how come stock eco run really rich is better to run rich or lean and if its better to run lean what should i do?

your car is constantly switched from rich to lean to remain stoich...

your computer does its job trying to keep the car stoich... stoich i basically a mixture of rich and lean....aka in the middle.


richer is safer, lean gives more power to an extent, but also runs hotter the leaner you can get.


if you dont know much about rich or lean, basically just let the computer do its job until you;ve read and learned more about when you richen or lean out the mixture.

most cars run somewhat rich from the factory. just the way they are. the most power can be made by running at the top edge of the lean side, but you better make sure your cooling system is up to par and you aren't risking running too lean. otherwise... well let's just put it this way. i have seen pistons bubble up and melt. bad things can happen when motors don't get that fuel to help cool things down.




I was a retard, and now I'm permanently banned.

If the ECU controls all of this, how come I hear people having problems running to rich or lean with mods? Can basic bolt ons cause such problems?

Rob Smith wrote:If the ECU controls all of this, how come I hear people having problems running to rich or lean with mods? Can basic bolt ons cause such problems?

ecu takes the input from a few sensors, main ones being 02, and iat, and adjusts. basic boltons (superchargers excluded) arent really a reason for rich or lean...

however alot of people either have faulty sensors, or sensors placed in the incorrect spot, (aka iat;s out in the open) which can give incorrect readings.

if one sensor gives an incorrect reading the other sensors compensate for it....

for example.... if your iat reads the air is 32 degrees, IAT BS EBAY mod....

and the air is around 97+ degrees, well the engine will try and run rich, but the 02 will try and lean it out as much as possible. basically mods, if you wanna call it that, things like that cause the sensors to in a way work against each other.



where you should begin to look for adjustment and tuning of fuel pressure is around once you reach cam land... granted some see it as a bolton, its more an internal than anything.


stuff like TB, intakes, exhaust.... no real need to adjust.... however maintainence is something people with basic boltons should look into....

some things can cause improper signals and confuse the ecu on what to do
i love stoichimetric ratios, aced that portion of chem class...