Megasquirt MS1 - Another tuning help request post..

[Fatboy]

Gents,

I.m really struggling with this... it seems to be going great for the first few minutes and then whilst autotuning at "cruise" speeds, throws a wobbly... then runs like a pile of junk.

I'm only tuning AFR about 1000rpm.

I've gone back to the original NB lambda, because it had been doing okay on that, now it does the same with it.

Something that has been bothering me - What should the lambda voltage be with the Megasquirt powered but the engine off? I'm getting 0.2V on the NB and can't see where to calibrate it.

[Fatboy]

That post above should have said "I'm only tuning above 1200rpm"..

I loaded a map that had been working and tried again, the VE figures were going mental and it did same again, loads of fuel and had to pull over, reload the map again and abort tuning to get home.

I tried moving the lambda earth from the redundant Fast idle relay terminal to the main Earth on the relay board, no difference, still 0.2v with no engine.

My amateur theory was that if it is wrong, the 0.2v could thrown the tuning out..

[Dave W]

There isn't a calibration for the lambda sensor however the fact that it shows 0-1v in the lambda meter in TS suggests you've not set the lambda environment settings up correctly to match your WB lambda. I'd get that right before you try anything else. Remember that the ECU also needs it's settings updated to support WB so make sure you are saving the settings to the ECU when you make your changes.

Remember that when you load/save the tune (.msq file) you are also saving all the Lambda settings that the ECU is using, if you revert to a tune that was saved using the NB sensor then you'll lose all the changes to the WB sensor. This is often overlooked if you are so focussed on the maps and forget that loading/saving them can wipe out changes you made other than in the VE tables.

Don't bother trying to autotune if it's not displaying and recording data correctly because all you'll end up doing (as you have been) is chasing your own tail. MS installations need to be done methodically and one step at a time. You need to take the time to get the basics right, make sure all the values, including lambda, are displaying as you'd expect before letting autotune loose on your maps !

0.2v doesn't strike me as an issue, as long as it changes when the engine is running. Remember that the lambda sensor is measuring oxygen levels, thankfully normal air does contain oxygen !

[Fatboy]

Dave,

Thank you. I went back to the NB and the last good map, which was with the NB. I had checked settings in the settings, and in the EGO, all okay.

Very good point re the Lambda measuring O2, I hadn't twigged that! Air contains 20% oxygen so it's probably okay....

[Cheesy]

There is a calibration procedure for the Spartan system, the controller outputs 2 voltages during the sensor warm up that you use to alter the values in the ECU

[Rangie46]

have you calibrated the wide band in fresh air? on my lc2 you have to calibrate the sensor in fresh air before fitting and tuning

[Quagmire]

Spartan2 doesn't need free air calibration, as it uses the later LSU 4.9 sensor, instead of the 4.2 sensor. You do however need to check for voltage offsets as per Cheesy's post above to make sure that the voltages MS sees match what it is expecting see.

[Fatboy]

NB sensor in, map from a couple of weeks ago loaded, EGO step set to 0, runs quite well... (EGO set to zero should mean it won't self-adjust...?)

I am wondering if I've screwed up the AFR table and thats whats causing the deterioration when I try autotune... and my lack of familiarity with it all has me in the dark somewhat. I've googled and read the manual, but not found any clear guidance.

So... when I was trying to narrow band tune, me EGO Control settings were:

With the NB, and Controller Step Size set to 1, the VE Table figures change which I assume means it is trying to home on on AFR targets from a reference. Indeed, on the VE Table, if I double click on a cell, it tells me how many times that cell has been hit, and what its target AFR is. The bit I can't figure out is, where is it getting the AFR figure from, because I had the AFR Target Tables' boxes both off:

Then, if I do turn the "For VE Table 1" box on, and view the AFR targets, I get:

The AFR Table displayed in VOLTS! ..... Is there some way that I need to convert my target AFR's to volts? This is where I think I may have made the error before, I might have input targets without noticing the table was in volts, thus was asking it to look for 14.7V etc, which might be why it tipped the fuel in..

Thanks for any tips / pointers you can give.

[Fatboy]

Nobody got any thoughts or advice?

