ej207 v5 swapped from vf28 to vf34 not runs rich @ idle

impreziv25 · 05-22-2007, 03:18 PM

Ok, so I swapped out my old turbo and put on a brand new IHI VF-34 and now the car seems to idle rough, can't seem to find any air leaks or anything of the sort.......

any idea?

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vinceGC8 · 05-22-2007, 04:41 PM

tune?

Matt Monson · 05-22-2007, 04:44 PM

I would take it out and drive it for a bit. It oftentimes takes a bit for the ECU to learn after a change like that. It's not really a big change since it's really close to the same turbo, but with a more modern bearing design. The stock ECU should run it just fine, though you have cleared all the learning the car has done since the swap and it's probably now looking for Japanese octane levels in the fuel, among other things...

impreziv25 · 05-22-2007, 06:18 PM

The power FC is on its way, I had reset the ecu and been driving it moderately for 3 days so I figured it would have gone through its learning curve by now. But yes, I am going to tune it, just wanted to make sure thee wasn't something stupid I was overlooking. I am figuring the restriction isn't quite the same as the other turbo at idle.

Hopefully the tune will solve it all, just hopeing the Power Fc gets here soon!!

Scoobie Steve · 05-23-2007, 05:30 PM

Sounds like a MAF on its way out. Is it cutting out up high? My car ran fine with the vf28. vf30 and vf22 on stock ecu. When you get the PFC make sure you pull a couple degrees of timing out under boost and tune the a/f ratio. Good time to trash that crappy MAF.

OT but do you still have the vf28?

impreziv25 · 05-24-2007, 04:44 PM

Its weird, its like its running just rich enough to slightly bog it down, but it still makes power, and plentty of it!!

Just smells richer than when I had the vf28 and idles a little rougher. Even pulled the IAC out and cleaned it, wasn't very dirty at all and it didn't change anything.

What are my options for replacing the MAF?? I mean what can be wired to work with the PFC??

impreziv25 · 05-24-2007, 04:46 PM

oh I don't have the VF28 anymore, gave it to a buddy that helped me with the swap.

05-22-2007, 03:18 PM	#1
impreziv25 Scooby Newbie Member#: 107105 Join Date: Feb 2006 Chapter/Region: MWSOC Location: GRIMMSPEED Vehicle: 2001 ver 5 STi swap Coupe BRP	ej207 v5 swapped from vf28 to vf34 not runs rich @ idle Ok, so I swapped out my old turbo and put on a brand new IHI VF-34 and now the car seems to idle rough, can't seem to find any air leaks or anything of the sort....... any idea? * Registered users of the site do not see these ads. Last edited by impreziv25; 05-22-2007 at 03:25 PM.

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05-22-2007, 04:41 PM	#2
vinceGC8 Scooby Specialist Member#: 72263 Join Date: Oct 2004 Chapter/Region: SCIC Location: Los Angeles Vehicle: 2008 Impreza STi Dark Grey Metallic	tune?

05-22-2007, 04:44 PM	#3
Matt Monson Scooby Guru Member#: 832 Join Date: Jan 2000 Chapter/Region: RMIC Location: Teh Ghetto Garage, CO Vehicle: 99 2.5RS, '85 911 '73 914 and 2012 BRZ	I would take it out and drive it for a bit. It oftentimes takes a bit for the ECU to learn after a change like that. It's not really a big change since it's really close to the same turbo, but with a more modern bearing design. The stock ECU should run it just fine, though you have cleared all the learning the car has done since the swap and it's probably now looking for Japanese octane levels in the fuel, among other things...

05-22-2007, 06:18 PM	#4
impreziv25 Scooby Newbie Member#: 107105 Join Date: Feb 2006 Chapter/Region: MWSOC Location: GRIMMSPEED Vehicle: 2001 ver 5 STi swap Coupe BRP	The power FC is on its way, I had reset the ecu and been driving it moderately for 3 days so I figured it would have gone through its learning curve by now. But yes, I am going to tune it, just wanted to make sure thee wasn't something stupid I was overlooking. I am figuring the restriction isn't quite the same as the other turbo at idle. Hopefully the tune will solve it all, just hopeing the Power Fc gets here soon!!

05-23-2007, 05:30 PM	#5
Scoobie Steve Scooby Specialist Member#: 2289 Join Date: Sep 2000 Chapter/Region: Tri-State Location: Bangor, PA Vehicle: 1998 11.87@112mph Subaru L Ver 6 STi Type R	Sounds like a MAF on its way out. Is it cutting out up high? My car ran fine with the vf28. vf30 and vf22 on stock ecu. When you get the PFC make sure you pull a couple degrees of timing out under boost and tune the a/f ratio. Good time to trash that crappy MAF. OT but do you still have the vf28?

05-24-2007, 04:44 PM	#6
impreziv25 Scooby Newbie Member#: 107105 Join Date: Feb 2006 Chapter/Region: MWSOC Location: GRIMMSPEED Vehicle: 2001 ver 5 STi swap Coupe BRP	Its weird, its like its running just rich enough to slightly bog it down, but it still makes power, and plentty of it!! Just smells richer than when I had the vf28 and idles a little rougher. Even pulled the IAC out and cleaned it, wasn't very dirty at all and it didn't change anything. What are my options for replacing the MAF?? I mean what can be wired to work with the PFC??

05-24-2007, 04:46 PM	#7
impreziv25 Scooby Newbie Member#: 107105 Join Date: Feb 2006 Chapter/Region: MWSOC Location: GRIMMSPEED Vehicle: 2001 ver 5 STi swap Coupe BRP	oh I don't have the VF28 anymore, gave it to a buddy that helped me with the swap.