Help me not bork my tune/Why does my Miata stumble on tip-in?

So, this is a two-parter but they tie in together. Last year, I dropped a Rotrex-blown 1999 Miata 1.8L into my 1990 Miata and set it up running with Megasquirt, the MSPNP9093. I hadn't done any tuning with college and this engine was going to live at high RPMs, so I got it to run and drive at lower RPMs so that I could break in the new engine and clutch, then took it to a shop to have it professionally tuned on a dyno. They did a great job, but rather than use my laptop, their guy used his won personal laptop, so I don't have a copy of the tune on my laptop. Car was always a little cantankerous on cold-starts (took a fair bit of cranking, would pop and stumble a little before catching) and was a little unhappy at lower ambient temps (50s and lower) and would need to warm up, but just chalked that up to it being a standalone ECU and I don't drive the car in the winter, so I didn't bother. This year, around late May, it broke a blower belt (worn-out) and after I replaced it, the issue cropped up. Now, that bit might just be a coincidence. Now, when the engine is first started, if you tip in the throttle, it spikes the AFR gauge to 22:1 and stumbles and misfires and will stall as well, doesn't matter if it's free-revving or under load. It's better once it warms up, but it still spikes the AFR to around 18:1 and stumbles. Once you are under way, it cruises at 15:1, which doesn't seem out of the ordinary, and under full throttle it's right at 13:1, maybe a little richer near redline, which also seems right.

I did call the shop that tuned it, because they said they offered 1 free recalibration if anything felt off with the tune. They said that they didn't feel the issue was with the tune and I had something going on mechanically. I've put new NGK sparkplugs in (the ones recommended by Track Dog with their kit), new NGK plug wires and a new fuel filter as maintenance already. The shop suggested a fuel pump, but that's a relatively new (1 year, ~10k miles ) Walboro, and it seems like a fuel pump that's dying would be fine down low and lean out up top. They also suggested injectors but they were replaced at the same time as the pump when I put the engine in and are Deatcshwerks 700cc injectors, so not some cheap eBay garbage.

I'd like to try going in and just adding some fuel to the tune where the stumble is to see if that helps. The issue is, when I hook my laptop up, it alerts me that the tune in the ECM does not match the tune in my laptop. It then offers to fix the difference by putting the old janky break-in tune from the laptop into the ECM. I don't want to do that. Seems like there should be an option to take the tune from the ECM and put it in the laptop, but I can't seem to find it, and I'm wary of losing my good tune and then having to shell out to have the car retuned. How do I access what is in the ECM?

Also, is there something else I am missing that could be causing the issue? My only other though is that maybe the coolant temp sensor for the ECM is flaking out and reading high, which is why it runs better when hot. But that's the one on the back of the engine that's a bit of hassle to change, so if I could solidly determine of that is or isn't the cause before I go through with that, that'd be nice.

Sorry this is wordy.

It's been a little while since I had the laptop plugged into our NA, but IIRC, when you open the software select to use the tune in the MS.  Once you're there, you should be able to "save tune" or "save tune as" in TunerStudio to save it to your laptop.  Then you'll have a copy of the current tune for backup.

To access the tune that's currently on the MS, when you plug it in and it offers to write your tune to the MS, hit No. Then it will load the tune that's on the MS into TunerStudio, and then you can save it as usual.

In reply to NickD :

My rotrex 1.6 miata engine'd exocet's low speed tip in sucks too.

Also low-speed tip-in is in general one of the hardest tuning problems to solve. Automated AFR-based fuel tuning tends not to work so well in that area of the map. Fixing it is either a guessing game or a black art depending on how much experience you have doing it...

Can't help with the MS software question, but I'd want to see a log of the problem happening if I were trying to tune it out. It sounds like you have a temp sensor that's not reporting properly for the cold warmup problem.

Cold starts and idle compensation are the hardest parts to get right. Don't accept it, it's what sets a well-tuned ECU apart from a poorly setup car. Cold starts are hard because you only get one or two shots at it per day, but poor running when cold should be a lot easier and will help cold start.

No reason why a Rotrex should have tip in problems. There's probably an accelerator pump analogue in the MS software, that seems a likely place to start.

Keith Tanner said:

No reason why a Rotrex should have tip in problems. There's probably an accelerator pump analogue in the MS software, that seems a likely place to start.

MS has a wide range of accel enrich options, but it's more likely that this isn't an accel enrich problem - if it was, there would be hesitation or detonation when stabbing the gas in a wider range of load and RPM conditions.

I also think it's more likely a tuning problem than a mechanical problem.

So the issue is warm up and transient fuel.  They should be separate, and the only reason they are "hard" is because nobody does them.  

