PLX DM-5/SM-AFR interfacing with the ecm

canadian

canadian

sy in progress
Re: PLX DM-5/SM-AFR interfacing with the ecm

jaystcb said:
Wish I would have sent you a pm. I just bought a box of 50 from NAPA. Look's like I'm going to have something else to add to the garage shelf of SyTy.
Click to expand...

How much was the box of 50?

Never mind, found another source for the connectors: http://www.repairconnector.com/products/GM-Micro%252dPack-Series-OEM-Repair-Terminal-Female-20%252d18-AWG.html

Mouser also stocks them: http://www.mouser.com/Search/ProductDetail.aspx?R=12089649-Lvirtualkey63000000virtualkey829-12089649

Looks like the best price I've found so far.
 
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92AcademyPhooner

92AcademyPhooner

New member
Re: PLX DM-5/SM-AFR interfacing with the ecm

turbodig said:
There's a couple things going on...probably the reason for the confusion.

In stock form (and most of the aftermarket chips as well) the AFR field doesn't reflect real AFR. It's a calculated number.

The people that are getting real AFR data in the data stream, either have a "patched" chip (see http://digware.lunarpages.com) or are running code59. (code59.org) Both have additional ECM code to read an additional input, and translate this input to an AFR value. This is what's getting routed to Pin F14.

The PLX (and others) will also let you simulate a narrowband output. This is what you would run into the stock o2 input. This won't give you an AFR reading. It will cause the o2 mv value to have a semi-consistent value, and based on how you programmed the "simulated" narrowband, you could make a chart such that .xxx mv = xx.x AFR.

Some people do both - they route the simulated narrowband to the stock o2 line, and run the F14 line to read real wideband data. This allows them to remove the stock o2 sensor, have the wideband "simulate" it, and the ECM doesn't know it's gone.

Code59 sorta eliminates the need for this, since it has code to actually use the wideband for closed loop fuel control. (Although, it's still open-loop at WOT like every other GM ECM)

Hopefully, that clears some things up. Bottom line, you really have to have a patched chip or code59 to get any useful data in the ALDL stream. (In a practical fashion).
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So, i just installed my PLX WB AFR gauge and PLX's AFR module and it seems to be working great. I am also going to install my newly bought code59 parts soon. So, do i need to do anything with the E14 NB slot on my ECU connector? It talks about E14 needed for open loop tuning, but i heard that if I have code59, i should be find to dismiss E14? I don't know if thats right or not since i haven't done anthing with code59 yet. Thanks.

Oh and also. I was able to get my AFR gauge to read realtime numbers without grounding it B9. Does that seem right? Because i grounded the PLX SM-AFR module's power wire and that seemed to run everything fine. Any ground should work right?
 
92AcademyPhooner

92AcademyPhooner

New member
Re: PLX DM-5/SM-AFR interfacing with the ecm

jaystcb said:
OK, finally got it all hooked up.

This is what I ended up with.

PLX-SYTY_0012.jpg
Click to expand...

Why does B9 still have to be used? Because i just hooked mine up today and it reads everything fine without me even using B9. Is B9 just the closes ground for the capacitors to ground to? That electrically seems like the only reason, unless i'm missing something, which i'm sure i am.
 
Quickstop [UK]

Quickstop [UK]

Combating adversyty.
Re: PLX DM-5/SM-AFR interfacing with the ecm

I think you want the same ground as the ECM so that any differences in voltage are the same in the ECM as well as the WBO2. It'll prob work fine though.
 
92AcademyPhooner

92AcademyPhooner

New member
Re: PLX DM-5/SM-AFR interfacing with the ecm

So i guess the over arching question for me is, if i am running $59, do i need to bother with the E14/NB wire?
 
Quickstop [UK]

Quickstop [UK]

Combating adversyty.
Re: PLX DM-5/SM-AFR interfacing with the ecm

I would do it. If you have problems with the truck then by installing the NB wire you can easily go back to a stock tune.

