Big cold start improvement
 

Since it's been cold, I've had a little tougher time with cold starts. Now, part of that was due to the fact that the lower temperature enrichments were not tuned, but the values were assumed as it wasn't cold enough to actually hit those cells, and not until today have I tried to actually tune them. My main problem was that each time I would cold start the car, it would run for only a few seconds then stall. I would start the car again, it would run for a few seconds, then act like it wanted to stall for a few seconds, but it would typically clear up and then go to cold start high idle.

Inspired by my "new" tuning laptop from DropTopDrifter, I decided that today is the day to clear up my cold start issue. Here's the fix:
In MegaTune, go to Crank/Warmup and open ASE Settings. Make sure the ASE Mode is Fixed Then Decay, MAP Mode During ASE is set to Fixed MAP, and set the Time Period to 15 seconds. My previous setting for Time Period was only 5 seconds, so the problem I was having was that when the Fixed MAP period was ending, the actual MAP was not stable enough to appropriately fuel the motor, and my car was going lean and stalling out. Now that I have MAP locked for 15 seconds after start, I am getting good, stable cold starts.

As it gets colder, I'll get my settings locked in better. But for your benefit, here's what I'm running for now:

I found with a fixed MAP setting the idle after *any* start was absolute bobbins :confused: as soon as I turned it off everything was fine

Apart from my cold start, I've never been able to get it to consistently start 1st time from cold, and generally the ASE looks *far* too rich (PW's at 5-6x normal), it idles really rough, but never stalls but as soon as the ASE ends it idles fine. leaning out the ASE just means that it won't stay running.

I'll check mine. It does not stall, but takes a quite a bit more cranking than normal to get started, and acts like it will stall.

I fixed mine. I put it in a garage and haven't started in in three weeks.

Yeah I hadn't touched mine in 2 weeks. Might man up and change my front brakes tomorrow. :dunno:

Phewww, its a good thing i don't have to worry about that stuff!! Coldest it'll ever get here is the mid 50's!!! All that sounds like a pain in the arse.

I had a little dilemma one night. Parked the miata behind my truck. 4 hours later the temp dropped close to 30*. Colder than i had ever tuned the cold start to. Kind of a pita when you have to tune the car just to move it. Now my cold starts are great though. I have my map lock on for 3 seconds though. I'll try 10 for the heck of it.

Good heads up Ben, thanks!

supersuk - add your location to your profile so we know where "here" is.

Here it was 59in the garage today , but the day the MS was installed it was probably 80. You can't nail the enrichment at low temperatures without it being cold out. You can only ballpark it. Likely, I'll give it one more go one morning that's really cold out (like the 1 day a year it gets into the upper 20s), and I'll be good for forever.

Don't have my msq on this computer, but I've noticed that the car likes it on the really rich side on cold mornings. I think my low temp ASE enrichments are a good 10-20% higher than yours and no cold start issues down to 30 or so degrees.

Ben,

Since it's been cold here I have been having the same problem, I'm going to give this a try

BTW: it's suppose to be zero degrees here today... So I get lots of cold start practice...

I didn't have any issues til it got to be around 20 or so, before it would start like stock.

Ben, would you mind posting up your Cranking and Prime table? Your ASE settings are similar to mine, but my May fixed MAP value is only 3 seconds.

My car runs pretty good when it is finally started, but when temps are in the 30's I have to crank it forever... I'm thinking I should open up my cranking PW

Stealth, best practice is to use the Cold Start Wizzard, and not to modify the table directly. None the less, the table is below. And FWIW, all the cold start default settings were way lean for my car. I don't know how my base settings compare to what DIY is offering now. But I think Tom's comment pretty much confirms that the base settings are indeed super lean.

Since my car is garaged, I haven't yet been able to start the car where CLT was below like mid 50's.

Thanks for the info. I'm still a n00b at this stuff, but I'm figuring it out.

15 seconds fixe dmap will ensure you're getting enough fuel... but that's ALOT of fuel more than likely as the fixed map setting is probably high, 80 or 100 kpa, and I bet the VE up there is much higher than at idle, meaning it's pumping the fuel in. This will be fine when it's super cold, but when it's 70 degrees out it will feel super rich.

Was it dying immediately after 5 seconds or sometime a bit later? I'd think it's an afterstart enrichment thing, but that fixed map may not be the 'best' answer. I use it for 5 seconds on these cars and that's it...


BTW Ben, notice the sig update. ;)

Well it's 8.4 degrees and my car starts w/o stalling, by Am it should -5 or so I'll try again then and see... Yeah it's F'n cold out...

Where's the Cold Start wizard? I have a Warmup wizard, but those settings aren't related to the cranking and priming table afaik?

is there a hidden menu somewhere that'd make my life a hell of a lot easier? :)

There and the cranking PW/Priming PW's, the afterstart enrichments, and the warmup 'wizard'. No cranky wizard, I mean cranking wizard.

I must have been mistaken.

Jerry, good job! I may indeed now have the second fastest miata in the county. :sadwavey: But not for long. I have a trick or two up my sleeve for the 1.6 :) (I'll probably create a thread about that later)

After PRI I've got a couple more things I'll be up to as well. I can't turn up the boost any further without spark blowout right now. But that will be fixed soon. Very soon ;).