Once you get the tune, use your WB on every single start, and just record it.  Then learn what MS has for each compensation.

I'd start with doing the cold steady compensation as best you can and the warm transient fuel- once you get warm 100% right, then you can start doing the cold adjustments.  

The real key is to understand what to change when:

1) rich immediately, lean after

2) rich immediately, rich after

3) lean immediately, lean after

4) lean immediately, rich after.

Those are the 4 general transient fuel situations- where the first part is an indicator that the mass component is too high or low, and the second part is the time constant- whether the compensation is too long or short.

The real key is that you just to got to keep doing it and doing it.  This is the long term development part that really makes cars drive really well.

And it is the tune, btw.  If it runs well warm, then it's unlikely that something broke- its just that the cold and transient compensations are not done.

I'll be happy to help, and do it here.  This is something I've done a lot- but I'm not familiar with MS, so that will take some study.  Did GRM make a spot where we can share files?

Sounds like you have the experts here, but I've got some experience tuning accel enrichment and cold compensation with my Miata using a Megasquirt as well. As others have said, don't just accept it. Once you have your tune loaded, some things that helped me...

* Make sure your coolant temp sensor is accurate, like Keith said. Tunerstudio can show you what it's reading.

* Disable EGO (closed loop fueling) while you try to figure this out, as it could be compensating for bad baseline fueling. You have after-start and warmup enrichment to play with. The more accurate your base fuel tables are, the better EGO will work when you're done

* Accel enrichment is where you want to spend your time after you have the base fueling figured out. Get it working nicely when the car is warm, and then you can mess with the Cold Accel Adder and Cold Accel Multiplier

I'm partially wondering if the new blower belt is partly to blame. When I put the blower kit on, TDR sent me the wrong belt and I was on a time crunch so I grabbed one from the local parts store that was the cheapo store brand and I always struggled to get to stop squealing, and that was what I had it tuned on. Then when it broke this year, I put a Continental belt on and that belt has gripped much better. I wonder if the old belt took a second to grip up on tip-in, and this one isn't slipping and now I'm getting more air on tip-in, causing the lean spike.

It does kind of irk me that the shop that tuned it basically blew me off. They told me when I got it tuned that I got "one free recalibration if the tune ever felt off." So after spending time doing mechanical diagnosis to needlessly harass them, I called them and he goes "Oh, well it was only if it happened in the first 12 months. You're just outside that." Explained the issue had cropped up earlier and that I'd been troubleshooting. Then he goes "Well, I want to make it right. What's it doing?" I tell him and he goes "Oh, that's not a tuning issue, that's mechanical. Probably fuel pump or injectors. Good luck."

My buddy said to email him, he is a MS GENIUS.  Linuxman51

At the mail that starts with g .com

Guys from Sweden get tuning advice from him about Volvos!

In reply to NickD :

The only way a better belt would be a problem is if it's now operating in an area that wasn't calibrated before.  Otherwise, the change in MAP is being measured, and it does not care how you get it, just as long as you get it.

For the MS tuner out there, is there a term about target a/f that is always running, and a term for the actual injected a/f to match that target?  I realize there's a measured term if you have the WB sensor.  The combination of the 3 of those if what you want to tune this.  Actually, does anyone have a list of ALL the a/f related parameters that you can record when tuning the MS?  Just record them all- including all the various compensations.  Nick- don't worry about getting too much data- just take as much as you can.  From start to fully warmed up, making sure you get the exhaust a/f on before you start.

The way most Miatas are tuned on MegaSquirt is with time-based accel enrichment- a function of throttle speed (TPSDot) and time. So, with a change in TPS velocity, a finite amount of injector pulsewidth is added to the amount demanded by the base fueling equation for a certain amount of time (on the order of 200ms). 

Section 12: http://www.msextra.com/doc/pdf/html/Megasquirt3_TunerStudio_MS_Lite_Reference-1.5.pdf/Megasquirt3_TunerStudio_MS_Lite_Reference-1.5.html

If OP is suddenly getting more air on throttle tip-in, that curve would need to be adjusted upward to compensate.

Another annoying feature is that most MS ECU's disable power to the wideband when cranking... which makes diagnosing start issues super fun 

morello159 said:

Another annoying feature is that most MS ECU's disable power to the wideband when cranking... which makes diagnosing start issues super fun 

That's a really easy fix, that's a matter of hooking into the right switched power.

Keith Tanner said:

morello159 said:

Another annoying feature is that most MS ECU's disable power to the wideband when cranking... which makes diagnosing start issues super fun 

That's a really easy fix, that's a matter of hooking into the right switched power.

