EJ20G running lean when cold.
 

Hi All,

Was hoping some one could throw some ideas my way.

I have a 96 WRX which is running lean when cold, but when warms up is fine.

I have a new walbaro fuel pump, new injectors, and Mafless with a ESL tune.

I am 95% sure this is not tune related as the car runs very lean cold, but when warm and operating in closed loop the ECU is removing around 15% of fuel to maintain 14.7:1 measured on a wideband.

Im purposely running a little rich now so that I can still start the car and use it when cold. But mean the ECU is taking out a bunch of fuel when the car is warm and in closed loop.

Could the FRP be effected by temp? It is the stock unit.

I am out of ideas, could it be filter? relay?

Is the fuel pump powered just on or off by the relay? our is there a high/low?

Any ideas would be great

Thanks
Dan

sounds like the cold start map? isnt there adjustable compensation for cold start on the ESL

ECU temperature sender not working? When this isn't working it probably guesses on a mid value which makes a cold start tricky and a bit rich for general driving?

Thanks for the replys.

Im not aware of a cold start map, I would presume its uses the stock ecu setup.
The temp sender seems to be working fine and slowly warming up to 90degrees....

Any other ideas?

Forgot the mention, The car was also a little hard to start when cold prior to all the mods.