Need Airbag Memory Erase Procedure
09-12-2005, 02:36 AM
#16
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My experience from using the Spanner is that a battery disconnect erases the codes. Also, stored codes themselves do not effect performance. It's what caused the code that may do that, but erasing a stored code in itself doesn't restore lost performance. John, you out there?
09-12-2005, 03:36 AM
#17
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Bill, remember that the electronics from 91(?) on are different than what your car has. I certainly speak with NO knowledgable experience of these things except for what I saw on the Hammer yesterday and had actually experienced after clearing codes. The Hammer showed several battery disconnects, Hall sensor disconnect and other errors/faults that I was not aware of. My guess, is that the computer compensated for whatever conditions arose in the past still maintaining operable status. Can't explain any of this and I am NOT imagining the performance increase. I am anxious to do another dyno as it seems some of these (most) conditions existed before the last dyno.
I expect that someone here who has a greater knowledge of this can shed some light, but I repeat, I am NOT imagining the increase!
I expect that someone here who has a greater knowledge of this can shed some light, but I repeat, I am NOT imagining the increase!
09-12-2005, 06:06 AM
#18
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Hi Bill/Keith,
Stored Hall and knock fault codes do directly affect the car's running, igntion is retarded to protect the engine, as the system is percieved to no longer be able to detect and dynamically retard the igntion as it does normally.
Ignition is only retarded at high loads. So performance degradation is often not noticed.
When you do a battery disconnect, you erase all the fault codes stored in SRAM, and also the "adaptation values".
Losing the former could perk up the performance, expecially if a Hall sensor code, or both knock sensors had a stored fault code, because this retards the igntion 6 degrees. Sometimes, during normal running, spurous knock sensor and Hall fault codes are stored. For this reason, it is always a good idea to clear fault codes, drive the car, and then read out any stored codes.
This tendency to store spurious fault codes appears to have been recognised by Porsche/Bosch, because the LH and EZK ECUs do automatically erase any stored fault codes periodically.
Erasing the fault codes with a diagnostic tool is better than doing a battery disconnect, because then you don't loose the adaptation values, which are also stored in the SRAM.
Hope this helps ?
Regards
Stored Hall and knock fault codes do directly affect the car's running, igntion is retarded to protect the engine, as the system is percieved to no longer be able to detect and dynamically retard the igntion as it does normally.
Ignition is only retarded at high loads. So performance degradation is often not noticed.
When you do a battery disconnect, you erase all the fault codes stored in SRAM, and also the "adaptation values".
Losing the former could perk up the performance, expecially if a Hall sensor code, or both knock sensors had a stored fault code, because this retards the igntion 6 degrees. Sometimes, during normal running, spurous knock sensor and Hall fault codes are stored. For this reason, it is always a good idea to clear fault codes, drive the car, and then read out any stored codes.
This tendency to store spurious fault codes appears to have been recognised by Porsche/Bosch, because the LH and EZK ECUs do automatically erase any stored fault codes periodically.
Erasing the fault codes with a diagnostic tool is better than doing a battery disconnect, because then you don't loose the adaptation values, which are also stored in the SRAM.
Hope this helps ?
Regards
Last edited by John Speake; 09-12-2005 at 09:03 AM.
09-12-2005, 02:08 PM
#19
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Right on John! I knew I wasn't crazy! The Hammer did show a couple of EZK faults, but I couldn't tell you what, as I was on the driver side manning the key and Dan was at the plug with the hammer spatting off faults and technical stuff that was flying right past me. I had to stop him a few times to ask what "this" or "that" meant. What ever, Dan is "the" guy to have around. Well schooled and technically skilled on P cars. I was impressed as he always carries around nitrile gloves if he has to make a "house" call. 
Noting this info John, tells me that it will be a wonderfully advantagious thing to have Dan with the Bosch Hammer reading, explaining and clearing codes for folks at Sharktoberfest.
Noting this info John, tells me that it will be a wonderfully advantagious thing to have Dan with the Bosch Hammer reading, explaining and clearing codes for folks at Sharktoberfest.
09-12-2005, 02:17 PM
#20
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Originally Posted by 928ntslow
Noting this info John, tells me that it will be a wonderfully advantagious thing to have Dan with the Bosch Hammer reading, explaining and clearing codes for folks at Sharktoberfest.
09-12-2005, 02:30 PM
#21
When I first got the GT...our local Pac NW 928 mechanic (Lief Johnson) brought his hammer out to one of our drag strip gatherings. He hooked it up the GT and checked the codes..(none noted) and then ran a procedure that runs the car through a series of tests..varying the idle and such...and then optimizing the settings and storing them.... I too felt that the car performed better after that.
Apparently the brains will adapt themselves over time to the various inputs from the engine...some cars will run like crap for a bit after disconnecting the battery as it adapts to the input...others disconnect the battery and see no difference when reconnecting...
I think Jim Bailey mentioned a while back that the further out from spec the engine is...the longer it will take the brain to adapt and make it run smooth...the closer to spec..the better it runs after disconnection since the input from the engine is closer to the factory defaults>>
Interesting for sure..
later,
Tom
midlman@rennlist.net
89GT
Apparently the brains will adapt themselves over time to the various inputs from the engine...some cars will run like crap for a bit after disconnecting the battery as it adapts to the input...others disconnect the battery and see no difference when reconnecting...
I think Jim Bailey mentioned a while back that the further out from spec the engine is...the longer it will take the brain to adapt and make it run smooth...the closer to spec..the better it runs after disconnection since the input from the engine is closer to the factory defaults>>
Interesting for sure..
later,
Tom
midlman@rennlist.net
89GT
09-12-2005, 02:39 PM
#22
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Originally Posted by John Speake
Hi Bill/Keith,
Stored Hall and knock fault codes do directly affect the car's running, igntion is retarded to protect the engine, as the system is percieved to no longer be able to detect and dynamically retard the igntion as it does normally.
