MS2 goes lean on acceleration
 

Hi,

I have my MS2 with sequential injection idling great, used one of Braineaks base maps. Problem is when I give it gas it goes lean. its not as bad if I slowly up the revs. Its a 93 1.6, 265cc injectors, mini charger, dual throttle bodies, FMIC. EGO off.
I done a VE analyse of the first base map and then accepted the new table to get what I have attached. This map was based on very slow driving.
I hope this is just a setting to change in tunerstudio but which one?
msq attached.

Any help lads?

thanks

read WAY MORE.

You can either use atuo tune and this will fix it, or adjust acceleration enrichment, or just add fuel to the VE table.

Dann

sounds like you just have a totally untuned map.

presumably you have a wideband (if not, get one NOW)

run some logs, add fuel

rerun the logs, check fuel

you can't always rely on VE analyze to tune if you're just starting out.

The fuel table is grossly out of tune:
https://www.miataturbo.net/attachmen...1&d=1328974493
I ----- this pic all the time, but here's what my fuel table looks like, and your ultimate goal in terms of shape and general shape:
https://www.miataturbo.net/attachmen...1&d=1328974792
Get this thing road tuned, work on enrichments, then come back. If you don't know how to road tune, tell use now.

Thanks lads, I have a wideband installed. I did autotune it on the road. It was just a very short easy run. The results of autotune was generaly lower numbers than the base tune in the VE table. Maybe it selected lower numbers instead of higher because I was driving so easy.

I tried the base fuel table again and decreased acceleration enrichment from 2500 rpm down to 1500 rpm. now I get high 10s afrs when I boot the throttle. I logged the run and also ran autotune, which again suggested lower no.s in the VE table. I suppose autotune is no good to me.

Does anybody see anything really wrong with my logs. I obviously not an expert and dont want to blow the engine. Thanks

I'm new to this too but I think I can help.

What is your REQ_FUEL setting?

You have a spark map and an air/fuel ratio map. Those are pretty much fixed (don't touch them). You also have a VE map, a volumetric efficiency map. This is what your computer uses to calculate the fuel it needs to squirt in for any given RPM and load.

RPM is the X axis, engine load is the Y axis. The autotune only tunes the areas of the map that you are driving in. If you drive easy, it does not tune your whole map to be lean - it will tune the areas of your VE map that you are driving in. There are areas in your AFR map that should be lean (light throttle cruising). As you drive in those areas, it will tune your VE table so that you match the requested lean AFR. The areas that need to be rich, it will tune to be rich.

Go out and do some more autotuning. In the advanced settings make sure the cell change resistance is on Normal or even Easy for your first runs. Make sure overrun fuel cut is turned off (in the extended settings menu). Make sure the 'update controller' box is checked - this means the software will automatically burn the changes it makes as you drive. Drive the car normally. Start easy. As you drive you might be too lean or rich but the autotune will change those cells to put your air/fuel ratios back where the AFR table is requesting.

I think you're overthinking it.

I dont know how to road tune. I thought road tuning was driving the car while watching the afr on tunerstudio, then changing the cells to add/take out fuel. high numbers adding fuel. Is there more?

Did you say you autotuned during that log you posted above? If so, you didn't, because the whole run the autotune was running a filter - MIN CLT - if your coolant isn't up to temp (above 160) the autotune will not change any cells.

Thanks Steven,

I probably am overthinking/worrying about this.

My req fuel is 11.7.

I didnt want to check the update controller button as I read its not the best if you dont know if the new values are correct. I think I will try it though, if it doesn't work I will jsut reload the base map. I think i need to drive a bit longer too. I am only doing 5 min runs. Again being cautious.

Thanks again

Oops, uploaded wrong file, the correct file is too big to upload.

Thanks

Andrew, no worries. Someone might correct me on this but if your injectors are stock your req_fuel should be 13.

Check the update controller box and try it out. Make sure the car is warmed up and no filters are being applied (click Advanced Settings, any filters will be in yellow in the bottom right hand corner. if there is a filter running the autotune doesn't make any changes). You might want to set the minimum RPM to 800 to be sure it won't try to tune your 500RPM cells if the idle dips.

Just start by watching your AFR gauge, when I first started aututuning my idle AFR was about 13.2. Immediately the autotune pulled fuel and AFR adjusted itself to 14.6. You will see the numbers in the cells change red (leaner) or blue (richer). Drive around normally, going up and down through the gears. You should feel the car start to run smoother and smoother as you go.

I did two sessions like this before I started feeling confident about getting into boost but the autotune works just as well there. I have just been doing this a few days but I haven't had any pinging and my car has tuned itself quite well.

If you click back out of Advanced Settings on the autotune page you will see the cell weighting. In the top box, the darker cells are the ones you are spending more time in (the computer has more data to make decisions with). You want to try to highlight all the cells. This means low RPM low load, medium load, high load, high RPM low medium and high load, etc.

Thanks Steven, sounds like you are a few days ahead of me.

I have 265cc injectors, so slightly bigger than stock. I did my first autotune when the engine was warm at idle and noticed the autotune did improve the idle afr. I will try driving it a bit longer tomorrow with autotune on. Really appreciate your time to reply to this as there is nobody I know that is familiar with megasquirts in Ireland.

...and tune enrichments last.

I tune at a higher minimum CLT, like 180.

Ok, I have enhanced acceleration enrichments off. Is this what you mean.

I have the accel wizard set to 100% TPS and everything else in the accel enrich tab is greyed out

Thanks

are you using the oem 1.6 tps? if so that thing is useless for ms. it is non-variable and is just a on off switch. i have a 1.6 oem tps and i couldn't get the AE figured out last year before i put the car up for winter. i hope this thread turns out some promising info for me.

im sure someone more knowledgeable will elaborate more on what i just said

Hi, I have a variable TPS fitted. I think you should fit a VTPS before you start tuining.

However I did find that when changing the map I didn't configure the O2 sensor to wideband, the MTX-L gauge and the gauge in tunerstudio were reading the same values but I don't think autotune was getting them. When I selected wideband and burned to the controller the AFR's under throttle load dropped to 10-12s instead of lean. Result. So I drove the car a bit longer gradually giving it more throttle but then heard a rattle under initial WOT that dropped off as the boost dropped. I suspect this is knock, so I'm off to do more reading about ignition maps and how to cure this. Thanks for the help, this forum is brilliant.