Stalling after MBC

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DTSJR
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Stalling after MBC

Post by DTSJR »

I think I have an idea of why Im having a problem, I just wanted to double check with you guys. Im still learning about turbos, so this is a learning experience for me.
I built a MBC yesterday. I want to buy a Hallman, but I figured a DIY one would be good for 10-12 PSI until I get an intercooler.
I installed it tonight using the directions from the write up in the library. I took it out and when I left my driveway it made 10psi of boost. I was only on it for a second to see how much boost it was making. I made it about 1/8th of a mile down the street, and going up a hill, just as it was about to make boost, the check engine light came on and it stalled. It wouldnt start back up again, so I rolled down the hill in neutral, and it started right up. I went home, double check all my connections, and went back out. Leaving the driveway it made 10psi fine. I got a couple hundred feet and the CEL came back on. Going up the hill it almost stalled, but I was able to save it. I made it to the end of the street and turned around. I gave it soem gas to see if it would make boost, and just as it was about to, it stalled again.
Now, heres what I think is the problem. I already had a T fitting on the vaccum line after the purge valve I was using for my boost gauge, so I used that for the MBC. Would this cause the CEL and the stalling? Im friggin freezing, so tomorrow Im going to move the T to before the purge valve and see if that makes a difference.
Thanks for any help.
00 Impreza RS
93 Legacy SS
Legacy777
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Post by Legacy777 »

You really should run the MBC off the nipple at the turbo compressor.

Can you draw up a diagram of how you have things plumbed up?
Josh

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1990 Legacy (AWD, 6MT, & EJ22T Swap)
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DTSJR
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Post by DTSJR »

I hope this helps. Dont mind the intake, haha.

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00 Impreza RS
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DTSJR
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Location: MA

Post by DTSJR »

This morning I moved the MBC T to before the purge valve, and when I drove it, it was running only at stock boost. I adjusted the MBC and it was still stock boost. It didnt stall at all setup like this. I brought it to the dealership and they read the codes, 21 coolent temp sensor (which I replaced about a month ago), and 45 pressure sensor. They said they didnt see any problems with how the MBC was hooked up before or after the purge valve. They did suggest moving from the vacum line to the turbo. I turned the screw in several turns and when I was leaving, it hit 15psi. I guess I just needed to play with the adjustment a little more. But I still dont know why it was stalling when after the purge valve.
00 Impreza RS
93 Legacy SS
Legacy777
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Post by Legacy777 »

Yeah I don't know why it would stall with it after the purge.......
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
sweetmeatz
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Post by sweetmeatz »

pull the code it will probaly help diagnose the problem
rallysam
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Post by rallysam »

Your hookup is not really the best approach for other reasons, but I dunno why it would cause stalling.

It's best to plumb an MBC straight off the turbo compressor.
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'91 Legacy Turbo 5MT - mothballed
13psi, TurboXS TBE, WRX IC, Hallman MBC, TurboXS FCD, KYB AGX, Phil's STI seat, SPT short shifter, David Carter hood, Zeitronix widebandO2, Kuhmo rally tires, STI IC spray, thanks:gearboxtech.com
DTSJR
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Post by DTSJR »

I was just following the directions from The Library. I dont know why it was stalling with the MBC after the purge valve, but its better now. I had the boost at 11psi today, and I hit fuel cut a few times :/.
00 Impreza RS
93 Legacy SS
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