rx7 SE

iTrader: (5)

I did a short install of an LC-1 wideband in my TII today just to see where my AFR's stand with the new BNR stage III setup I recently installed. After calibrating it it read low 13's at idle which sounds correct but and during regular driving it was around 14's or so which I think is still correct?

What made my heart jump out of my chest was when I went under boost my AFR's were reading low to high 15's!!!!!! What is that all about? Since it was a short install I just pulled my stock 02 out and placed the wideband 02 in it's place for the short time being. I figured since the stock 02 sensor wasn't reaching operating temperature the car would just run in closed loop mode and run pig rich but that wasn't the case! Anybody know what could have happened there?

And if it was really running that lean could the 30-40F degree ambient temps kept me from possible detonation?

gxl90rx7

iTrader: (1)

it will only use o2 sensor as feedback in vacuum. are you sure it wasnt just a lean spot when secondary injectors turn on? how much boost?

rx7 SE

iTrader: (5)

I hit at most maybe 8 psi with 720cc secondaries and a walbro pump with rtek 1.7 for some tuning. It seemed to hold around 15.1 all the way a 3rd gear pull once I hit boost...that just doesn't seem possible, me and a friend pulled it out and recalibrated it and it still said the same thing, but that's just ridiculously lean I would never drive my car under boost if that is the case

K-Tune

iTrader: (26)

does your car have a distinctive smell after boosting?

the stock o2 sensor doesn't affect mixture at WOT.

how much boost are you running? going by your signature i don't see enough fuel injector for a BNR stage 3...

i wouldn't boost that motor anymore until you upgrade your fuel system, or get something to control your fuel (S-AFC)

rx7 SE

iTrader: (5)

that's good to know that the 02 sensor isn't accounted for at WOT, cuz that's mainly wut I was worried about...maybe I can fall asleep now, lol.

Yeah, I've been running the turbo off the stock wastegate pressure but it creeped to 10psi a couple nights ago so a friend of mine let me borrow his wideband so I could see if I was running lean at 10psi and 15.1 AFR was the surprise I got.

It smells like fuel most of the time, no cat, no emissions...it stinks, but it didn't smell any different than usual, it was running slower than usual w/o the 02 sensor it seemed

K-Tune

iTrader: (26)

what made you think it was ok to run the stage 3 with only 720cc sec injectors? that setup can be outflowed even with a stock turbo.

check that your fuel pressure is adequate, then upgrade to 1.8 with 720cc all around, tune with an S-AFC with the wideband until the AFRs are safe.

if it's feeling slower it may be because the motor is nearing the end of its lean running life... check your compression.

arghx

iTrader: (3)

check your grounds. white and green LC1 ground wires should be grounded to the same spot as the ground for the LC1 display gauge.

Did you perform a heater calibration?

rx7 SE

iTrader: (5)

This is why http://rx7.com/cgi-local/2ndgencalc.cgi

I've done my research and if everything is working right there is no possible way that I should be that lean at stock boost even on a stage 3. I shouldn't be making more than 265 rwhp at 7-8psi which I'm positive my fuel can handle. A friend of mine runs a hybrid t04e on 15psi with 550cc and 680cc and only see's low 12's on a long pull.


The directions I found said to ground the blue and the white to the same ground spot, the green was an additional analog input wire. Idk, maybe, hopefully that was wrong?

rx7 SE

iTrader: (5)

Another idea. Could it be getting a bad reading from being several inches from the turbo (stock 02 spot)? Could the heat and pressure from the turbo be throwing the reading's off possibly? I have a 3.5 straight piped exhaust so there's no such thing as back pressure with this setup.

rx7 SE

iTrader: (5)

Nevermind.....I'm just going to get this baby dyno'd. I'll post up my results....if my motor doesn't blow that is, lol.

Rote8

Have the dyno use a stand alone wide band.
If you get anything over 13 on the dyno, under load, shut it down.

rx7 SE

iTrader: (5)

Just a little update, looked in my engine bay and the vacuum line to my boost pressure sensor is gone. I'm guessing then that my car didn't know how to compensate for the boost because it wasn't reading any.....which could explain the readings....

12AllWays

iTrader: (20)

Haha^ that was simple... How are the AFR now?

bad 83

iTrader: (3)

Geez. That would explain the lean condition. I hope that it didn't cause any detonation. BTW, get that stock sensor hooked back up. I just bought another O2 bung and put it beside the stock one in the down pipe. I put the stock O2 in the stock location, and the wideband in the new one.

rx7 SE

iTrader: (5)

Did a compression check... 97 98 on the front rotor and 101 101 on the back rotor. Still runnin strong amazingly even though I've been driving like that for 2 weeks!! Amazing....

Anyways fixed everything and it's stutters like crazy but when I hit boost it's runnin much much stronger and boost creeping like crazy, lol. I was getting on the highway with my mom and decided to see how it would boost so I floored it and hit close to 10 psi in under 2 seconds and sent the car sideways. All the while I didn't realize there was a 2007 civic with his friend trying to keep up, lol. Anyway, I waited for him to catch up then floored it again in third...boost gauge read 12psi so I shut her down . Not taking anymore chances like that again.

coolmike711

iTrader: (7)

What kind of smell are we talikng about? I do get a smell after boosting, it doesn't smell like fuel.

rx7 SE

iTrader: (5)

If you haven't welded in the new bung yet, I would weld it about 24" from your turbo. The wideband sensors are a little more sensitive to temp and pressure from the turbo and life will be decreased from being too close.

K-Tune

iTrader: (26)

hard to describe, i have smelled a car running lean before...