Recently I had problem with EGT now with my haltech pro harness wideband which shows incorrect AFR level. Car behaved strange so I decided to check AFR with external sensor I connected this sensor in place where normally is stock narrowband sensor but I don’t have cats so both haltech and this external sensor were very close to each other and external sensor with display shows AFR on the level of 13 and my haltech wideband on the level of 15 . Generally haltech wideband runs normally but strange is that when I put gas pedal in the floor haltech first go down to 12 and then go up on this external sensor immediately after WOT I see 10s stable. Anybody has similar problem?
I checked all connections and everything is in line with manual. I made 100 times sensors calibration and still I see higher AFR then it is reality.

 

Check your ground connections. Make sure both wideband controllers share the same ground and recheck readings. Could be a faulty O2 sensor I suppose.

 

Check for exhaust leak

 

^ good point - I had a bolt pop off on manifold heat shield (when I had jwt kit) upstream of o2 sensor and it would suck in air at idle raising afr a full point.

 

My haltechs are dead nuts. I mounted them in the OEM upper wideband location.

After re-reading his post it sounds like the sensors are close to each other so they should both be affected if there is an exhaust leak (note that his posts are hard to read but English isn't his first language and punctuation isn't either )

Could be a bad sensor. Also don't mount them to close to each other since you want both to be in direct stream.

 

Thanks a lot I will check ground connections

 

Sorry for my English but this is not my first language One ground connection is stick to Haltech ground (black cable) second to car body I understand that both should be connected to haltech ground?

 

I have no experience with Haltech, but can you re-calibrate the sensors open air like the LC-1?

 

Yes. Each sensor has a calibration trim pot.

 

Thanks a lot ! works fine after proper grounding but sensors shows different values on idle 14 vs 13

http://m.youtube.com/watch?v=cDYvNinfMXg&feature=youtube_gdata_player

 

can I ask a dumb question...do those 10mm bolts that hold the heat sheilds on seal the OEM headers??

sorta came across this by accident...I am currently running OEM headers / stillen test pipes and stillen exhaust while I figure out some over-oiling/excessive smoke issues with my greddy 18gs and I have an exhaust leak that I otherwise cannot track...