Vacuum line coming from intake to alda - Page 2 - PeachParts Mercedes-Benz Forum

ggspeed · #16 01-17-2009, 04:48 PM

Quote:

Originally Posted by LUVMBDiesels

Clean out the switch as well. Just run some carb cleaner through it.

What I did was to remove the ALDA all together. Remove and plug the lines and take off the ALDA unit. There are posts on how to do this.

The EGR system and the ARV can be disconnected as well.

Just plug the vacuum lines going over to the right (passenger side) across the front of the engine.

Is this a good idea?

Aren't those put in place for a reason?

sixto · #17 01-17-2009, 05:42 PM

The IP is designed to deliver as much fuel as the engine can use for a given throttle position if the turbo were blowing full tilt. Since the turbo isn't always blowing full tilt and excess fuel just goes out as smoke, the ALDA leans fuel delivery in proportion to manifold pressure. The ALDA is factory tuned conservatively to reduce smoke. You can adjust the ALDA to allow more fuel to the engine or remove the ALDA altogether for maximum power potential. To maintain fuel economy and not blow a lot of smoke, your right foot has to just lead the engine's ability to accelerate. You should probably tighten the bowden cable accordingly since you get more power out of the engine with less throttle input. Many don't notice the change shift points.

Sixto
87 300D

ggspeed · #18 01-17-2009, 07:34 PM

Will this assist me in failing my emissions testing in a few months?

sixto · #19 01-17-2009, 09:32 PM

Disabling EGR might. Removing the ALDA might if they do a dyno test with a heavy foot. Disabling ARV won't.

If you disable EGR by blocking the vacuum line, unblock it before testing. If you remove or adjust the ALDA, put it back before testing.

Sixto
87 300D

LUVMBDiesels · #20 01-17-2009, 09:53 PM

Quote:

Originally Posted by ggspeed

Is this a good idea?

Aren't those put in place for a reason?

EGR is a half @ssed attempt at emissions control. What it does is cause all the gunk in the intake manifold and reduce performance considerably. I left the thing on the intake (there are block of plates available from members if you do a search on 'remove EGR') but I took it off and stuck a genuine US quarter dollar betwen the EGR valve and the manifold. It is an exact fit and when you put the EGR valve back on, it looks stock. I took the vacuum lines off, but I could plug them back in if my state had a requirement to test 23 year old Diesels for emissions.

The ARV was put on to help the OxTrap get hot quickly. Since your OxTrap should have been removed, it is no longer needed.

The Overboost switch is a safety feature for the very remote change that your turbo's wastegate fails and the turbo spins up too much boost. In that event, the switch cuts off the boost signal to the ALDA cutting off the fuel enrichment and slowing down the turbo. If you remove it, first make sure that the line going to the wastegate is in good shape and then install a boost gauge. It will be up to you to take you foot off the pedal if the turbo boost goes over 15psi. DOn't get me wrong, a lot of people have done this -- do a search on remove ALDA for a lengthy thread on the subject with all the pros and cons...

In my case the switch port was broken off and the PO had stuck a golf te into the line going to the ALDA -- he NEVER got fuel enrichment and the car was a total dog. That was one of the reasons I paid $2000 for a rust free SDL with all accessories working! I took it off to replace the shut down valve which is right near the ALDA and just 'forgot' to put it back. The difference in off the line performnce is pretty amazing and you can learn to not make smoke by keeping your foot out of the pedal until the turbo spools up. I am averaging 27+mpg without the ALDA so my MPG has actually gone up.

Jeremy5848 · #21 01-17-2009, 09:53 PM

Do we know what year SDL this is? Was there an older SDL with a 617 engine or does this have to be a 603-engined car?

Brian Carlton · #22 01-18-2009, 10:46 AM

Quote:

Originally Posted by Jeremy5848

Was there an older SDL with a 617 engine or does this have to be a 603-engined car?

All SDL's have 603 engines.

#23 01-18-2009, 11:46 AM

Right, unless its an SEL conversion.

Jeremy5848 · #24 01-18-2009, 11:52 AM

Quote:

Originally Posted by Brian Carlton

All SDL's have 603 engines.

So there was not an extended-length chassis version of the early '80s 300SD with the OM617 engine?

Brian Carlton · #25 01-18-2009, 11:55 AM

Quote:

Originally Posted by Jeremy5848

So there was not an extended-length chassis version of the early '80s 300SD with the OM617 engine?

I'm not aware of one.

Naturally, Lance will give you the definitive answer.

LUVMBDiesels · #26 01-18-2009, 12:45 PM

Quote:

Originally Posted by Brian Carlton

I'm not aware of one.

Naturally, Lance will give you the definitive answer.

I almost had a 617 powered long wheelbase car. I found a 420 SEL with a clapped out engine to stick a spare 617 into, but I gave up on the project. There were no factory built 617 powered SDLs

Taking the ALDA off a 617 is OK, but I don't think the 617 responds to the modification as well as the 603 does. I could be wrong on this, though...
On my 300SD I did the same EGR 'fix' with the quarter inserted into the manifold port...