WickedX1

Whats up forum, well the day has come as sad one that is. I have been running my daily evo x for 29xxxk miles with zero issues until couple of days ago.
mods are very moderate AMS base flash, two piece downpipe(stock o2 housing) AMS single catback, And simple open filter intake with a metal pipe

Also car is not abuse in anyway

Couple of days ago while driving very slow 5th gear all of a sudden ASC, service hazard and check engine went on, and i lost control of the Gas pedal...
At first i thought MAF so i barely limped back home pretty much idling my way there and scanned it
Code were Mass airflow metering, bank 1 sensor 1 negative current, and rear 02 sensor circuit negative current.
Just FYI the rear o2 sensor hasnt been working for a long time it broke and just went dead but that was 15thousand miles ago.
I went a bought a reman MAF from napa, threw it in and it ran pretty decent but after 20 miles it acted up again.
Also when i look at live data on the scanner both of the 02 sensor are flashing excatly same time and they show 1.275Volts , ? how is that possible?
Right now its just sitting in garage and i dont know what to look for if anyone has some good insight please help me out thanks again in advance

WickedX1

also last night it threw this code

MAP sensor Coorelation , something like that and it threw it once and never came back.

WickedX1

im putting on the stock airbox and oem filter to see if maybe the maf is freaking out due to the cold, but i really doubt that, no body has any pointers ?

20gmr

iTrader: (7)

not really very helpful, but i find it very interesting that 0-1v sensor is signaling 1.25v

LaXGSR

Just a thought - could it be your tune combined with the cold weather lately?

Also, if you scanners says both o2 sensors are stuck at 1.25v when the car is running, then something is wrong or maybe your scanner is wrong. Do you have a wideband? If so, just check if you car is still targeting 14.7 afr during closed loop idle.

WickedX1

i have no wideband, i have two scanners and both say same thing both sensor flash 1.275Volts excatly at the same time, also both scanners show target of 14.5 afr and it varies when reving up to 3K RPMs sometime goes 14.3 ,14.2 then back to 14.6 ,
i also find very weird that it shows 1.275V when arent both of them 0-1volt sensors?
Car is not tuned it just has the base ams reflash done about 15thousand miles ago
and both scanners show Car is running in OPEN LOOP even driving or at idle or cruise , as of now it runs very poorly when it warms up to operating temp, when i start it cold from the night it runs pretty ok , but once i start driving it after half hour tops it acts up again

WickedX1

today morning i started the car let it warm up almost full temp and it started acting crazy idle jumping from 0 to 1500 engine jerking strongly and afr was jumping to 15.06 at idle

ikt

iTrader: (18)

are you running factory bov?

AJ PwR

Check your spark plugs, vacuum system, O2 sensor and your air filter.

WickedX1

yes literally the car is all stock under the hood i even put back the stock airbox and everything today, ran it for 4 miles or so and watched the scanner at one point the 02s started showing 0.670 volts both of them flashed that voltage at excatly same time, car was cuttin out on the throttle i held it steady and it just cut out the went back in to throttle. AFR was climbing into 15's , and smelled hella RIch
i rechecked all wires and connections that go to the o2 sensors underthe floor board and everything is connected and clean, when i went WOT just once it begged 27 psi and right away ASC and SERVICE HAZARD went on the dash display , i then checked the codes and it showed me front sensor cirucuit NEGATIVE , , and MAF sensor showed up again.
COULD the REMAN MAF be defective out the box?
This is so annoying i really doont know what to look for anymore

WickedX1

i checked vac system , and the only open vac source is the boost gauge line but i checked that and the T fitting is secure and closed up, Question for you guys lets say if the front 02 sensor really is DEAD , will the car act like this in the first place?
Thanks again for replying guys any help is much appreciated

i Checked all 4 plugs and they look fine, just nice a black from running so rich

08 Evo X MR

https://www.evolutionm.net/forums/ev...s-do-asap.html

try that out bro. good luck