Maintaining ECM Memory
01-20-2003, 02:32 PM
#1
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Maintaining ECM Memory
Simple but elegant:
http://www.autosportcatalog.com/index.cfm?fa=p&pid=52
This might come in useful for those who have had their timing advanced.
http://www.autosportcatalog.com/index.cfm?fa=p&pid=52
This might come in useful for those who have had their timing advanced.
01-20-2003, 04:08 PM
#2
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Re: Maintaining ECM Memory
[QUOTE]Originally posted by y2kse
[B]Simple but elegant:
http://www.autosportcatalog.com/index.cfm?fa=p&pid=52
Hmmm. How does that work, do you plug it in before disconnecting the battery, seems like it could turn into a bomb if that's the case.
Or is there a small windows of time where settings are still remembered after disconnecting the battery, giving you time to plug it in?
[B]Simple but elegant:
http://www.autosportcatalog.com/index.cfm?fa=p&pid=52
Hmmm. How does that work, do you plug it in before disconnecting the battery, seems like it could turn into a bomb if that's the case.
Or is there a small windows of time where settings are still remembered after disconnecting the battery, giving you time to plug it in?
01-20-2003, 04:25 PM
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Re: Re: Maintaining ECM Memory
[QUOTE]Originally posted by grey2002_ny
Hmmm. How does that work, do you plug it in before disconnecting the battery, seems like it could turn into a bomb if that's the case.
Or is there a small windows of time where settings are still remembered after disconnecting the battery, giving you time to plug it in?
I imagine you'd probably plug it in just before you disconnect your battery. And if you did that, I doubt a 9V battery would produce enough amperage to turn your battery into a bomb. 
Hmmm. How does that work, do you plug it in before disconnecting the battery, seems like it could turn into a bomb if that's the case.
Or is there a small windows of time where settings are still remembered after disconnecting the battery, giving you time to plug it in?
01-20-2003, 06:24 PM
#4
Re: Maintaining ECM Memory
Originally posted by y2kse
Simple but elegant:
http://www.autosportcatalog.com/index.cfm?fa=p&pid=52
This might come in useful for those who have had their timing advanced.
Simple but elegant:
http://www.autosportcatalog.com/index.cfm?fa=p&pid=52
This might come in useful for those who have had their timing advanced.
01-20-2003, 06:43 PM
#5
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Re: Re: Maintaining ECM Memory
Originally posted by sloppymax
im having mine advanced later this week by a local performance shop. i spoke with a guy with a 2k who had his advanced almost 9 months and took it back in to check to see if it had adjusted. it was still at +1 from -2 or 18 from 15. The reason he came back in was that he had disconnected the battery while the car sat for a while. im not sure if anyone has had trouble keeping the settings. ill certainly post if my settings are lost.
im having mine advanced later this week by a local performance shop. i spoke with a guy with a 2k who had his advanced almost 9 months and took it back in to check to see if it had adjusted. it was still at +1 from -2 or 18 from 15. The reason he came back in was that he had disconnected the battery while the car sat for a while. im not sure if anyone has had trouble keeping the settings. ill certainly post if my settings are lost.
By the way, if your friend had his ECM adjusted from -2 to +1, his advance is not currently set at 18 degrees BTDC. Remember that a setting of 0 equals 15 degrees BTDC. That means that his timing was adjusted from 13 degrees (15 minus 2) to 16 degrees (15 plus 1). He can still advance his timing another degree and remain in spec.
Last but not least, there's an interesting note in the Electronic Service Manual regarding timing changes. It says that the throttle position sensor harness connector should be disconnected before advancing or retarding the timing. You guys with an ESM can check this out for yourselves It's on page EC-733 of the manual.
01-20-2003, 07:31 PM
#6
Re: Re: Re: Maintaining ECM Memory
Originally posted by y2kse
Good info, sloppymax. My suspicion is that the ECM contains different kinds of memory just as a regular computer contains different kinds of memory. Some of its memory may be volatile and some may be non-volatile. If I'm correct, then settings programmable by a Consult are probably stored in non-volatile memory. That would mean that disconnecting the battery would have no effect on them. But some people may want to back up their ECM memory anyway just to be on the safe side. And $16.00 is a cheap enough price to pay to do that.
By the way, if your friend had his ECM adjusted from -2 to +1, his advance is not currently set at 18 degrees BTDC. Remember that a setting of 0 equals 15 degrees BTDC. That means that his timing was adjusted from 13 degrees (15 minus 2) to 16 degrees (15 plus 1). He can still advance his timing another degree and remain in spec.
Last but not least, there's an interesting note in the Electronic Service Manual regarding timing changes. It says that the throttle position sensor harness connector should be disconnected before advancing or retarding the timing. You guys with an ESM can check this out for yourselves It's on page EC-733 of the manual.
Good info, sloppymax. My suspicion is that the ECM contains different kinds of memory just as a regular computer contains different kinds of memory. Some of its memory may be volatile and some may be non-volatile. If I'm correct, then settings programmable by a Consult are probably stored in non-volatile memory. That would mean that disconnecting the battery would have no effect on them. But some people may want to back up their ECM memory anyway just to be on the safe side. And $16.00 is a cheap enough price to pay to do that.
By the way, if your friend had his ECM adjusted from -2 to +1, his advance is not currently set at 18 degrees BTDC. Remember that a setting of 0 equals 15 degrees BTDC. That means that his timing was adjusted from 13 degrees (15 minus 2) to 16 degrees (15 plus 1). He can still advance his timing another degree and remain in spec.
Last but not least, there's an interesting note in the Electronic Service Manual regarding timing changes. It says that the throttle position sensor harness connector should be disconnected before advancing or retarding the timing. You guys with an ESM can check this out for yourselves It's on page EC-733 of the manual.
can you give me a heads up on disconnecting the tps connector? im planning on taking it either wednesday or thursday. also, any idea why its supposed to be disconnected? thanks for the info y2kse.
01-20-2003, 08:16 PM
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Re: Re: Re: Re: Maintaining ECM Memory
Originally posted by sloppymax
im glad you said something about disconnecting the tps harness connector because i have not seen anything concerning that. any idea why its supposed to be disconnected?
im glad you said something about disconnecting the tps harness connector because i have not seen anything concerning that. any idea why its supposed to be disconnected?
01-21-2003, 05:51 AM
#8
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Thats a great idea!
NOTE: Your cars ECU holds the program info in an EPROM or PROM. They do not lose their memory when power is disconnected. If the memory would be lost, your car would never run agian after the battery was disconnected.
NOTE: Your cars ECU holds the program info in an EPROM or PROM. They do not lose their memory when power is disconnected. If the memory would be lost, your car would never run agian after the battery was disconnected.
01-21-2003, 12:19 PM
#9
Re: Re: Re: Re: Re: Maintaining ECM Memory
Originally posted by y2kse
My guess . . . and this is only a guess . . . is that the position of the TPS affects timing. If I'm correct, then you probably want to set the base timing without allowing the TPS to affect it.
My guess . . . and this is only a guess . . . is that the position of the TPS affects timing. If I'm correct, then you probably want to set the base timing without allowing the TPS to affect it.
01-21-2003, 02:30 PM
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Before you guys disconnect the TPS harness connector, you may want to check this out:
http://forums.maxima.org/showthread.php?threadid=183297
I don't know if disconnecting the connector has anything to do with the problem my tech ran into, but I'll try to find out and let you know.
http://forums.maxima.org/showthread.php?threadid=183297
I don't know if disconnecting the connector has anything to do with the problem my tech ran into, but I'll try to find out and let you know.
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