1.6 MS3x wont idle
 

Hey all, this is pretty much just a continuation of my last thread here but I figured the old "crank no start" title was a little misleading now.

So here's where I'm at. Me and my step father are prepping my car for a MK turbo kit that I recently acquired. I ended up going the DIY route with the megasquirt for two reasons. So I have a better understanding of what the heck MS is and how it works (which is proving to be a big learning curve), and two I'm nineteen and broke. I have recently finished assembling my MS3x following the instructions off trubo kitty. After working out some kinks I now have it installed in the car and am able to get it to start and run, but only with the assistance of some throttle. The car will not idle on its own. Anywhere under around 1500 rpm and the car will die. The car seems to be running very rich, it reeks of unburnt fuel, lots of backfires, and the plugs are completely black.

Tonight I started adjusting the main VE table in tuner studio. I turned off the Idle VE table in attempt to simplify things for myself and only work off one table. Then started to lean out the main table in 5% increments to see how that affected the car. It ran quite a bit better but still wouldn't idle on its own. At low rpm its just dies, if I start to give it alot of rpm it backfires. It can run for as long as I want around 2-3k rpm. So I ended up just resetting the table and I'm in the same spot I was earlier obviously. I am also having issues getting a proper afr reading both from the gauge and in tuner studio. Before I was able to get some readings that seemed fairly correct but now it just pegs our at 18.5 afr and will randomly spike down to a value that seems about right.

Below I have posted my tune and a log from earlier. HELP

Some basic info on the car:
1.6L
Stock injectors
vTPS
AEM UEGO 30-4110

Looks to me like you didn't RTFM.

Did you set base timing? If so you now need to tell it to use the ignition table. You're still locked at 10 degrees.

Did you go here and tell it what wideband you're using?

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Which manuel are you referring to? So far I have just been referring to the megamanuel, trubokitty, and diyautotune. But I'll but the first to admit I still probably fucked something up. I'll go back read a bit more carefully.

I have not set the base timing. Which is why I am set to fixed timing. My from understanding the next step is to get the static value of 10 degrees in TS to line up with the mechanical timing on the car using a timing light and adjusting the trigger wizard accordingly. I guess my new question is can I set the base timing even though the car will not stay running on its own? Like I said above the car just dies below without any throttle below 1500 rpm.

Upon further searching it seems the actual values of my wide band do not line up with the pre existing AEM settings in tuner studio. That's on me and 100% RTFM moment.

that info was found here - https://www.miataturbo.net/mspnp-55/...s-gauge-95073/

From your other thread.

You were driving the car around at fixed timing and wondering why it was running like crap.

If you setup your wideband correctly then I suspect the reason it's pegging lean is because it's misfiring because the timing is so far off.

You should reload the basemap from trubokitty because whatever changes you made are for the worse. Setup the sensors correctly. Try to start the car. If it doesn't start without throttle adjust your timing offset until it does.

Sorry should have clarified a little better in my other post. I haven't drove the car around at all, I went across town in another car. I came back and somehow j1 on the daughter board and expantionn board had came unplugged which is why it wasn't starting the second time. I still have the MS outside of its main because I found myself opening it multiple times to check things over. I mainly didn't mention that since that was big idiot move on my part.

I will reload the basemap. As I have done a few times, the car starts fine without any throttle, but dies a few seconds later. I have played with the ASE in attempt to fix this but it still dies right after start up. Will the timing offset angle help this issue?

Thanks for all your input.

Gotcha. That makes more sense than how I read it.

You really can't do anything effective tuning wise until you set base timing. It doesn't have to be at idle. If it smooths out at 2000 rpm then set it while running the engine at 2000 rpm.

Brain's basemap should be very close which is why I suggested reloading it, and focusing on the thing we know is fucked up which is your timing.

Awesome, thank you! I'll update once I get that all squared away.

Update.

I decided to tear apart the front of the engine this past weekend to verify my timing wasn't all jacked up. And sure enough it was. After getting that squared away earlier tonight I was able to start the car and set base timing. The car was able to idle on its own for a while but died before getting all the way up to operating temp.

