One cylinder drop out causes EGT changes in other cylinders

[Rozsko]

Hey guys,

Today I was experimenting a bit with my STi and ran into something weird that I can't get my head around.

My intention was to do an indirect individual lambda measurement on all four cylinders, by disconnecting the injectors one after the other and see how lean the lambda becomes each time. I assume if all four cylinders work with the same lambda.

While doing this test, all four times when an injector was disconnected, the lambda leaned out roughly to the same value, however the EGTs changed as well.

For example when I disconnected inj#4, EGT#2 increased. See attached picture, log and map for more details.

Do you have any idea what is causing this?

Thanks,

Béla

screenshot:https://1drv.ms/u/s!Ale4oyMCOgLThYou9l_dlHBVUSR70Q?e=kJcjH8

log: https://1drv.ms/u/s!Ale4oyMCOgLThYovPZ-3id31fZXaPg?e=1NYmcq

map: https://1drv.ms/u/s!Ale4oyMCOgLThYowND06D62f_6at1A?e=SvW6AL

[Adamw]

I dont think there is much risk of charge robbing on a WRX10, but your EGTs are pretty warm so I would guess possibly the extra oxygen going through the dead cylinder can find its way into the adjacent cylinder exhaust manifold and allow a little extra of the combusted fuel in the manifold of the still working cylinder to burn.