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Old Apr 4, 2011, 05:04 PM
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bucking at boost

Forgive me I'm new to tuning, and I'm trying to learn. My EVO IX has turbo back exhaust, Intake and IC piping. I installed my Grimmspeed boost solenoid, the lines from the turbo and from the waste gate were replaced, I followed what the instructions said (or so I think). Checked all my connections twice. I used ecuflash, changed my WGDC to 70%, and reflashed the car with tephra mod V7 88590715. I took the car on the road, slowly ran the car up to spool, once it hit boost, the car started bucking and jerking, almost felt like I was hitting fuel cut at 3500rpm. Evoscan says 2 counts of knock at that bucking interval, boost wasn't higher than 15. What did I do wrong?
Old Apr 4, 2011, 05:05 PM
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maybe a leak somewhere?
Old Apr 4, 2011, 05:18 PM
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It did feel that way. i thought that maybe there was something I did wrong in the hook up stage or tune.


Originally Posted by WRXGONE
maybe a leak somewhere?
Old Apr 4, 2011, 07:04 PM
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What is the "WGDC = 100% under this load" table set to? If you just barely pass that threshold then WGDC will immediately drop back to what's in your WGDC table, which will make the boost drop below the threshold, so WGDC goes back to 100%, boost increases beyond the threshold, and the cycle repeats.
Old Apr 4, 2011, 08:18 PM
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Make sure u have boost cut set to max, if u read the sticky at the top of forum I'm pretty sure it tells u how to set boost cut to max. Make sure u set wgdc low at first and get ur fuel and timing in check first
Old Apr 5, 2011, 04:05 AM
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Boost cut load is at 255 up to 4500 rpm, then tapers down to 235 by 7000.


Originally Posted by evoRS06
Make sure u have boost cut set to max, if u read the sticky at the top of forum I'm pretty sure it tells u how to set boost cut to max. Make sure u set wgdc low at first and get ur fuel and timing in check first
Old Apr 5, 2011, 04:18 AM
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check your plugs and the gap
Old Apr 5, 2011, 04:46 AM
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Originally Posted by CaptianSellout
Boost cut load is at 255 up to 4500 rpm, then tapers down to 235 by 7000.
If you want to use fuel cut feature, do yourself a favor and use the X2 by setting 0x4D00 under fuel cut multiplier. set then to around 280-290% and your issue should be resolved - if you need anymore help pm me.
Old Apr 5, 2011, 09:29 AM
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I'm new at this, too... but, did you zero out the turbo boost error correction table? With the change in control solenoid and the different base WGDC map, I can see the error correction fighting to hit the old load map and causing boost surges. The error correction table will likely need to be different than the stock table with the new solenoid (different sensitivities), but it should be zero until you get the new base WGDCs figured out.
Old Apr 5, 2011, 06:40 PM
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OK..Would anyone be willing to work with me a little one on one? Maybe over the phone, even just PMs? I'm having multiple issues here with different things, and I really need someone to point me in the right direction. I would really appreciate the help.
Old Apr 5, 2011, 09:55 PM
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Originally Posted by CaptianSellout
OK..Would anyone be willing to work with me a little one on one? Maybe over the phone, even just PMs? I'm having multiple issues here with different things, and I really need someone to point me in the right direction. I would really appreciate the help.
Captian, I'll be glad to help with whatever I can. Shoot me a pm mate!
Old Apr 7, 2011, 01:07 PM
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i suggest re-reading the sticky how to tune threads. summary is:
1. turn off error correction, start on a low wgdc like 40%
2. adjust your fuel cut.
3. start tuning your boost. make sure you monitor your afr, load, knock sum, as you slowly add boost.
4. when you get to your desired boost. dial in the afr, and timing.
5. setup you fuel cut tables and error correction tables.
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