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Discussion Starter #1
This is on a 98 3.4L 4runner 189K, I believe the S/C has almost the same miles. Its the gray first gen S/C on a completely stock vehicle.
The owner couldn't remember changing the S/C oil and it was sounding noisy.
Having to removed the S/C to change the oil I recommended we rebuild the S/C while were at it. The rebuilt went fairly smoothly. Replaced all the seal, bearing, hoses, and o-rings.
The problem is I'm only getting 3psi max and it drops off to zero by red line. It feels down on power as well.
The drive belt is new and tight- I've tried over tightening it to.
Engine vacuum readings are 17inhg and no leaks detected.
No boost leaks I can find- tried clapping off hoses and disconnecting By-pass valve.
By-pass valve is good

Could I have screwed up the rebuild some how? Forgot something? Are the rotors the same, could the rotor clearances be off?
Any help or Ideas would be greatly appreciated.
Thanks Ethan
Green's Automotive Service
Bend, OR. 97702
 

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Check to make sure the boost gauge/boost line is connected correctly.
 

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Did you get it sealed up and bolted or torqued down well to the intake when you did the reinstall? I assume you installed a new intake gasket.

17" of vacuum if max vac sounds a tad low, at what RPM, idle?

Checking that the bypass is working as it should is easy. Look at it with the engine off, it should be closed and again with the engine at idle, when it should be open allowing bypass.

I hope you got all the rotor clearances in the SC right when you put it back together.
 

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Discussion Starter #5
QUOTE=Dick Foster;2467426]Did you get it sealed up and bolted or torqued down well to the intake when you did the reinstall? I assume you installed a new intake gasket. Yep I did

17" of vacuum if max vac sounds a tad low, at what RPM, idle?
Elevation here is 3700 feet, the most I see is 16-17"

Checking that the bypass is working as it should is easy. Look at it with the engine off, it should be closed and again with the engine at idle, when it should be open allowing bypass. Yep it works like that, holds a vacuum to. Hoses were replaced and check valves are good.

I hope you got all the rotor clearances in the SC right when you put it back together.
This is what has me worried. I'm sure its not rubbing the end plates or the rotors- turned freely during all the steps of putting it back together. Could the rotors and gears have too much clearance and not be rubbing. It worked before I took it a part.:confused:
Thanks
 

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Discussion Starter #6
Had the customer come down and drive the truck. He agreed it was low on power and sounded different. He also told me he replaced the S/C drive pulley with a larger/ lower boost one he got for TRD. I guess this was one of the cheap band aids they had in the beginning.
I'll call the the place I got the rebuild kit from in the morning and see if they have some ideas.
 

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Probably. Say one rotor is a tooth off leaving too much rotor to rotor gap for decent compression.
You might try asking Magnuson. If push comes to shove you can send it there and they'll make sure it right. Don't know how much they charge though, it's been years since they went though mine.

QUOTE=Dick Foster;2467426]Did you get it sealed up and bolted or torqued down well to the intake when you did the reinstall? I assume you installed a new intake gasket. Yep I did

17" of vacuum if max vac sounds a tad low, at what RPM, idle?
Elevation here is 3700 feet, the most I see is 16-17"

Checking that the bypass is working as it should is easy. Look at it with the engine off, it should be closed and again with the engine at idle, when it should be open allowing bypass. Yep it works like that, holds a vacuum to. Hoses were replaced and check valves are good.

I hope you got all the rotor clearances in the SC right when you put it back together.
This is what has me worried. I'm sure its not rubbing the end plates or the rotors- turned freely during all the steps of putting it back together. Could the rotors and gears have too much clearance and not be rubbing. It worked before I took it a part.:confused:
Thanks
 

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A larger pully ain't good. As shipped they made six pounds of boost which is OK for a stock engine as long as you do something to add fuel to go with all the extra air.
I wouldn't listen to shit that TRD had to say about it, they are the idiots who fucked it up in the first place. They just can't be trusted.

Had the customer come down and drive the truck. He agreed it was low on power and sounded different. He also told me he replaced the S/C drive pulley with a larger/ lower boost one he got for TRD. I guess this was one of the cheap band aids they had in the beginning.
I'll call the the place I got the rebuild kit from in the morning and see if they have some ideas.
 

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Discussion Starter #9
Talked to the re builder today. He said they see maybe half the rebuilds that people do don't work afterwords and then have to be send in to them. The rotor gap has to be perfect and they have a jig for it.
My next question was why the F are they selling kits if its that critical.

I'll be pulling off the S/C and taking some rotor measurements.
Hope I wont have to send it in.

The S/C and then the larger pulley was put on 140k miles and maybe 12 years ago. I was surprised to hear it to. He said it dropped the pressure by 1-1.5 psi and stopped the pinging. I'm not sure the owner understands what that did. The guy tows with the truck and if they hadn't the engine would of fried by now.
 

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Discussion Starter #10
I removed the S/C. Looking at a bunch of pictures online, it looks like I have the rotors switch side to side. Clearly I wasn't as careful as I thought with marking and keeping parts together. Its an easy fix to press them back out. Practice makes perfect right?
 

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Well that would certainly do it. The school of hard knocks can be a real bitch sometimes.

I removed the S/C. Looking at a bunch of pictures online, it looks like I have the rotors switch side to side. Clearly I wasn't as careful as I thought with marking and keeping parts together. Its an easy fix to press them back out. Practice makes perfect right?
 
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