First of all,my wife and I are celebrating our 5th year anniversary so we decided to go for a long drive. After 2hrs of driving in highway, everything was fine until I felt a jerk once in a while. Then I waited for it to happen again and looked on my afr gauge. It went to full rich (like 10 on my afr gauge) then went back around 15-16.

Pulled over and check for any loose connections and hoses. Nothing is disconnected even the little fpr hose. Started the car and my idle is fine. Goes around 14.6-15.5 and rpm below 1k. The problem starts when I step on the gas pedal. Then it goes completely rich (10) then goes lean like u know it wants to correct for itself.

I was leaning towards either maf sensor or my front 02 sensor problem. Mind you, this happens when engine at operating temp. I do understand that logs and codes would help alot. But my wife and I didnt expect to happen in the middle of nowhere. I mean in the middle of 2 mountains.

Vehicle has tbe and boostpill mode. It has 85k kms on it. I got it tuned months ago with no issue.

I'm in the hotel with my wife still trying to enjoy and stay positive on our anniversary. We left the car for now and blessedly, two canadian couple with their baby allowed us to ride with them. It was snowing at around 9pm in the middle of mountains. I guess it's slmething memorable.

Any inputs will surely help with the issue. Thanks for reading!

 

Update:

I'll try swapping my dad's maf or upstream o2 sensor. If they dont work, vehicle will be towed... 200kms...

 

Update!

hooked up my scan tool and got lots of codes regarding map sensor, frt 02 sensor and even a cold crank starting something.

So I cleared everything and flashed my car to v3.007 basemap. I got a code P2253 regarding negative current too high on front o2 sensor. I love my wideband as it helps me confirm the problem. I believe the vehicle is running at open loop right now as my wideband is stucked at 13.7 when idling which is very reasonable for axplace 3000ft above sea level.

I'm guessing that it uses map sensor right now to calculate the fuel delivery whem idling.

The vehicle is still in the mountains. I'll try to drive it home and watched out my afr.

Update!

Reflashed back to my custom tune map. Drove back home for 137kms. And car was fine along with the afr just like nothing happened. I will monitor the car for sure. Wow! isnt it something?

 

lol wow that's so random. At least everything is fine.

 

Dang! Glad it worked out!

 

P2253 code cameback this morning and I'm on my custom tune. With this code on, I realize that my idle is at 13.7-14.2 And my cruise is at 14.4-14.8.

I thought maybe my O2 sensor is shot so replaced it with new one. My old O2 sensor was so black. Clear the code and roadtest vehicle.

Code cameback after driving 6kms and vehicle still behave as described above. I reflashed to v3 basemap and drove for 10kms. This time my idle is at 15.1-15.2 but my idle is still at 14.1-14.6

My stft and ltft are both 0 based on the live data.

I may have to dig a little bit about this code.

 

I would say from this thread:

https://www.evolutionm.net/forums/09...253-10-ra.html

It has something to do with your custom tune. I'm running the V3 basemap and haven't had an O2 issue yet. Given I haven't been running it long, I have ran it longer than 6kms.

Try flashing the GST Basemap or your stock map with stock pill and pull the battery leads to kind of reset things in there. It might just go away.

If it doesn't go away, you might wanna think about returning as close to stock as possible and heading to the stealership.

 

thanks for the info though. I did flashed back to gst and that's what I'm using right now coz my cruise is better with gst than my custom.

right now vehicle is idling at open loop based on my wideband sensor (it's at 13.7-14.1).

I did find a TSB at mitchell on demand regarding its diagnostic tree. I just couldnt finish diagnosing it coz of work. My shop foreman is helping me also. So far, I verified that #4 terminal at the O2 sensor connector (which is LT BLU in color) is shorted to power.

Right now, I'm prepared to whatever solutions possible which could include replacing the ECM.

I'm just trying to figure out, just in case it's a faulty ECM, could our custom tune damage the ECM? Coz I highly doubt it. So why would the ECM break especially on that particular circuit?

Plus, u know there's something worng coz my ltft and stft are zeor.

Any smart inputs are appreciated

 

Update!

So I finally had the time to check the wiring. Upon testing, found that terminal #4 that goes to the ECM (feedback line), was shorted to power. Ignition to off position, removed the connectors from ECM then I got out of limits. Put back the connectors to ECM then I got 0 resistance. It's supposed to be out of limits all the time when Ignition is off.

So, time to get a new ECM.



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