Guidance with recent LS Swap, startup surge, log and tune included.

[kunta0908]

So I recently finished up this install, have had issues the entire way, from bent transmission shift rod, to a bent reluctor wheel not giving me injectors on 4 and 7, to a faulty coil extension cable...

Lo and behold, everything was remedied and I fired the car up the other day. Now to sort out base tuning on this thing to be able to get it out on the road for cruise tuning. This is a stock gen 3 5.3 motor, ss2 mild cam, 3 bar map, 80lb SD injectors, AFPR set to 58psi vac line off, and twin 61mm turbos, stuffed into a 91 300zx. Nothing crazy....

I want to say that first fire and subsequent fires that first day of idling, the car would fire and dip down to commanded idle rpm quickly without surging like it is now. It needed the idle tuning procedure ran on it, but I knew I needed to get the VE dialed in as best as i could first. Fast forward to yesterday/today, and upon starting the car, it surges to nearly 3k, holds for a bit, then drops down to around commanded idle. AFR error is off the map though. Did some fine tuning of the VE to hopefully fix its readings, but started getting so far out that i was worried something else was amiss.

Would anyone be so kind as to take a glance at this recent startup scan and current tune and let me know if something is way out of whack that I missed? And why would the car randomly act like this after starting fine the first day of fire??


I appreciate any assistance/guidance.

300stock 80lb 3bar.hpt
startup log.hpl

[kunta0908]

bump for the evening crowd. 😊

[kunta0908]

Anyone see something glaringly obvious?

[5FDP]

Maybe related and maybe not but there are few things I would do the file.

You never want the open loop EQ ratio to be 1.00 for all cells. You want the computer to command a richer value when the engine is cold and slowly work it's way to stoich above 130-140 degree coolant temps.

Was this computer a factory manual or did you change the drop down menu to say manual? Changing that can do weird things unless going to a 80e segment which you aren't doing.

What 3 bar MAP is that?

Are you positive you have zero vacuum leaks, have you smoke tested all the lines and intake manifold?

[kunta0908]

Changed drop down to manual.

3bar map is from On3

Will smoke check tonight.

Will bring Open Loop EQ back to factory tonight.

In the scan, commanded EQ drops down to .33 at one point during cranking, is that normal?

[5FDP]

For the sake of the auto/manual part, leave that as stock and don't set it to manual. Just go into the torque mngt/abuse settings and disabled them (which you did I believe). Then run through all the DTC's related to the transmission and disable all of those. If you altered any of the idle airflow settings or base running airflow for park, try putting those back too.