I noticed today that my fuel pressure is noticeably higher than it used to be (like 2 days ago). I used to idle at about 56 psi, now I idle at almost 60, and hit almost 70 under moderate boost, like 5 psi. I have the stock in-tank pump and the Walbro inline that came with the Radix.

I decided to log my O2 sensors, and bank 1 switches at 14.7 commanded AFR, and my wideband is hooked up to the driver's side Y-pipe. Bank 2 reads lean until I command roughly 13.7:1, then it starts to switch and bank 1 reads rich. Has anyone ever seen anything like this before? The only two things I can think of off the top of my head are to switch the driver's and passenger's O2 sensors to see if it is a problem with the sensor, and to try hooking my wideband up to the passenger side and see if it still reads lean, at least that way I'll get sensor error out of the picture.

 

also make sure there isnt no exhaust leaks

 

leaks have killed me when it comes to this. Smallest leak will screw things up.

Yeh get the sensor error probabilty out of the way first before you scratch your head too much.

 

I'll check for leaks when I swap sensors.....

 

I had a lightning and had all sorts of problems with my left bank running lean. I had an oil brether cap instead of an oil cap and that was the problem. I ran myself stupid until I found that out......Tightening headers, exhaust, vacuum leaks etc.

 

I switched the O2 sensors this morning and bank 2 still reads lean, so its not a sensor issue. I'm pretty sure I have an intake manifold gasket leak. When I am in vacuum, it reads lean, when I am in boost, it reads rich, and when the boost gauge shows roughly 0 the two O2 sensors seem to respond just about identically. I bought some starting fluid, gonna go spray around the gaskets and see what happens.

 

Damn! Can't get the sprayer close enough to the gaskets to spray accurately.....J-tube from the s/c is in the way...

 

get a can of wd40. should get in closer with the red straw

 

I pulled the Radix off last night and the rear gasket on the passenger side looked like it might have been damaged. I didn't have a new one, so I tried to fix it and put it back on. It's a little better now, but still not fixed so I'm gonna have to get a new gasket and install it. Hopefully that will fix it.

 

Update.....installed a new set of instake gaskets, no change. I bought and installed the Vette O2 sensors (Bosch P/N 13111), still no change. The only thing I can think is exhaust leak....

Bank 2 only reads lean if I am pulling more than 10 hg-in vacuum. Any less than that, or under boost, and the O2's read almost identical. Exhaust leak? Is it more likely to be the collector gasket or headers gasket? That's all that I have left to check out.....or a bad injector?