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Crazy backfire issue!


jacob80

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I don't think that we set up the overboost limit, so I assumed that 0 disabled that function as in many other places in megatune. Do you think that this might be the root cause -- spark being cut right out of the gate and fuel being dumped into the exhaust, then ignited once the spark resumes?

 

I don't think so, but 0 isn't valid for that option. If you look at it you will see what I mean, when you try to close the window megatune will complain and then put a default value in there. Certainly set it to 200kpa or 255kpa and try again just to make sure. I would be more inclined to believe the big jumps in the VE table are causing some issues with fuel jumping too much. I would add some more bins for kpa so you have a smoother transition from 30kpa up to 100kpa and then try tuning again.

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I don't think so, but 0 isn't valid for that option. If you look at it you will see what I mean, when you try to close the window megatune will complain and then put a default value in there. Certainly set it to 200kpa or 255kpa and try again just to make sure. I would be more inclined to believe the big jumps in the VE table are causing some issues with fuel jumping too much. I would add some more bins for kpa so you have a smoother transition from 30kpa up to 100kpa and then try tuning again.

 

 

Ok, we will give all of those a try, including bumping base timing up to around 23 at idle. We were going for ultra-conservative on the timing to start so as to avoid any detonation, but maybe we're causing ourselves some trouble in the timing table as well. Thank you for help, and any additional observations are greatly appreciated!

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There isn't really a control for the fuel pump. There are the rev limiter settings which yours look OK, the overrun settings which you have turned off(that is OK), decel settings look OK, and the over boost setting which was not correct. How do you know the fuel pump or fuel is being turned off? That doesn't fit with the original description of going rich.

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There isn't really a control for the fuel pump. There are the rev limiter settings which yours look OK, the overrun settings which you have turned off(that is OK), decel settings look OK, and the over boost setting which was not correct. How do you know the fuel pump or fuel is being turned off? That doesn't fit with the original description of going rich.

 

Blown fuse was the issue, more on that later

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