Running/Timing Issues

[DuoWing]

Well I've been trying to actively get my Z going and I'm running into some issues. 1976 280Z with L28ET. Running an 86' Z31 Turbo ECU with my Nistune board. Last year I had the Z running pretty decent. I was playing with getting it to idle better, had nice steady timing, and timing via light matched right up with what I was seeing on the laptop. Since then I've converted my coil and igniter over to the 90's PRW-2 igniter and wired it over to use a late Z31 style ignition coil. Since doing that I can't seem to get timing to be accurate at all and the car is running terribly. I tried wiring it back to the original coil/igniter and it still seemed to run poorly. I know the gas is definitely old, I was driving for a while, dumped half a can of sea foam in the gas. Drove a bit, then put 6 gallons of premium in. I'll keep driving to try and get the gas better. Anyway I've got timing set as close to 20 before TDC as I can get it. The light is showing the mark jumping all over the place and when watching through consult the timing is rapidly changing and jumping all over the place. I'm rarely if ever seeing it anywhere close to my Idle/Decel values. A lot of times instead of 20 I'm seeing up around 35, etc. I know a couple months back when I wired in the PRW-2/Z31 coil I went to check for spark and when turning the ignition to ON the ECU was rapidly clicking the fuel pump relay on and off. I messed with it a bit and it was still doing this. Finally I took the ECU apart pulled the Nistune board from the socket and reseated it back in the ECU and it's seemed to have been fine since. Consult is throwing Fuel Circuit, Speed Sensor, Fuel Temp Sensor, and occasional Ignition Circuit codes. The Fuel and Speed codes are of no concern. I've wired everything with the ignition just like the FSM for the Z31. I'm not sure if the ECU has gone bad and this is just it on it's way out. I can't figure out why I can't seem to get the timing values to go anywhere near my set values, and why they're all over the place. I'll have to go grab my laptop in the morning and upload my current tune which isn't much more than just playing around with a base tune. Just looking for some kind of direction on this?

S30_L28ET_1983_26P00_MT.bin

(16 KiB) Downloaded 114 times

I'll try and grab some logs later on as well

[DuoWing]

Well I luckily had an old 84' Turbo ECU that I always thought was a bad 87. Turns out it's a good running ECU, it just does the common 84-85 thing of constantly running the fuel pump. Anyway I threw that in and started the car up. Timing is dead still, set the timing at 20* before TDC and it seems to be doing good. I can match the mark up, vacuum is just about spot on, still a very slight miss at idle, but it revs up nice and smooth, idles pretty darn smooth. So apparently something must have happened with that 86 when it went crazy a couple months back. So to continue I have another 86' non-turbo ECU that was socketed when I bought it. I kind of ruined the EPROM chip when I tried to pull it out. So is there any way to test the Nistune board or should that more than likely be ok to throw into my other 86' ECU?

[Matt]

This one is a bit long to read which makes it difficult to diagnose issues. I'll try breaking this up

86' Z31 Turbo ECU with my Nistune board. I was playing with getting it to idle better, had nice steady timing, and timing via light matched right up with what I was seeing on the laptop

So car running fine with Nistune board until the coil and igniter was upgraded and then car ran badly.
Going back to original coil did not fix the issue...

Anyway I've got timing set as close to 20 before TDC as I can get it. The light is showing the mark jumping all over the place and when watching through consult the timing is rapidly changing and jumping all over the place

So there appears to be a problem with the timing controlled by the ECU following the coil upgrade

Finally I took the ECU apart pulled the Nistune board from the socket and reseated it back in the ECU and it's seemed to have been fine since. Consult is throwing Fuel Circuit, Speed Sensor, Fuel Temp Sensor, and occasional Ignition Circuit codes

Codes are thrown when sensors are out of parameter range. Ignition Circuit DTC- the feedback after spark is not received in expected time by the ECU

something must have happened with that 86 when it went crazy a couple months back

I think somehow the feedback from the coil corrupted the Nistune board. Check your maps against the factory ones. If they look fine then the board may need a reflash. In the USA you can contact AutoVaughnPerformance or post back to myself here in Australia