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Discussion Starter #1
This is on a 94-99 VR-4 with stock 11 psi boost. After the tech told me I had two blown head gaskets, low compression in cyl 1 and 2, and multiple exhaust valve leaks in other cylinders (engine had 290K on it), I took the plunge and bought a $5100 VR-4 engine from JDM with 45,000 miles on it. Luckily it came with turbos and a transmission. Dealership tech did a great job overall for the installation; I've tried a couple aftermarket shops and both ended up disappointing for more than one reason, so I'm back to the dealership with this dinosaur of a car. A lot of specialty shops here in CA will not even work on a car this old, so not many other options in my area. Engine and transmission is very smooth now, but I'm missing that mid-range torque punch the last engine had, and the newer engine/turbos don't seem any faster than the old engine that was on its last legs. No check engine lights besides AWS PWR which is probably just some bubbles, because the fluid is 100% topped off.

I originally bought the car with 59,200 miles on it and that original engine pulled hard to 100+ mph for many years until about 180,000 miles, the turbos started going bad at that time. Before then, the stock 'boost' gauge, which some on here say is really a total engine load gauge disguised as a boost gauge, pegged the top of the scale way over 14 psi. It did that over and over again in 3rd through 6th gear, consistently all the way to 180K miles. No boost issues at all before the turbos themselves got old. I guarantee that the engine was not previously modified at all, so maybe the wastegates were disconnected or something, not sure. When I later put in a GReddy aftermarket boost gauge, it read 0 when the stock gauge read 0, but after that the aftermarket gauge read about 40% lower, as in when the stock read 7, GReddy would be 5, stock read 10, Greddy would be 7, stock read 14, Greddy would be 10, etc. When everything was boosting good before 180K on the original engine, the Greddy would read 10-12 psi, and the stock would be above 14 psi, like it always did (I had a boost controller on at this point at well).

Well, welcome to the year 2020, boost controllers have been outlawed here for 10 years, smog station ripped out the aftermarket solenoid in 2017, and now with the newer engine and turbos, the stock gauge psi peak is a little over 9, Greddy psi is only reading 4! It's not even reading 6-7 like before. I'm pretty sure the Greddy boost is correct, that's what it feels like, about 60-80 less HP than the last engine when it had 140-180K on it. What can I do? Should I try to find someone to disconnect the wastegates? I can't do it in my garage. Should I drive it later to Phoenix AZ and have someone install another boost controller and then hide it from the CA smog station? What other options? I'll call the dealership but I doubt they can do anything if they just worked on it.
 

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It sounds like either A) wastegates are connected directly to boost reference/source (removed EBC solenoid and tied intercepted lines altogether) and/or B) boost leak(s). It is most likely the former though.

Is the GReddy boost gauge just a gauge, or is it also your controller? e.g. PRofec e-01, B-Spec II, etc.
 

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Discussion Starter #3
It sounds like either A) wastegates are connected directly to boost reference/source (removed EBC solenoid and tied intercepted lines altogether) and/or B) boost leak(s). It is most likely the former though.

Is the GReddy boost gauge just a gauge, or is it also your controller? e.g. PRofec e-01, B-Spec II, etc.

Thanks for that. The GReddy Profec Type-S is disconnected. It never read psi digitally anyway, it was a 100% analog controller. So this is a completely separate boost gauge where the ashtray was, by the shifter. Now...how the aftermarket shop hooked it up many years ago, I don't know. When I was talking with the tech that installed the engine, he said nothing is complicated EXCEPT the turbo hoses. So maybe he really did screw that up. If it's something simple like 'Disconnect hose B and D from solenoid" off a diagram I can do that, otherwise I'm going to need a mechanic to do it.

Can you briefly explain how they should be connected or disconnected from/to what, so I can tell whoever is trying to work on it? I know that sounds dumb but I swear most mechanics do not know how to work on 90's turbo cars now, seriously. They just hook up a scanner and reprogram stuff on the newer post-2000 vehicles, they don't even know how to actually decipher an induction hose diagram any better than I would.
 

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There's a restrictor orifice in the feed hose to the stock boost control, the stock solenoid bleeds off pressure to increase boost. I would bet money that hose was replaced and the restrictor is gone. The solenoid will do nothing but serve as a boost leak with that restrictor missing.
 

