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420A My car is running rich for some reason

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Giomyman11

Probationary Member
9
2
Jun 13, 2021
Cocoa, Florida
I have a 1998 Eclipse RS with a turbo me and my dad put on. My car was parked for a week cause I’ve been waiting for parts (new Spal fans, thermostat) and we just put them in.

Before I parked everything was reading and working properly but as I tried to start this time it gave me a hard time. After pressing on the gas the car came alive however, the idle was going up and down and the air fuel ratio gauge was showing at idle to be super rich (on the 9s). After allowing to somewhat stabilized (13.3 which was not right as it idle at (14.5), I took the car for a spin and it was not running right, again, super rich. It boost right but is just to rich.

We have installed in the past aftermarket fuel injector 330cc (if my memory isn’t failed me) and I have a 10 to 1 FMU.
Would you think the FMU could be the villain this time?

One of this days I will have enough money to go full Stand Alone but for now please keep your comments on the set up I have, thank you!
 
How are you measuring AFR? Do you have a wideband O2 sensor? Narrowbands will oscillate like what you're describing. Otherwise, putting larger injectors in your car without a way to adjust the base fuel pressure can certainly cause you to run rich.
 
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