I've been going through the problem Chuck has reported about battery voltage being reported wrong. The memory address is different for 1986/1987 ECUs so for these a firmware update is required. Please contact me to organise
So this is what we have
Z31 1984,1985 ECUs
Dual ROM require 1984-1985 address file
*Battery voltage at RAM location 0009
Z31 / CR31 1986 N/A ECU
Dual ROM require 1986 address file
*Battery voltage at RAM location 0009 (this was 000A)
Z31 1986-1987 ECU
Single ROM require 1986-1989 address file
* Battery voltage at RAM location 0009 (this was 000A)
Z31 1988-1989 ECU
Single ROM require 1986-1989 address file
* Battery voltage at RAM location 000A
1986/1987 Z31 ECUs and Battery Voltage
Moderator: Matt
Matt, chuck and I were discussing what would happen with an incorrect battery voltage, and this is what I came he came up with that could be a possibility.
I asked what would bat. volts have anything to do, and he said that injector latency and what not could be affected by a ton.
Could this explain why my car doesnt run to well at all even after using "injector resize", I know "injector resize" wont make it perfect, but damn close...
Or have I lost my mind
Its so weird...
I would have the car running... and nistune see's 4.5volts, and then 2 mins later, 4.6... another 2 mins 4.7, etc etc... up to like 5.0 or 5.1...
I asked what would bat. volts have anything to do, and he said that injector latency and what not could be affected by a ton.
Could this explain why my car doesnt run to well at all even after using "injector resize", I know "injector resize" wont make it perfect, but damn close...
Or have I lost my mind
Its so weird...
I would have the car running... and nistune see's 4.5volts, and then 2 mins later, 4.6... another 2 mins 4.7, etc etc... up to like 5.0 or 5.1...
Unfortunately that is probably no longer the case...
Originally we thought the actual battery voltage inside the ECU was a problem and that is was being reported by NIStune software correctly. This issue with injection could have been directly related to voltage problems
However now we know the voltage inside the ECU is probably fine... and just the board reporting to the PC the wrong. All that is going to be fixed when Chuck installs the updated firmware is the display for Voltage and Fuel Temp are now going to be correct. I've sent an updated board off to Chuck to try out.
In regards to your original problem where you resized from 260CC to 450CC in the thread below. What is your current K Constant, and Injector Void Time (Latency). Can you also post logs of your run with the wideband attached to see what AFRs you are getting in the trace window
viewtopic.php?p=1408&
Originally we thought the actual battery voltage inside the ECU was a problem and that is was being reported by NIStune software correctly. This issue with injection could have been directly related to voltage problems
However now we know the voltage inside the ECU is probably fine... and just the board reporting to the PC the wrong. All that is going to be fixed when Chuck installs the updated firmware is the display for Voltage and Fuel Temp are now going to be correct. I've sent an updated board off to Chuck to try out.
In regards to your original problem where you resized from 260CC to 450CC in the thread below. What is your current K Constant, and Injector Void Time (Latency). Can you also post logs of your run with the wideband attached to see what AFRs you are getting in the trace window
viewtopic.php?p=1408&
Firehawk told me that ECU Battery Voltage effects the injector offset table?
Hes saying that when he noticed the low battery voltage, that he messed with the table and it made things A TON better.
Im supposing that even though the ECU truly is getting 12 volts (confirmed by a multimeter), things are changed a ton since its seeing such low voltage.
Im not NEAR as smart as you guys, but im trying to learn.
thanks matt, hope to get a reply soon!
Hes saying that when he noticed the low battery voltage, that he messed with the table and it made things A TON better.
Im supposing that even though the ECU truly is getting 12 volts (confirmed by a multimeter), things are changed a ton since its seeing such low voltage.
Im not NEAR as smart as you guys, but im trying to learn.
thanks matt, hope to get a reply soon!
Got the new board in!
IT WAS the problem!
As soon as we plugged it in, the voltages were all correct!!!
Chuck messed a couple things on the laptop...
BAM!!!!
car was seeminglessly FLAWLESS.
It looks like the batt voltage had a GIANT affect on AFR's big time....
but now all the car needs is a tuning and thats all!
p.s.
Matt.... on my first start in the morning... car runs like CRAP, seems EXTREMELY rich so we we went to the tables and moved everything down to 0, so that there is NO enrichment at coldstart, it did get a TON better but the car is pulling timing.
