Scan Master with MAFT- Pro Sd question

[supr91tt]

My newly acquired scan master 2.1 is showing me me inaccurate afr mV 's. I have 87 GN essentially stock with 50 lb injectors, hotwire kit to high volume fuel pump, adjustable fpr, extender pro chip for MAFT pro. I recently bought and installed a scan master, primarily to set the open loop parameter on the chip and the added bonus of knock sensor readings real time. My problem is the TunerPro software connected to the MAFTPro demonstrates clearly that I have control of afr and boost, so far, now that I have achieved open loop from apparently the git-go via the extender pro chip settings. The SM readings for afr is consistently around 940 mv's yet the Tuner pro demonstrates wild gyrations of anywhere from 11:1 to 30:1 afr's during normal driving with boost (15 lbs). I suspect I've spliced instead of tapped, or vice versa during the installation of new MaFTPro harness and Casper adapter harness and additionally tying in the LC-1 wide band.
I'm pretty sure that currently the ECM is seeing wideband signals (analog output 2) which explains the unexpected high values? Should I instead route the ECM feed to the LC-1 analog# 1 narrow band signal to solve this?
Sorry for asking simple questions, at least I anticipate in hindsight this will be simple, but I'm enjoying trying to wrap my head around all this


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[supr91tt]

Update, that didn't work per we but the signal jumps between high and low values which to me seems to be how narrow band works, sending the ecu high and low depending on which side of 14.7:1 the read value is. If I ever do figure it out I'll try to remember to update this post.


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[TurboDave]

I've read and re-read your post and still a bit confused! You've got so many things talked about in that post, but..... You need to make sure of a couple of things.

1. Never feed a wideband signal into the stock ECM. I recommend retaining the stock narrowband o2, and leaving it feeding the stock ECM as normal.
2. Always feed the Translator Pro with a wideband signal so it can take over WOT control of fuel.
3. Always make sure you understand the difference between Closed loop (computer in control via O2 sensor feedback), and Open loop (fuel controlled by table calculations without using the O2 sensors).

 

[supr91tt]

I have the wide band installed in the stock o2 sensor location currently until I can acquire a 3inch downpipe. That being said the LC-1 has two analog outputs, one is wide band which is feeding the MAFT-pro and the other is simulated narrow band signal which I expected to render values in the SM mV similar to those of a factory narrow band. The SM user guide indicates the reading should be pretty stable in the 700-800 range but mine currently oscillates between below 500 and above 500 (no real consistency that I've determined).
I have the extender-pro set to open loop and the retard decimal is blinking all the time which indicates open loop as desired. So I believe the MAFT-Pro is in control and monitoring via TunerPro also indicates this to be true. Now that I'm running open loop full time and have the PTT configured it's running much better.

At this time I'm just trying to determine if I can get the SM display to be usable instead of oscillating which it sounds like I can do when I get the downpipe installed and install the factory wideband back in the stock position.
Thanks for the feedback, I'm getting back in the saddle with the MAFT-Pro now with this new toy. Re-learning so to speak as I initially had it installed in my 91T Supra that met its demise about 3 years ago.


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[aminga]

The wideband won't be happy in the stock 02 sensor location. Too much heat and pressure and it will start to have problems.

 

[supr91tt]

Sounds like ample reason to place the downpipe higher on the list!


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[aminga]

Or put the narrow band back in.

 

[supr91tt]

Pretty sure I need the wideband for speed density mode on the MAFT-Pro. I'll manage to satisfy both requirements (down pipe with o2bung and reinstall action of the stock narrowband) within fa few weeks which equates to maybe 2000 mikes as this is now my daily driver


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