Ignition is only retarded at high loads. So performance degradation is often not noticed.
When you do a battery disconnect, you erase all the fault codes stored in SRAM, and also the "adaptation values".
Losing the former could perk up the performance, expecially if a Hall sensor code, or both knock sensors had a stored fault code, because this retards the igntion 6 degrees. Sometimes, during normal running, spurous knock sensor and Hall fault codes are stored. For this reason, it is always a good idea to clear fault codes, drive the car, and then read out any stored codes.
This tendency to store spurious fault codes appears to have been recognised by Porsche/Bosch, because the LH and EZK ECUs do automatically erase any stored fault codes periodically.
Erasing the fault codes with a diagnostic tool is better than doing a battery disconnect, because then you don't loose the adaptation values, which are also stored in the SRAM.
Hope this helps ?
Regards
Stored Hall and knock fault codes do directly affect the car's running, igntion is retarded to protect the engine, as the system is percieved to no longer be able to detect and dynamically retard the igntion as it does normally.
Ignition is only retarded at high loads. So performance degradation is often not noticed.
When you do a battery disconnect, you erase all the fault codes stored in SRAM, and also the "adaptation values".
Losing the former could perk up the performance, expecially if a Hall sensor code, or both knock sensors had a stored fault code, because this retards the igntion 6 degrees. Sometimes, during normal running, spurous knock sensor and Hall fault codes are stored. For this reason, it is always a good idea to clear fault codes, drive the car, and then read out any stored codes.
This tendency to store spurious fault codes appears to have been recognised by Porsche/Bosch, because the LH and EZK ECUs do automatically erase any stored fault codes periodically.
Erasing the fault codes with a diagnostic tool is better than doing a battery disconnect, because then you don't loose the adaptation values, which are also stored in the SRAM.
Hope this helps ?
Regards
Keith, John is saying battery disconnects WILL erase the fault codes. So, I don't get the stored battery disconnects you mention.
09-12-2005, 02:53 PM
#23
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Bill, they were there, as Dan showed me on the Hammer.
Randy, there will be a sign up sheet, and a nominal charge for the procedure.
Randy, there will be a sign up sheet, and a nominal charge for the procedure.
09-12-2005, 02:54 PM
#24
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Thanks John. So, if I fix the broken knock sensor (as I did when I reconnected the loose connector in my 89) and do NOT erase the stored codes, it will still act as if the sensor is disconnected? That's interesting.
>>>>>>>>>>>>>>>>
Hi Bill,
Yes, I believe it will do that, until it goes through its periodic self erase sequence. I can't remember how often this is, every so many ignition off cycles. They changed the number at one point.....
Tom M - The idle and cruise fuelling are "adapted" by the LH, using the O2 loop and idle stabiliser loop system as measures. The main item they are adapting to is the MAF. Also any slight false air sources such as valve stem seals, throttle spindle, etc. So the further out of sp[ec the MAF, the longer the adaptation takes.
The "Spanner" will also read and clear all fault codes, except the later airbag ones.
Regards
>>>>>>>>>>>>>>>>
Hi Bill,
Yes, I believe it will do that, until it goes through its periodic self erase sequence. I can't remember how often this is, every so many ignition off cycles. They changed the number at one point.....
Tom M - The idle and cruise fuelling are "adapted" by the LH, using the O2 loop and idle stabiliser loop system as measures. The main item they are adapting to is the MAF. Also any slight false air sources such as valve stem seals, throttle spindle, etc. So the further out of sp[ec the MAF, the longer the adaptation takes.
The "Spanner" will also read and clear all fault codes, except the later airbag ones.
Regards
09-12-2005, 03:55 PM
#25
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Keith
Right on with the extra HP!!!! You should get it on a dyno soon to see the comparison from the previous dyno run! That would be interesting to see how much of a difference it made!
Brian
Right on with the extra HP!!!! You should get it on a dyno soon to see the comparison from the previous dyno run! That would be interesting to see how much of a difference it made!
Brian
09-12-2005, 05:13 PM
#26
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Originally Posted by 928ntslow
Bill, they were there, as Dan showed me on the Hammer.
Randy, there will be a sign up sheet, and a nominal charge for the procedure.
Randy, there will be a sign up sheet, and a nominal charge for the procedure.
09-12-2005, 06:28 PM
#28
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Keith:
Thanks, but I'm OK. I have the Spanner and it has been a lifesaver. It identified the fact that I had not properly seated the knock sensor connector. It found a problem with the throttle position switch on Seth Weisman's GT. Without the Spanner I would probably have never figured out both issues. Invaluable. I'd bring it to Sharktoberfest, but you've got it covered with a professional like Dan doing it.
Thanks, but I'm OK. I have the Spanner and it has been a lifesaver. It identified the fact that I had not properly seated the knock sensor connector. It found a problem with the throttle position switch on Seth Weisman's GT. Without the Spanner I would probably have never figured out both issues. Invaluable. I'd bring it to Sharktoberfest, but you've got it covered with a professional like Dan doing it.
09-12-2005, 08:54 PM
#29
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Bill--
For those of us pre-'90 cars with no airbag fault code, I for one, would love to see a demo of John's Spanner. There may be enough interest to make it worthwhile having one in the local SoCal community if nothing else. I have a few extr cookies in the cookie jar right now.
For those of us pre-'90 cars with no airbag fault code, I for one, would love to see a demo of John's Spanner. There may be enough interest to make it worthwhile having one in the local SoCal community if nothing else. I have a few extr cookies in the cookie jar right now.