[bodumatau]

hey fatboy, I too am struggling to get my head around all this.

I think the AFR table is voltage from your TPS, so that the ECU can calculate your TPS position, relate it to your MAP and AFM and fuel given from your injectors and with all that info figure out a good VE table for you.

one thing I did learn on Saturday is that your exhaust system has to be in good form when auto tuning, one of my connections (directly behind my Y-piece where my NB Lambda sensor is) came apart during an autotune drive and TS autotuned it so rich it wouldn't run anymore..... after fixing the VE table manually I tuned it on the way home again (after bolting the Zorst together again) and she was running fine by the tie I got home.

I am fiddling today trying to get my startup better and once that is done and I have done a tuning run I will post my current settings, maybe you can glean something from them.

[Bowie69]

Noooooo almost completely wrong.

Don't have time to write this up, bit it is all in the mega manual -where I it from.

[FridgeFreezer]

As Bowie says, some wrong ideas in that post but you are bang on about the exhaust system: if you think about how Autotune works you should be able to see that unless the sensor reading is reliable, the whole thing is pointless. As air contains 20% oxygen, any exhaust leak is going to totally screw the pooch on that. Likewise, any damage to the sensor, clogging up or dirt from burnt oil (seen that) or over-fuelling (seen that - for example one sticky injector will tilt the whole thing) or from the sensor/exhaust getting cooled down by splashing through puddles (had that happen to me - don't auto-tune in the p***ing rain!)...

It goes for anything really - megasquirt is a basic system, it only uses a few measurements to calculate the fuel, but if the measurements are thrown off by dodgy sensors or mechanical problems then you are on a hiding to nothing. Always sort out the basics, including ANY mechanical issues, before you think about trying to tune it. The good news is that MS 1 is basic, so when something's not right it's not too hard to spot and the ECU isn't going to do anything clever to try and compensate for it - the rules don't change, and that's really helpful when fault-finding.

I'm sure those of us who've played with MS (or indeed other EFI systems) could reel off many examples where a "wrong" result was actually caused by something simple back up the line.

[need4speed]

Noooooo almost completely wrong.....

There's my diplomatic Bowie!! Lol

[Bowie69]

They did offer me the job of foreign secretary, but decided to go with someone that had a softer tone

[bodumatau]

good thing then that I am wildly changing values in my MS without having a cooking clue whats going on......

bit of Jeckel and Hyde and hoping Frankenstein comes alive....

off to tamper some more, if you hear a far off THUD of an explosion then this might be my last post ......

Bowie?

"where I it from?" ...... is that english? ..... I have an excuse as I come from the colonies, I am allowed to make grunting noises and expect to be understood......

[Bowie69]

Typed quickly -'where I got it from'.

[Fatboy]

Well, over many months I've tried to understand the manual, I've done a pile of googling and burnt a bucket of fuel. I've tried to avoid troubling folk with questions that may be simple...

I'll get back to the book.

[bodumatau]

fatboy, the manual is written by people who understand electronic injection and know whats going on FOR people who understand electronic injection and understand whats going on.

Newbies like us just have to bump our heads till we see the light.......

Bump

Ow..... it hurts......

Bump

[Bowie69]

Less fiddling, more reading.

Yes, EFi is confusing, so you do need to spend time learning it, and the way to do that is a combination of reading and practice.

The AFR table in volts is an issue, there is something fundamentally set up wrong, and once you get that sorted, the rest will fall into place but.

Again, read the megamanual or other tuning guides, and the TS help files are also great.

[Quagmire]

Am posting from phone so forgive any typos.

Fatboy- you have auto tune ("ve analyse" or "veal" for short) confused with the exhaust gas oxygen control, they are slightly different things.

Veal is for tuning your ve table and homing in on values that allow you to hit the target AFR you have set. A couple of things to note about tuning with veal:

The ve table is the fuel needed at steady state conditions, when tuning try to move into an area of table and hold it there for a few seconds. this can mean holding onto gears longer than usual, driving at 10mph in 5th or other generally weird driving to achieve this.

