Oft Tune E85 Showing Codes P1170 P117B

[steve99]

Originally Posted by gonzo

Steve, around what voltage should the o2 sensor be reading when there's 0% throttle and in gear (engine braking)? Mine is over 4.2v, which doesn't make sense so that's why I'm thinking my headers are leaking now.

look at the front O2 sensor scaling in your tune you should be seeing about at idle as this corresponds to afr of 14.7, it may vary around slightly especially on cold start.

on engine braking the AFR will go full lean like 20 as the injectors are shut off to save fuel

you be better just looking at the AFR

your tune may have 02 sensor scaled differently

[gonzo]

Originally Posted by steve99

look at the front O2 sensor scaling in your tune you should be seeing about at idle as this corresponds to afr of 14.7, it may vary around slightly especially on cold start.

on engine braking the AFR will go full lean like 20 as the injectors are shut off to save fuel

you be better just looking at the AFR

your tune may have 02 sensor scaled differently

I didn't think about the scaling being different. Mine is shifted to the right (goes from -.76 to .58) and I forgot that the car would read more air since the injectors are off

I'm going to get under the car on Saturday and look for a leak. If it isn't that I'll clean the MAF and o2 sensors. If it isn't that I'll get a vacuum test. If it isn't that I'm going to go crazy.

[J-W]

Originally Posted by gonzo

Try putting it in neutral and holding it at 1500, 2000, 2500, and 3000 rpm. I read that if your positive fuel trim starts going down closer to 0 then it's a vacuum leak on the intake side. Mine would go down from 20% to about 15% so I figure it's not a leak.



http://www.easterncatalytic.com/educ...agnostic-tool/

I tried this yesterday, fuel trim holds. So, I guess we can rule out that vacuum leak.