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Old 06-14-2018, 07:08 PM   #1  
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Default Engine Cutting out in boost

Hi everyone! I'm new to the forums and new to tuning.
When I get into about 4700 rpm in first gear, it seems to hit a rev limiter? It is at about 5psi of boost or so there. In second gear and up, the "rev limiter" drops to about 4000 rpm.
I thought it was spark blowout and tried gapping down the spark plugs to .025. It didn't make a difference. I turned off overboost protection, and it made no difference.
Any ideas? Also, I'm running MSPNP2. I attached a datalog of two quick pulls.

Thanks!
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File Type: msl 2018-06-14_15.04.58.msl (126.7 KB, 11 views)
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Old 06-14-2018, 07:51 PM   #2  
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What are your overboost settings like? It could be hitting that
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Old 06-14-2018, 11:30 PM   #3  
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I disabled overboost to test if it was that so there is no overboost protection right now.
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Old 06-15-2018, 05:16 AM   #4  
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What sort of injectors are you running? I'm seeing close to 100% duty cycle.
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Old 06-15-2018, 11:59 AM   #5  
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Originally Posted by phipplet View Post
I disabled overboost to test if it was that so there is no overboost protection right now.
Not a good approach. Overboost protection can save you engine from inadvertent changes in MS settings / popped boost control hoses / etc.

I know of at least (2) situations where a replacement engine could have been avoided if overboost had been employed.

Pretty sure it saved my rods when I re-plumbed the EBC incorrectly.
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Old 06-15-2018, 11:10 PM   #6  
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What sort of injectors are you running? I'm seeing close to 100% duty cycle.
Im running RX8 injectors. I might not be getting enough fuel with those?
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Old 06-15-2018, 11:11 PM   #7  
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Not a good approach. Overboost protection can save you engine from inadvertent changes in MS settings / popped boost control hoses / etc.

I know of at least (2) situations where a replacement engine could have been avoided if overboost had been employed.

Pretty sure it saved my rods when I re-plumbed the EBC incorrectly.
Ok, thank you for the input. I'll be sure to raise it instead of just disabling it.
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Old 06-16-2018, 04:53 AM   #8  
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Im running RX8 injectors. I might not be getting enough fuel with those?
If they're the real deal, those injectors are good enough for what you're trying to do. I've heard stories of fake rx8 injectors though. If there's any time to upgrade to EV14 injectors (e.g. flowforce or id1000), this would be a good one.

It could also be that you've tuned your car based on a low fuel pressure, which could be the pump or fpr.
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Old 06-17-2018, 10:02 PM   #9  
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If they're the real deal, those injectors are good enough for what you're trying to do. I've heard stories of fake rx8 injectors though. If there's any time to upgrade to EV14 injectors (e.g. flowforce or id1000), this would be a good one.

It could also be that you've tuned your car based on a low fuel pressure, which could be the pump or fpr.
So I ended up putting on a secondary fuel pump to bump up the fuel pressure, and while it helped my tune, I am still having the same issue of my engine cutting out in boost. I'm going to try new spark plugs tomorrow and see if it helps.
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Old 06-18-2018, 02:40 AM   #10  
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So I ended up putting on a secondary fuel pump to bump up the fuel pressure, and while it helped my tune, I am still having the same issue of my engine cutting out in boost. I'm going to try new spark plugs tomorrow and see if it helps.
Be sure to check your logs for injector duty going near 100%. In your previous log your car was also running pretty lean during the 'cut out'. You might also get some hefty detonation in those situations.
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Old 06-18-2018, 02:55 AM   #11  
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So I ended up putting on a secondary fuel pump to bump up the fuel pressure, and while it helped my tune, I am still having the same issue of my engine cutting out in boost. I'm going to try new spark plugs tomorrow and see if it helps.



If the pump is determining your fuel pressure you got problems friend.

If you're concerned about the fuel pressure put a gauge on it. You have a fuel pressure regulator that should be handling pressure controlling duties.
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