$5B
Thread Starter
Junior Member
Joined: Sep 2001
Posts: 16
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From: Orlando, Florida
$5B
Am really collecting a lot of $5B codes (88-90 Reatta among others) and it is beginning to come together. Found what I was initially looking for: cooling fans vs temp ($88E1 - 88, $88E3 - 89,90); idle rpm vs temp ($8C48 - 88, $8C80 - 89,90) and is all starting to unravel.
What I was wondering was is there a common set of the low locations for sensor inputs & outputs listed anywhere ? e.g. $0088 "appears" to be the coolant temp.
In addition the "constant multipliers" appear to be the same across many families such as (191/255)-40 for coolant and either 1.25 or 2.50 for RPM/10. Are there any generic tables like that anywhere. Sort of an index ov values.
For example I found the idle RPM table in different PROMs by scanning the data area ($8000-$8FFF) for a declining series of 17 values starting under $80 and finishing above $28. The different locations just pop out when you do that.
Was just wondering if reinventing the wheel and if table formats, standard coefficients, and typical sensor addresses were posted somewhere. Would think something like that would make deciphering unknown PROMs a lot easier.
What I was wondering was is there a common set of the low locations for sensor inputs & outputs listed anywhere ? e.g. $0088 "appears" to be the coolant temp.
In addition the "constant multipliers" appear to be the same across many families such as (191/255)-40 for coolant and either 1.25 or 2.50 for RPM/10. Are there any generic tables like that anywhere. Sort of an index ov values.
For example I found the idle RPM table in different PROMs by scanning the data area ($8000-$8FFF) for a declining series of 17 values starting under $80 and finishing above $28. The different locations just pop out when you do that.
Was just wondering if reinventing the wheel and if table formats, standard coefficients, and typical sensor addresses were posted somewhere. Would think something like that would make deciphering unknown PROMs a lot easier.
Supreme Member
iTrader: (1)
Joined: Oct 2000
Posts: 1,062
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From: Pasadena, MD
Car: '87 Camaro IROC-Z
Engine: 385 HSR
Transmission: 700R4
Axle/Gears: 3.42 posi
Go here:
http://www.geocities.com/MotorCity/S.../prog_101.html
for most of the conversions you're looking for. Also try the main page at:
http://www.geocities.com/MotorCity/Shop/9938/index.html
for tons of info on ECM hacking and tuning.
------------------
Greg Westphal
'87 IROC 355TPI/A4
http://www.geocities.com/MotorCity/S.../prog_101.html
for most of the conversions you're looking for. Also try the main page at:
http://www.geocities.com/MotorCity/Shop/9938/index.html
for tons of info on ECM hacking and tuning.
------------------
Greg Westphal
'87 IROC 355TPI/A4
Thread Starter
Junior Member
Joined: Sep 2001
Posts: 16
Likes: 0
From: Orlando, Florida
Thank you Gary, those pages are helpful. Am still looking for the sensor input points.
These are going to be the memory mapped I/O addresses in low memory - not in the PROM.
Am hoping this will not take a full engine mock-up and a logic analyzer (can do but not trivial) and was hoping to find pointers by "reviewing the literature".
For example, in the $5B, the coolant temp is stored at $0088, at least the software always expects it to be there. However this is in the non-batt-backed RAM area so must be bing loaded from the $4000 range (see
http://www.diy-efi.org/gmecm/ecm_info/p4_registers.html ).
I "assume" that the $4002 map is used to select which ADC (analog/digital converter) input port is selected. Does anyone have a index of which port maps to which sensor ?
[This message has been edited by padgett (edited November 03, 2001).]
These are going to be the memory mapped I/O addresses in low memory - not in the PROM.
Am hoping this will not take a full engine mock-up and a logic analyzer (can do but not trivial) and was hoping to find pointers by "reviewing the literature".
For example, in the $5B, the coolant temp is stored at $0088, at least the software always expects it to be there. However this is in the non-batt-backed RAM area so must be bing loaded from the $4000 range (see
http://www.diy-efi.org/gmecm/ecm_info/p4_registers.html ).
I "assume" that the $4002 map is used to select which ADC (analog/digital converter) input port is selected. Does anyone have a index of which port maps to which sensor ?
[This message has been edited by padgett (edited November 03, 2001).]
