My N/A 99' with MSpnp2 was running okay on the tune I established on the OEM injectors. This past weekend I installed a set of Flowforce EV14 (640cc) injectors and now I'm having a problem with it pegging full lean on throttle lift. Hoping to get some feedback to see if I've set this up correctly. I've adjusted the FUEL REQ using the average injector flow rate on the card I got with my injectors (I did try a couple different calculations based at the NB fuel rail being 60 psi (4bar), but it didn't seem to like the values I used) and I believe I adjusted the injector dead times and battery voltage correction correctly based off of the data over at the Flowforce injector website (I am using the 4 bar data as that's what I recall the NB fuel rail pressure being as it's a returnless system). It started just fine and after making adjustments to the idle cells in my VE table I was able to go out for a tuning drive, but when lifting off the throttle AFR's shoot up towards lean and I'm not sure what the problem is. It definitely happens during shifting and I am getting some backfire, burbling and popping from time to time.

I did not change anything from the previous tune and it's definitely not overrun fuel cut as it happens instantaneously (no delay - I even turned this off at one point). I also don't believe it's DECEL FUEL in the AE section, I do have this at 98 (as it was part of the base map I didn't touch), but I am finding it hard to believe that a 2% decel fuel cut would peg full lean. I also thought that maybe it was my 2 lower kpa rows on my VE table as they were originally very low (~40) and I raised them to about ~70 and it seemed to help, but could this be the issue? Could it also be a vaccum leak? I'm sure I put everything back together right, fuel injectors are seated good as I don't smell or see any fuel leaking and I did check the injectors for vacuum leaks. But I did not check the intake manifold or intake area, but a vaccum leak didn't seem obvious. Also could it be that I'm using the wrong data? That I should be using the 3 Bar data and not the 4 Bar? As mentioned above it seemed to like me using the flow rates on the FF injector card I got (for the FUEL REQ calculations) which are tested at 3 bar.

I've attached my latest tune, a quick idling datalog and a quick driving datalog that show my AFRs go lean on throttle lifts. Any help/input would be appreciated, thanks!

 

Someone went full retard on that tune.

MAP sensor settings are wrong unless you're running a separate sensor for baro correction.
It's currently set to run batch injection.
Your MAT values recorded in the log seem inaccurate. Make sure you tell it what temp sensor you're using.

What basemap did you start with?

 

Ha! That retard would be me.

I started with the DIY Autotune basemap (where I also received my MSpnp2 from). The Baro correction has always been set up for 2 independent sensors from the basemap and I've never changed that. Should that not be the case? Should I change this to initial MAP reading? Same thing with the batch (untimed) injection, that was on the basemap and I never changed it. I am also currently using the OEM IAT sensor which isn't in an ideal location (between radiator and front cam cover) and I know it is heat soaking like crazy, probably why my MAT values look out of place. My intention was to use this set up temporarily to learn MS while N/A and then switch over to the GM IAT sensor when I install my turbo kit. I do plan to take this to a pro tuner once it is boosted, but as mentioned I'm trying to learn MS and at least be somewhat familiar with it.

I'll definitely do some digging around here, I recall doing a quick search and seeing at least a thread or two that seemed similar to the issue I'm having, but I'm all ears for any feedback as well. Thanks!

 

Today I learned the MSpnp2 has a second sensor for real-time baro correction but your log sits at a steady 105 kpa so I don't think it's configured correctly. Definitely isn't right for Colorado.

I would set up sequential injection immediately.

 

Thanks for pointing that out and yep 105 kpa is not right for CO. I will say that I did change the BARO sensor (when calibrating) from the base map, they had MPX4115 but I switched it over to the same as the MAP (MPXH6400) since the footnote said that the BARO sensor is usually identical to the MAP. I think they may have had it set different for a reason now. I will change that and see how it affects things. Thanks!

I'm not 100% ready to switch to sequential injection, I've done some light reading but I'm not confident enough to make the switch yet. I've read that the NB is somewhat already wired up for sequential injection, but as mentioned I don't know what settings I need to change or what I need to do to get it to work (some old threads on here mention wiring in a module). But I do have some more HW to do regarding this.

