-edit... P0137 is rear bank 1 sensor 2. I skimmed over the code and missed the sensor designation.

 

honestly, ive been trying to find a straight answer about this for weeks now, i only put it on yesturday to try and get rid of the damn code, im desperate, do u have any ideas?

 

P0137-0140 is rear 02 with different errors. P0131-0134 is front 02 with different errors.

So your P0137 is rear 02, low voltage

 

My fault, I skimmed over the codes too fast and missed the sensor designation. Its bank 1, but sensor 2 so yes low voltage is correct for #2.

# P0130 02 Sensor Circuit Malfunction (Bank I Sensor 1)
# P0131 02 Sensor Circuit Low Voltage (Bank I Sensor I)
# P0132 02 Sensor Circuit High Voltage (Bank I Sensor 1)
# P0133 02 Sensor Circuit Slow Response (Bank 1 Sensor 1)
# P0134 02 Sensor Circuit No Activity Detected (Bank I Sensor 1)
# P0135 02 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)
# P0136 02 Sensor Circuit Malfunction (Bank I Sensor 2)
# P0137 02 Sensor Circuit Low Voltage (Bank I Sensor 2)
# P0138 02 Sensor Circuit High Voltage (Bank I Sensor 2)
# P0139 02 Sensor Circuit Slow Response (Bank 1 Sensor 2)
# P0140 02 Sensor Circuit No Activity Detected (Bank 1 Sensor 2)
# P0141 02 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)

Many of the off the shelf anti foulers don't work to keep the code off. It has to be the right length and orifice size to work correctly.

 

What length and orifice size is correct for a "standard" 3" Turbo back, test pipe exhaust? Or does it vary by each car.

 

perhaps if i add a third fouler it could work?

 

could someone tell me (that absolutely knows, no guessing), how many o2 sensors the evo x has and in what locations

by my belief, there are 3, at the:
o2 housing
precat
postcat

many of the codes say bank 1 sensor 1, bank 1 sensor 2, and bank 1 sensor 3. So if i get P0137 (low voltage bank 1 sensor 2) that should be the precat o2 sensor no?

 

No guessing here...

Front O2 which is the main sensor to run the car on closed loop is in the Downpipe section or the lower half of a O2/DP combo pipe. The stock O2 on the Evo X has no sensors in it.

Rear O2 is in the Cat/Test Pipe section of exhaust and is referenced for emmissions to determine if the Cat is working properly. If it reads too rich or similar to the Front O2 it will flag that the cat is inefficient, If it is hanging in open air or has too many spacers/defoulers taking it out of the exhaust flow it may read too lean and call BS as well.

Hope that helps clear things up.

 

I'm having all of the problems people are, but my ecu is trowing no codes at all. it is cutting boost and idling weird. also at idle the afr's are way lean in the 16-17 range. i have swapped mafs with someone and it didnt change anything.

 

Vacuum line to the fuel pressure regulator probably came off.

 

I am glad that I found this thread!
I throw the p1235 code alot but it is mostly when I do a 4th 5th or 6th gear pull. Sometimes I also get the p1870 thrown in there too (it just seems random)
Well anyways I'll be say in 4th gear step on the gas and boost will spike to about 26.?psi then go to about 20psi for a sec and then its like the car shuts off for a second>I loose all power but am still pressing on the gas. I get a high idle of about 2200 rpm. So when I pull off the road to reset the ecu I have the mr so when downshifting to come to a stop the transmission is extreemly jerky!!! I mean I'ts Fing bad! when I am amost to a complete stop and the tranny switches to first the car takes a mean jump(seems like its killing my tranny jerking like this, it can't be good!)
Seems like for normal driving I never throw either of these codes but when getting on it (even 3/4 throttle) in the last three gears I seem to have this problems. I can stomp 1st, 2nd and most of the time 3rd with no problems but can't for the last three gears! I want to believe that this is caused due to the fact that there is much more load on the engine in these gears.
My mods are K&N cone air filter, AEM EBC, cat back exhaust.
Also would like to know if getting a WGA with a stronger spring (say the Forge) would lower my spikes in boost or would that keep the high spikes and just help me hold a higer boost (21-22 instead of 19-20)?

Anyway this problem has to be fixed I didn't buy an evo to be babied around town! so any help here would be greatly appreciated.
thanks guys!

 

Check out these two links regarding your MR's tranny behavior:
https://www.evolutionm.net/forums/mi...-remedies.html

https://www.evolutionm.net/forums/mi...o-2-4-6-a.html

I would not recomend using any kind of boost controller on the MR. There are some threads discussing that in the turbo section I believe. I also have read about issues with oil type (K&N) filters "fouling" the maf with oil, causing some issues. With the mods you are running, I would recomend a tune.

 

Can you have a MAF problem without throwin any codes????????.....Im boosting only 5lbs.....ive passed all boost leak testing I have new plugs, turbo is in great working condition...even if it was a wastegate id still boost 11lbs.....I have NO vacuum leaks....people tell me the MAF, but wouldnt I have some sort of check engine code??? Any help is appreciated....thanks...

 

Perhaps you don't have a low enough voltage reading via your MAF to throw the code, but do have a low enough voltage reading to incorrectly meter air. Is your car running like crap? Idling like crap? Explain more symptoms.

 

my car idles perfectly.... i still get good gas mileage....the only problem is that is hesitates in first gear,,,, but with WOT it only peaks at 5lbs in any gear...