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Are you in SoCal or NorCal? If SoCal, you should look to Chai at C&A Auto for anything 3000gt related, assuming you don't want to do the work yourself. You can PM me if this is relevant for you and you want more info.

I also had the some question similar to above comments/questions - how are your vacuum lines to the turbo wastegates currently ran? Through he stock boost controller? Directly from reference to wastegates?
 

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Discussion Starter #6
Here is a picture of how the hoses are connected to the various solenoids. I can take more at different angles if this is not good enough. Any clues from this picture? Should I just order the correct hose with restrictor for the boost solenoid?
 

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It is difficult to tell, but it looks like the factory "H" tee is missing... the stock BCS "bleeds" off [restricted] pressure back into the rear turbo's intake pipe. Basically, what Larry "RealMcCoy" said is correct and applies to you lol.
 

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Discussion Starter #9
It is difficult to tell, but it looks like the factory "H" tee is missing... the stock BCS "bleeds" off [restricted] pressure back into the rear turbo's intake pipe. Basically, what Larry "RealMcCoy" said is correct and applies to you lol.

OK, just so a mechanically retarded can understand this: it almost sounds like a staged or sequential system where the front turbo first gets a certain amount of air. and then the rear turbo gets some extra air that was intended for the wastegate but was diverted to the rear turbo to help boost that one. Is any of that correct at all? Why would the rear turbo only get any extra air from the solenoid instead of opening up the wastegate spring? Does this happen with the front turbo too or does that boost up without any air diversion until its wastegate opens? If it doesn't happen equally, does that mean our turbos are a 1/2-assed version of a staged/sequential system? Why the bleedoff to the rear one only? Does the rear turbo end up getting more air overall because of this H-tee diversion away from the wastegate? Sorry but I tried reading online and that's the best I could distill these questions down to.
 

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OK, just so a mechanically retarded can understand this: it almost sounds like a staged or sequential system where the front turbo first gets a certain amount of air. and then the rear turbo gets some extra air that was intended for the wastegate but was diverted to the rear turbo to help boost that one. Is any of that correct at all? Why would the rear turbo only get any extra air from the solenoid instead of opening up the wastegate spring? Does this happen with the front turbo too or does that boost up without any air diversion until its wastegate opens? If it doesn't happen equally, does that mean our turbos are a 1/2-assed version of a staged/sequential system? Why the bleedoff to the rear one only? Does the rear turbo end up getting more air overall because of this H-tee diversion away from the wastegate? Sorry but I tried reading online and that's the best I could distill these questions down to.
Check the factory vacuum diagram... I don't know if yours is plumbed correctly or not, couldn't tell in the pic.

The factory system had both hoses to the wastegates, the feed hose from the Y-pipe, and the hose to the solenoid, all converge into a 4 way vacuum tee. The feed hose from the Y-pipe had a restrictor to limit flow, and the solenoid would cycle to control the pressure in the system. Both turbos were controlled equally.
 

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Are you familiar with how a manual boost controller works? that might be easier to understand...

Or just think about no boost controller at all - you have a vacuum line from a pressure reference that T's to the two turbo wastegates. In this case the wastegates will open at spring pressure (6-7psi stock).

Now if you add a basic MBC into the loop, you basically just bleed off some of the air before it reaches the turbo wastegates - you "intercept" this boost reference. In this way you might be making say 10psi of boost, but the MBC bleeds off a little air such that the wastegates see only 7psi. Thus, you are able to make 10psi of boost with a 7psi wastegate spring.

The stock boost solenoid is the same idea, it controls the pressure in the system to allow you to each boost levels above spring pressure.
 

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Discussion Starter #12
It's supposedly both the EGR solenoid and the stock boost solenoid. The tech did a bunch of tests, hoses all correct and working, all valves working, so he thinks it's the solenoids by process of elimination. Let's hope so. NAPA had the EGR for $75, 3SX had the stock BCS for $117 with shipping, that's coming Monday. Probably an hour of labor.

You know what Trevor Noah said about 'classic' cars? Ours will be classic in about 10 years. He used to be an amateur mechanic in his dad's garage. He said in a Howard Stern interview that he can't stand working on anything over 10-20 years old, precisely because of all of these little issues. Jay Leno shows him his garage of classic cars, Noah walks right out, doesn't even want to look at them. I hope the VR-4 doesn't ever get to that point, where I can't even find a mechanic to work on it anymore. That time may be coming, especially if Mitsubishi leaves North America.
 

