I have another thread with my megasquirt fails on here but it seems to have died. Hopefully this one is more specific and helpful.

The setup:

MSPNP MM9495 with MAF
95 1.8L bored 30 over w/stiffer valvesprings
Begi Shanghai kit with fmic (2854 churbo)
rx7 550cc injectors

Basically, the car idles like crap and at 10.5:1 afr. The pictures explain where I'm at so far with my settings. That afr target table seems way out of wack to me. Am I correct? Any ideas what it should be roughly?

If I turn off the afr target table and run just based on VE am I going to be better off? I'd just like to get the car on a basic fuel map that we can break it in with, then later worry about fine tuning. I figure we'll just leave the base map's timing table in there for the time being as it's presumably safe.

Engine Constants:


VE table


AFR target table for VE table


ANY input and helpful words are much appreciated. I'm sure to those who know this stuff well I'm rowing a sinking n00b canoe, but I'm trying to get a grasp!

 

First thing you should do is convert those volts to afrs
https://www.miataturbo.net/megasquirt-18/using-afr-instead-volts-aem-wideband-afr-target-table-28005/
It won't help anything but it will be a lot easier.
Then make sure your req fuel is the right calibration with your 550cc injectors.

 

download and install tunerstudio and junk megatune.
http://tunerstudio.com/index.php/tuner-studio
use tunerstudio instead
your reg fuel should be lower then 6.2
4.9 for reg fuel
And I would try .75ms for injector dead time
Probably need around 50-60 for idle cells

 

tunerstudio now has a VE table generator.

 

Update:

I tried to change the .ini file according to the thread that was linked here and it said permission denied. I opted to turn off the afr target table and give 4.9 req fuel and .75ms injector time a shot. It ran awesome for a few minutes, idling around 13.5-14 afr according to my wideband after a little tweaking of the VE table. The value that seemed to be appropriate was right around the base map's number of 48. I had a few set to 45 or so as well. This was with the base map's spark table.

Once the car got to operating temp though, the idle went back to crap and afr's dropped to 11.5 steady. What happened? Watching the VE table live it seemed that the same cells that were in use during the warmup were the ones being used after warmup. Should I lean it out after warmup? I'm a bit afraid that my values will be like 30 to achieve a proper 14.7.

Thoughts?

 

These are fundementals, dude. Get the AFR table done, then smooth out that fuel table with value that increase directly with the X&Y axis.

 

ok first off for tuning. Let the engine warm up to operating temp before tuning.
Just get it to idle enough to warm it up to operating temp.

Next disable any corrections. IAT correction needs to be disabled to tune properly in your fuel table.
Your idle cells will probably be between 50-60 at idle.

Also datalog datalog datalog, you want those datalogs to use!

 

Hustler and Tech: On it. Warmed up the car and got it idling nicely. Seemed that .9ms and 4.9 req fuel did the trick. Idle cells were around 48-50.

After that we took it for a spin while I made some corrections in the fuel table. Cruises on the highway in 5th with afr of 13-14 and is just a touch richer in town. Safe. The car ran great and we wound up putting 35 miles on it. Can't wait to get out and do a bit more tuning. I still have the target afr table disabled until I can figure out why it won't let me change the ini file. Once I have that sorted it should get even better.

Thanks for all the help! I'm PUMPED to finally have this thing drivable!

 

I wouldn;t cruise with anything less then between 14.7 - 15.4
if you don't disable the mat correction while tuning you will find that you will chase your tail.

 

As far as I can tell, I'm only using the VE table, with no corrections. Unless I have to go somewhere to turn the corrections off? I've searched around through a few things and don't see anywhere that specifies MAT or IAT correction.

I suppose I could lean it out a bit more. I was being careful, since this was the first go around. Wanted to stay on the safe side of things.

 

check your datalogs!
there is other things that effect fueling, like the hard coded ideal gas law for IAT correction. when IAt is over 80f it starts pulling fuel, under 80f it adds fuel. around that range.
Its GAIR in the datalogs.