UEGO: Just Installed and Now a Problem

[alice]

After searching and reading tons of posts, I could not find a concrete answer to my question.

Today I went to troubleshoot some minor issues and finish wiring up the UEGO. It works great as soon as the car starts. It reads around 14.5-.9 or so then as the car warms up it slowly creeps towards 17.0 where it then proceeds to max out and read ---. This is all at idle and as the car warms up. Give it a little gas and it goes back to reading out proper numbers. Let the gas off and it creeps back up and then reads ---. The O2 sensor is about 36" from the turbo and I do not have a cat. Power/ground are wired into the cig lighter and the white UEGO output wire is wired to the stock rear O2 signal wire to the ecu so I can log it with link. I also have a small fuel leak at the sending unit and it's really the only thing that I can relate to the gauge not functioning properly because base fuel pressure would be off a bit (2-3psi) leaning it out?. Anybody have any ideas about my UEGO situation?

 

[turboglenn]

Well, the AEM starts out reading 14.7-14.9 while it's warming up ( about 20 seconds from cold) Then it will start reading your true AFR's. This sounds like you are just really lean at idle. What are you tuning with? I would add some fuel at idle and see if it comes back up to a real number and will hold steady.

 

[alice]

After some more research, I have come to the conclusion that the exhaust leak I have between the o2 housing and DP may be the cause of my readings. I have to fix that first and see what happens. However, I have the Megan Racing 3" cat-delete downpipe to the stock o2 housing. It's almost impossible to tighten the nuts to the o2 housing because they are so close the the piping. I can't fit a socket around the nuts no can I fit a wrench around it either. I gotta get to the store and pick up a stubby 19mm and see if that works. Thanks for the quick reply.

Also, I am tuning with link but I am a completely stock set-up except for: AFPR, Wally 255, and this exhaust. Once I get the leak fixed, I will see what happens and go from there.

 

[turboglenn]

The exhast leak can definately cause it. I blew out my flex section the other day and untill i put the new one in, the readings were all over the place at idle and light cruising.

Keep us posted on the results!

 

[alice]

I certainly will update it. I can't work on it until Friday, however, but I will be back with the update immediately after. Thanks for the help glenn.

 

[STM tuned]

sounds like the exhaust leak is doing it.

I had the same combo, stock 02 housing with megan 3" DP. Had to get a "crows feet" set from sears to get it tightened, took awhile ahah. Ended up having to hammer a socket onto the nut and was finally able to tighten it.

 

[alice]

^^^ I have always wondered what "crows feet" would be for and now I understand. I was about to blast a socket on there too but I was afraid of either breaking the stud in the o2 housing or damaging the weld on the DP. I can get this done Friday. Probably going to need some more S6's and line but we will see.

 

[alice]

I went to tighten it up and for the life of me, I can't get the nuts to tighten fully and I ripped the 02 housing to DP gasket. I think I am just going to get the MR O2 housing to complete my exhaust set-up anyway.

 

[Chicken Patty]

Yes an exhuast leak causes really lean conditions at idle. I can tell you from experience. ALso I Believe the sensor has to be put at a certain angle as well. HOw is yours?

 

[STM tuned]

Yes an exhuast leak causes really lean conditions at idle. I can tell you from experience. ALso I Believe the sensor has to be put at a certain angle as well. HOw is yours?

I don't believe a specific angle is required for correct readings, just to keep moisture out of sensor/housing.

heres excerpt from instructions

To prevent collection of liquids between the
sensor housing and sensor element during the cold start phase, the installation angle
should be inclined at least 10° from horizontal with the electrical connection upwards,
see below.

 

[alice]

Exactly what Gleason says^^^^

 

[Chicken Patty]

I don't believe a specific angle is required for correct readings, just to keep moisture out of sensor/housing.

heres excerpt from instructions

thanks for clarifying that. Looks like the person that told me that wasn't to clear on that neither.