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Old 01-29-2009, 05:46 PM   #1
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Default Cold weather starting

I've been emailing back and forth with Matt about my recent issues with starting when temps are around freezing. The car takes a couple times to crank and then does't want to stay running. I figured out I can keep tapping the throttle (holding it kills the engine) and keep the revs up around 2K until things warm up enough to hold on its own (2-3 minutes).

Matt suggest tweaking the cranking/prime table below 40.

Anyone been down this road with suggestions?
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Old 01-29-2009, 05:53 PM   #2
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paul on the forum had a problem like this and he concluded that moisture was getting in the MAP sensor and freezing. When he hooked up a laptop and turn the key on when it was freezing, and crank the car, it would register high map, and run poorly till the sensor "warmed up" and began to read correctly. Try bringing in your MS for the night and then reinstall it and see if it cranks fine.

https://www.miataturbo.net/forum/t30396/
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Old 01-29-2009, 06:38 PM   #3
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What constitues high MAP? Initial cranking is about 34. First few minutes ranges 36-39. After about 4 minutes it settles back down to 34 during idle.

I have the data log if anyone wishes to see it. Totals about 5 minutes.
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Old 01-29-2009, 06:41 PM   #4
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It sucks tuning the cold start settings you just have to keep changing until it starts up fast..... change the PW's .1 at a time until it starts reliably at that tempature..
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Old 01-29-2009, 07:10 PM   #5
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If it doesn't want to start, it probably needs more cranking PW. Your table will probably have 20* and 40* values, so add a little to both. Read through this thread and see what other people with your same size injectors have gotten to work reliably. If you get it started and it dies right away, your after start enrichments probably need adjusting. The bitch of it is you really only get one try per day, on that first startup from cold.
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Old 01-30-2009, 11:18 AM   #6
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Still a work in progress. I made some changes and it cranked on the second try today, versus on the fourth time yesterday. It did run a little longer before trying to die.

If you want to follow along, learn from this or try and help, I have started a webpage to follow this process of dialing in for cold weather starting.

MSPNP Cold Weather Starting Project

Last edited by Wardsweb; 01-30-2009 at 12:12 PM.
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Old 01-30-2009, 03:43 PM   #7
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****.

I still can't get mine to crank below 35. Period.
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Old 01-30-2009, 03:53 PM   #8
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I'm not sure I'm reading your web page correctly, but are your left/right settings 4cranks vs. 2cranks? If so, you stop extra enrichment after the 40* box. Does your need to tap the throttle correspond to hitting 60* CLT? If so, keep the enrichment higher until the car is warm. I'm running MS-II, but I bumped my entire range up until it cranked within 2 tries. Once I sort a bunch of other more important stuff out, I'll go back and try and fine-tune it more.

Also, your AFRs aren't rich after your run, they're SUPER LEAN. I'm guessing incorrect AFR calibration as I had similar readings before I got the calibration correct. Do they look semi-normal during driving?

I'll play captain obvious and really, really, really recommend that you spend the upcoming weekend in the megamanual learning the basics of tuning before you break something. Asking how to fix a rich condition when you're running super lean has tipped your noob hand. Being a noob myself, you'll find much more help if you read-up and search before posting. The information is out there. Just gotta be persistent and find it.

Good luck!
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Old 01-30-2009, 04:18 PM   #9
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If your car starts but doesnt stay running without gas then afterstart enrichment is your problem.
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Old 01-30-2009, 05:04 PM   #10
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Thanks for the feedback guys. Matt sent me the link to the extra tuning manual and I've bee reading it all day. Then I called and talked with him a bit to better understand what controls what when. From all this I now know my first bit of tweaking is to the VE fuel tables while warm. I've got the pulse width good, as it cranks and the ASE good as it will run until it decays. So the next step will be a combination of the fuel table and the warm up wizard. The engine is going rich after the ACE fades, denoted by needing higher RPM's to stay running.

Yes TOTAL NOOB ! I didn't setup the car origially so I'm getting the crash course now. I would rather be seen as knowing nothing and asking for help, in place of having you think I know something and end up hurting the engine.