You can always change the sensor back as long as you don't cut the wire and tuck it away somewhere as well.
 
jaystcb

jaystcb

Sy 0902, 92Ty 0909
Re: PLX DM-5/SM-AFR interfacing with the ecm

92AcademyPhooner said:
Why does B9 still have to be used? Because i just hooked mine up today and it reads everything fine without me even using B9. Is B9 just the closes ground for the capacitors to ground to? That electrically seems like the only reason, unless i'm missing something, which i'm sure i am.
Click to expand...

i just got this email from PLX today. It says.

Hello,

Please note that the capacitors were intended for use with first generation O2 sensor modules. These were actually not meant to be included with your combo kit. The user manual also does not mention the use of capacitors.
Rest assured that the SM-AFR Gen 2 you currently own does not need capacitors in any situation.


So I guess we dont need it. Im going to unhook mine and see what happens.
 
WyoSyclone

WyoSyclone

Active member
Re: PLX DM-5/SM-AFR interfacing with the ecm

jaystcb said:
i just got this email from PLX today. It says.

Hello,

Please note that the capacitors were intended for use with first generation O2 sensor modules. These were actually not meant to be included with your combo kit. The user manual also does not mention the use of capacitors.
Rest assured that the SM-AFR Gen 2 you currently own does not need capacitors in any situation.


So I guess we dont need it. Im going to unhook mine and see what happens.
Click to expand...


If that's what they say, cool! They must have done a re-design and built in a fair amount of noise suppression between the power supply and signal sides of the board...should have been done in the first place, but glad they've fixed it.
 
92AcademyPhooner

92AcademyPhooner

New member
Re: PLX DM-5/SM-AFR interfacing with the ecm

SonomaGTlover said:
Sounds like an idea... I have EGR delete as well so I could just use that one.
Snip the EGR wire, remove from plug and insert into F14?
Then connect the WB output to the pigtail of old EGR wire that is now in F14.
CORRECT??
Now to go looking for the patch to monitor it in TunerProRT (I don't have the "Actual AFR" option unless it mysteriously shows up once connected)
Click to expand...





If I DO use the EGR and the stock IC Pump are there any other wires that I can afford to pull from on the ECM? I need just one connector!! :rant:
 
atkonkler

atkonkler

Is this your bush?
Re: PLX DM-5/SM-AFR interfacing with the ecm

Or just follow the directions and plug them into the ecu vs. Snipping stuff! ;)
 
92AcademyPhooner

92AcademyPhooner

New member
Re: PLX DM-5/SM-AFR interfacing with the ecm

No, I actually put in my PLXs (O2 and AFR) months ago and they works great. But the connecting pin that comes with it keeps sliding out and cutting the car off. I already found a few GM connecting pins so when they get in i can crimp them on, but i was just wondering if there is anything in the ECU (doubtful) that i can afford taking away.
 
TYTILIDIE

TYTILIDIE

METH HEAD
Re: PLX DM-5/SM-AFR interfacing with the ecm

There really isn't I can get you some of the ECM pins if you need them. Let me know.
 
Mephisto

Mephisto

These trucks are cursed
Re: PLX DM-5/SM-AFR interfacing with the ecm

i've been reading through this thread and over at the code59 site and have a couple of questions...

can i use my old ALDL to serial cable or do i have to buy the ALDL to USB cable for this to work? I also just bought the AEM UEGO gauge... is that gonna work for code59 or should I return it and get the PLX instead?

this is all completely lost on me right now... any socal guys running code59 that wouldn't mind letting me check out their set up? I'm more of a visual learner, so watching someone do something makes more sense to me than reading it.
 
Ian Turgeon

Ian Turgeon

Cascading Inspiration
Re: PLX DM-5/SM-AFR interfacing with the ecm

I just realized my diagram for this was hosted in a gallery that's gone now.

I dug through my files and created a quick HowTune article for it. It should live a longer life there: PLX SM-AFR wideband oxygen sensor wiring diagram

Though the newer version looks like installation is even simpler, nice.
 
Quickstop [UK]

Quickstop [UK]

Combating adversyty.
Re: PLX DM-5/SM-AFR interfacing with the ecm

Just to add to that diagram, some of the newer PLX gauges need an 8v inptut and for that they have a special component that should come with the kit. It didn't with one and the gauge acted really screwy - finally got it working but if anyone is using a DM5 gauge, watch out! :D

Great diagram Ian.
 
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