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-   -   cold start FTL (https://www.miataturbo.net/megasquirt-18/cold-start-ftl-13219/)

devin mac 10-09-2007 08:46 AM

cold start FTL
 
well, i THOUGHT i had his ironed out last season, but apparently i was lying to myself.

seems that below 55 or so i can't start my car... not a pop or a sputter, just cranks on the starter over and over again...

unfortunately, the battery in the laptop i've been tuning with is also junk, so i can't even mess with settings right now.

blaaaaaahhhhh...

now, if i'm not mistaken, the only window that should matter as far as getting the car to fire beyond cranking on the starter is the "cranking settings" window, right? after it starts but won't keep running, it's ASE, correct?

i need to either get a USB to serial adapter or a new battery for this laptop...

cjernigan 10-09-2007 08:54 AM

You need a $10 inverter from walmart so you can keep the laptop plugged in. Alot cheaper than a $30 usb-serial adapter.

devin mac 10-09-2007 08:56 AM

i have one. unfortunately the miata battery doesn't seem to have enough juice to run the one i bought without it complaining unless the car's running...

magnamx-5 10-09-2007 08:58 AM

Yep our electrical system is underpowered.

devin mac 10-09-2007 09:45 AM

well, i'll get a laptop connected to it at some point in the next couple days, but i'm really after the question i posted.

am i correct with my assumptions about what i need to mess with to try to get this thing to start up?

also, anyone want to reassure me that a slight change on that dialog can mean the difference between doing nothing but cranking on the starter, and actually firing up? because my settings don't look like they're THAT far off from what people have posted in the past.

FoundSoul 10-09-2007 11:05 AM

Cranking Pulsewidths to get it to start-- increase them in small increments at lower temps to get them to start. Don't mess with them at the temps where they've been working fine at or you'll have problems when it's warm-- it was fine there already.

Afterstart Enrichment (ASE) if it dies pretty much immediately after starting successfully.

Warmup Enrichment (WE) if it's too lean/rich while getting itself to operating temp.

ASE and WE work together for the first few seconds while ASE is engaged so keep an eye on how they can effect one another.

devin mac 10-09-2007 11:11 AM

ok. sounds like what i was expecting, then. hopefully a few minor tweaks will let me start the damn thing when it's below 60 or so outside... lol

akaryrye 10-10-2007 01:26 AM

mspnp? if not, make sure your ignition mods are cherry. its probably fueling though.

devin mac 10-10-2007 08:43 AM

it's not mspnp. and i also didn't build it. hopefully just tweaking the cranking settings will get me there, because i don't really know the first thing about the ignition mods... lol

devin mac 10-13-2007 05:52 PM

ugh... i can't figure this out for the life of me. i've changed everything i can think of in the cranking settings window, and messed with the "more cranking stuff" window as well.. nothing.

i hopped in today and it started then sputter-died quickly thereafter, and then every time after that just cranked and cranked...

are there any other settings i should be playing with to try to get this to fire when it's 50F or less? that's not even that cold, but i just don't have a single problem with it when it's warm out...

so frustrating..

devin mac 10-13-2007 05:56 PM


Originally Posted by FoundSoul (Post 161208)
Cranking Pulsewidths to get it to start-- increase them in small increments at lower temps to get them to start. Don't mess with them at the temps where they've been working fine at or you'll have problems when it's warm-- it was fine there already.

Afterstart Enrichment (ASE) if it dies pretty much immediately after starting successfully.

Warmup Enrichment (WE) if it's too lean/rich while getting itself to operating temp.

ASE and WE work together for the first few seconds while ASE is engaged so keep an eye on how they can effect one another.

here's the thing. should i just be increasing the cells it's currently in (it's 50 deg CLT reading, so the 40 and 60 cell would apply), or should i increase everything from those down to the coldest?

also, how do i know if i've gone too far and am just flooding it?

devin mac 10-13-2007 06:04 PM

hmm, after looking at the MSPNP 90-93 base map, my values are possibly off by a bit...

maybe i'll give those a shot...

devin mac 10-14-2007 12:50 PM

it runs!

i ganked DIY's cranking settings from the 90-93 MSPNP without AFM, and it fired right up immediately with a 43 deg coolant temp and 60 deg manifold temp.

feel a little silly for not being able to figure it out, but at least i can drive the car now. :-)

Thanks DIY!

FoundSoul 10-14-2007 01:28 PM

Great-- I figured it would, we got a chance to dial those in pretty well last winter in coolant temps down to around 40 degrees. I'm glad it worked out for you man!

devin mac 10-14-2007 01:41 PM

me too. lol. been really bummin about that.

my question, though, is how the values in cells below the current temp might affect startup. for instance, if it's 43deg CLT, does having a higher or lower value in 0deg make any difference? my gut tells me no, but i thoguht i remembered something in the megamanual about MS using all the values to essentially draw out a curve. that said, i could be imagining that i read that.

oh well. i'll keep an eye on it if i get down below 40deg. i'll probably see a 20deg morning before i put her away for the winter.

Braineack 10-15-2007 08:50 AM

took me about 15 minutes of fustin' around to get mine to crank this morning (40° coolant). how not fun. had to drive really fast to make up for lost time, which equaled things out, so my day has thus started as usual.

devin mac 10-15-2007 09:26 AM

lol.

mine actually wouldn't start last night. probably just under 40deg...

i wonder what the calculation is that MS actually does using those tables, when you're between cells. anyone know?

like if you're at 43deg does it use the 40deg cell value alone? but if you're at 38 will it use the 20 deg cell?

i noticed that DIY's values are a little strange. i would think that the values should be higher as the temp goes down, but the DIY table is higher at 40 than at 20. Jerry just mentioned they messed with it down to about 40, which might explain this. i'll hopefully get a chance to fiddle with the <40 cells tonite and see if i can get something for 20deg.

devin mac 10-15-2007 09:29 AM

also, i have noticed that i'll get a different start/no start outcome depending on manifold temp, even when coolant readings are the same. looks like MS takes ONLY the coolant reading into account when cranking, which probably explains why it started in the afternoon at 60deg manifold temp and 43 coolant, but not last night at 10:30 with probably closer to 40 - 45 deg manifold temp and roughly the same coolant temp as in the afternoon. (i didn't run the extension cord out to the laptop to check...)

Braineack 10-15-2007 09:49 AM

you can have it average the two.

devin mac 10-15-2007 10:00 AM

is that the "CLT only" value in the cranking settings dropdown?

i looked at the other value in that dropdown and i coulda sworn it said something about MAF values. so i thought it best not to bother (probably shoulda bothered) and left my settings the same as what DIY's got, which are CLT only, always on, twice, and priming table.

that said, i may try giving that a shot tonite when it's cold again, since again, i don't think that the coolant temp was much different on the two startup attempts. afternoon, it fired IMMEDIATELY, but at night with colder air, it just spun on the starter again.

just got get unlazy and mess with it for awhile at a time again.


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