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It's supposedly both the EGR solenoid and the stock boost solenoid. The tech did a bunch of tests, hoses all correct and working, all valves working, so he thinks it's the solenoids by process of elimination. Let's hope so. NAPA had the EGR for $75, 3SX had the stock BCS for $117 with shipping, that's coming Monday. Probably an hour of labor.
I've seen no reference to the fact that he confirmed the restrictor orifice is in place. As you've been told several times, the system will not work without it. If you're going to keep us updated, that would be the one update we want to hear about before trying to help you any further. We don't want to waste time any more than you do...
 

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Discussion Starter #14
I've seen no reference to the fact that he confirmed the restrictor orifice is in place. As you've been told several times, the system will not work without it. If you're going to keep us updated, that would be the one update we want to hear about before trying to help you any further. We don't want to waste time any more than you do...
You know what would be really nice? If you'd type the exact part description instead of saying a "feed hose", along with the part number, that would be very helpful. If you are trying to help, that would seal the deal, I would be truly appreciative. Try to look at it from my side, you can't just throw out lingo about some hose and expect everyone to know exactly where to find that part. This is why I ignored your advice, because it's simply not specific enough, sorry! When you talk in mechanic-ese with informal language about hoses, you can't expect a non-mechanic to understand everything. You do understand that concept, right? When I was typing up experimental protocols in molecular biology research labs, I made them so frigging detailed that anyone could come right off the street and get them to work, no college education required, just knowledge of how to use some of the instruments. That's technical communication, and it was 100% dummyproof.

On a more positive note, I finally found the VR-4 specific EGR solenoid: Charlotte NC Mitsubishi dealership, part number MR323103. The other one from NAPA was the 2WD version. No one else had the turbo/AWD version. Even 3SX said they could not find it but the parts guy at the dealership said they trade parts with them all the time. The boost solenoid is coming today, EGR hopefully Friday. If things still don't work, then I will be looking out for that feed hose part number, because typing in feed hose brings up nothing. I know you are trying to help, but details matter.
 

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I'm not going to go back and quote myself, but I'm pretty sure I offered a pretty complete description of how the system works, suggested referencing the factory vacuum diagram, and described the feed hose as the hose between the Y-pipe and the 4 way vacuum tee.

If there was something in there you did not understand, all you had to do is ask. I would be more than happy to try and clarify. I don't understand how ignoring my attempt to help you is going to fix your car...? Isn't that the goal here?
 

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You know what would be really nice? If you'd type the exact part description instead of saying a "feed hose", along with the part number, that would be very helpful. If you are trying to help, that would seal the deal, I would be truly appreciative. Try to look at it from my side, you can't just throw out lingo about some hose and expect everyone to know exactly where to find that part. This is why I ignored your advice, because it's simply not specific enough, sorry! When you talk in mechanic-ese with informal language about hoses, you can't expect a non-mechanic to understand everything. You do understand that concept, right? When I was typing up experimental protocols in molecular biology research labs, I made them so frigging detailed that anyone could come right off the street and get them to work, no college education required, just knowledge of how to use some of the instruments. That's technical communication, and it was 100% dummyproof.

On a more positive note, I finally found the VR-4 specific EGR solenoid: Charlotte NC Mitsubishi dealership, part number MR323103. The other one from NAPA was the 2WD version. No one else had the turbo/AWD version. Even 3SX said they could not find it but the parts guy at the dealership said they trade parts with them all the time. The boost solenoid is coming today, EGR hopefully Friday. If things still don't work, then I will be looking out for that feed hose part number, because typing in feed hose brings up nothing. I know you are trying to help, but details matter.
Jesus, it's like you don't want to be helped. You literally just follow the line off the back of the intake Y-pipe and make sure it is run correctly. There are a million posts on here about the stock vacuum line routes you can go back and read.
 

