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Power FC problem

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Endless

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hi all, just got my Power FC installed and tuned by a shop a month ago on my S15 Spec R, boost is set for 0.9bar low and 1.2 high (stock turbo). After the installation, the tech there told me that the previous guy that did my oil change had put way too much engine oil and therefore my car might feels a little stumble once in a while (is that possible?), anyway, been running for month and the car seems fine and response is good (water and oil temp are normal), however, i would feel the car to be stumble for a short time whenever in higher rev (from 5000 - 7000rpms) when I'm on full throttle. And today it got worse, and I can almost feel the engine knocking sound at high rpms for few times, check the knock level on my FC commander and highest record is 75, is that a big problem with it and what are the possible causes? I'm going to bring it back to the shop this week to check, but just want to know some possible causes in case they BS me, thanks guys.
 
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oilrag22

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http://paulr33.skylinesaustralia.com/docs/powerfc-faq/powerfc-faq.htm#30

Have a look at this site, i gives you some good tips on the PowerFC, also mentions knocking and so on...

Avoid the high load, high rev knocking till you get the tune up sorter, since this type of knock is an engine killer...

Sometimes an overfill of oil can cause certain problems with vacuumlines, boostcontrol and so on. So yes it is possible, especially Scooby's are known for this. But as soon as the oil level has been brought back to the correct level, it should sort itself pretty fast...
 
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j@garagemac

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when we mapped mitto's (D1Gb driver) s14.5 a on a stock motor using det cans we recorded a crack of knock at 122 on the pfc so it depends as any lower than 90 was fine on the car but i would get that oil sorted asap

kind regards jamie@garagemac
 
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I would say 75 knock on a power fc is pretty high....
manual says anything higher then 60 is high... so i would be carefully.
i only get max 25 knock on mine and it needs a tune badly.

would definetly bring it back.

too much oil would cause your breaker hoses to be full of oil going back into your intake and might clog your intercooler if you dont have a oil catch can..... i might be wrong......

running 1.2bar just make sure you got a fmic and bigger injectors. especially in hot climates.....
 
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sillbeers15

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PFC will warn by flicking the check engine light whenever the knock level exceeds 60. However, knock is only audiable when it exceeds 130level in PFC knock measurement!

So, is 75 high....gauge yourself!
 
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Endless

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But what do you guys think are the most likely causes for this stumbling at high rpms? too lean or rich in fuel or others?
 
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well seen that your knock is high the chance is, it's running lean too much air.

would defently bring it back to the tuner, he should be able to tell you.
or unless you got a wide band o2 sensor to monitor it.
 
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sillbeers15

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Retard the ignition timing at the rpm/load point which the 'check engine' light flashes.
 
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Endless

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I finally get the problem of stumble at high rpms solve, turns out it is not the issue of tuning PFC, I'm actually having major boost spike (run as high as 1.5 bar at high rpms). Found that my old HKS actuator is getting loose and could not hold up the boost properly, get a new one installed and problem solved, takes a while for my mechanics to found out though.
 
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good work.
im currently experiencing boost creep.:(

dont think mine the actuator as it is new.

what boost controller you using??
 

japmadlad

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are these any good? was thinking of buying one cause theyare cheaper than the hks evx5 or apexi avc-r. also been told the solnoid on the apexi isn't gr8
 
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Endless

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are these any good? was thinking of buying one cause theyare cheaper than the hks evx5 or apexi avc-r. also been told the solnoid on the apexi isn't gr8

I think the Greddy Profec B that I'm using now is quite good, have 2 setting (high and low boost) and can be switch anytime
 
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