Try to always tune at the same ambient air temp. If you don't you will find it changes the table every time and you end up chasing your tail. Get it dialled in at one air temp,and then alter the other corrections (I forget what they are in ms1 for now) to get decent correlation at others temps.

Don't tune with a leaky exhaust (as fridge said) and don't tune in torrential rain.

Be aware that too much fuel can read as too little. A misfire will cause a lean reading as the oxygen in that combustion event didn't get burned and gets seen by the sensor. Use what your lambda is telling you combined with what your nose says.

Ego control is to be used when you are happy with your ve table and have finished using ve analyse. The job of ego control is to "trim" the fuel settings on the fly to keep it in line with your afr targets. Settings made by ego control are not permanent and it doesn't change the ve table.

With a tuned ve table, and decent air temp corrections you should find that ego control only adds or subtracts a couple of percent of fuel when driving.

For now I'd disable ego control by setting authority to zero and just get the veal tuning sorted. Easier said than done with the temperatures we are having at the mo!

[Fatboy]

Thanks for the tips Jamie, some more stuff I hadn't realised there! I'm tied up with work stuff this week, hopefully I'll have another crack at it at the weekend.

[FridgeFreezer]

fatboy, the manual is written by people who understand electronic injection and know whats going on FOR people who understand electronic injection and understand whats going on.

Newbies like us just have to bump our heads till we see the light....

Unfortunately this is the curse of our times - at least there is some documentation! MS suffers from being the jack of all trades, so there are a million options on how to set stuff up, how to tune it, etc. etc., if anything there's too much info out there, and most of it won't apply to your setup.

At its core it's a simple system, doing one very straightforward calculation ("how much fuel now?") based on some basic info from sensors. That calculation is written down in the megamanual but good luck finding the page

[lo-fi]

Why insist on messing with the auto tune thing?? I've done a bunch of MS installs from highly modified K series to turbo BMW engines, all tuned manually. I tried auto tune once, decided it was a time wasting gadget and never touched the thing again! More trouble than its worth, especially of you don't know what you're doing to start with. Really isn't hard to sit there with someone else driving while you watch the wideband lambda readout and play with the VE table. Even better on a rolling road with steady state...

My advice, as someone who done this many, many times, and for what it's worth:

Get your static timing right and set up your spark timing table before ever messing with the fueling. You can make a good starting spark map by understanding what a dizzy does.

Get the engine started by modifying the req fuel value - you can trim later and globally modify the table and if the VE values are insane.

Tune the no-load parts of the map on the driveway. Hopefully before attempting this, you know what AFR you're looking for in the various parts of the map, right? If not, do some more reading. Not just the MS manual! Try to remember that what you're "mapping" is air flow for a given manifold vacuum at a given RPM. This is what's calculated.

Get a mate to drive. Turn off acceleration enrichment, start off gently, and tune the lower rev, lower load part of the map. You'll want steady, slow runs up the rev range and nice slow throttle movements. Third gear is good because you won't end up going too fast, and you can get some load on without the revs shooting up too quick. Keep eyeing the lambda readout as you hit different bins and adjust accordingly. You'll soon get a feel, and can often figure out what adjacent bins will want before you ever get there. Keep running up the rev and load ranges, and you'll soon (about an hour) find you've built a solid map. Remember, if you change the timing map (pinging, hunting or just trying to optimize), you'll find you need to tweak the fuel map again in that area.

You'll learn far more doing it mannually, and can have the mapping done by the time you've finished fiddling about configuring that abominable auto tune!

[Bowie69]

To counter that, I find autotune excellent, and found the mega log viewer method before that very good too.

Once you have the software set up properly, which is all the problem above is, then you just drive and let it do its job.

[Quagmire]

+1 for auto tune and wideband.

Not slating lo-fi's post at all, he has a point about learning more by doing things by hand. I have found veal to be excellent, You can go from a car that basically idles to one that drives pretty well across most of the map (the corners can be hard to reach) in less than half an hour. It's especially handy if you don't have someone to take out with you tuning.

The biggest problem is that like any automatic system junk in= junk out. You need to make sure that your hardware is all working well, good sensor readings etc, and that your settings and targets on the software side are OK. If not then you'll end up going round and round and never get an acceptable tune.