95 LT-1 Idle Cell Comparison - Humidity?

[Rocko350]

Here's a short log of a drive this afternoon. In general it's not running very impressively, but as I've mentioned the transition to closed loop was unnoticeable if that means anything. I noticed some popping in the exhaust when decelerating from a few PE "events".

I suspect that the humidity is causing the MAF to register inflated airflow #s. I say this because I've always logged less spark knock in humid conditions, and I'm presuming that's caused by the water vapor increasing the cooling effect on hot / heated parts. I haven't tried swapping to SD mode yet but will if I can get it to start and stay running reliably.

Wideband is a LC-2 on D27 using default settings. I'm not sure how meaningful any of the data is except to use for cylinder balance testing. I pay it almost no attention unless I drive the car a few minutes to get the exhaust hot. Even then, Missouri's laws on ethanol are stupid - it's considered required in some concentration but they don't have to tell you how much or that it's even present. I'm guessing the 93 octane I'm running has a stoich about 14.5:1.

By the way, with the help of a definition file I found in kur4o's build folder I found I could display the wideband units in Lambda with this in the definition.csv:

54,WIDEBAND_D27,Wideband O2 @ Pin D27,^,EXTENDED,8,2,0.007874016,,0x01,0xFF,,,,,

Your phone have a baro sensor built in or have you checked local baro reading from weather bug or another trusted source and see if your within 3 kpa of reported. If it was humidity related, a smaller plug gap would yield a driveability improvement. Wide band would report a richer mix also if the MAF was over reporting due to increased air mass from the humidity. startup ve is usually about 60% of normal VE.

[kur4o]

That 02s and BLM reading looks weird enough. Did you mess with the closed loop settings. Does the AIR system present and functioning. 02s looks frozen at stratup and really slow moving after that. They should be pig rich at startup and I noticed blms were 120 at open loop meaning they are pulling fuel.

You can set mode4 controls before starting the engine. Like setting target afr and spark for startup.

Humidity revealed some hidden problem you already had. Is it a tune or mechanical.
Humid air takes alot more energy to ignite, You lose about 10-20% power and there is water vapor condensation inside the cylinder untill it gets warmed up, which can foul the spark plugs with water.
But that is likely to happen at much lower temperatures.

The engine gets less efficient and draws more volume for the same amount of oxygen. That can explain the maxed out IAC counts at stratup.

To elimimnate CL tune problem I will start by running Open loop and than CL SD and OL SD.

It could be also 2 different problems mixed up.
1 is hard startup, which can be the result of spark syncronisation, Crank ve table, or slower fuel pressure build up.
2 is crap runninng untill warmed up, the result of weak spark, CL setting off chart, MAf table off chart.

[spfautsch]

That 02s and BLM reading looks weird enough. Did you mess with the closed loop settings. Does the AIR system present and functioning. 02s looks frozen at stratup and really slow moving after that. They should be pig rich at startup and I noticed blms were 120 at open loop meaning they are pulling fuel.

AIR system has been deleted. Closed loop settings aren't stock b/c of headers and cam. But I suspect the injector constant is proabably too high causing the weirdness.

I wasn't aware that long-term trims were used before the engine has run in CL.