Hot weather running issues

[bpimm]

I noticed this last summer as a hot start issue on hot days, I tweaked the after start enrichment and thought I had it fixed but that wasn't the case. This year it seems to be much worse. It runs pretty good on 70 degree days but last weekend at an autocross, the first day was 70ish and it wasn't bad, the second day rained in the morning and it ran fine but the afternoon was mid 80's and it wouldn't idle well at all and when I came off course it just died and was hard to start. On cooler days the idle seems to hunt a bit not real stable, also on hot restart the afr is 16-17 range for a while. I added after start enrichment until that came down but when the wife drove it to work the next day it ran like poo so I switched back to the old map for the autox.

2017-06-20_07.00.33.msq

I tried to add the log files but their to big, I tried zipping them and it wouldn't accept a zipped file, I tried to cut out the pertinent section of the log but don't see a way to edit the log...
How do I get the log files down to an acceptable size?

02 VVT Miata in a 90 Miata. MS3 pro pnp release 1.3.4

[bpimm]

Ok got it edited, copy of log viewer on the desktop is lite and can't edit. this is a run in the afternoon when it was dieing before and after the run.

2017-06-18_Hot later run_LOG1353 - Copy_modified.msl

[ChristianK]

Optimize the mat correction curve!

[bpimm]

I looked that up and it requires MAF, I'm running speed density.

I went with PNP thinking I would have a stable starting point.....

[kjones6039]

I looked that up and it requires MAF

Quite the opposite in MS2 I think............
Is it different for MS3?

Ken

[ChristianK]

I looked that up and it requires MAF, I'm running speed density.

MAF is the better way. But it doesn't require any MAF!

That is the requirered table:


I think, a log of only the mistake doesn't help.
Make a log at the early morning. arround 4.00AM. Drive the car to normally warm clt. Than hold on and start the log, from cold to hot mat in the idle by standing car. And than you will see, where the issues are....

[bpimm]

I looked that up and it requires MAF, I'm running speed density.

MAF is the better way. But it doesn't require any MAF!

That is the requirered table:


I think, a log of only the mistake doesn't help.
Make a log at the early morning. arround 4.00AM. Drive the car to normally warm clt. Than hold on and start the log, from cold to hot mat in the idle by standing car. And than you will see, where the issues are....

I went back and re read the help... It says "you must not use MAF" and I read "you must use MAF" So unless it changed over night must be dyslexia striking again...

I'll try the log you suggest and see what it shows.

Thanks
Brian

[bpimm]

Log showed a 5.5% increase in AFR over a 64.6*F change in MAT.
AFR went from 14.5 at warm idle to 15.3 at warm idle as the MAT went from 82.2*F to 146.8*F.

Is this what I'm looking for?

[ChristianK]

Yes, absolutely!

And now, let calculator burn and fill up the new data in the mat cor.

Correction at 140°F ist 87.1% x 1.055 = 91,1%

The rest of the temperatureskales also look at the log.

[bpimm]

Just ran another log,

MAT from 86*f to 146*f
AFR 14.8-14.9

Much flatter, I'll take it out for a drive later and see what happens, it might not be hot enough today for it to be a problem.

Thanks
Brian

[ChristianK]

There is no problem, if this curve is well!

[bpimm]

seems to have stopped the dieing, at least in 70* weather. She'll drive it to work tomorrow and see what happens.

Still had some hot start issues, I tweaked the ASE and ASE taper and now it starts pretty good, still won't do a foot free hot start it needs a touch of throttle.

[ChristianK]

An thousend year old law says:
If the wife is happy, the man's live is easy.

Cheers...

[bpimm]

After another hot day, it is still dieing, coming up to a stop push in the clutch and it drops dead. seems to run good everywhere else just won't slow to idle when it's hot out, above 85*f. It's also over rich on accel, I think that is due to the over correction I had done for the bad MAT curve, now that that is correct I'll correct the acceleration enrichment.

I'll post up a MSQ and log shortly but the only thing that has changed from the previous one is the MAT correction curve.

[bpimm]

I may have found something, The Idle RPM timing correction curve gave it some advance until it got to about - 100 rpm below target then dropped back to zero as the rpm continued down. I bumped it up to 9*advance at 0 RPM for a positive slope. I'll take it for a drive later when it warms up and the thunder storms pass...