Backfire on startup, and idle Kpa

General Topics for configuring, operating and tuning the Megajolt. Also see the <a href="http://www.autosportlabs.net/MJLJ_V4_Operation_Guide">Operation Guide</a>

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wvitpr
Posts: 7
Joined: Thu May 14, 2009 6:38 am

Backfire on startup, and idle Kpa

Post by wvitpr »

HI,
I have finally got my megajolt V4 setup, installed and running. I do have a couple of questions however.

It seems to have developed a backfire through the exhaust, only if the engine is hot and you restart it, it scares the crap out of you. Any Ideas ???

Also I am using the Map optioned MJ, and at idle it is around 60Kpa, does that sound correct.

My Cam has the following advertised duration 280 Inlet 276 Exhaust would this be contributing to the idle map kpa ??

Many

Thanks

brentp
Site Admin
Posts: 6282
Joined: Wed Jan 24, 2007 6:36 am

Post by brentp »

Hi,

Are you running the default map still, or have you made adjustments or loaded a different MAP for your engine?

With aggressive cams I can see how your engine may idle at a slightly higher than normal KPa. You can tune the idle advance to see if your engine runs better/smoother.

As for the backfire, does it happen on cranking, right after start, or after it's been running for a bit? Does it otherwise start smoothly this way?
Brent Picasso
CEO and Founder, Autosport Labs
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wvitpr
Posts: 7
Joined: Thu May 14, 2009 6:38 am

Post by wvitpr »

Hi Brent,
the backfire happens on cranking, after it has been running eg. warm

I am using a the basic map found on the forum, I added a little more advance at low kpa, for light load crusing

Basic MAP.mjlj
Description:

Download
Filename: Basic MAP.mjlj
Filesize: 793 Bytes
Downloaded: 843 Time(s)
Yes after the backfire it runs very smoothly.

What would cause this ??

Phil

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