Unable to hold steady 2500rpms in neutral

[TheHeavyHat]

Hey team,

K24a2 swapped into a 1995 ej1. Kpro v4. Just went from NA to turbo. Car runs great, idles fine and pulls hard, but absolutely refuses to maintain a steady 2500rpms in neutral. It will bounce from 2500, to 1900, back to 2600 etc in a perfect rythm with no CEL. The short term fuel trim bounces and the A/F ratio does as well. All weird, because driving it's perfectly steady and idles just fine. If I blip the throttle over and over, or raise the rpms way up, then lower it, it'll sometimes balance nicely at 2500rpms, but it didn't do this when I was NA, so I'm not sure at all what the issue is.

Without being able to balance it at 2500, so I need to figure out what's going on. I attached a data log and my tune to show you what I mean after the car has been warmed up. Any ideas or thoughts are appreciated! Also happy to answer any questions.

- Grant

[TheHeavyHat]

Bumping after 48 hours. Any ideas or advice is appreciated.

[Spunkster]

The battery voltage is fluctuating constantly and it should be more steady.

The short term trims are going wild when this is happening as well.

[TheHeavyHat]

Thank you Spunkster, any ideas of how I can fix the fluctuating battery voltage or what might be the issue? Not sure where to even look for that problem.

[Spunkster]

It could be any number of things. You should use a multi-meter to check the voltage and see where it starts fluctuating.

[TheHeavyHat]

I found the electrical issue and repaired it, but my tuner says that it's just the 1000cc injectors unable to regulate at high vacuum. Unfortunately this means I won't be passing emissions this way. Bummer.