OFH and loose O2 sensor, fuel in oil
 

I installed my OFH in December last year, OFT last Spring. My O2 sensors do not screw all the way in and at least the front one gets loose and I can hear it vibrate around 3000 - 3500 rpm.

I tend to tighten about once a week but it is usually loose again in a day or so.

I send my oil off to get analyzed and this last time it came back with 1% fuel.

I did my first data log today to see if it is running rich.
http://datazap.me/u/travis23832/1-o2...a=1-2-9&solo=9

How can I get the sensor to stay tight or fit all the way? And does my log look ok?

It seems ok at slow speeds but it's rich at WOT for sure. your MAF scale needs to be adjusted. When I got my OFH I had to chase the O2 bung's with a die. Mine were tight. I gess you could try some red loctite but I think it would burn at that high heat.

What size die? I remember seeing it mentioned before but I cannot find the thread.

I'd like to get the sensor resolved first and then see how the tune is running.

Sorry it was in a set and I don't remember. you will have to mic it any way. my bet is you will have to have a new sensor now. Sorry

I purchased an o2 sensor thread chaser. It is 18x1.5. I can barely get a couple turns before it becomes almost impossible to go further.

You can see from the picture how far the sensor goes before it stops too.

Suggestions? Did I get an improperly threaded header?

It looks improperly threaded then and it explains the trace of fuel dilution in the other thread where I told you to datalog. How hold is the OFH? They are warrantied for one year, I suggest you call (925) 415-9148 (that's openflash's number) on Monday, but also email them sales@openflashperformance.com


Also I'll ping over shiv to this thread @Shiv@Openflash

Hopefully this can get sorted out, they have very good customer service when they actually respond.

Thank you. I got the header in December last year. #412 and sensor threads were "ok" .

What are you using to turn the chaser? It's going to be tough, you're going to go so far, push it a little, then back it out to clean it. Repeat until it's clear. Use PB Blaster or at least WD40. If the chaser still won't work, just get a tap that's the right size as it would cut new threads in a smooth wall, so it's going to work to clean them (though you HAVE to make sure it's going in with the threading).


Leak by an O2 sensor is bad for the reading, in this case it's probably reading leaner than it should because of the leak and calling for enrichment which is causing the fuel in your oil.

Seconding what @Poodles said, you need to add some lube to the thread chaser. Mine was tough to thread IIRC even with lube.

the fuel trims look ok but your running pretty rich higher rpm.


assume you running petrol not E85 so you AFR should be about 11.8 top end and its off the end of scale 11.25 which is limit that stock o2 scaling reads.


For the sensor, remove it then run an M18 by 1.5mm pitch thread chaser/tap through the o2 bung in header. It should then screw in all the way and seal correctly. The sensor should easily screw in by hand then just torque to required level, they are easily broken or damaged if you have to force them in


do both sensors


Take some more logs and see what it look like.


If its still rich top end you will need to do some maf scaling. or use wayno's maf scales and/or tunes

If I need to purchase a new O2 sensor, can I get a generic one and still be compatible with OFT/OFH or do I need a Subaru one? Any advantages towards one or the other besides price?

I have an updated log from today. I was able to get the sensors threaded nicely into the header. Hopefully it will stay that way.

Old log:
http://datazap.me/u/travis23832/1-o2...zoom=3184-4008

New log:
http://datazap.me/u/travis23832/2016...zoom=2679-2744

This is already zoomed in to a 3rd gear pull. For some reason I had some data drops where everything set to zero. I noticed one time when I glanced at the OFT the screen flickered off and on real quick. Maybe the cable was a little loose.

Anyway, this log looks better to me. But I am definitely not an expert. Let me know what you think.

Edit - I also logged the wideband AFR this time and it stayed at 18 the entire time.

Thanks!

Calling @steve99 @FRSBRZGT86FAN
Would you guys mind taking a look at the post above this one? Thanks!

Why did you install a header in December and not fix the O2 sensor issue from day one?

That's really your problem and your only solution.

-alex