Anyone have any feedback on if I set up the new injectors correctly?

As I mentioned, my understanding is that the NB fuel rail pressure is 60 PSI (4 Bar), the FF injectors are tested at 43.5 PSI (3 Bar) and based on this tidbit on the FF website "If your vehicle has a different fuel pressure, make sure you adjust for this! For example, a 640cc injector at 4bar of fuel pressure will flow at 739cc" I originally made some calculations using the flow rates provided to me ended up with something around 770cc that I inputted into the FUEL REQ calculation and if I recall the FUEL REQ was 4. The car started but it didn't like that very much as it was surging. I then changed the value to the average of the 4 injectors I had and ended up with a FUEL REQ of 4.7, it like that much better and no surging.

But I am using the injector dead time data from the FF website for 4 Bar, should I be using the data for 3 Bar since the FUEL REQ calculations liked the flow rates at 3 Bar?

 

Changed the BARO sensor back to the one that was used in the basemap, BARO values are correct now showing ~82 kpa.

Ok, after doing some more reading. Yes I should be using calculations and data for 4 Bar (60 PSI) for my NB. So thinking out loud:

• My AVG flow rate of all 4 injectors is 658.5cc @ 3 Bar. Calculations show that at 4 Bar, injector flow rate is 773.4cc. Using that # into the FUEL REQ calculations gives a FUEL REQ of 4ms.
• Based off of this thread here: https://www.miataturbo.net/diy-turbo...5/#post1314428 I should be using an injector dead time of 1.261ms and with a battery voltage correction of 0.160ms/V

My last tune had a variety of mixed information using FUEL REQ calculations at 3 bar and injector dead times at 4 bar + a mis-calculated battery voltage correction value. I made some changes today and re-tuned my VE table, but I am still experiencing the AFRs go lean on throttle lift. I did check for vacuum leaks around the intake, throttle body, intake manifold and at the injectors but it didn't seem to be any kind of vacuum leak. But all the "tuning" I did today may have been for naught as I am changing the values yet again. So I don't think it'll be of any value to post the current tune as the values are wrong.

Will do another tune session tomorrow with these new values and see what happens.

Everytime with the tuning... one step forward, two steps back...

 

Is it possibly misfiring when you let off?

The injector pulsewidth/MAP/VE etc is staying consistent when you lift, but AFR gets pegged lean. Also, I'd recommend going back to the basemap ignition table and not ******* with it until you know what you're doing.

 

You're also getting some seemingly random sync loss. You'll want to figure out why.

 

Don't believe it's misfiring, engine doesn't run rough or stumble in any way. I only slightly messed with the ignition map, mainly only making changes in the idle areas to 10 degrees and adjusting some of the RPM values, other than that I didn't want to mess with the ignition map as I for sure have no clue what adjustments to make. I'll change it back and see what happens with my new injector values.

I don't have the logs in front of me (and can't access them, but I'll double check), but if that's the log of me driving I was tuning while driving and making changes on the fly and burning (while at red lights) new settings in (turning overrun on and off, etc) so I'm wondering if that's what the sync loss you're seeing.

Once again thanks for all of your help and time!

 

Still going lean on throttle lift and at the moment I'm not sure what my next steps should be. Here's what I did today:

• Burned in the new FUEL REQ, Injector Dead Times and Battery Voltage Correction values using the 4 Bar data. Reset ignition timing map back to base map values
  • Adjusted the VE table to get it running as it was surging at first, ater that it started running fine
  • Still experiencing lean AFRs on throttle lift (FF Injector RevA.8 Idle.msl)
• I thought, maybe AE is causing issues so I tried some higher values (FF Injector RevA.8 + AE Adjustments.msl). NOTE: EAE is turned off!
  • I tried some lower values too, but it didn't seem to like that (no datalog) as it felt like it was hesitating to respond to any throttle response
• Got sequential injection running (FF Injector RevA.9 + Seq. Inj Idle #1.msl)
  • Felt like it was idling kind of high, thought maybe some bad CL idle parameters, change some of those (FF Injector RevA.9 + Seq. Inj Idle #2.msl)

The only thing that seems to be affecting this is the overrun cells (last two rows) in the VE table. My current idle cells are around 49, I tried some crazy high numbers in my last 2 rows, some as high as 80 (tune file uploaded in this post) and this seemed to help the issue in some spots. I am still pegging lean in some areas, but it doesn't seem to be lean for as long as shown in the datalog (FF Injector RevA.9 + Seq. Inj Idle #3 - High VE.msl).

