First time start issues?

[DuoWing]

I'm not exactly how to title this one, but it was a quick question I had. My 76' 280Z has my old L28ET in it. I've seemed to fix the issues where the Laptop would lose consult connection while starting. Anyway upon the very first start-up a cold start I have trouble starting the car. On my 88' N/A Z31 ECU with a NIStune board I haven't installed the USB port yet so I was just using the ECU's diagnostic lights. It was flashing red and green and I looked it up, saw it was flashing for fuel pump and ignition issues. Anyway though it will take a bit of cranking and won't start up right away. After finally starting I waited maybe 20 seconds and tried again and the car fired up immediately and every successive attempt to start seems to start with no issues other than the ECU lights flashing for fuel pump. I don't really worry much about this as even when I was running the Z31 ECU in my 280ZXT it ran perfectly fine, but would give me the fuel pump code.

Anyway I have the car stored in a garage and the NIStune ECU being expensive, I'll unplug the ECU and bring it home with me when I'm done messing with the car for the day. I was wondering if the Z31 ECUs or the later 88-89 Z31 ECUs have some kind of working out the memory sort of thing when it comes to initial start after being plugged in for the first time? I'll have to try leaving the ECU in the car and coming back the next day to see if a cold start is still the same.

[Matt]

ECUs keep a closed loop feedback record in memory when car has been running for a while

Since you have only just started using it, probably nothing would have been recorded yet. Sounds like it could be flooding perhaps on cold start or not enough fuel. Cold starts should be immediate when the cold enrichment tables are correct (and temp sensor is working). Might be able to use AFRs during cranking to determine if too rich or lean but may be difficult to get an accurate measurement (especially with voltage drop during cranking affecting wideband heater etc)

[DuoWing]

Still been messing around and I think the issue is related to something else. I've tried two different ECUs an 86 with Nistune and my 88 N/A with Nistune. I can get the car to run on both, but it has a heck of a time starting up. Anyway I don't have the USB port installed on the 88 at the moment so I can't actually use the consult. Anyway I was looking at the 86 Turbo ECU and I noticed when I synced it up everything seemed okay except one of the I want to say Warmup Timing Control maps was in orange like there was an issue with it. I opened up an 87 VG30ET rom from the rom pack for manual and burned it to the ECU. I turned the car off and back on then upon resync it was still showing that one particular setting as orange. I'll have to go check which one it is exactly. Also I was curious, with there being 4 different Rom files for the 1987 VG30ET I'm not sure which to use. I just used the one labeled MT. Also this is on my 280Z with an L28ET.

I currently think the problem though is related to clogged/stuck/partially clogged injectors.

[Matt]

You cannot swap rom images from different year ECUs with your board (even if the physical ECU is from a different year)

You need to stick with the part number that is on your board (even if you plug a 1988 26P00 programmed board into a 1986 ECU) and use the matching address file (with same part number)

Use the 1988 26P00 file since I believe that is probably what I used with your board (check part number displayed inside Nistune and that should match the file that you want to use)

[DuoWing]

Interesting, this is something I didn't know. I'll do that. So essentially if you want it to run like the 87 ECU you need to actually modify the 88 ROM image with the maps and values from the 87, but not actually try to burn a completely different ROM image? I'm going to give my ECU from my 87 Z31 a try and see how that works out.

Thanks for the info.

[Matt]

thats correct. With Z31 1986 - 1989 ECUs can use any different image file

We generally stick the 1988 VG30ET SS ROM image in there since its a common one used for this vehicle

You can put others in there but we generally dont