It's something with the 02 sensor circuitry I bet. Cut the wire to your 02 sensor and run the part coming from your harness to the 0-1V input of your wideband and it should clear up...I think our old ECU's are starting to show their age because everyone is starting to have this problem.

 

I'll second the O2 circuit sucking in general on our aging, modded cars. Except i say just don't even worry about running closed loop. I just cut the O2 to the ECM wire and quit running closed loop totally years ago for similar issues when just cruising or more so the transition from closed loop to needing open. Even very minor throttle adjustments or engine load adjustments while still cruising was making it go too lean.


With no O2 to the ECM i have it tuned to high 13s/low 14s on cruise and that's fine with me. Being able to monitor my exact air/fuel and adjust everything i see little need for closed loop anyway.

 

Thanks guys! So I cut the O2 sensor wire this morning &.... No more Lean Bullshit! Yay!

I think I have another o2 sensor floating around that I got with my exhaust that I'll swap in sometime. For the time being, I'm going to enjoy the good idle, and rich, hesitation free acceleration and cruising!
And now back to our regularly scheduled programming...

 

Cool, I don't actually think it's the 02 sensor malfunctioning because my problem would persist despite replacing it with brand new one's...I think it's just faulty wiring or coding somewhere in our ECU. Finding out the exact cause might not be worth the time when there are simple alternatives. Now you can tune out the rich part of your maps sense the computer is no longer going into closed loop, ie, relying on the 02 sensor.

 

I mentioned earlier than I have been seeing an odd little hesitation/surge at low RPM/low throttle, and it does seem to be related to the ECU going in/out of closed loop. It seems to only do it when the engine is partly warmed up, and when I was using 550cc primaries, it was non-existent. The larger primaries seem to have something to do with it, but with no way to adjust the fuel in closed loop, I guess the only real solution would be to disable the 02 sensor like you guys are talking about. At least in my case it's only a very tiny issue; not like Nick's problems.

 

F iortunatelI have yet to experience this closed loop leaning situation, I guess my ecu likes the simulated narrow band output?

That's what I assumed, only a gsl-se isn't an s4...

 

Ya when a 02 is going bad or totally dead it makes it richen up closed loop not too lean. When an O2s output is 0v the ECM makes it more rich, .6v and up is when the ECM makes it lean. I've never seen a bad O2 giving off too much voltage. I seriously doubt the sensor is the issue.

I think the amount of fuel enrichment possible in closed loop is to narrow of an area for our needs. Even more so with non 550 primaries and/or altered fuel maps. Not even getting into closed loop to open loop slow transition problems.

Not that i'm happy to see others with problems but at least i'm not the only one to have had this same symptom and same solution. I've been running with it unhooked for a long time now.

 

Got a good 3rd gear pull in on Friday and it's way rich in boost... Max airflow reading of 857. The N326 topped out at 715.

 

Airflow is a beautiful thing!
That is pretty rich, I have to redo the boost area of my map now because I was hitting 9.2 after I got my secondaries working again...

 

Your lead timing looks much smoother than mine at WOT, wonder why that might be.

 

See that spike after that run? WTF? Inj. DC of 114!? WAT?!

Well, I'm going to try and hook up the narrowband from the WBo2 and get an AIT sensor and lean it out!!

 

Well, at least it wasn't in boost, probably just the flapper style afm, playing games w/ you

 

woa...I didn't catch that the first time, that is weird...X-Files

 

finally figured where my logs were hidden, and how to post them up. these two logs were spur of the moment logs and i didn't know what all to log so i just picked a few. also the analog 2 is my wideband which i have yet to figure out how to scale.

 

opinions please ! any idea why my afr's spike up like that on both pulls?

 

Generally there will be a lean spike when you jump on the go pedal, if that's what your referring to. Or could be injector staging if your referring to that little spot in the middle of your pull (log injector staging & DC(pulse width). How did it feel? It looks ok, possibly some lean spots and some rich spots, but W/O having your O2 scaled it is kinda hard to see what you have going on. What kind of setup are you running?

To setup your Wideband scaling on the PLViewer go to preferences,custom sensors, and your specific input (analog 1 or 2), input your scale depending on your Wideband brand/type(refer to manufacturer specs). (see image attached)

As for the logs, you can also post up the actual PDB file on here as an attachment, but either you must zip it up, or rename it to .zip instead of .pdb. I suggest you to log a bunch of parameters. Boost index, TPS, AIT, Airflow, Secondary Staging, DC, Timing...

Here's a third gear pull from Friday. Been pulling fuel like crazy and finally got some movement.. still more to go...


The attached log, 6_9_11-18_20_19_-_RX7L.PDB.zip, file should be renamed to 6_9_11-18_20_19_-_RX7L.PDB , O2 scaling: 0v=10afr and 5v=20afr

 

allrighty i think i figured it out, i was able to look at your log. And i have attached mine. somehow i figured out the wideband scaling also good day.

 

^What is the scaling for the WB?

 

same as yours. when pulling fuel and adding fuel what is a good % to + or - to make a difference?

 

bikeboy, the boost signal on your log is really erratic. Do you have a restrictor pill in the vac line? Location can also have a role. Closer to the intake ports can see some turbulence from port opening/closing.

 

i noticed that also and remembered hearing something about a pill on this fourm. i dont have one. i can just pick one up from the dealer?

the darker blue hose is the line going to the sensor. it isnt under stress like it looks in this picture.

 

Try connecting it to the bottom port on the front of the UIM or the bottom port on the back of the UIM. Those feed right from the plenum and I've had good luck using them. A restricter is also an option. I think Mazdatrix has the part. It's a very tiny plastic piece.

 

Went out and did a 2nd and 3rd gear pull this afternoon. car felt great and really fast. this is still a untouched fuel map. i logged a lot more parameters this time , please take a look

analog 2 / wideband is 0v= 10 afr 5v= 20 afr
( also the palm is .10 - .20 higher afr than the gauge )

- Shane

 

You can also make your own restrictor. I made one out of a small piece of plastic with a 1/32" hole drilled in it.

The mixtures in your log don't look too bad considering no adjustments have been made. It does look like it trends up into the low 12s at higher RPM/higher boost, so it could probably use a bit added in the 5500+ RPM/8+ psi area.

 

i will make one tomorrow

thanks for the reply. i didnt think they looked to bad for no adjustments either, i know i need to do some work to it but im in the ball park. im still not sure what % of fuel i should add up top , or if i wanted to pull some in the 10 afr spot. what would you recommend? i also noticed my timing in this log is way smoother than the other ones i posted.

also what is the factory rpm opening for the secondarys?

- Shane