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2G Wastegate or BCS issue?

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DevineAstral

Proven Member
81
21
Jan 1, 2020
Irvona, Pennsylvania
Okay guys, I’ve exhausted all my research and I’m completely confused as hell now on my issue, where to really start, troubleshoot and how to actually narrow it down to what it is.

A few weeks ago I did a pull in my car (because turbo of course.!) and my check engine light came on. Went and got it scanned at autozone and it said there was a wastegate actuator solenoid malfunction. Tried to do some research on it, read somewhere that it could be the BCS was shot. Can’t find any anywhere online to replace it.

The current issue I’m having with my car is confusing because, I don’t know if it’s my BCS or if my wastegate is possibly stuck open (or closed, even?) Driving the car normally I don’t have any real issues. Boosts fine at 5psi and 10psi. And just normal cursing on level roads my gauge is reading -10psi (vacuum).
Here is my concern. When I’m driving down hill at all (regardless of speed) and when coming to a stop, my gauge reads -20psi (vacuum), and when I really let on the gas to full boost (15psi) it’ll get up to 15 psi, but only hold it for a few seconds it will begin dropping to anywhere between 11-14, sometimes gradually from 15psi to 10. A few times it hasn’t even reached full boost and only gets to 10psi.
On top of the positive boost issues that I’m having, when I give it the throttle there are times that the car seems like it isn’t even doing any acceleration! (the RPMs will go up, but the car hardly accelerates when this happens. Which hasn’t happened ALOT but is still happening nonetheless.) I don’t think I have a boost leak because that’s the first thing I thought of when I first experienced this (haven’t bought a boost leak test tool yet, but it’s in the cart. Just waiting till pay day or taxes come in.) and checked all of the lines and hoses and they all seem to be fine.

Where exactly should I start other than the obvious blt (when I get the tool)? I can’t track down any replacement BCS’s at the moment and I have no idea to find out if it’s the wastegate/actuator.

My car is completely stock other than a turboXS BOV. Thank you in advance my friends.!
 
Last edited by a moderator:
Super easy way to start with the wastegate would be to get a simple hand pressure pump from harbor freight or amazon that you can use to pump positive pressure. Unhook the tube going into the top of the wastegate and hook the handpump to it. Pump up the pressure slowly and watch for the wastegate to open and then once fully open it should hold the pressure and not drop off. If it does not open or does not hold pressure then get a new wastegate.
 
To test the bcs, just supply 12v and ground to the solenoid and it should click. Polarity doesn’t matter and it’s located under the intake. It has two vacuum hoses (one from boost source and the other going to the wg actuator), and a two wire connector. Sounds like you have a slipping clutch but idk if bcs issue will have the same symptom.

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For the BLT, please do not spend $50 on one, they are very simple to make ..

Go to Home Depot, in the plumbing section
In my case, I needed a 2" hose coupler and a 2" cap, the size you need will correspond to your turbo inlet. ~$5
Then go to O'Reilleys, or any auto parts store and get a schrader tire valve stem that screws on with rubber grommets. ~$5

Drill a hole in the cap, feed your valve through, then fasten it down tight.

For a pressure reading while doing the boost leak test, I used an old boost gauge and unhooked my vacuum line to my current boost gauge and kept it under the hood so I could read it while pressurizing the system.

There's alot of ways to slice this pie, others have things that work better for them and their set up, this is what worked for me!


Good luck!
 

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Boost leak test, Feed pressure to wastegate make sure it moves, send 12v to solenoid and make sure it clicks is what i would start with. Depending on RPM and load It's common for stock turbo to drop off in boost at high rpms.
 
Thanks for the help folks.! Long story short, I had to change my battery because the old one died and wouldn’t hold charge. While replacing the battery, I was also doing an oil change. While I was under their I figured “why not just unplug the BCS and plug it back in.? Couldn’t hurt anything I suppose.” Needless to say, it hasn’t thrown codes, nor am I having ANY of the issues as before. I still intend to do a boost leak tester for whenever I have problems in the future. I still donno WTF happened and kind of wished I would’ve been able to do all of thee above that was mentioned, just to get some more hands on experience, but I guess I can’t really complain. I assume after it kicked the light on it might have put the computer in a limp or loop.? Why else would changing the battery (and in doing so it resetting the computer) then disconnecting/reconnecting the BCS solve the mentioned issues.?
 
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