Wiring a Wideband to a SCTx4

[bigwave]

Maybe one of you geniuses can help me here. I'm trying to wire in my Wideband for AFR into my SCTx4 tuner. I have followed the directions from their website, and tried a few other things, from SCT, but I get no reading on my X4. I will not go into great detail other than the basic instructions.
Attach signal (0-5v) wire to Firewire (red) and plug into SCT, set SCT to analog red wire and put on a gauge, in a nut shell that's it. There is no specific setting on the SCTx4 for AFR input, that I can see. What am I missing? I tested my red wire in my firewire with key on and it shows 3.57 V, well within the range, and my AFR gauge reads fine 14.6~8 something like that. But I want to data log my AFR along with several other settings and so far not luck.
I am splicing and wiring into the Firewire I do not have the little SCT interface box. I'm using a Firewire from an old computer application, I assume red is red, I wonder which pin on the Firewire is supposed to red, on the plug itself. I have not yet found that information.

Thanks

 

[DSG2003Mach1]

you then need to go into the logging software and enter the formula to convert voltage in AF but you can at least get it set up to where its reading voltage before worrying about that

 

[bigwave]

I've seen this diagram which does not exactly match what SCT says to do, in my case I'm only needing one input, which in theory would only be one wire, assuming the system is grounding through the ODB2 port already, but, this one does show a second ground for the analog port, ??? I'm going to tinker some more tonight, I did go into tuner and turn analog port on and choose a "convert" but there is not an exact match for AFR. if I start getting some real numbers I'll try every convert option until I match my external AFR gauge ;-)

Thanks

 

[zredfire04]

this is going to sound funny, but.....

not all "grounds" are actually ground. most circuits require a signal and ground wire. the level of the signal is relative to the associate ground, not an absolute ground.

basically, if you're just using one wire you aren't giving the sct enough information. it's reading a voltage, but doesn't know what that voltage is relative to.

also, there's no current flow without a complete circuit.

 

[03cobra#694]

I did a write up on this about 7-8 years ago. I’d have to find it, it also configures it in live link.
Depends on the wide band what formula to use.

 

[bigwave]

Ok, I did get it to signal to the SCT last night, but I can't find a canned equation that matches my wideband gauge in the SCTx4. But, if I put in raw voltage it was 3.26v compared to my gauge at 14.5-AFR, Is the equation linier? Is it that simple or no? 14.51afr / 3.26v=4.45 therefore 4.45 is my multiplier?? so, I can just take my raw voltage times 4.45 and get my AFR?? Seems too simple, probably an X factor in there. Is there a way to plug this into the SCT or do I just do it manually?

 

[03cobra#694]

What wideband?

 

[DSG2003Mach1]

look for the wideband post 03cobra made, thats how I figured out mine (thanks, btw). I believe once you read through his post you can go to your wideband company and get the info to complete the calculation.

 

[bigwave]

Wideband:
PLX Devices SM-AFR Air/Fuel Ratio UEGO Wideband Oxygen O2 Sensor + MultiGauge Link Combo with Bosch LSU4.9 O2 Sensor
They've been pretty good about responding to me, I will shoot them an e-mail.

 

[c6zhombre]

Wideband:
PLX Devices SM-AFR Air/Fuel Ratio UEGO Wideband Oxygen O2 Sensor + MultiGauge Link Combo with Bosch LSU4.9 O2 Sensor
They've been pretty good about responding to me, I will shoot them an e-mail.

Is this it? found this pdf

https://www.plxdevices.com/v/vspfiles/support/user_guides/SM-AFRGen2_user_guide.pdf

It says

(V * 2) + 10

 

[bigwave]

That is exactly what I have and the instructions I followed, but that formula puts me at an AFR of 16.52 at idle, now, that formula plus 8 puts me dead on where my gauge was reading.

 

[c6zhombre]

That is exactly what I have and the instructions I followed, but that formula puts me at an AFR of 16.52 at idle, now, that formula plus 8 puts me dead on where my gauge was reading.

View attachment 1460605

Hmmmm....interesting.

The PDF clearly says the stoichemtric voltage (14.7 AFR) should be 2.35 volts. I would double check your firewire wiring. Or call them see what they say.

 

[bigwave]

Already did contact PLX, they've been good about getting back to me, so far, I have checked with a Fluke DMM and my voltage is a dead match. I'm still waiting to hear from PLX. I installed the bung and wideband exactly as the directions stated, the readings on the IPhone are reasonable, other than my lean at WOT issue, which started all this fun!

 

[bigwave]

I also used and compared to this info:

 

[bigwave]

I'm an idiot, thanks guys, but I do believe I have found my issue, and the problem is me being stupid, I'm in volt stead 3.3 for powering my WiFi on my PLX box, not the Wideband pin-out!! I will move my signal wire 3mm tonight and hopefully have a dead on reading for my logger. Of course it bumps a little with voltage, not being perfect, on the logger, dam I had in ignorant moment. I have 4 pins, volt steady 3.3, narrow band 1/0 and wideband 0-5, and a second narrowband. I was thinking I was working on the jeep or ATV and having a 10-beer night and not the mustang 1-beer night, not paying attention. I have to confirm this with actual readings but, I'm pretty sure I was pretty careless!! Thanks fellows.

 

[DSG2003Mach1]

lmao, it definitely happens...hopefully that gets ya straight!

 

[bigwave]

Not only is the formula (v*2)+10 now dead on with my gauge, but there is a setting for "PLX" on the SCTx4 that needs no formula and matches my gauge perfectly for my data logging to the laptop, no formula needed! Wow, I'm going to blame this one on the Barrett Jackson Auto auction, I had it on the TV in the garage all while working on the car, every time something cool rolled up I stopped and watched, lack of focus; and the 10 Bush Lights ;-)

 

[04torchred]

Did you wire up just the analog signal wire on the firewire cable or did you hook up the corresponding analog ground wire also? I don't have a PLX Wideand, but a AFR500v2 and not sure if I should wire up the analog ground also or just the analog input wire.

 

[Wings65288]

Sorry to bring up an old thread but isn't the WHITE hooked up to a power source. Looks like guys in this thread used red.

 

[bigwave]

I'd have to look back at what I did it's been a while, I just dug out an old USB 2.0 cable from my junk box and cut one end off and wired the other end into my setup. I used a tester to test my voltages and grounds, the wire colors did match up to what was stated above, one signal, two grounds, one power. Pretty simple, unless you don't pay attention, like I did when I started this thread.