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Old 01-18-2012, 02:08 AM   #1
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Default Priming Pulsewidth help MS2

Gday guys,

I've done some searching couldn't come up with what I was after, If there is a relevant thread that would be great.
This is the priming pulsewidth settings that came with my brain ms2.

Is this right lol?



Thanks,
Dann
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Old 01-18-2012, 02:08 AM   #2
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More specfically why are all the temperatures -18c? should there be a full range of them?

Dann
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Old 01-18-2012, 02:11 AM   #3
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I don't know much about MegaSquirts, but what little I know is enough to tell me that something is corrupted, or flat out wrong, or someone is ------- with you with that table. Brainy, did you troll a customer? :P

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Old 01-18-2012, 03:15 AM   #4
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Obviously enough, the temperatures are wrong. Scale them from the coldest you are going to face in your area, up to 200*F. The pulsewidths are also off the chart. I would start with 20ms at the coldest, and drop down to 4ms at 200*F.
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Old 01-18-2012, 03:42 AM   #5
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Thanks,I thought maybe that gave a generic PW and it scaled with something else, or mostly used the cranking PW to start it. It does start ok.

Dann
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Old 01-18-2012, 09:37 AM   #6
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Can you check everything else in your map isnt like that, like the fuel and ignition settings,/tables?

Its possible when you converted the map from F to C, it didn't convert over?

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Old 01-18-2012, 09:56 AM   #7
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yeah, mine vary from like 3ms down to 1ms..thats way too high
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Old 09-25-2012, 06:03 AM   #8
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Old bump here.

But does the Prime PW setting vary depending on injector size or any other hardware variables? Rev you said start with 20ms at the coldest, i'm only at like 4.0 at the coldest. I'm trying to figure out if that's my coldstart issue. Though i have 750cc injectors, not sure if that would make a difference.
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Old 09-25-2012, 08:05 AM   #9
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cranking PW is based on/scaled to Req_fuel. I can't say for certain but I would guess this is as well. when i put in larger injectors, i didn't bother changing this and it worked well/the same.
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Old 09-25-2012, 09:54 AM   #10
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priming pulsewidth in the amount of time the fuel pump runs when you turn key on.

it is not to be confused with cranking pulsewiedth
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Old 09-25-2012, 10:14 AM   #11
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Okay, so by changing Priming PW it won't effect my coldstart issue. I was thinking i needed a bigger inital shot and by priming longer i could get that. I was also thinking the injectors would spray for *X ms* before cranking, they don't do this?

Basically i have to key over 2 or 3 times (crank then off crank then off ect) before it fires. It gets worse when it gets colder. I was just wondering what i should be looking at as far as numbers go, and what's my max, i've read 65ms but i'm nowhere near that.
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Old 09-25-2012, 10:21 AM   #12
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I guess it does:

Quote:
The Priming Pulse is the amount of fuel added when the ignition is first switched on. It is to help the engine start a little quicker during cranking. I tend to leave this at zero when messing about with the install, etc, as flooding can soon occur if your switching the ignition on and off a lot. So this is best set after the engine is running.

why not just work on simply tuning your cranking table? that's a start.
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Old 09-25-2012, 11:06 AM   #13
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Quote:
Originally Posted by Braineack View Post
why not just work on simply tuning your cranking table? that's a start.
Why would i have to key over crank then turn the key to off then crank, priming the system over and over to get it to start when it's cold? I dunno. I guess i'll try both, i'm as i'm sure it's a combination.
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Old 09-25-2012, 11:09 AM   #14
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turn off priming pulse completely.

lower you crank pulse table significantly and try to crank at that troubled temp. increase the pulse width until car starts.

congrats, youve tuned.
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Old 09-25-2012, 11:39 AM   #15
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That's how it was before it started getting cold and i was having this problem.

Okey dokey then, i'll give it a shot.
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Old 09-26-2012, 02:25 AM   #16
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from this thread, i have learned what the priming pulse is. this makes me

next stop - learn what cranking pulse is.

this guy? <- soooooooooooooo noob.
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Old 09-26-2012, 05:52 AM   #17
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Quote:
Originally Posted by imperfekt View Post
from this thread, i have learned what the priming pulse is. this makes me

next stop - learn what cranking pulse is.

this guy? <- soooooooooooooo noob.
See that's weird because i came in here thinking i knew what it did. Now i have no idea, i don't even really know what the point of it is anymore.

Learn yourself some cranking pulse though, that's kinda important.
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Old 09-26-2012, 09:25 AM   #18
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Quote:
Originally Posted by Erat View Post
Learn yourself some cranking pulse though, that's kinda important.



The priming pulse gets fuel at the ready, otherwise if the car sits you can lose pressure at the rail. The priming pulse turns on the fuel pump with key on, so the lines get build pressure and apparentlyh you inject some fuel so when you do crank, everything's rarin' to go.

the cranking pulse is simply how much fuel is injected when youre cranking. couldn't be simipler than that.
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Old 09-26-2012, 09:34 AM   #19
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I was mocking you, because appearantly i don't know enough about how important cranking pw is.
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Old 09-26-2012, 09:37 AM   #20
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the morning it's 20F out, late for work, and the car wont start, you'll learn yourself some cranking PW really fast.
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