Erratic A/F Ratio under Cruise

Would somebody mind posting a log of their new O2s at idle/cruise. It seems like mine are pretty crappy but I have nothing to compare them to.

Let's back up to the part where you mentioned "surging". When does this happen? light to moderate load? goes away when introducing more load, or letting off and resuming, but returns at steady load?

I did not see it in you mod link, but guessing front mount with hard pipes, or just hard pipes?

I have the exact symptoms as you if the above is fact. I have narrowed this down to the hard pipes and 9b's so far. This did not happen until I put DNP pipes on my side mounts, and got worse going to an ETS front mount. I believe so far that it has to do with how efficient the 9b's are with the hard pipes fighting each other at the above described load situations.

All that said, my afr's are mirroring the surging on my wide band and the boost gauge. I have yet to figure out a solution, but have a couple ideas peeps have bounced off me yet to try...


Or, I just wasted your time... Let me know!

Honestly I can't determine a pattern to the surging. Seems to do it more when it is warming up but other than that it's random. If I back way off it'll go away, but I haven't tried giving it more throttle as I don't want to risk damaging anything.

I also have stock turbos and IC system.

Boost gauge is steady (but it is a cheap stepper motor, so a 1-2 psi fluctuation may not be noticeable on the gauge.

Definitely didn't waste my time, I appreciate you replying! Hope you solve your problem!

Do you have google docs? MB3000 turned me on to this>>

https://docs.google.com/spreadsheet/...HhHUzNrVkg4ZFE

Works pretty good. You can pan through/check rpms to see when the log is triggered. I believe this should show different conditions with typical readings. I don't have a WB.

Hm very interesting... I took a brief look through it but it didn't seem too accurate (O2s flat lined at zero,etc) but I will take a better look later. Thanks!

Well I tried unplugging the stock O2s tonight to no avail. Still jumps around a lot, just shifted slightly richer.

I'm beginning to think emanage, exhaust leak (doubt it), or fuel. I pressured tested not too long ago and everything was fine so I doubt that is the issue. My vacuum is also great which further disproves that theory in my eyes...

Should I get a fuel pressure gauge? I'll unplug the emanage sometime it's just cold and rainy right now and I don't feel like shoving cold hands through all the plastic toget to it while I'm upside down in my seat lol



Edit: Just shut off my car after driving it and turn the key back on so the wideband would operate and it was fluctuating from like 13:1 to 16:1. Now I know the wind is rushing into the tailpipe/etc. but do you think that indicates a problem with the exhaust/wideband? It is a few years old probably but not that many miles... It reads pretty steady during warm up and under engine braking..

make sure the wiring is good, if it is I would consider trying a new sensor.

Wiring for the NBO2, WBO2, or fuel pump?

I also wanted to mention that I think my knock sensor is messed up. Before this issue I was able to induce knock by giving the engine moderate load under low RPM but now I can't get a single count.. Doubt a bad knock sensor would cause the problem but maybe it's related?

Ok another update. Since the knock sensor isn't working right I was looking at the wiring right out of the sensor up to the plenum connector and I noticed it was real clean. It looks like my rad cap came loose and got some coolant in the area? That would make sense as to why the knock sensor isn't working (is there a fuse I can check or is the sensor fried?) but is there something else in that area that might cause the car to have a funky A/F if it got wet? Hope it's nothing major as it could have been easily preventable :(

Edit: I see one of those connectors is for the rear injectors. Can I unplug that and do some multimeter testing or do I have to take the plenum off? Again, any fuses for this stuff?

yeah I meant to check the wbo2 wiring. I had a hole cut through mine once and it acted funny like yours.

There are some resistance tests in the FSM for the rear injector harness. You can do it with the plenum on.