How do you make it so that at COLD START it doesnt pull timing?
IT WAS the problem!
As soon as we plugged it in, the voltages were all correct!!!
Chuck messed a couple things on the laptop...
BAM!!!!
car was seeminglessly FLAWLESS.
It looks like the batt voltage had a GIANT affect on AFR's big time....
but now all the car needs is a tuning and thats all!
p.s.
Matt.... on my first start in the morning... car runs like CRAP, seems EXTREMELY rich so we we went to the tables and moved everything down to 0, so that there is NO enrichment at coldstart, it did get a TON better but the car is pulling timing.
How do you make it so that at COLD START it doesnt pull timing?
It was also showing up on the injecotr offset table (not sure what nistune calls this). It would vary on the table matching the reported battery voltage. New firmware fixed this.Matt wrote:Yes some of the tables are affected by battery voltage. But if the NIStune board reports the wrong voltage (which it was) then only the PC display will have it wrong
Chuck
owner, 300+ Parts and Performance
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Jason84NA2T
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Matt,
This is probably unrelated but my 84's batt voltage reported by both of my old REVA/B boards with 88 Z31 ECCS's appears at 12.3vdc with the car off despite the battery reading 12.6vdc There is no voltage dropped between the battery and main power lead in the bay. Would it be at all normal to be dropping .3vdc between the wiring harness in the engine bay and the ECU's power lead wire (I honestly have not checked it yet) or could this be an issue related to the board? I'll check when I get time and let you know if the .3vdc is being dropped in the wiring.
This is probably unrelated but my 84's batt voltage reported by both of my old REVA/B boards with 88 Z31 ECCS's appears at 12.3vdc with the car off despite the battery reading 12.6vdc There is no voltage dropped between the battery and main power lead in the bay. Would it be at all normal to be dropping .3vdc between the wiring harness in the engine bay and the ECU's power lead wire (I honestly have not checked it yet) or could this be an issue related to the board? I'll check when I get time and let you know if the .3vdc is being dropped in the wiring.
low battery voltage
I have noticed I show low battery voltage, I show around 4.5 volts. I have a 86 z31 with a 87 z31 ecu.
what should I check to make the battery voltage correct.
what should I check to make the battery voltage correct.
The board would require a firmware update to update the consult table to correct the memory address reported.
Two ways to do this.... either I can send a replacment board out in exchange for your other one (email me about that)
or if you have a Willem programmer you can reprogram the board yourself (requires a two diodes a resistor and some hookup wire) and I can provide details
Two ways to do this.... either I can send a replacment board out in exchange for your other one (email me about that)
or if you have a Willem programmer you can reprogram the board yourself (requires a two diodes a resistor and some hookup wire) and I can provide details
firmware update
It it possible the incorrect voltage reading can cause other problems ?
my AFR seen off
my car sounds like 1SIKZ31 car, from start to finish.
when I installed my nistune unit and resized my injectors, My car ran bad, almost to the point it would rev like 1,200 rpm max, thick black smoke out of the exhust pipe, I have it running fair now, not the best under boost, some times it goes pop like a gaint pop under boost.
maby this low battery voltage is causing part of the problem. its like 4.3 volts.
when I installed my nistune unit and resized my injectors, My car ran bad, almost to the point it would rev like 1,200 rpm max, thick black smoke out of the exhust pipe, I have it running fair now, not the best under boost, some times it goes pop like a gaint pop under boost.
maby this low battery voltage is causing part of the problem. its like 4.3 volts.
What injector size did you upgrade to? What values did your Injector Multiplier (K value) and Latency end up being?
The only update to the firmware was to report the correct value to NIStune for the battery voltage since 1986-87 models are slightly different. This will affect the battery display and maptracing in voltage based injection tables... but that is about it
How did the car run prior to the injection upgrade with the board install? It shouldn't affect vehicle operation apart from the changes that are made with the software.
The 4.3 volts you see is actaully the fuel temperature sensor memory address
The only update to the firmware was to report the correct value to NIStune for the battery voltage since 1986-87 models are slightly different. This will affect the battery display and maptracing in voltage based injection tables... but that is about it
How did the car run prior to the injection upgrade with the board install? It shouldn't affect vehicle operation apart from the changes that are made with the software.
The 4.3 volts you see is actaully the fuel temperature sensor memory address