Once again I checked for vacuum leaks although my check only involved spraying brake cleaner fluid around the intake, throttle body, intake manifold, various vacuum hoses I touched during the install and at all 4 fuel injectors. Any other suggestions or feedback as to what I'm missing?

Thanks!

 

I really don't think that particular issue is tune related. The injector is still flowing fuel. It's not like the ECU is closing the injectors when you see AFR drop.

Exhaust leak pre-o2 sensor?

 

Doesn't sound like there's an exhaust leak. I'll check that tomorrow, but I've looked into and figured out what the sync loss is but I have yet to figure out what it means. Looking over my last idle datalog, I don't recall changing any settings and doing any burns. Just idling and revving in place. It counts 5 sync losess, I revved it about 5 times. Maybe a coincidence, but the lost sync reason is 31 which according to this thread (https://www.miataturbo.net/megasquir...reasons-43775/) and the msextra manuals is "2 cams not seen" so I'll have to dig around what this means. Although I'm not sure how this relates to lean spikes on throttle lift.

Just some quick reading shows it could be related to the cam and/or crank sensor. Could be causing a possible misfire?

But it is confusing, some of my other logs I took today show 1 sync loss even though I revved it 4-5 times and the lean spikes still happen after each one.

Looks like I may have to take a composite log. Need to read more on how to do that.

 

I think I may have figured out what is the root of the issue! But I've yet to determine what is causing it and what the fix is. I BELIEVE IT IS AN ISSUE WITH THE PW/Dead Times.

1. It isn't an exhaust leak/vacuum leak
2. I don't believe it's related to the sync loss.
   • I'm not sure if I did a good job capturing the composite log, but I according to the date stamp I started (composite log #2) then I ran a datalog for (todays date - idle #1). It says it counted 4 sync losses, but the composite log doesn't show any? Maybe I didn't do this correctly? Maybe it didn't run long enough?
   • 
   • That does look correct to me, based on my research. It should read 4 crank pulses - 1 cam pulse - 4 crank pulses - 2 cam pulses then repeat

According to this post: https://www.miataturbo.net/diy-turbo...3/#post1311522



It appears that a ~1.7ms pulse width is about the borderline of what the FF injectors can reliably do. According to my datalogs after throttle lift PW drops well below the 1.7ms threshold, hitting as low as 1.4ms (datalogs attached).



If that is the case, then I have reason to believe that the PW's are dropping too low and in turn the injectors are shutting off. Which explains the lean spike, until PW's recover to ~1.7ms, then my AFR's return to normal. I'm not sure what is causing this? I believe I have the injectors set up correctly within TS.

Engine and Sequential Settings:


Injector Dead Time Settings:


As mentioned, the dead time values I pulled from this post (using the 4 bar data) from Nigel and he even mentioned to me that these values are good to use: https://www.miataturbo.net/attachmen...ine=1457509174



So what exactly is causing my PW values to drop? As mentioned, EAE and Overrun fuel cut are OFF. I tried using different dead time values as an experiment, going to 1.1 killed the car and it wouldn't start. Going up to 1.4 helped the lean spike but I was running rich (~12-13 AFR) which in turn I had to lower the values on the VE table to get to stoich, but then the lean spikes returned.

So I'm not sure what causing this to happen and what needs to be done to my tune to fix it as I am using data values that should be ok. I'll definitely do some more reading and research but some input would be greatly appreciated!

EDIT: FYI, I replaced the fuel pump (Denso) and fuel filter (WIX) earlier this year with brand new parts.

 

I looked at the original driving log again and you're right. It's like they stop flowing fuel below ~1.7ms PW.

