Hey Everyone,
I just got my 93 with a 97 1.8 swap running Naturally Aspirated on a ChatGPT tune and took it for its first drive. I am wanting to break it in rich as a precaution. Can someone take a look at my tune and log and see if there is anything obviously wrong? My AFRs don't seem terrible but are a little high here and there, especially at idle. Any insight is appreciated as I am entirely new to tuning.



Mod List:
BMW TPS
GM IAT
MSPNP2 (90-93)
97 1.8 Swap (FM Kit with 93 electronics)
36-2 Trigger Wheel (has cam/crank sensors going into CAS plug)
Supertech 8.7:1 Pistons
Manley Rods (Squirters Deleted)
Boundary Oil Pump (2 shims)
Glowshift Wideband O2

 

You're very lean. If i highlight the entire log, your average AFR target is 13.0, your average AFR is 15.5, and that's with over run fuel cut off. EGO is a short term fuel trim, it's currently set to not do much. Only activates above 1300rpm, 160* coolant temp, and between 20 and 90 kpa. When it does activate in the log, it shoots pretty quickly up towards it's max 15%.

While your AFR targets are included in the fuel calculation, you need to tune it to make sure AFRs match. I'd start by selecting the entire fuel table 98kpa and below, and multiplying it by 1.15. That'll add 15% fuel everywhere, and should get you closer to where you wanna be.

As you said your targets are a bit rich, at WOT you're closer to low boost targets. This doesn't save or protect your engine, it only wastes fuel, lean those out to 14.7 at idle, mid to high 12's at WOT.

Your TPS signal is pretty noisy, check to make sure the mechanical linkage doesn't have play, that'll make it difficult to tune.

You've got the "bad" MAT air density table, which pulls a lot of fuel as air heats up. This makes sense for air alone, but it's pretty commonly known that the rest of the mechanicals also heat up, needing more fuel, not less. I'm surprised GPT didn't pick up on that, we say it enough.

 

I have bumped VE 15% under 98 kpa. Should I have EGO disabled while working in the VE table?
What else do I need to change to work in the break in map?
Thank you!!!

 

TPS signal is still really noisy, your targets are still rich, and your MAT table is still the "bad" one. Do you need help with these things? Two of them are tune related, I think the TPS signal will need to be inspected visually and checked with a multimeter. You should be running a Miata TPS, not a BMW TPS. Is this an FM adapter to run a 1.6 throttle body on a 1.8? You only need that if you're running the stock ECU. Get a 1.8 throttle body, preferably NB, with wiring pigtails, and reverse all the swap mods you did. But, if you stick with what you've got, I've seen the BMW TPS installed incorrectly on the adapter, so check that first. There should be a little spring you have to push past to bolt it on, if it's loose, it's not installed correctly.

That being said, your AFRs are now much closer to where they should be, although still lean according to your targets. Again your targets should be leaned out about half a point, but your AFRs are only .1-.2 lean now.

Your biggest issue is the TPS, you gotta fix that. Then set EGO to only work at idle and tune the fuel table with some new targets.