Differing AFR Reading.

[maxyray]

Hi Guys,

I have an Innovate LC1 plumbed it with blue and white earths earthing at the battery same as the MS. I’ve connected the LC1 to MS via output 2 (the brown wire) and havent changed any of the factory settings.

Original I was going to connect my pc to it via a usb to rs232 adapter but had no luck after trying for a day.

I know that output two settings are 0v =7.35 AFR and 5v =22.39 AFR so have selected Innovate LC1 default, 0-5v = 0.5-1.5 Lamdba in EGO o2 Sensor under settings in TS.

With the car running I get two differing readings. One from TS and one from the innovate gauge.

here are my findings.

RPM TS AFR Gauge AFR
1500 14-14.5:1 9-10:1
2000 14.5-15:1 9-10:1
2500 12-13:1 10.4:1
3000 12.5-13:1 10.4:1

The gauge stops at 10.4:1 AFR and will not go any higher. I’m I right in thinking that the correct values are from TS?

Anyone had this problem?

[trbugman]

If you stand behind the buggy and you can smell fuel or its blowing black smoke the gauge would be right.

On another note the MS and LC1 should be grounded to the engine block and nowhere else. Grounding anywhere else can cause a voltage offset and give you bad readings in various systems.

[maxyray]

If you stand behind the buggy and you can smell fuel or its blowing black smoke the gauge would be right.

On another note the MS and LC1 should be grounded to the engine block and nowhere else. Grounding anywhere else can cause a voltage offset and give you bad readings in various systems.

Ohhh thats a good point. I did not know that thanks.

Will move my earths tomorrow and see if it changes anything.

PS here is my build if you want to know what I'm talking about...

http://www.shoptalkforums.com/viewtopic ... 3&t=138344

[Piledriver]

I agree everything needs a common ground, but as a T1 vw engine (typically) doesn't have the battery mounted right next to it and the ECU close by, grounding ~everything at the ecu very near the battery, with a big fat ground strap to the battery is in my experience a much better plan. (aluminum mount plate for ECU pretend it is the "engine")

Note that this is not exactly the same as grounding everything at the battery - terminal...

We don't have Chevies or Hondas. The MS install guide instructions suit them, not ACVWs.
All signal/sensor grounds should go back to the common ECU ground.

Engines have all the current for the starter and alternator passing through them, as well as switching currents.
No point dragging those signals into your sensors.

Noise avoidance is job one.

If you have ls2 coils or remote mounted ignitors or such, power grounds go to the block, nothing else.
Many WBO2s have separate heater power grounds, do the same.

The transmission ground strap is critical for many reasons. I run two... One goes to chassis as factory, one goes direct to battery. The good brass battery terminals cost ~a buck more, highly recommended.

Wire brush ground strap contact areas and smother in Vaseline before bolting together.
(preferably coat in Vaseline WHILE SS wire brushing, prevents the instant surface oxidation of mag/aluminum)
Wipe the junk from wire brushing off, recoat, assemble.

On my first MS2 install, power/switching (injectors/coils/idle valves etc) and sensor harnesses were broken out and run on opposite sides of the car, ecu mounted under back seat. I had a separate ignition and injector driver box with it's own power and separate signal (back to ECU) and power grounds (direct back to battery)...Many OEMs setups do similar, for very good reason.

Any analog WBO2 setup will require some tweaking for perfect accuracy, but yours sounds miles off.
Note: LC1s IIRC also put out ~10:1 or such if in an error condition.

You need to be able to talk to your LC1 over serial to calibrate or see errors...
What cables/USB adapters are you using?
If using a "real" 16550A serial port, set FIFO size to 1 (easy under Windows control panel>system>hardware...) do same for MS comms.

[jhoefer]

How is your gauge getting its signal? You can't run a wideband gauge off the LC1 yellow wire's narrowband signal. The gauge readings you list are very close to what you would get if you did so vs the correct TS wideband signal values.

14.7 (real) -> 8.55 (narrowband signal into wideband gauge)
14.5 (real) -> 9.15 (narrowband signal into wideband gauge)
12 (real) -> 10.65 (narrowband signal into wideband gauge)
10 (real) -> 10.65 (narrowband signal into wideband gauge) value is clamped at 10.65 due to narrowband voltage limits.
Reading variation from ideal is likely due to resistance in the wiring.

[maxyray]

How is your gauge getting its signal? You can't run a wideband gauge off the LC1 yellow wire's narrowband signal. The gauge readings you list are very close to what you would get if you did so vs the correct TS wideband signal values.

14.7 (real) -> 8.55 (narrowband signal into wideband gauge)
14.5 (real) -> 9.15 (narrowband signal into wideband gauge)
12 (real) -> 10.65 (narrowband signal into wideband gauge)
10 (real) -> 10.65 (narrowband signal into wideband gauge) value is clamped at 10.65 due to narrowband voltage limits.
Reading variation from ideal is likely due to resistance in the wiring.

You're correct. I'm running my gauge off the yellow wire which is on is factory default of narrowband hence the differing in the reading to TS.

I will need to connect a PC to the lc1 and run LM programmer to change the output to wideband.

Annoyingly i don't own a PC so had to borrow one from a friend and it wouldn't connect.

[Piledriver]

I thought LC-1s had a wideband and programmable narrowband out.
I suspect you may just need to hook up the proper wideband signal output wire, probably the brown one you thought was hooked up.

If you have changed nothing in the settings, both should be live.

[jhoefer]

I thought LC-1s had a wideband and programmable narrowband out.
I suspect you may just need to hook up the proper wideband signal output wire, probably the brown one you thought was hooked up.

If you have changed nothing in the settings, both should be live.

That's correct, you can reprogram the yellow wire output (Analog Out 1) of the LC1 to match the wideband output on the brown wire (Analog Out 2) with the LM software. He's already using #2 for the ECU and you can sometimes run into issues running multiple devices off the same signal source. I would probably do some testing first to see if attaching the gauge to that same wire has an effect on the voltage output.

[Piledriver]

I guess I was reading it wrong, thought issue was the AFR readout in Tuner studio...


Was missing the dash gauge part.