You ask why your PW values drop and it's because they're suppose too. MAP in the teens, like the screen cap you posted, will do that. A random log of mine shows that a MAP of 11.4 kPa requires a PW of 1.20.


So the question shouldn't be why your PW is dropping. The question is why aren't your injectors able to flow any fuel at less than 1.7ms PW. I would probably measure voltage at the injectors and confirm that value matches what you see in TS. Definitely grasping at straws though.

 

I may look into testing the injector voltage. At the moment I don't feel like pulling the injectors out again (probably me just wanting to be lazy). I may try a few other things first. I'm considering re-calibrating my WBO2 sensor, even though I've already done it twice. My other option is to attempt to tune it out by setting a bottom row dedicated as an overrun row (~15kpa) and have the VE values there much higher than what I'm seeing at idle. According to this: How MegaSquirt(R) EFI Controllers Work the PW is calculated by

• PW = REQ_FUEL * VE * MAP * E + accel + Injector_open_time

Where:

• E = gamma_Enrich = (Warmup/100) * (O2_Closed Loop/100) * (AirCorr/100) * (BaroCorr/100)
  • Warmup is the warm-up enrichment value from the table the user enters in MegaTune,
  • O2_Closed Loop is the EGO adjustment based on the EGO sensor feedback and the EGO settings the user enters in MegaTune,
  • AirCorr is the adjustment for air density (based on the intake air temperature), and
  • BaroCorr is the barometric correction based on the ambient air pressure (usually taken at start-up, but a second baro pressure sensor can be added to MegaSquirt-II for continuous updates to the BaroCorr).

The REQ FUEL and Injector Dead times are constant, the MAP isn't constant but maybe I can assume (based on datalogs) that I know it will be around ~15 kpa in decel and maybe I can assume that Egamma may swing plus/minus 25% (at most?) based on corrections, then maybe I can calculate what VE values I need to maintain a PW that's >1.7ms on decel.

While I understand that overrun is there for a reason and you'd want your injectors to shut off during low loads to "save" fuel I just don't like the idea of my injectors shutting fuel off completely (or not injecting enough fuel) in between shifting gears. AFR's don't have to be perfect, but I think if I can achieve that with the tune I'll be happy with it for now until it gets professionally tuned.

Any input to my approach?

 

You shouldn't have to bandaid this. I'm not really understanding nigel's post where he says he doesn't get any flow below 1.7ms. That's the reason we have deadtimes. If 1.7ms isn't enough to get the injector to flow then I would think the deadtime has to be that high.

https://www.miataturbo.net/ecus-tuni...ad-time-56061/

Deadtimes vary based on the system they're attached to. You could try following the instructions in that thread and see what value you can come up with.

 

I've seen that thread and skimmed through it, but wasn't sure if I wanted to venture down that path. It doesn't necessarily give specifics on how to do this in MS, but I'll go over the thread some more and give that a shot tonight to verify the dead times. Otherwise I may only be left with my bandaid for my tune (unless others also suggest otherwise).

Thanks!

 

Have you tried a deadtime of 1.7ms?

That should keep the PW >1.7 any time you aren't in fuel cut.

It shouldn't need to be that high but it definitely looks like the injectors aren't flowing anything under that pw.

 

I have not. Highest I went up to was 1.4ms, I was afraid of going any higher than that yesterday. It might be worth to try as an experiment.

 

Collected and plotted the data for the "supposed" deadtimes. Ran 2 test and here are the plots:





Both PW values seemed within reason of one another (i.e: one wasn't .9 and another one was 1.5) so I assumed 2 test were ok and good enough.

I averaged the 2 PW values to try, BUUUUUUUUUUUUUUUUUUT no change. I've attached the 2 datalogs using the 2 different PW's, it still acting exactly the same. I can't say for certain but I felt that with the lower PW value it felt a little bit worse.

Ended up trying my bandaid fix and ended up around ~30+ VE values in my overrun cells and while it helped, it still pegged lean some areas, which most likely require some fine tuning to iron out the VE values I need... But as mentioned, this seems like a bandaid fix and doesn't seem the correct way to do things. I am all ears for any other suggestions as I'm not sure what else I should try.