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4.2 auto with ms2


mik711

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That's good progress but you're getting way ahead of yourself - auto-tune and WUE wizard are for when you've got stuff a bit more dialled in.

Also bear in mind that autotune works from the lambda (O2) correction, unless you've got a wideband lambda sensor it can't do anything useful around idle where O2 correction is (or should be) inactive. Narrowband O2 sensors work msotly like a switch so you can't infer anything much about AFR from them besides rich/lean:

O2_sensor_voltage.gif

First step is to get it running & idling OK, that will give you one corner of the map and you can extrapolate out from there.

Here's what mine (4.6) looks like when idling:

datalog_idling.jpg

 

REQ_FUEL is sort of the "master" amount of fuel, it's the number that everything else gets multiplied by to arrive at the right amount of fuel so changing that moves EVERYTHING up or down by a fixed amount - if you have it at the regular value (about 20) then you should not change it. I'm still wondering what tune your ECU came with, or if @Hybrid_From_Hell has a suitable tune he could send you for your engine. @Bowie69 might have something too?

Just for reference, very approximately (this image is a general one not Rover specific):

afrtable.GIF

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The ecu came from hybrid from hell along with everything else for the conversion. Idle seems fairly nice at the moment and I wasn't particularly happy going and altering req fuel as it's what he gave me. Req fuel is at 14.1 when I input the engine size.  I haven't altered the injector size from the original setting of 250cc but not sure if this is correct. Been looking and see them as being 200 or 250 depending on which site I look at. I have a NB lambda fitted but not using it yet as most people mention that it does nothing at tickover so it's switched off. Didn't realise that autotune needed it switched on to work. Will have a look at your ve map and see if I can compare and contrast with mine and extrapolate out. With the generic AFR table at the bottom of your reply, I've been floating around in the idle columns and in to cruise when I've been driving round the yard but obviously can't do much else with limited space. If I look at your ve bins and compare to mine I should be able to adjust the table (saving the original beforehand) and see if I can smooth things out and lessen the fuelling slightly. This will be my last message here this year and so I will wish everyone here a happy and prosperous new year and if sober enough tomorrow I will get back to the garage and have a play. Cheers everyone!

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If Nige supplied a map pre-installed then you should never have had to input the engine size or injector specs etc. as the map & all the other settings will be very close to right "out of the box" and you should only need to do fine-tuning once you've got the spark trim dialled in.

If Nige didn't supply a map then he's clearly slipping :rtfm: or the latest hospital trip has affected him more than usual :stretcher-smiley-emoticon:

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At work at the moment so can't check on the exact name of the pre installed map but pretty sure it says 4.2 auto in the title. In the general settings page it was set as 3500 cc v8 and injector size of 250cc. I altered the 3500 to 4200 assuming this would give me the correct req fuel. I left injector size as it was. Maybe I put it back to 3500??

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I'd put it back, sounds like a 4.2 may have been tuned with the wrong engine size as a variable, as such if you change it the maps will all be wrong.

Personally I'd just get it running using the proper settings, and map it myself with a wideband O2 (essential, really) and a lot of time, you will get better results and things will match your setup rather than a fairly rough and rich map supplied by Nige.

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Got to wait till the weekend now before I can get back to it but will see if putting it back sorts out some of the over fuelling I'm getting. The plan is to get to a point where it will pass an mot then tune on the road with narrow band first as that's what I got off Nige then depending on results may finish off with wide band. As an aside, I'm assuming that I would need to re tune if I connect the airbox back up to the snorkel at a later date. The snorkel I fitted years ago when it went to 300 tdi but no hard off roading planned now so don't really need it. (looks nice though)

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It probably won't care about the snorkel unless it's significantly restrictive, and even then it will only matter at full throttle / high RPM as there's not much air flowing in the bottom left of the map.

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Good to know. Think I'll leave it off for now and if I can work out a route for the pipework may re connect it at a later date. Will report back at the weekend with any results good or bad.

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