The car still runs very poorly. It is super rich. It seems like it has dropped a cylinder. Cylinder 1 plug is completely black. With no throttle the idle jumps up and down +- 300ish rpm. It feels like there is a rev limiter at 2000 rpm once it gets there the car breaks up and backfires. There's my noob explanation at what the car is doing.
I leaned out low RPM low KPA stuff in the main VE table and the car was running a little better, I was actually getting AFR readings. But again would die with no throttle.

It was a long night after school re assembling the car and getting to this point. Finding the messed up timing was a step in the right direction. But the car still doesn't run as it should. Below I attached a quick log I took earlier. Somebody tell me I'm a idiot and point me in the right direction. Thanks.

Log shows you're still locked at 10 degrees timing. That's not doing you any favors.

Ahh crap. Thanks for the heads up... Sorry for my ignorance but how do I see that in the log?

In Megalog Viewer on the left hand side are several drop down boxes. You can change those options to display what you want to see.

update. Now using the timing table and also using the AFR target table. Idle was much better for a short amount of time not running rich anymore. The car runs smoothly immediately after start up then rpm starts oscillating and it ends up dying. We saw the AFR's doing this as well.

log 2 with was with the fuel pump jumped
log 3 was without
log 4 was with

Hey Guys-
Acey's step dad here. I've been helping him, but am new to ECU's as well.

Tonight we started using the timing table and AFR target table, and that helped.

Run 1:
I saw the AFR's swinging when the idle went unstable on run 1 (not posted here) about 7 seconds after start, and figured something had to be changing to cause it. Afterstart enrichment should be done before 7 seconds, warmup enrichment should be consistant since CLT really didn't change. I wondered about falling fuel pressure...

Run 2:
We jumpered the fuel pump to keep it on. Had a steady idle, with solid AFR for over 20 seconds. Then Fuel Pressure shows falling and the oscillations start in AFR and RPM again.

Run 3:
Took the jumper off to do a a-b-a test

Run 4:
Fuel pump jumpered again.


I'm thinking now that we have fuel pressure issues causing this. What in the ECU tells the pump to run?

MS-37. Pin 37 on the MS3 connector. Should show ground when the pump is running. I don't think that's your problem though. 4 had the same problem as 3. The car wouldn't start at all if the pump wasn't running.

any ideas what might be causing the idle oscillation that leads the car to stalling out?

IMO log 2 shows a car that just needs idle tuning. Your IACV is jumping up and down causing the rpm swings. Do some reading on tuning idle. Lots of info on here.

Logs 3/4 seem strange as the AFR seems to peg lean suddenly with no huge swings in injector PW or idle valve change. Is the car misfiring at the points where it shows full lean? RPM signal doesn't seem erratic enough for that but I don't have a better explanation.

Update. Spent some time trying to tune the idle today and made some gains.

We were able to get the car running long enough to come up to operating temperature. We put the car into open loop and enriched the main VE table and smoothed out the ignition table. The car then basically idled poorly around 1700 rpm. We also went in and entered the real Max and Min values for the IAC. Changed the Accel Pump Enrichment to use TPSdot over MAPdot. Then put the car back into closed loop. Idle then came down around 900 and is not stable enough to go below that. The car seems now to be running lean and the rpm oscillation is still there. Our VE and Ignition tables are tremendously crude and sloppy. We'll be doing some more reading before our next session.

tune and log attached as well as changed the accel enrich to TPS. any advice/input is much appreciated

You're making this so much harder on yourself by changing things you don't understand.

There's no reason to turn off idle ve and edit the ignition table the way you have. Start by reloading brain's basemap and just tuning idle ve. Add fuel to that table until you're able to idle around 13-13.5. Most of your log shows you're pegged full lean. If that's accurate I'm shocked it idles as well as it does.

I have been doing research trying to understand why/how each thing I have adjusted is going to change the car. So I'm not just aimlessly just pecking at random settings hoping it fixes my problem.

That being said I am clearly overlooking some things. How does the Idle VE table work with the main table? I don't quite understand how changing the cells in the main table that the car idles at is different that using the Idle VE table.
I'll reload basemap and go from there.

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