black box on valve cover. - PeachParts Mercedes-Benz Forum

polarisrmk · #1 04-19-2010, 01:32 AM

I just purchased a 617 turbo for a project i am doing. The motor is from an 82 300d. What is the black box on the valve cover that has a few vacuum hoses going to it. currently no vacuum lines are connected... What do i need to connect to make sure the overboost protection is still functioning.

FYI The motor is not going back into a car it is going into a boat

300SD81 · #2 04-19-2010, 01:37 AM

The box is for the EGR, I removed mine.

vstech · #3 04-19-2010, 08:13 AM

overboost does not go near that box.
overboost attaches to the intake manifold near the firewall, and flows to the OPR relay mounted on the firewall. then to the ALDA. it's NOT vacuum. it's pressure from the turbo.

bluetypewriter · #4 04-19-2010, 10:23 AM

I took apart mine and repaired it according to this walkthrough

http://www.dieselgiant.com/trannyleverreplace.htm

EDIT: Just read that the engine is going into a boat. Disregard what I said.

toomany MBZ · #5 04-19-2010, 10:40 AM

Quote:

Originally Posted by 300SD81

The box is for the EGR, I removed mine.

I've done the same thing, depending on what transmission you're going to use, you won't have to worry about it at all. It would seem the egr system has been bypassed, just remove it.

tangofox007 · #6 04-19-2010, 10:43 AM

Quote:

Originally Posted by vstech

it's NOT vacuum. it's pressure from the turbo.

Actually, it is vacuum some of the time.

vstech · #7 04-19-2010, 11:18 AM

Quote:

Originally Posted by tangofox007

Actually, it is vacuum some of the time.

welll, sortof... I suppose it could be under a vacuum after a downshift, pulling against the turbo, it's NEVER associated with the vacuum system though. totally separate system. so you could pull the vacuum pump and all the vacuum lines, and still not affect the alda/overboost.

Diesel911 · #8 04-19-2010, 12:01 PM

You can pull a Vacuum in a Diesel Intake Manifold if your Air Filter is Plugged.

When the Turbo kicks in that Vacuum can get worse to to point it starts pullin Oil past the Turbo intake side seal.

Anyway, I have seen that happe on Truck Turbos.

You would have to ignore the loss of power symptoms before that could happen

polarisrmk · #9 04-19-2010, 12:46 PM

Ok i will get rid of it then.... What do i need for the overboost protection then. I still have access to the car it came out of.

toomany MBZ · #10 04-19-2010, 06:10 PM

It has an electrical lead and I wouldn't know if it's just powered all the time or not. I've been driving my CD since I bought in '03 with the switchover (over boost protection valve) bypassed, you have a waste gate on the turbo, right?

polarisrmk · #11 04-19-2010, 09:21 PM

Quote:

Originally Posted by toomany MBZ

It has an electrical lead and I wouldn't know if it's just powered all the time or not. I've been driving my CD since I bought in '03 with the switchover (over boost protection valve) bypassed, you have a waste gate on the turbo, right?

Yes i do .... well the turbo that i am buying for it has a waste gate .... the motor currently has no turbo.

300SD81 · #12 04-19-2010, 09:28 PM

The overboost valve is always powered with a switched ground. Wire it from 12V to the valve, to the pressure switch on the intake manifold.

tangofox007 · #13 04-19-2010, 09:28 PM

Quote:

Originally Posted by toomany MBZ

It has an electrical lead and I wouldn't know if it's just powered all the time or not.

The manifold switch is powered except when the key is in the off position. An overpressure condition closes the switch and provides a ground for the overboost protection valve solenoid.

vstech · #14 04-19-2010, 09:30 PM

Quote:

Originally Posted by Diesel911

You can pull a Vacuum in a Diesel Intake Manifold if your Air Filter is Plugged.

When the Turbo kicks in that Vacuum can get worse to to point it starts pullin Oil past the Turbo intake side seal.

Anyway, I have seen that happe on Truck Turbos.

You would have to ignore the loss of power symptoms before that could happen

not on the intake manifold you can't...
you could easily pull a vacuum on the airfilter Utube/ oil canister.

polarisrmk · #15 04-19-2010, 09:36 PM

Quote:

Originally Posted by 300SD81

The overboost valve is always powered with a switched ground. Wire it from 12V to the valve, to the pressure switch on the intake manifold.

The pressure switch on the intake manifold grounds out the valve and the 12v to the valve is constant in key on position? Just want to make sure i understand this correctly....

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