Shaking violently and feeling gutless tells me it may not be running on 4 cyl. On 1.6s you can reach the injectors while running. Disconnect one at a time while idling. Do they all noticeably decrease the idle?

 

First of all, Thank you for helping me, this problem is driving me crazy…

In these days i tried a lot of things:
- check Ignition table
- set dwell to 5ms
- lowered spark duration (for what i’ve read online, the stock ECU 1.6 spark is 0.5ms with 5ms dwell correct me if i’m wrong)
- slight adjustment to Injector dead time and curve, based on the stock 1.6 Blue injectors
- fixed AFR table and VE (i was running 80% on Fuel VE table in idle with 13.5 on the afr table but the afr reading was still super lean. After i modified the inj dead time it all got set properly)
- fixed cranking engine backfire with lazy fuel priming
- tuned the accel. Enrich

but none of them solved the problem.
apparently it doesnt matter if i’m running lean or rich, with more advanced or retarded timing. The engine keep running like ***.

i honestly don’t know what to do. I’ve red online that this problem may be caused by a bug in the MS firmware so today in going to reload a fresh firmware and see if solves this demonic problem.

 

Im going to try also this today as soon as i get home. Thanks!

 

Tried a bunch of things today:

- checked injectors (all cylinders got fuel)
- checked sparkplugs & coils (all cylinders got spark)
​​​​​​- checked fuel pressure regulator (cause i plugged the MAP vacuum Line to that)

everythings works fine. But the problem still there.

btw, i’m not using a vtps (so i have the stock miata 1.6 1990 useless one). Can it be the cause of this problem? I mean, besides of the hesitation at WOT (that i still got cause i need to add more fuel per MAPdot), is there some other options that i need to change for maybe excluding tps and only using MAP?

 

No other TPS settings I can think of off hand, except CL idle activation, but you're still open loop.

I actually took some time to look at your log and tune today, you're running extremely lean, especially in the partial throttle stuff, which I think is all you're trying (since it's running like ****). Try big changes first. Start by saving your current tune as "original", then save again as "experimental", or similar. Never edit "original", and if "experimental" is every completely undrivable, go back to "original". Take your entire fuel table from 2150rpm column to 8000rpm, and multiply by 1.3. That will add 30% fuel. Take another log when you blip the throttle a bit, if it's still running 16 or higher AFR, you've got some other issue. Another way to do this is to give EGO a large authority, like 10-20%. Hold the engine in each RPM column, and look at the EGO correction factor. If it's 20%, multiply that column by 1.2. You'll only be able to hold one load row, but it might give you an idea of how far off each column is.

That or put VEAL on "easy", and go for a drive. I still can't tell if you have a fundamental issue with your setup/MS, but if it's firing on all 4, I can't tell what else. Your lack of VTPS will start to hold you back, I'd look into upgrading asap. Only other thing I see in your log is an weirdly steady MAP signal. I'm used to seeing a couple blips here and there at idle, yours is rock steady.

 

Thank you for your precious advice!
Today im going to try this method hoping to get some knowledge for the problem.
For the weird MAP signal do you know why it looks rock solid? (Im using the vacuum line provided by the DIYAUTOTUNE ms3pro kit hooked up to fuel pressure regulator with the T adapter, tried switching hooking point and it looks the same)
I've also got me a VTPS kit so maybe it will help, tomorrow i'll get it installed to my sick miata.

BTW i think i need to give you some more details about what i mean with "engine runs like ****"... Basically at minimum (850/900 rpm) it sounds and shakes like a bloody helicopter, when i increase the rpm to around 2000/2300 it shakes a LOT and i can feel all the plastics squeaking in the cabin. Also, if i blip the throttle the exhaust sounds just like a straight piped Subaru...
When i went out for a drive this problem got exponentially bigger, making it impossible to drive. Today maybe i'll try to do another lap cause since last time i've changed a lot of stuff. I will provide you the log and maybe i'll upload a video of it.
Thank you again for your time!

 

Have you made any changes to your fuel table since last week?

 

update: nothing has changed...
i've played a lot today with my air fuel mix and i can tell that it's not the problem.
it doesn't matter if i add or remove fuel, it doesn't change! I tried to go super rich (11:1) to super lean (19:1) with all the tables... obviously i hear the engine suffocating by to much or to little fuel but the idle ALWAYS "grumble" like sh*t.

i've done a quick video of the idle with a little increase of the rpm, you can find it here: (Please consider that the video is representing like the 20% of the real sound and shake)
Also im attach my updated map and the latest log.