The issue isn't only jsut on startup, it persists for a good 10-15 minutes after starting, basically until coolant gets to operating temperature. Which makes it a bit easier for diagnosing, if a bit more irritating.

alfadriver said:

For the MS tuner out there, is there a term about target a/f that is always running, and a term for the actual injected a/f to match that target?  I realize there's a measured term if you have the WB sensor.  The combination of the 3 of those if what you want to tune this.  Actually, does anyone have a list of ALL the a/f related parameters that you can record when tuning the MS?  Just record them all- including all the various compensations.  Nick- don't worry about getting too much data- just take as much as you can.  From start to fully warmed up, making sure you get the exhaust a/f on before you start.

Yeah, I need to hook in and even see what the options are. I haven't been hooked up to it since May of '18, and even then I was barely scratching the surface. I was just tweaking timing and the regular fuel tables to get it so it ran and drove to put miles on the clutch and engine

NickD said:

Keith Tanner said:

morello159 said:

Another annoying feature is that most MS ECU's disable power to the wideband when cranking... which makes diagnosing start issues super fun 

That's a really easy fix, that's a matter of hooking into the right switched power.

The issue isn't only jsut on startup, it persists for a good 10-15 minutes after starting, basically until coolant gets to operating temperature. Which makes it a bit easier for diagnosing, if a bit more irritating.

Understood, but there's no reason for the wideband to power down during cranking. This post was not a diagnosis of your specific problem but a reply to morello15's comment.

All- which MS is the MSPNP9093?  I see that the tuners change for the various kinds of MS's out there.

In reply to alfadriver :

It appears that it should be either an MS3Pro or an MS2:

https://www.diyautotune.com/product/megasquirtpnp-g2-mm9093-for-the-90-93-mazda-miata-manual-trans/

https://www.diyautotune.com/product/megasquirtpnp-pro-mm9093-for-90-93-mazda-miata-manual-trans/

TunerStudio should work just fine for either and provide a more standardized interface:

http://tunerstudio.com/index.php/tuner-studio

It is an MS2, I'm pretty certain. Like 99.9%

NickD said:

It is an MS2, I'm pretty certain. Like 99.9%

Oh, man- after looking at the MS3 version, I wish it were that- it has X-Tau transient fuel, which is really good.  Still, once you work through the "adhere to" and "suck off" wall stuff, you can tune the crap out of transient fuel, and it will run great.

And it would be great to keep it a live thread, as others will benefit by the tuning effort.  This is the part that takes a long time in my environment.  Between it and the emissions development- that's the 1000's of hours that goes into the real development of your cars.

Either way- if there was a way that we can commonly share files- if you do manage to download the base file, post it someplace, and take some data, and we can all help.  

I wonder if this would be a good Wed subject for one of GRM's live streams.  After we get through some development.

NickD said:

I'm partially wondering if the new blower belt is partly to blame. When I put the blower kit on, TDR sent me the wrong belt and I was on a time crunch so I grabbed one from the local parts store that was the cheapo store brand and I always struggled to get to stop squealing, and that was what I had it tuned on. Then when it broke this year, I put a Continental belt on and that belt has gripped much better. I wonder if the old belt took a second to grip up on tip-in, and this one isn't slipping and now I'm getting more air on tip-in, causing the lean spike.

 

It does kind of irk me that the shop that tuned it basically blew me off. They told me when I got it tuned that I got "one free recalibration if the tune ever felt off." So after spending time doing mechanical diagnosis to needlessly harass them, I called them and he goes "Oh, well it was only if it happened in the first 12 months. You're just outside that." Explained the issue had cropped up earlier and that if been troubleshooting. Then he goes "Well, I want to make it right. What's it doing?" I tell.him and he goes "Oh, that's not a tuning issue, that's mechanical. Probably fuel pump or injectors. Good luck."

Wow. What a joke. That'd be a bad review from me on whatever your favorite review site was..... 

alfadriver said:

I wonder if this would be a good Wed subject for one of GRM's live streams.  After we get through some development.

Yes.  

Had some free time tonight and hooked my laptop open and went to open TunerStudio and got an error message saying "Unable to get upgrade, please try a manual install." I had this hooked up about a month ago and didn't get that issue. Tried an uninstall and reinstall, same deal

Tunerstudio is trying to update itself and failing.  You should be able to bypass that error and use what you have installed.

It has nothing to do with your MS install and entirely to do with the back end pieces they use on EFIAnalytics website to provide updates automatically.  Sometimes these can get overloaded, etc. if a new version or update is released.

You can likely solve this by downloading the latest version from their website (make sure you have your registration info handy), installing and entering your info.

Phil aka EFIAnalytics is pretty responsive to help requests if you drop him a line via the web, FB, MSExtra Forum, etc.