So hearing/ reading a lot of posts I decided to tackle running a j-body on a wideband O2 sensor only. I've read some people saying its impossible, but as many know I'm not one to just buy into banter (often writ by wieners), and decided to try it for myself.
The test subject is my stock 2004 1SV eco coupe.
Those of you with HPTuners, know that in the help file it comes with this nifty little diagram:
I have an XD-16 gauge, so I didn't have to wire the pushbutton/ LED part of the diagram.
*Be careful on the plug for the O2 sensor because I found that the female and male sides have different locations for the A,B,C,D connections. Make sure to tap the FEMALE side (the one attached to the stock O2 sensor, NOT the plug on the engine wiring harness).
I ran the wires as pictured. I used a left over O2 plug from the skwirl so I could easily return to stock if I wanted.
I then free-air calibrated the LC-1, then screwed the sensor into the bung on the manifold.
I programmed the LC-1 to output channel 1 as the narrowband emulator (very easy because its programmed like this from the factory) I left all the settings alone EXCEPT for the sample rate (put at 1/6th of a second just as stated in the picture).
I then set the output of channel 2 for my wideband settings, and plumbed that to HPT. I did a voltage offset, and am now ready to tune.
The only issue I had with this was a heater circuit CEL because I no longer need to use the OEM O2 heater wires. You can solve this with either a resistor connected to those two wires, or use HPT to disable the O2 sensor 1 heater CEL.
The car runs exactly like stock, and I didn't have to deal with the pain of welding another bung for a wideband sensor.
I then did some wide open throttle pulls to see what the AFR on a stock jbody is.
When the injectors begin to clip, it'll get as low as 12:1, but in low gears from a dig, the AFR under WOT is around 13.8-14.1:1 which is ridiculously LEAN.
I'll have some datalogs tonight and post them up when I get home from work.
but this setup will make it a LOT easier to upgrade to a wideband without the chore of adding another O2 bung to a manifold/header.
unfortunately, the more digging I do, the more obvious it becomes that the stock injectors are overworked, and unable to support even the stock engine. This MAY explain the reason why I've been seeing up to 8* of knock retard on an otherwise stock engine.
Logs tonight.
Good work, PJ!
It's funny how much work you do for these cars.
Why didn't you just use the factory heater wire to run the +12V of the LC1...then you wouldn't have to disable the heater circuit. btw, who said it can't be done? I ran my AEM's narrow straight into the pre CAT O2 input for the factory setup. I've been running like this for quite awhile, no CEL yet. -But that might mostly due to the fact that AEM uses standard Bosch sensors which may read exactly the same as stock?
Edited 3 time(s). Last edited Tuesday, April 28, 2009 1:51 AM
"Never argue with an idiot. They'll drag you down to their level, then beat you with experience!" -Anonymous
Yep there's definitely enough info out there to confirm that the stock eco injectors are not enough even for the stock engine. There is no room to tune in a decent AFR.
I could have used the info on replacing the narrow band a couple months ago...
Eight degrees of KR is too much, even with the lousy AFRs. Where do you get your gasoline?
gasoline is from sunoco, some different gas stations but sunoco mostly.
AFR under WOT stock was around 13.8-14.1
I've thrown in the skwirl's old 440cc injectors for @!#$s n giggs and sure enough, my kR has been drastically reduced. AFR is exceedingly rich at 11.5ish with a peak around 10 in some sudden throttle shock situations.. but I haven't begun to tune it yet.
I'm experimenting with changing the injector constant number. I'll post logs when I have more concrete proof to my theories. Gonna be a couple days or so.
I tried something very similar to this before and I got a slow response code, the heater code was easily killed with a resistor, but the slow response kept coming up, did it with both the cav and the cobalt I tried on both, perhaps the innovative has better narrowband emulation than my plx did
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
Joshua Dearman wrote:Why didn't you just use the factory heater wire to run the +12V of the LC1...then you wouldn't have to disable the heater circuit.
"Never argue with an idiot. They'll drag you down to their level, then beat you with experience!" -Anonymous
Joshua Dearman wrote:Joshua Dearman wrote:Why didn't you just use the factory heater wire to run the +12V of the LC1...then you wouldn't have to disable the heater circuit.
that would kill two birds with one stone, but its already wired, and the code is already disabled.. either way works.
by doing this i can log AFR's with my wideband through HPT.... I dont have the Pro version of the MVPI I have the standard
