So I have a Maruti Esteem engine with a dual carburetor on an engine dyno and everything was already installed when I joined this lab. We seem to have a problem when trying to fire the engine. 1st and 2nd cylinder are not combusting at low loads and 3rd and 4th are. I know this by looking at the temperature readings at individual cylinders(have installed individual temperature probes in every runner in the exhaust manifold, lambda sensors are not available at the moment).
When running the engine at high loads, all the cylinders are firing (again, I know this by checking the temperatures at the exhaust manifold). I am confused on why certain cylinders in a carbed engine would not run at low loads and then would run at high loads?
P.S. I am a newbie in carburetors and this might be my chance to learn. I can post pictures of the setup tomorrow.
Any help would be deeply appreciated.
EDIT: Here are the pictures