably no longer be correct. And still the PCM will not know that a relearn is needed.
If the learned information is not correct, the PCM may not be able to detect valid misfires and/or may detect false misfires. P0300 codes
Regards
Paul
09-27-2004, 05:49 PM
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If its the same PCM then the CASE CKS value in PCM is still OK as long as CKS has not been wacked.
Repairing wires will not require a relearn be done.
If a relearn is needed and you do not have access to a tech-II, if you know someone with a Ease PCM scanner versions 2.5 to 3.5, go to bi-directional screen and use the CASE relearn command while in the correct RPM range ( 4K and higher) at idle with brakes ON.
Repairing wires will not require a relearn be done.
If a relearn is needed and you do not have access to a tech-II, if you know someone with a Ease PCM scanner versions 2.5 to 3.5, go to bi-directional screen and use the CASE relearn command while in the correct RPM range ( 4K and higher) at idle with brakes ON.
09-27-2004, 06:56 PM
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Originally Posted by Team ZR-1
If its the same PCM then the CASE CKS value in PCM is still OK as long as CKS has not been wacked.
Repairing wires will not require a relearn be done.
If a relearn is needed and you do not have access to a tech-II, if you know someone with a Ease PCM scanner versions 2.5 to 3.5, go to bi-directional screen and use the CASE relearn command while in the correct RPM range ( 4K and higher) at idle with brakes ON.
Repairing wires will not require a relearn be done.
If a relearn is needed and you do not have access to a tech-II, if you know someone with a Ease PCM scanner versions 2.5 to 3.5, go to bi-directional screen and use the CASE relearn command while in the correct RPM range ( 4K and higher) at idle with brakes ON.
