Mentalbiker12

Just so everyone is clear. The table 3 stuff was already in and active from the guy that built the megasquirt. That is where the cold advance was at when we first powered up the megasquirt (I believe) also the wue was auto tuned to where you see it. The afr table was built for maximum mpg at the request of the owner. There has never been sounds of ping, knock or detonation the entire time we have tuned the car. So I'm just trying to understand why everyone thinks the car is going to blow. Our tuner initially did something to make the ignition table "hidden" so that people couldn't read it correctly but to my understanding we got rid of all that so that we would take that out as a possible issue. I already pulled back a lot of timing after I compared it to a base map table to help with the mpg issue we had in the beginning. You can see my novice mistake of making it linear but the car has always been running great outside of the warm restarts

Mentalbiker12

Also the long fuel pump prime was me trying to test possible solutions for the lean restarts while warm. I have not yet pulled those back

Injectors in the car are force flow and were flow tested at 620cc @ 43.5psi iirc. But the rail pressure is stock around 32? So we have them scaled at around 530 I believe. The car would not run at the recommended 0.63 ms dead time so I moved that up until they ran correctly. This is also an issue I have heard from other megasquirt users with these injectors as well with stock rails/regulator

curly

iTrader: (25)

Oh hell, you poor bastard. I just tuned a set of FF and WTF. Rail pressure should be 60psi, but if you do the req_fuel for that it won't run until HUGE VE table values. Especially with the recommended dead time.

And you're semi close, if you wanna make the drive...

Warm restart is pretty simple, up the hot WUE percentages.

Mentalbiker12

We tried that and it was still stumbling and running 17+ afr at warm restart idle until ego correction kicked on than it would settle out to stoich and 100% ego correction after about a minute

curly

iTrader: (25)

More WUE and WUE taper!!

Mentalbiker12

I'll give that a shot and get a data log once we crank those up. Thanks for the help curly. You've been awesome so far!!!

aceswerling

Cool. This is a lot of great feedback. Let's jump in. My responses are inline.

I'm running off fuel and spark tables 1. Even if it's activated, I'm not switching tables. Maybe I should disable the Fuel Table Switching?





I'm using the Flow Force injectors people recommended on here. It's the kit at Flow Force 610cc Injectors with PNP Kit for Mazda Miata ? Flow Force Injectors



My tuner said he had to back off some settings because my fuel pressure at the rail was lower than the injectors were expecting. I'm using the OEM regulator on a Vishnu rail. I asked about getting a new regulator to bump up the pressure but heard that wouldn't be necessary. Does that help explain the dead times?




Do you have a suggestion for what they should be instead?



I've autotuned WUE a couple of times and this is what the system came up with.



It's hard for me to comment on this since I don't know what it's supposed to be. I thought the fuel pump was supposed to run when the key is turned to the ON position.




We leaned out the AFRs in an attempt to improve fuel consumption. This was based on a recommendation in a whole big thread about that at http://www.miataturbo.net/prefabbed-...-expect-87066/. Are you objecting to the cells that are leaner than 14.7? I'm open to modifying those?



I've autotuned VE myself so I know it reflects the AFRs in AFR Table 1.



I appreciate your feedback and don't feel I'm in a position to comment on this. I'd like my tuner to jump in on this point.

Mentalbiker12

im completely open to using the spark table used in table 3, since im new to megasquirt i would like to understand this though, the crank trigger offset, would that change the way the ignition table looks? because i know on my miata im at 0* offset and Ace is at i believe 6* offset, will that change the required output of the ignition table and if so how?
i appreciate everyones help here, i know i could go to my shops tuner but between him being swamped and also kind of a hot head, bringing up this subject gets him going a bit so i have taken over to help get this situated

Braineack

iTrader: (62)

it depends on the physical rotation of the CAS. No two MS equipped miatas running off the CAS should have the same trigger angle.

the offset has to be tuned, once. All that number does is confirm to the MS that the spark angle it's demanding is the number you're actually getting.

the number means diddly-squat if it hasn't been tuned, you have know idea if 10° of timing actually means -10° or 32°.



the subject will get him really going when you tow a miata on fire into his garage and tell him to pay for the damages because he's a ******* moron.

Mentalbiker12

ok, so no matter what that is the offset has nothing to do with the ignition table readout? would you recommend we have ace run spark table 3? he will be coming down to the shop tomorrow so i can send him a new tune file have him autotune the fuel table until then, get some feedback from him tomorrow than go through and clean up his fuel table after the autotune has run its course

aceswerling

And if we change to use the settings in Ignition Table 3, do we need to change anything other than retuning VE?

I realize there's a lot of other stuff like WUE and ASE that we should change, but I'd like to know if there's anything else we must change at the same time so we're safe.

Braineack

iTrader: (62)

did i just read this?

It's running the most aggressive timing map I've ever seen posted on this site in the last 10 years.

I'm only guessing that it hasn't blow yet because you numskulls have luckily never tuned the trigger angle correctly and it's not actually outputting 30° of timing at idle like the logs show.

Braineack

iTrader: (62)

your tuner is dumb.

Flow Force posts their deadtime values on their own website:



using those values posted, and copying them into -/+ % values I get this:



so I'd plug those numbers in my tune like this (i put them in bank 2 so we could see the difference):




this curve is a lot more typical. I think the .63ms deadtime is aggressive, but you can always scale that up if need be, but the curve should stay the same. This will probably change your fueling through your tune -- if anything it will probably lean it out since it reduced the deadtime value and reduces the pulse above 13v (car should be running around 14.2v).


