Having a strange issue that I've not come accross before with an S13 SR20DET running Nistune. Just finished putting the car together after a few months of building (engine has been installed into an MX32 Toyota Cressida). I have rubbed heads together with Andrew from Hyperdrive here in Perth and he doesn't know the cause off the top of his head yet, but we have not put it on the dyno yet.
Basically, loaded a 50F00 base map into the ECU, set AFM to Z32, changed injectors to 850cc and set latency to 760us (correct value for the SARD 850cc Side feeds AFAIK).
I also turned the 02 bit setting off (it has no standard 02 sensor anymore, running an innovate MTX-L)
After these adjustments, they car would try to start but was extremely lean (as to be expected due to E85). I manually adjusted the K Const up from around 17000 (which is what it ended up at after the resizing) to 22000 and was able to get it to idle, but still, very lean.
I ended up taking K const to about 32000 before I got idle around 14.8:1 and free would dip nicely into the 12-13 range. First of all, it seems extreme that I had to increase the multiplier so much to get the AFR's reasonable (even on a stock base map) as stoich for ethanol is not 50% lower than BP 98, so a little stumped by that...
Anyway the real issue is once the engine is hot (does not do this when cold), you shut it down, re-start the engine and once again its EXTREMELY lean, like 20:1, and idling very lumpy.
Weird thing is, you go to rev it, and AFR drop straight down into normal ranges, and rev's very happily. As soon as it returns to idle it goes back to 20:1 and does not love life.
Its probably worth mentioning that the TPS Idle indicator is always lit up red when this occurs in Nistune, and it is idling.
Now this is the part that's got me stumped, to fix this issue, all I have to do is open up the Inj Multiplier K Const box (which is still set to 32000), and NOT EVEN change the value, just simply press "Apply" and IMMEDIATELY the AFR's at idle drop straight down to 14.8:1, and stay there for the remainder of the running time of the engine. It will idle beautifully.
As soon as I shut off the engine, restart it again, I am back to 20:1 at idle until I click "apply" on the inj multiplier box.
Normally I would think its jumping to some sort of idle adjustment that's causing it to idle super lean, but I don't understand why as soon as I hit apply on the Inj Multiplier box it comes good... It is like I am reminding the ECU that K Const is set to 32000 and not 3200.
Anyone had a similar experience before? Only thing I can identify as a possible cause is Injectors not playing nice
I also apologise for the long winded post. Hope it makes sense, I am trying to work this out before dyno in case its actually an issue.
Cheers,
Hayden