Thank you!

 

Thanks for this info, I had thought you meant it idled well, but not once you were on the throttle.
This behaviour means your timing is way way off, or not all of your cylinders are firing.
So go back to Curly's advice to pull one plug wire off at a time and see how things change.
Is it one cylinder or any of them randomly, that don't fire? That will be important diagnostic info.

 

Thanks for the reply!
That's strange! cause for the timing i checked with a screwdriver in the 1st cyl and when it is at TDC it alligns my pulley mark with the T... i also kinda have a mark (like a white scratch) the complete opposite angle of the pulley but i don't think that the engine can run with like 180° of allignment difference... the thing is that the timing belt got replaced by the previous owner and maybe it could be mounted in the opposite way but as i said earlier i don't think that the engine will run at all with all that degrees.

For the sparks i checked with the timing light and all 4 cyl are sparking, i also tried to pull the plug out while running and i heard the engine dying.

For the injectors i did some tests but i think i'm going to double check them.

BTW is there any kind of hidden setting that i'm probably missing wich could cause this?

 

I agree if it were 180 degrees off it would not be working, so your crank to cam timing sounds OK, and it would not have run well on the stock ECU if it were off.

It is not hidden, but the Megasquirt does require you to adjust a calibration or offset to get the timing the ECu thinks it sets to match what you measure with a timing light.

What value of offset do you have now?
What happens if you start playing with it, can you smooth out the engine?
How did you use a timing light to set it to begin with if the car is shuddering and shaking? I would think that would make for very unstable timing light readings.

The timing for the injections is also set by the ECU, and there are different ways to do it. Can you pull a few base maps from places like Trubokitty and DIY, or this forum, and compare how your injector timing is set up compared to any of them?

 

Okay so the first thing I did as soon as I finished assembling the MS kit was correct the timing. So I armed myself with a timing light, positive clamp on the 12 volt output of the alternator, negative clamp on the throttle valve adjusting screw and induction clamp on the spark plug cable of cylinder 1. Already at the first start the engine ran badly but once warmed up and set the idle to 850 rpm (using the IAC valve) I was able to take measurements despite the engine shaking.
correcting the angle from tuner studio in the end I centered the notch on 10 degrees using a trigger angle/offset of 1.5 degrees.

I actually don't recall playing with the trigger angle/offset setting but i remember the difference between the basemap value (like 4 deg) and mine (1.5 deg).

for the injection timing i need to use the sequential fuel injection but i still haven't wired the injectors as the manual said. I'also red tho that some first gen 1.6 miatas got seq injection stock, how can i tell if mine is one of them? for example, if i set fully sequential injectors mode but my car can't support it will it shut itself off? Cause i did a test some time ago and it was running the same as batch fire.

Thank you!

 

Maybe worth playing with the offset timing value. The worst that can happen is it stops running, and you go back to your initial value.

I never had to play with injector timing, so I do not really have any advice to give, beyond checking other setups you can find on the internet.

 

Yea tomorrow i'm going to play with ignition settings! i really hope i'll get this sorted out xD
Thank you!!

 

Oh this is an NB 1.6, right? So you shouldn't be on the 4G63 ignition setting, that's for a CAS, but you have a crank/cam sensor like a US 99-05. There may be other wiring issues, but try the attached tune and see if it runs better. Timing will need to be reset, but if it doesn't run or is still ****, a couple degrees isn't going to make a difference. With NB sensors, you shouldn't be off by more than 5 degrees either direction.

 

nono i got the first gen (NA) miata from year 1990/1993 so in theory the 4G63 is good? I’ve red a lot of stuff saying that is the one for my car model so i haven’t changed it, should i?

 

Still nothing changed…
i’ve played a lot with the timing: if i increase the offset value the engine runs worse and then it shuts off, if i decrease it, it doesn’t do anything lol i even tried to put like -90 and still changed anything. The problem is still there.

i really don’t know what else i can do…
i’ve done a new video for you to check, i suggest you to listen to it with some headphones or at high volume cause from the video its hard to describe the hell i’m living.

PS: listen also at the sound it’s making when i rev it, it sounds like a raspy a** v8 without the exhaust xD it never sounded like this before


Thank you guys for your time

 

Sounds like it's running on 3 cylinders. Its been a few months now, ever figure this out? Try switching back to stock ecu to see if it is still running alright that way?

Edit, saw your other thread, glad you figured it out!