There will always be someone who knows more and someone who knows less. Point being, the learning never stops.
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Old 01-30-2009, 08:42 PM   #11
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Ok the next step in this saga.

After work, I hooked the laptop backup and started the car. I let it get to temperature and started playing with the fuel table in the low kPa and low RPM ranges. Running these blocks even up to 75 only took the Air:Fuel ratio from 28 to 17. The idle was rough and I could smell the gas. Something is amiss. Anyway I drive home and when I come to a stop and push the clutch in it dies everytime. I get home, stop in the driveway and reset the low ranges back to where they were and now the air:fuel is 14.7. Something is wrong. All I did was change four block and then change them back again and now it is fine.

Bad O2? Bad connection?
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Old 01-31-2009, 04:57 PM   #12
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Most of us are too lazy to click on your website to figure out what you're running, so write out your build info in your sig. I recall that you have a BEGi setup, but nowhere in this thread does it say what size injectors you have (which may have prompted someone else to post their cranking PW table earlier) or what model wideband you have. Help us help you.

There is definitely something amiss with your WBO2, either in the calibration of the sensor itself or in its communication with Megatune, because if your AFR was truly 28:1 the car would not be moving down the road. This is the first thing that needs to be addressed, because you can't reliably tune without it. Search this forum for info on configuring your particular model of wideband (LC-1 and AEM are popular here) and that should get you started.

As for tuning, the Megamanual (go to megamanual.com and click on "tuning" in the left frame) recommends tuning idle first before you drive around tuning the rest of your table. As you've seen, getting the idle right first will make it easier to road tune, since your car won't die every time you come to a red light. The main problem though is that your WBO2 isn't configured properly, which made you think you needed to drastically increase your idle VE cells, which causes MS to dump enough fuel when you put the clutch in that it stumbles & dies. Getting the WBO2 sorted will let you fix your idle. And in the name of all things holy, don't go driving around (especially under boost) trying to tune the VE table in the meantime because you have no way to know you're running an AFR that is even remotely safe.

Last edited by ScottFW; 01-31-2009 at 05:02 PM. Reason: fix link url
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Old 01-31-2009, 06:51 PM   #13
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Thanks Scott - to be continued...
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Old 02-02-2009, 01:40 PM   #14
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The combination of a lean AFR reading and a smell of gas suggests it's not firing on all cylinders. Could this be an ignition problem? Alternatively, I've seen this happen when a car runs so rich it misfires. In that case you'd see black smoke too.
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Old 02-02-2009, 01:43 PM   #15
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how is your lc-1 hooked up? PM coming...
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Old 02-02-2009, 01:52 PM   #16
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first of all, turn off EGO correction for now, there is no telling what the LC-1 is doing. Mine is whacked out right now so I don't run EGO correction because the LC-1, although incredibly accurate, seems to be a raging pain in the *** to make function correctly.


issues I've had that caused stuff like this:
compromised map signal hose
fouled plug
dead stock FPR
corrupted msq save with whacked out x and y values in the tables
I had this problem once and after cleaning out the IAC valve with carb cleaner, the car idled.


is it doing this:
Video - TinyPic - Free Image Hosting, Photo Sharing & Video Hosting
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...I cleaned out the IAC valve and it ran like clockwork after that.
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Old 02-02-2009, 04:19 PM   #17
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While there are many potential issues, what has me thinking it could simply be a WBO2 configuration issue is that he's reading 17-28:1 AFRs. 28:1 shouldn't even be in a wideband's vocabulary. With my LC-1 (installed according to their directions and working just peachy) the leanest it will read is 22.4, and the richest is something in the high 9s IIRC. That's on the DB gauge. Megatune should be configured for 0-5V = 10-20:1 AFR. From his description it sounds like it's pig rich when reading 17:1. While that could be a rich misfire causing a lean reading, it could also be just a simple output scaling issue. 28:1 is so much leaner than the leanest it should display that it cannot possibly be configured properly.

Some of the above is hand waving because I don't know for a fact that he has an LC-1. Come to think of it, I don't know if it's been specified whether he even has a WBO2 or is still running the stock sensor.
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