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Old Sep 25, 2005, 11:59 PM
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Exclamation Boost Problems!

Hey guys, I am having an issue with some sort of boost or fuel cut with my '03 EVO after installing a MBC. My power upgrades are, K&N Intake system. RNR Intercooler Piping, HKS SSQV, RNR Turbo Back exhaust, & Forge Unos MBC.

Supposedly you can set the MBC to 1.4 or about 19-21 psi. When I set it to about 1.3 kgcm, I get some sort of boost or fuel cut. The car would just cuts out for a second or 2. So I remove the MBC, and put the stock vacum lines back, and the problem goes away. So I figured it was the MBC, so I buy the Forge one, I installed it according to Forge, Turbo/wastegate, and it starts doing it again but at about 1.2kgcm. So I decided to "T" it off the intake, and now I can get about 1.3 but I still sometimes get that boost or fuel cutout. Its so weird, my friend has the same setup and he is not getting a boost, fuel cut issue and holds about 1.4kgcm. Also I had the 1st MBC installed by RNR, they removed it when they couldn't figure out the problem. The Forge Unos was installed by the dealership friend of mine turbo/intake, and I just switched after getting that boost/fuel cut.

Is there anything I can checkout, do, or change?

Thanks to everyone who can help!
Danny

Last edited by bigboybusa; Sep 26, 2005 at 05:42 AM.
Old Sep 26, 2005, 07:41 PM
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have you ever had a reflash?
Old Sep 26, 2005, 11:36 PM
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Originally Posted by titaniumkingpin
have you ever had a reflash?
The dealership flashed the ecu to get rid of the misfire code.
Old Sep 26, 2005, 11:43 PM
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what kinda gas are u using?
Old Sep 26, 2005, 11:46 PM
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Originally Posted by bigboybusa
The dealership flashed the ecu to get rid of the misfire code.
No like a tuner actually giving you a custom tune?
Old Sep 26, 2005, 11:50 PM
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My car ran like crap until I got rid of that piece of sh** K&N Intake
Old Sep 27, 2005, 12:20 AM
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Originally Posted by wirespeed
what kinda gas are u using?
91 octane
Old Sep 27, 2005, 05:43 AM
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Originally Posted by bigboybusa
Supposedly you can set the MBC to 1.4 or about 19-21 psi. When I set it to about 1.3 kgcm, I get some sort of boost or fuel cut. The car would just cuts out for a second or 2. So I remove the MBC, and put the stock vacum lines back, and the problem goes away.
what was your boost gauge reading when you put the stock lines back on?
Old Sep 27, 2005, 07:54 AM
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Originally Posted by Doogie Howser
No like a tuner actually giving you a custom tune?
No it hasn't
Old Sep 27, 2005, 07:55 AM
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Originally Posted by AlwaysinBoost
what was your boost gauge reading when you put the stock lines back on?
1.35 cmkg then peters off at about 1.2
Old Sep 27, 2005, 09:59 AM
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try this.....

take your K&N intake out, and leave the MBC in.
Old Sep 27, 2005, 10:03 AM
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sure your boost gauge is correct? Sounds like its peaking too high. Make sure you tap off bov line for your mbc.
Old Sep 27, 2005, 10:30 AM
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Originally Posted by bigboybusa
1.35 cmkg then peters off at about 1.2
your getting fuel cut because the ECU is seeing something it doesn't like. did you replace the vacume lines when you installed the MBC or just reuse your stock lines? did you leave the stock boost solenoid plugged in?
Old Sep 27, 2005, 10:49 AM
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You might want to try a different boost gauge. Where do you have your boost gauge hooked up at?
Old Sep 27, 2005, 03:44 PM
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Originally Posted by AlwaysinBoost
your getting fuel cut because the ECU is seeing something it doesn't like. did you replace the vacume lines when you installed the MBC or just reuse your stock lines? did you leave the stock boost solenoid plugged in?
Yes to both questions.


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