I'd highly suggest running the deadtime values quoted from the company, copying spark table 3 values to spark table one, disabling tableswitching, zeroing out cold advance, and then actually getting a timing light and syncing the trigger angle properly.

as far as WUE and ASE is concerned, these are the values I typically see in installs:




WUE really needs to be tuned once the fuel table is closer to perfect.

aceswerling

OK, folks I had a fun and interesting time playing around with my Miata yesterday. As always, I want to offer my thanks to Braineack for helping to fix my tune.

As suggested, I changed the injector dead time curve, started using the base spark table, turned off table switching, zeroed out cold advance, and then set the timing. The timing was way off, which likely makes it the root cause of all my issues. I don't know how far off it was because I had to physically adjust the CAS. Suffice it to say it was pretty far off.

I also set the AFR targets that were leaner than stoich closer to 14.7, figuring that we can lean out the mixture again if we need to. We'd leaned out the mixture based on suggestions received in my fuel economy thread. So it is reasonable to run leaner than stoich or should 14.7 be the upper limit for leanness? I'll be interested to see what my fuel consumption looks like now.

Of all of these changes, I was most surprised about the changes to the cold advance. Nate said those settings were came like that in Rev's base tune. Is timing advance not desired on cold start? I haven't had the chance to try, but I wonder how the engine will start with the current configuration when it’s dead cold.

As I was driving yesterday I noticed that the engine was going full lean when I let off the throttle. I don’t recall that it was doing that before. I also want to pay some attend to Accel Enrichment. I saw AFRs going lean when I hit the accelerator as I was driving to the shop today. I added a bit of AE and it seemed better on the drive back home but I need to check the logs on that.

Other than that, I think it’s a matter of retuning the spark table and then doing fuel. And then, of course, there are all the little driveability refinements. It’ll be very interesting to see what my fuel consumption looks like since we’ve rebaselined the tune.

How do things look to you all? I'm attaching the new tune file and a rather large log. The log was large enough that I had to upload it to Onedrive, where it can be downloaded from http://1drv.ms/1QWa1pc.

aceswerling

Here's a slightly updated tune after autotuning WUE. I'm still seeing a couple more issues and would appreciate your collective insight on a few more questions.

1. I'm still seeing a lean condition after warm startup. Last time that went away after enriching and lengthening ASE but I removed a lot of that based on suggestions here. Clearly I went too far. Would you be able to suggest something that would work better? I've uploaded a log file so you can see what's going on.

2. I'm still seeing engine speed drop pretty quickly off throttle, totally lean out, and then recover. Previously, the engine speed dropped reasonably slowly after I took my foot off the throttle. I figured there was some kind of dampening going on to make it drop so slowly. I looked for some settings in TunerStudio and searched the forum but couldn't find anything. Can you point me to some settings that will boost that dampening function again?

Mentalbiker12

when i tried tuning those injectors to those dead times the car wouldnt run, it may be from before i calcualted for the difference in rail pressure compared to the test pressure, so hopefully that is working this time around, its def upsetting to see my tuner made that mistake with the physical timing, his reasoning was that he sets it in the megasquirt but personally i dont like that idea, so im glad we found that. Ace, the lean out issue, is it when you let off throttle like when you push the clutch in? i remember turning on progressive fuel cut, and turning the delay to 0.5s, if you look under fuel settings/over-run fuel cut, you will see those options in there, see if they are still set up. as for the AFR table, leave them at 14.7 for now, and we will see what the economy is, it should keep pretty close to 30mpg highway like before, if it is, we will leave it be, under low load driving such as highway cruising a more leaned out AFR is completely safe, i cruise at 16.0 AFR on mine (non F/I) and was able to see 29mpg highway, just make sure this is only in the cruising range, any where else it can be a dangerous idea. on the warm restart, maybe we have the idle valve open to much? im no expert with this but its one of the things i have not messed with yet for the warm start issue. hopefully braineak will have some helpful input on this as this was one of the last things i was trying to fix (before finding out the timing was way off)

aceswerling

Were your changes to the injector dead time values the way you adjusted for the lower fuel pressure? Or was that done somewhere else? I'm wondering if we need to revert back to the previous dead time values.

Regarding the lean out issue, yes that happens when I'm driving, I press in the clutch, and let off the throttle. And yes, we've got progressive fuel cut enabled and the delay was .5 sec. I increased that to 2 secs in an attempt to address this problem but it's not making a difference.

Regarding the idle valve and screw, that's one of the next things I want to try. I asked the tuner in your shop about setting the idle screw on the throttle body and he told me the same thing, namely that he'd configure that in the Megasquirt. But we know that on a Miata, if the idle screw is set improperly then the idle valve is working all the time and it messes up a bunch of stuff.

Braineack

iTrader: (62)

id leave the DT value as it was, but use the updated correction curve. .6xxx ms just seems WAY too fast, especailly when you compare to what FI stats for their injectors.

Mentalbiker12

They way I adjusted for the fuel pressure was in the calculated fuel. I found a calculator online for difference in pressure and set injector size to the appropriated value I got which was somewhere around 530cc I believe

Braineack

iTrader: (62)

you mean like overrun settings?

I'd tune the idle valve some on a very cold day, with the idle valve set to the lowest PWM% (~25-30) you can still idle at around 600-700RPM or so.