I've been slowly tuning my car for some time now and my AFR's fluctuate quite a bit. I'm not sure what normal looks like. My car is half bridged. Its hard to tell if the car has an exhaust leak cause of the pulsing of the brap in the engine bay. My gut tells me I have a leak and I've pulled the manifold/turbo (single btw) off several times. I think maybe my manifold to block gaskets are done. I've been reusing those oem ones quite a bit. Before I go replacing those I was wondering if someone has a video of a half bridged wideband from idle and just a cruise around. Or a log for the AEM Infinity I could check out. I'm staring at one of my logs for an example steady throttle at 4k for a cruise my target that I'm shooting for is 13.7 it will bounce around 13.5 almost to 14.0. Is it normal to get oscillation of about a half a point?

 

yes, it is. plus that's a little on the lean side for a bridgeport but your sensor might also be registering on the leaner end of the scale.

 

Cool! good to know thanks for the information.

 

bridgeports like to bounce all over the map at light loads, so it's very difficult to get them totally smooth in AFR, hence why you usually just richen up those areas versus trying to fight the battle of fuel efficiency with the hyperactive ports.

 

That probably explains the oscillation I get with the map too. It's light but it correlates to my AFR.

 

when it braps, its misfiring, so the o2 will read lean. this is kind of ok, as its light throttle, low rpm, and if its consistent you just tune like normal, but know that the o2 is bogus.

for example, when i was tuning light load on my P port, i found that it didn't like anything leaner than like 13.5:1 and if it was richer than say 12.5:1 it would get angry, so i run 13.2:1, and its happy. not sure what the ACTUAL AFR is, but it doesn't matter. it runs well, and its consistent.

at high load, its not misfiring, so you can tune as normal.

 

Makes sense. Thanks for the help.