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Old 09-26-2016, 11:54 PM   #1
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Default trouble starting up below 70*

I've got an MS2 built by Rev. Initially, startup would take lots of cranks to get running at any temp. I changed some stuff (just from googling and trial and error) and got it to normal above 70* which was good for summer. Now that it's cooling down I wanted to post up my settings and see if I can get some tips to fix my startup when it's cold.

If it is below 70* It will take 3-5 seconds to crank (exponentially longer the colder it is), and will stutter for another couple seconds before idling properly.. but before I just add more fuel I thought I'd get input.

'95 with stock injectors. have not messed with cranking timing settings at all. regular timing is offset because it was at 15 when I put turbo in. let me know what other info is needed for diagnosis.







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Old 09-27-2016, 07:43 AM   #2
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Next time you start the car in the morning. Drag the cranking pulse down low at that CLT temp.

So adding fuel until the car starts, adding a little more more for good measure. You're probably injecting too much currently (but keep laptop handy and be smart about the curve -- you dont wanna get stuck somewhere cause you now dont have enough fuel to ever start)
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Old 09-27-2016, 01:28 PM   #3
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so you're thinking too much fuel? I've added so much at this point that's probable.. will try that tonight/tomorrow.

can you (or Rev) post suggested startup setting for fuel and spark you put on your builds with stock injectors? or do you leave that to the customer. I'm wondering if my startup settings were overlooked or not set properly.

Last edited by babydriver; 09-27-2016 at 01:47 PM.
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Old 09-27-2016, 02:30 PM   #4
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I agree that you're adding too much fuel

Tune your VE table first

Warm up enrichment is crazy high

priming pulse is a bit much. I'd probably half the values to start

After start enrichment is normal ish looking, but only adjust the values at the temps you are trying to start at.
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Old 10-27-2016, 10:18 AM   #5
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Yeah.. my thought process was since it was running great when started, that I just add to the ASE and WUE and I should be good.. but turning up the fuel at 500 RPM did the trick, I dropped my startup settings down to normal as well
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Old 10-27-2016, 10:20 AM   #6
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why are your triggers set to 4G63?
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Old 10-27-2016, 10:26 AM   #7
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uhhhh that may be a question for rev.. i don't think i've touched that
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Old 10-27-2016, 10:38 AM   #8
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so I just looked up what that is.. yeah that doesn't seem right hahah.. but it seems like it runs great (??)

is it supposed to be on wheel?
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Old 10-27-2016, 11:02 AM   #9
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Quote:
Originally Posted by 18psi View Post
why are your triggers set to 4G63?
4g63 is correct for CAS triggering I think?
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Old 10-27-2016, 11:07 AM   #10
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https://www.diyautotune.com/support/...rt-your-miata/

ctrl+f 4g63

seems to be correct for miatas
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Old 10-27-2016, 11:14 AM   #11
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is it really? Ok. I tune mostly NB's and they don't use that code.
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Old 10-27-2016, 12:12 PM   #12
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too much fuel: sputters to a start
too little fuel: dies smoothly
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Old 10-27-2016, 12:26 PM   #13
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sometimes it goes full circle and you don't know which one you're at

which is what makes cold start tuning such a time consuming task

You only get 1 real shot at it every time
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Old 10-27-2016, 12:41 PM   #14
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Quote:
Originally Posted by 18psi View Post
why are your triggers set to 4G63?
Because he has a 95 and that is the setting you use for the CAS.
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Old 10-27-2016, 12:45 PM   #15
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switch to 2jz settings for more power
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Old 10-27-2016, 12:47 PM   #16
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Quote:
Originally Posted by bmxfuel007 View Post
[...]
priming pulse is a bit much. I'd probably half the values to start
[...]
Priming pulse can vary a LOT depending on your injector size since it's given in PW and not %.
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Old 10-27-2016, 04:04 PM   #17
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You could also check the idle and cranking settings. If it starts better with the throttle open a little bit, I'd start there.
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Old 10-27-2016, 04:11 PM   #18
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Too much ASE, too much WUE, too much cranking fuel IMO. Start with cranking fuel, then tune warm idle, then tune WUE on your next cold start, then tune ASE on the cold start after that. Use the WUE Autotune feature, it's quite good.
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