After reading here, I decided to suck it up, weld in a new bung on my mid pipe up by the downpipe (about 3 inches from the stock o2) and install a wide band o2 sensor to go with my "band aids" Greddy based turbo system that I've been running more or less unchanged for 15 years or so on my 1990 (no ****).

I installed it, calibrated it and went for a drive.

Pretty much whenever I'm not in boost it is telling me 22.4 which I understand is all A and no F? Then when I hit boost it drops to 7.5 or so. I thought under normal driving (no boost) I should be looking for 14-15?

I use a Bell AFPR and a Walbro 190LHP. Base fuel pressure at idle is 40.

Any thoughts about why I am seeing these things?

Thanks!

 

What wideband is it?
It sounds like it is not calibrated right, or its setup for a different type of fuel. If you were legitimately that lean the car would fall on it's face.

Either that or the car is misfiring. A miss will show as super lean like that.

 

Stock ecu? As in, no logs?

 

Innovate gauge.
Yes stock ecu...band aids includes an msd.
Seems to be running great. Purring along like usual, pulls good under boost.

I did the normal calibration. Power up disconnected, turn off. Power up again connected with the O2 sensor dangling in the air...

I powered it off the cig. Lighter wires. Are these gauges finnicky about power?

 

You are the sixth noob to ask this week, does anybody read directions?

It reads full lean and full rich. If you can't tell if your car is doing either, you have no business driving it.

 

if you're running band aids I assume the rest of your setup is dog crap too
so you probably have a huge exhaust leak and then when you're on it the car goes pig rich because that's how aidz cars run

 

Here's the question. Are there any obvious mistakes I might have made installing the gauge?

Great guesses thanks! Unfortunately I am sure my car has not been running on pure oxygen out of boost and spewing gasoline from the exhaust under boost these last 15 years. No exhaust leaks either. 18psi maybe you haven't been around long enough to realize that in 2000 "band aids" we're a relatively good option for moderate boost applications vs. the expensive and very diy piggy back ecus available back then.

 

I'd go back and redo your wiring to make sure you have good connections both power + ground. They are finicky about that.

 

They were never good, they were just all we had. We also thought the JRSC was awesome back then.

It is good that you have a wideband, that is a very good step in the right direction. You may not want to hear it, but youre next step is going to be MegaSquirt. You have no idea how much better your car could be right now if you ditched the aidz.


So do you have the MTX-L or an LC-1 or what?

 

I'm flattered you edited the post to address me by name, guess you re-read the responses and got mad? LOL

As FTB said:
They sucked just as much in 2000, but when you have nothing better, things seem ok or "good enough".
It's 2015, so many of us try to use at least somewhat modern methods for control.

Anyway, back to your question:
there's really only a couple things that could be wrong: either a fried sensor, bad wiring (there's only 2 wires since you're not logging iirc), or a weird combination of both. If innovate maybe calibration or firmware problem too.

 

MTX-L.

Awesome. I think I'm going to just run a dedicated ground to the battery.

18psi I edited my first response because I thought it sounded kinda bitchy and because based on your and another response you guys were getting hung up on "wtf band aids in 2015". I still have it because I already have it, it's been rock solid reliable for tens of thousands of miles and because step 1 if I do decide to fix what ain't broke is...a wide band O2 sensor.

I considered a JRSC. Glad I got the Greddy.

 

fair enough
at least you're heading in the right direction

 

OP, your car wouldn't run at 21.8, and it wouldn't run at 7.5 either. It's not a mistake that those are the max/min that the gauge can read, it sounds like it's in narrow band mode, if there is such a thing for MTX-L.

 

Thats what I was thinking. If it was an LC-1 with a gauge I would think he had used the yellow narrow band output instead of the brown wideband wire. Im not sure if something like that can be done with the MTX-L.

I suppose it could be ground offset, but I would think if it was reading super lean under cruise/idle it wouldnt be showing super rich under load.

Maybe the sensor is trashed? Was it new?

 

Mtx-l will always display wideband. Can output either.

 

Narrow band mode is 0-1v, wideband is 0-5v so even if you had it in narrowband mode it wouldn't have the full swing.

OP can you connect an MTX-L to a computer and use the LM logging software available from innovate. It tells you if you have any errors.

 

Mystery solved. Found a small hole in the bung weld seam. Will drop it, zap it and pressure these with a compressor this time. My welds are tool ugly you for eyeballing.

 

oh?

 

Well, not until I tried to install the wide band anyway. But yes you were right about the problem.

Working perfectly now, running on its own dedicated switched circuit to the battery.

 

What are AFRs now?

In case they are still off - another method is to take the sensor out and hit it with propane flame. I forget the correct AFR for propane but I have seen it used to calibrate and check operation.