Need your help with AFR on 2nd gen 3sgte swap Options

[team_omega]

94 celica gt with 2nd gen 3sgte swap. Everything is stock with AEM EMS. Harness done by Dr.Tweak. The AFR would read 14-15 from cold start but when it starts to warm up it would gradually move to 16-17. Is this normal? Here is a short video of it. Any clues or suggestions would help Thanks in advance

http://www.youtube.com/watch?v=Bic419UjtsE

[lagos]

my problem is not vacuum. it reads 18-22 inhg at idle.

Then work your way down the list I posted and check your exhaust and mechanical timing.
But whenever I have a vac leak, even a small one, I first notice it as a lean reading on the wideband.

I was just dealing with this issue last week. At idle I was very lean, while at cruising it was fine and my vac readings were about 18inhg. Poking around the engine bay I first found that a small vac cap that I was using on my AC Idle up valve had blown off. I fixed that, and now my car was idling at about 16 afr. Then I did some more investigating and found that my downpipe is starting to develop a small crack right next to the factory o2 sensor. I wrapped the crack in some exhaust heat wrap and put a clamp around it. Now im back to a 14.7 idle. So in my case, it was two issues that caused it.

You also have to remember that on a 2nd gen 3sgte, a "vac leak" means any air leak past the AFM. So the problem could also be cause by a leak in your intake piping.

This post has been edited by lagos: Apr 20, 2013 - 11:38 AM

[garin]

my problem is not vacuum. it reads 18-22 inhg at idle.

Then work your way down the list I posted and check your exhaust and mechanical timing.
But whenever I have a vac leak, even a small one, I first notice it as a lean reading on the wideband.

I was just dealing with this issue last week. At idle I was very lean, while at cruising it was fine and my vac readings were about 18inhg. Poking around the engine bay I first found that a small vac cap that I was using on my AC Idle up valve had blown off. I fixed that, and now my car was idling at about 16 afr. Then I did some more investigating and found that my downpipe is starting to develop a small crack right next to the factory o2 sensor. I wrapped the crack in some exhaust heat wrap and put a clamp around it. Now im back to a 14.7 idle. So in my case, it was two issues that caused it.

You also have to remember that on a 2nd gen 3sgte, a "vac leak" means any air leak past the AFM. So the problem could also be cause by a leak in your intake piping.

yes good advice