How do I get my bug to start like factory

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paullanzarotti
Posts: 37
Joined: Sat Dec 13, 2014 4:01 pm

How do I get my bug to start like factory

Post by paullanzarotti » Wed Jul 19, 2017 6:27 am

With the stock ECU my Mexican bug used to start immediately like this:https://www.youtube.com/watch?v=d2GNVS3a5x4

However, since moving to Megasquirt it take a few seconds to start. I have dialed in the start up sequence and I have been playing around with the settings for nearly 2 years now and still it doesn;t get close to starting as well as it did with the factory ECU.

It seems like the spark takes a few seconds to kick in (I'm using wasted spark) and although I have reduced the "skip pulses" from 3 to 2 it still make no difference.

IS there anyone out there using MS on a bug that has managed to get it to start quickly?

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ps2375
Posts: 302
Joined: Mon Aug 18, 2014 10:04 am
Location: Meridian,ID

Re: How do I get my bug to start like factory

Post by ps2375 » Thu Jul 20, 2017 11:56 pm

Found this explanation on a forum w/ a google search: "It's a number of tach pulses to skip on startup before sending spark. Useful to build oil pressure before spinning the crank quickly or to get a good sync. 3 is a decent number to use."

You could reduce it more if you want. Have you tried '0"?

paullanzarotti
Posts: 37
Joined: Sat Dec 13, 2014 4:01 pm

Re: How do I get my bug to start like factory

Post by paullanzarotti » Fri Jul 21, 2017 4:53 pm

It needs a couple of tach pulses to get its timing. I haven't tried reducing to zero because the difference between 3 or 0 revolutions of the engine when it's cranking at 200 rpm is about 0.9 of second and I am trying to figure out why the engine cranks for 2-3 seconds. I have reduced it to 2 and that's made no difference so I don't think that's where the issue lies.

It would be helpful if anyone has a video of their MS bug starting to use as a comparison.

paullanzarotti
Posts: 37
Joined: Sat Dec 13, 2014 4:01 pm

Re: How do I get my bug to start like factory

Post by paullanzarotti » Fri Jul 21, 2017 4:53 pm

It needs a couple of tach pulses to get its timing. I haven't tried reducing to zero because the difference between 3 or 0 revolutions of the engine when it's cranking at 200 rpm is about 0.9 of second and I am trying to figure out why the engine cranks for 2-3 seconds. I have reduced it to 2 and that's made no difference so I don't think that's where the issue lies.

It would be helpful if anyone has a video of their MS bug starting to use as a comparison.

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ps2375
Posts: 302
Joined: Mon Aug 18, 2014 10:04 am
Location: Meridian,ID

Re: How do I get my bug to start like factory

Post by ps2375 » Fri Jul 21, 2017 5:24 pm

how are you priming pulses setup? and your cranking pulses? And do you have an AUX Air valve/idle valve?

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