I hope you're the one that outbid me by a dollar on ebay on a set of COPs.

I said "county" :)
At minimum, I want to have the most powerful Greddy known. So have to beat 268.7 from FM's site, though I'm sure that's a heavily "corrected" figure.

That would be just like me, but no, I think I might have found something better. I'll know soon and when I prove it I'll share.

I caught that afterwards and edited my post... for a second there I thought maybe you were getting a little delusional. Not that it's not a great goal or anything ;).

What gears are you running the rear end now? I compared our graphs and though I start making my torque a good bit earlier and that's great on the street or road course, that won't matter much in a drag race when the revs never fall that low. My rear end is a 3.909, and when I compared yours at 4.30 (what it was the last time you were on my dyno), that could give you a slight advantage still in a drag race, if you can put the power down. And I've driven your car and wheelspin didn't seem to be a huge problem with the tires you had on it then. With the gearing difference, even with my slight torque advantage, you're multiplying it more and putting slightly more torque to the pavement. I don't have to shift quite as soon though, but that difference will be negligible. Let's just say Commerce will be fun in the spring ;).

Just to make somethings clear for me. The cranking/prime table is the one that dictates how long the injectors fire for at that particular temperature. What do the ASE and the Warmup wizard do? Is ASE the time an engine is cranking, and warmup wizard when its already started?

I'm running 4.10's with a tight RX7 clutch LSD now. Your gears and your nice 3" cat deleted exhuast are huge spool advantages for you.

Curious to see your new ignition solution. I was considering going with a pair of large coils bolted to the firewall (like what Tec does) but these COPs have been pretty damn good for me. No blowouts to 17.5 psi, which is the highest I've tried. .040" gap on stock ngk plugs.

Sam-

The best answer is 'read the manual', the MS1 Extra manual that is, as there's way to much on this subject in there to cover here. The fast answer is ASE and Warmup work together to add extra fuel both right after the car is first started (ASE) and anytime it's not up to temp yet (WUE) to help the car run at the proper AFRs until it's running and up to temp. Fuel doesn't atomize as well at cold temps so you have to spray a bunch more knowing part of it will not be atomized, but you spray enough that you get the AFRs you're looking for. You then phase this out as the car warms up as the fuel will properly atomize then.


Ben-

If you're running an .040 spark plug gap at 17.5psi with no spark blowout , you're ignition solution is just fine. What I'll be running should theoretically be able to boost 40+ psi, at more like .028-.030. Not that I have any plans of putting 40psi into this motor and sending the whole head, (in one piece), through the hood. I don't think it would just lift, it would lift off!

OH. That make sense now. So would it be wise to tune for 14.7 afr during these stages?

Im gonna go find the manual and get to reading otherwise.

Eh... these cars tend to be happiest idling in the low to mid 13's, especially N/A. My car seems to be happy idling a little leaner now with the turbo, but I still keep it around 14:1 at idle at the leanest. You'll get occasional misfires at idle if you idle it too lean.

I'm idling at 14:7 without any issues, no burps. Even with a blown head gasket: http://www.youtube.com/watch?v=HxCO3EVoQtI

I shoulda been clearer in my question.

During Warmup Enrichment, should the car be tuned to idle lean, meaning as lean as it should idle during regular running when the WUE phase has ended? Or even simpler, are there two idle targets I should be aiming for, one for when the engine is cold and one for when its hot?

My car doesn't idle with anything over 13.1. It starts to sputter and die if its anything leaner.

Wow, I suddenly feel so special that my car idles great, hovering between 14.5-15.0:1, even during WUA!

Jim

So what's your special trick.

Probably adjusted the throttle screw?

I still dont get how adjusting the VE table will lower map.

Honestly, I dont know. I used to have the random misfiring problem and James (jsmcortina) recommended that I rewired my injectors from what I originally had to something else (IIRC from 1+3&2+4 to 1+4&2+3?) and that helped immensly. I'm also running a modified version of 029v that resyncs the wheel when I press Q, it seems to work a lot better for me for some weird reason.

Jim

Ok guys, I'm new with MS and still learning (I installed it last week)
I have the MS on my 1.6 without AFM. Motor is stock, N/A and I'm waiting for my turbo from BEGI. In the mean time I want to make the motor run good without the turbo.
Yesterday I changed the MAP time period to 12 seconds and also got into the Warmup wizard and cranked the fuel enrichments up as the originator of this tread showed in his tables. The car started much better, it only took one long crank to start (BUT IT WAS 50 degrees outside).
This morning it was 26 degrees and it took a long time to start, it almost didnt start. After I shut it off, I put it in contact and it backfired, wtf!!. So I decided that maybe its too rich and I went to Cranking PWs and I lowered then by 1ms less each one. Still hard to start
Any tips. I'm trying to learn this plz dont flame.

too much fuel, lower the PWs.

backfire = unburned fuel igniting.

Interesting that changing your injector batching helped so much. I've run both ways and saw no difference. That's good you got your random misfire fixed up.

I'll haver to work on my enrichments, The car stalled once at 11 degrees, using a fixed Map of 15 Seconds.

Also my car likes to idle ~13.1:1 or so..

Man I'm glad I live here and not there with you. It's 50, here at noon, and still climbing.

indeed. I got to get that bottle in to see if I can keep up.