I am looking for some help with my evo that is stuck running rich. There is a CEL on and I am going to get the exact codes tomorrow but its a front o2 sensor code.

The sensor has already been replaced and it seems there is another issue with it, like possibly in the wiring or something to do with the tune.

The short term fuel trims are maxed out and the car runs crazy rich. Getting only 10mpg.

At idle its at 10.7.

At light throttle (like 10% or less), or on decel (off throttle while moving) it stays in the 10's as well.

I will get the exact code which should help alot on here but is there anything else i should know? Or is there a way to patch the ecu so it doesn't compensate so much when there is an issue with the front o2??

 

Sounds like all the symptoms of a bad front 02 or fault in the wiring.

 

If you are running MAF, do check that the plug is properly connected.

 

running a gm maf with maf translator.

 

got the code. its a p0134. Front o2 sensor no activity.

Anybody run into this??

Also if i do figure out how to run full open loop only, the car should not try to adjust its fuel trims at all correct?

 

Yes but thats a band-aid, you should find the problem with the front O2 sensor or circuit. Did you install it yourself? (damage during install). Get a DMM and a workshop manual do some voltage measurements at idle and operating temp. and let us know.
What rom are you using?

 

Ok sorry it took so long but i was waiting for my tactrix cable in the mail.

I am still having the same issues with my car and that code.

I attatched a screen shot and i am running tephra v7 rom id 94170715

 

you can disable closed loop from periphery bits (don't remebmer which one exactly but you can find it easily, it's named "allow closed loop" and set it to 0)

or you can lower the values in "open loop load/tps threshold" tables

 

Please don't use the periphery bits to disable closed loop the system still tries to use the rear o2 sensor in its place and it frankly blows at doing a good job with it. Even more so if that sensor doesn't exist and is emulated with a tephra rom.

The open loop load values work wonderfully and I definitely suggest using them in its place.

 

^^

good mention, didn't know about that

load tables should be lowered both, #1 and #2 or one of them is enough ?
what about tps tables ? should they be lowered also, together with load tables ?

 

Can you explain a little more on how you want the open loop load values to be changed?

 

Ryan we have tried getting the car to run on open loop.

 

yea what did u do to try. u didn't explain anything to me

 

set values in all tables - say at 10, instead of 88.1, 60 etc.

 

hm i will check when i get home but i don't believe i even have those options on my rom. Do i need to copy and paste more info into my xml file for my rom to add the "global fuel settings" if i do not have those options currently??

if so do u have the appropriate xml patch