hello
i tuned alot of cars with crome,
but lately i have some issues with idle,
i do all the usual things, offsets, timing sync, with lights on,
but when i turn off the lights the car starts popping/misfiring like its leaning, but afr's are 13.9-14.2. battery voltage dosnt change alot, when this happens,
spark plug gap is usually .028-.030.
eld is disabled, on all the cars i tune,

any idea?
thanks

 

Plug wires? Igniter?
Maaybe try another ecu? Idk. Just throwing random ideas that I've seen do weird **** before.

 

Injector Battery Offset. When this is off you'll see different characteristics of fueling when theirs voltage draw from lights or other components that weigh on the battery.

You stated the battery voltage doesn't change much but is the offset tailored for you injectors?

 

put on all electrical loads i.e. lights, rear defroster, heat and adjust the battery offset tables. I have tuned many cars on crome and i never had that issue once the battery offset tables are adjusted

 

You can even unplugg the alt from the battery so you can tune the battery injector offset table on battery voltage and below. AFR should not waver from just a change in voltage.

 

In my car with a P30, Crome wouldn't detect the battery voltage correctly. It wouldn't detect over 14.1 very well.

I would use a multimeter to verify the battery voltage isn't fluctuating vs what Crome is telling you through datalog.

It's probably offsets that's the cause, but it may be Cromes fault.

Now that I've switched to Neptune, battery offsets work as they should, and voltages are detected correctly by the ECU.