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Mr Noisy

Sam's 3.5 Disco MEGASQUIRT START/FINISH INSTALL THREAD! :)

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Yes that's how I've been setup so far.

The last time I did a retune the VE table hardly changed so it's obviously pretty well dialed.

As such I just need to change some settings over and swap sensors.

I've run it before on NB a while back but I'm a bit rusty on the settings :D

Thanks again fridge!

P.S. What will the NB sensor actually do once installed?!

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Some small trimming based on (what it thinks is) rich/lean. Not as detailed as the wideband, obviously, but more than good enough for basic trimming.

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Sad news today, after taking my sensor out at the weekend and recalibrating etc and it all seeming to work ok, today there was no sensor activity again.

I had to assume it had died a temperamental death.

Tbh I was slightly concerned that if the readings were out at all it was as good as broken anyway.

As such, I ordered a new one from euro car parts, managed it for £46+ vat in the end after some bargaining, which was ok.

Will get that calibrated and fitted then I want to do another WUE tune and will do another quick VE tune and then will remove the WB so I don't break it again!!! :o

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Is it necessary to run it with it in, does it make much difference?

Running with some sort of O2 sensor in means the ECU can fine-tune on the fly, which makes a difference to MPG on a run, but it's not essential.

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Yeah it was mostly handy for me to have the WB in cos I could watch my AFR on the motorway and back off slightly to get me into the late 14s/early 15s when sometimes I was gassing too hard unnecessarily

But the amount of fuel saved probably just cost me same in new sensor so I'm gonna use the advantage of new sensor for an accurate trim up on the VE table and WUE and then remove it and keep it safe on the shelf :D

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You can still do pretty much the same with a normal narrowband, that will always aim for 14.7:1 AFR (decent cruise economy), MS ignores it outside the given rpm/load/temperature ranges and just runs direct from the fuel map.

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Hi fridge

Thanks for help

Yeah I am tuned to 14.7 for cruising anyway for this reason i think, can't be sure but I don't remember putting any lean values on the AFR table

So could I use AFR tables with narrowband??

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So could I use AFR tables with narrowband??

No, as it basically behaves like an on/off switch that switches at 14.7:1, there's no way to measure any other AFR with it other than "when it switched, the ratio was 14.7:1".

A bit like your oil pressure light cannot tell you what the oil pressure is at any given moment - if you know the pressure it switches on at (say 10psi), you can say "at the split second the oil light came on, the pressure must've been exactly 10psi", and you can say the pressure must now either be higher or lower, but that's it.

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Right!

Just that without AFR tables how can the ecu be expected to attempt to tune to 14.7 on the fly?

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The ECU uses regular VE tables which equate to a fixed amount of fuel to inject at a given RPM/MAP, then fine-tunes by trying to make the O2 sensor voltage half a volt. It will, of course, spend its entire time flipping back and forth across that knife-edge, but when it's doing so it will be near as damnit 14.7:1.

The ECU uses the EGO correction settings to constantly do the folowing:

  • Look at O2 voltage
  • If it's more than 0.5v, apply -1% correction (inject 1% less fuel next time round), if it's more than 0.5v, apply +1% correction
  • Wait for the defined time/number of engine revolutions
  • Repeat

Note that 1% step is what I use, you can set it to whatever you want (and set a maximum total amount) in the EGO correction settings, but it's probably best not faffed with.

Here's a very old datalog snapshot of mine doing exactly that - the bottom trace shows O2 voltage and correction being applied / adjusted in small increments:

datalog_l2b_motorway.jpg

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Than you again fridge for the insight.

I have now fitted the NB again and set up tuner studio accordingly, one thing I did notice is TS interprets the NB sensor well and makes a determined effort to give a believe able AFR indication.

Anyway, the WB is tucked safely away in its box and we're ready for action.

Now I understand what the controller step size means!

Mine is set to step 1 and I'm back to max 10, was 20 for WB

All is well.

Pleasantly, beta version of TS has gps capability which I have now setup so I'm keen to get out on the road and see what it reckons my real time mpg figures are!

Cheers :D

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^^

"Megasquirt dilibrium Infection"

You've got it bad !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! :D

Nige

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[blackadder mode on]

I'm sorry, sam. I'm anispeptic, frasmotic, even compunctuous to have caused you such pericombobulation.

[/blackadder mode off]

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BUMP!

so I've been happily squirting for a few years now

the wideband sensor I bought from euro car parts did not work, equivalent part number sure, but no good.

i bought one in an innovate bag and it works good, just hooked up my wideband again so I can check out my tuning and see how things are

wouldnt pass mot last year on emissions so we had to use another vehicle, but the point is I'm interested to see what my current CO is and at what AFR, I am tuned to 13.5:1 at idle, im going to play around with dropping the ego control to 500rpm rather than the original 1100 to see if it will tighten up the emissions for the sake of a slightly more lopey idle

 

anyway the real reason for posting was I was picking up lambda earth on the spare socket on my relay board which would normally be used for fast idle valve, and during installing my wideband last night and Calibrating the heater I noticed I lost or perhaps even had no earth from the get go

 

after some head scratching I found a burnt link on the relay board

 

super easy to get around the problem, but just thought I would mention it so that folks don't make the same mistake in future!

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