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Discussion Starter #17
Got the car back Saturday, it's more or less fixed. Check engine light came on again about an hour later, as I thought it might but I don't need a smog this year. The EGR solenoid part number above, by the way is for the one next to the intake plenum in the center of the car, not for the back firewall solenoid group. I'll keep it just in case. Speaking of which, the real EGR solenoid is missing, completely gone from the back firewall. I have no idea when that happened, it may have happened in 2017 during the smog check and they just gave up on it and passed it anyway. The actual part I supposedly need goes by many names, mostly something like vacuum purge solenoid --- it's the one on the lower left under the fuel pressure solenoid. No matching part numbers online for it (hard to see the numbers anyway). Two pictures of it attached. Spent a decent amount of time looking for a more or less exact match visually and came up with a Mitsubishi Shogun Pajero (British version of the Montero) solenoid for $20 on E-Bay, it will come in a few weeks. That was the ONLY one that had two nipples on top, the plug on the bottom facing down instead of parallel with the nipples, and the copper third hole on the bottom sticking out a decent length (one other had a silver hole on the bottom but it was only a few mm long). It looks like it will fit, we'll see. Again, this is becoming very frustrating to get parts when the parts themselves are not even listed on most auto part sites because they are too trivial, not to mention discontinued for 20 years.

The new and correct boost control solenoid is working...without the 'correct' hose. 3000 rpm reads about 12 psi on the stock gauge; interestingly 4000+ rpm creeps up a bit to 13 psi, which didn't happen in the past, with or without an aftermarket controller (I don't have a controller on now --- California outlawed them in 2010). The aftermarket boost gauge is still reading 4 psi peak --- they probably screwed up that reference hose during the engine swap, oh well. 13 psi peak is not quite as much as in the past but I'll live with it, it's enough. At this point in 2020 I just want something that runs and doesn't break down. Maybe one day I'll mess around with it and put in a restrictor pill and see what happens.
 

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You know what would be really nice? If you'd type the exact part description instead of saying a "feed hose", along with the part number, that would be very helpful. If you are trying to help, that would seal the deal, I would be truly appreciative. Try to look at it from my side, you can't just throw out lingo about some hose and expect everyone to know exactly where to find that part. This is why I ignored your advice, because it's simply not specific enough, sorry! When you talk in mechanic-ese with informal language about hoses, you can't expect a non-mechanic to understand everything. You do understand that concept, right? When I was typing up experimental protocols in molecular biology research labs, I made them so frigging detailed that anyone could come right off the street and get them to work, no college education required, just knowledge of how to use some of the instruments. That's technical communication, and it was 100% dummyproof.
wow.

You know what's detailed? The service manual. Tech - Manuals! Service, Technical , Reference | 3SX Performance Home Page
Take yourself there next time you need help. If you had even a basic understanding of the components involved you can help yourself with writing a friggin' detailed issue, what you've tested, why you did, results, etc so that anyone could come right off the street and understand the problem and troubleshooting logic. That's technical communication. or just keep taking it to the dealer for parts replacement.
 

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The new and correct boost control solenoid is working...without the 'correct' hose. 3000 rpm reads about 12 psi on the stock gauge; interestingly 4000+ rpm creeps up a bit to 13 psi, which didn't happen in the past, with or without an aftermarket controller (I don't have a controller on now --- California outlawed them in 2010). The aftermarket boost gauge is still reading 4 psi peak --- they probably screwed up that reference hose during the engine swap, oh well. 13 psi peak is not quite as much as in the past but I'll live with it, it's enough. At this point in 2020 I just want something that runs and doesn't break down. Maybe one day I'll mess around with it and put in a restrictor pill and see what happens.
Not sure what you mean by messing up the reference to the aftermarket gauge. If it wasnt on a boost reference you wouldnt read boost at all... Whats your vacuum at idle? Or decel? The only way that would read boost inaccurately is if it was not sealed and there was a leak in the line from your reference to the gauge.

The stock gauge is not accurate. I would suspect you are not actually running 13 psi... Also, you can easily slap on a manual boost controller in CA, that is the least of your worries.
 

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Yea the stock gauge is WILDLY inaccurate as it basically shows engine load. If you were to be going like 30mph and dropped into 5th and floored it, it would show boost on the stock gauge even though your engine would struggling to even stay running. Where is the gauge referenced from? Can you provide a picture? If the car is running fine, I'm betting your gauge is showing is showing 18-22inHg at idle with the AC off, which would be normal, suggesting your gauge is reading right.
 
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