Newbie question about boost leaks

[Karnich]

Hello

Im a young guy at the age of 20. in under education as a mechanic so i know some stuff but all tuning / turbo stuff etc is pretty new. but im very interested in learning!

i recently bought a japanese Mitsubishi eclipse GST 4g63-t witch im very happy for.
the recent owner have build intercooler and a blow off valve on the engine.. it runs everything else stock. oh and it also have a wideband gauge and boost gauge.

before i bought it the owner told me that it had something called fuel cut. that i could cut off the fuel at 4500 rpm if i gave it full throttle. that it was normal on japanese cars.

i wanted to find out how to remove it. with a fuel cut defenser. but i read on this site that i shouldnt do that, and that its possible a boost leak when i run stock boost, 1,09 BAR. (dont know it in PSI)

a few weeks ago i wanted to switch the hose from the blow off valve to the intake. cause it seemed broken. i soon discovered when unmounting it that it wasnt broken. but it was sitting on (english isnt perfect so dont know the word) picture to describe it:

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the hose dosnt sit perfect on it you could imagine.. and the new hose i bought couldnt fit.. so i pulled the old one half over it as good as i could.

NOW im thinking.. this hose.. witch goes into the intake, and have acess to other air than just the one from the blow off (since it fits poorly) COULD this be the reason for the FUEL cut as early as 4100 RPM?

EDIT: have to note that i have enough power, no problem there runs the 1,09 BAR of boost with no problem . but fuel cut betwen 4000-4500 isnt satisfying :/


sorry for a long text and question. im still learning!

 

[DSMunknown]

1.09BAR is about 15PSI.

You should consider buying a kit like this. I hope you're recirculating the BOV back into the intake pipe.

 

[clipse4u2c]

fuel cut is not a good thing or normal. It means you have a problem not getting enough fuel. That hose connects after the mas so it's unmetered air meaning that you have more air going in that what your ecu thinks so it could be possible..What I would do is remove the hose and tape/block off where the hose goes into the intake....It's not good to vent to atmosphere but it's worse to have unmetered air going into your system. ...If that fixes the problem then you know you should get that fixed asap....IMO you can get an adapter to recirculate the bov or the more expensive route would be to get a maf and maf-t and you can leave it vented.

 

[4G63dsm1]

all you have to do is remove that piece of the BOV that you circled and replace it with the one on that link DSMunknown gave you. The Hose will never fit on that piece of that bov you have now.

 

[Karnich]

thanks alot guys ill try that

 

[OddNotion]

Karnich, does your BOV actually have a bell-shaped outlet with holes around the outside like the picture you posted?

If the hose is slipped haphazardly over the bell shaped nozzle, and those holes are there, meterd air would escape through the holes.

Please take a picture of your engine if you can, it will help a lot in diagnosing the problem.

 

[Karnich]

yes it does have holes and is bell shaped.. a week after i bought it i saw it.. the hose looked weird so i thought it was broken.. i took it off and found it it was pushed around the bell shaped outlet of the blow off >.< didnt know at that time if it had any effect other than it could suck some "false" air.. but since it ran smooth and without any problems i didnt think much about it. (its aprox 2 weeks ago)

but i just messured the bell outlet to 29 mm so ill try and call a danish store monday and see if they got it. if not ill order it from the US site (ya im from denmark )

cant take a picture right now since im on my way out of the door :/

 

[clipse4u2c]

just as you said it will "suck" in air because it is preturbo causing you to run lean if it was after turbo you would be blowing "out" air causing you to run rich

 

[SpiralOut]

So off topic a little bit, Your DSm has a 4g64? That is pretty cool, What compression are you running?

 

[jasonwinnell]

dang

 

[Karnich]

So off topic a little bit, Your DSm has a 4g64? That is pretty cool, What compression are you running?

sorry mistyped its a 4G63-T

what are those bell shaped outlets for anyways with them holes in it? is it for the "pppfffff" sound or what?

 

[DSMunknown]

what are those bell shaped outlets for anyways with them holes in it? is it for the "pppfffff" sound or what?

It's supposedly there to "enhance" the sound of the venting air. This should mean nothing to you, because you're recirculating the air back into the intake pipe.