Motor stalls out right before turbo spool

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xise
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Motor stalls out right before turbo spool

Post by xise »

So I have an odd issue that appeared out of nowhere, whenever the turbo is about to start compressing air (around 2500RPM) the motor wants to die. Not just like that hit the wall fuel cut feeling, it stalls for a second until I let off the gas pedal. Just wondering if this is a known issue with the 4EAT or if I have to go hunt this one down. I will note that it did this yesterday and flipping my power mode switch on and off seemed to fix it yesterday, but now it is doing the same thing in both regular and power mode.

Boost gauge is not indicating any sort of leak, it almost feels like the injectors are sending too much fuel and drowning the spark out, but that is just a complete guess, anyone have any ideas before I get into this thing?
2004 Impreza 2.5RS Fränkenpreza Daily Driver
1993 Legacy Sport: Sedan Sex Panther-R.I.P. @ the boneyard
1991 Legacy L Wagon: Sex Panther II
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Legacy777
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Re: Motor stalls out right before turbo spool

Post by Legacy777 »

Do you have a wideband O2 sensor that would be able to check AFR's?
Josh

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1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
xise
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Joined: Sun Aug 01, 2010 11:17 pm
Location: Rhode Island

Re: Motor stalls out right before turbo spool

Post by xise »

I do but I have not installed it yet, The controller I have has both digital for the wideband gauge and an analog output for what I assume is supposed to go where the orig 02 harness is...will it work like that or can I use the port on the header's collector, which is pre turbo....I just don't want to cut the 02 sensor's harness and have the voltage not be the same between the original sensor and the new output.

You think an injector might be clogged or something?
2004 Impreza 2.5RS Fränkenpreza Daily Driver
1993 Legacy Sport: Sedan Sex Panther-R.I.P. @ the boneyard
1991 Legacy L Wagon: Sex Panther II
2005 Outback XT Turbo grocery-getter Wife's Daily Driver
Legacy777
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Re: Motor stalls out right before turbo spool

Post by Legacy777 »

What wide band brand do you have? You need to verify what the output from the WB controller is. Some have an analog output for a EM systems, and some also have a narrow band O2 simulator. If it has a narrow band O2 simulator you can use that, otherwise you can't.

You shouldn't put the WB pre turbo. Exhaust pressure will affect the AFR readings.

I asked about the WB because you said it felt like it was getting too much fuel. A WB would be able to tell you whether you're running too rich or not.

You could temporarily install the WB, see what the readings are and then put the NB O2 back in.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
xise
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Location: Rhode Island

Re: Motor stalls out right before turbo spool

Post by xise »

Well I will try that and see how it goes, I figured that the sensor needed to be after the turbo so it would be accurate and not be reading the scavenging gasses. i'll have to compare the controllers narrowband signal to the actual sensor to see if they are compatible, probably not though...

It might be worth mentioning that I am pretty sure the turbo exhaust gasket is leaking, the stupid shop that did my transmission reused the ancient one that was on there in the first place, and I can smell uncatalyzed exhaust whenever I go over 10 Psi.
2004 Impreza 2.5RS Fränkenpreza Daily Driver
1993 Legacy Sport: Sedan Sex Panther-R.I.P. @ the boneyard
1991 Legacy L Wagon: Sex Panther II
2005 Outback XT Turbo grocery-getter Wife's Daily Driver
Legacy777
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Re: Motor stalls out right before turbo spool

Post by Legacy777 »

As long as the leak is post turbo, it shouldn't affect things too much. I would recommend getting a new gasket, but if the leak is post turbo, it shouldn't really affect the operation.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
xise
Third Gear
Posts: 576
Joined: Sun Aug 01, 2010 11:17 pm
Location: Rhode Island

Re: Motor stalls out right before turbo spool

Post by xise »

Aaaaaaand it did it once today then was fine......maybe this is just an ECU brain fart, I am going to get the codes if I have time tomorrow.
2004 Impreza 2.5RS Fränkenpreza Daily Driver
1993 Legacy Sport: Sedan Sex Panther-R.I.P. @ the boneyard
1991 Legacy L Wagon: Sex Panther II
2005 Outback XT Turbo grocery-getter Wife's Daily Driver
freefall
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Re: Motor stalls out right before turbo spool

Post by freefall »

If you get ecu code 45 than try replacing the pressure bypass valve. I was experiencing similar issues (although not exactly the same) and thats what was causing it for me. Dont bother spending $85 on a new one from subaru, i found one on a early forester xt at an auto wrecker/pick and pull for $5 And it was the exact same part. Plugged straight in.
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