I understand (primitively) that the ALDA adjusts the amount of fuel the engine receives by measuring boost pressure (among other things). That line seems intact, as near as I can tell.

(The root of this is that i'm still not 100% convinced all my vacuum stuff is as it should be. Rough shifts and transmission not acting quite like it should be based on tests.)

But does the turbo or wastegate or anything actually receive vacuum (or pressure) input through hard plastic vacuum lines? At the moment, there are literally no vacuum lines whatsoever, of any sort, going over to the turbo side of the engine comartment. The egr is gone and blocked off with one of Brian's "Testing" kits, and we removed those lines and RTV sealed the little double-T thing instead of plugging existing lines. We removed one more little doodad over there, also with approval. It was sort of half buried down under there, almost under the air cleaner in that area. Not under it but close. Perhaps the ARV? Not sure.

Anyway... I now have no hard lines on the passengers side of the valve cover. (Easiest reference I've got). Am I missing something valuable as far as overboost or getting boost or anything? Or is it acceptable to run it that way?

Also, if I MityVac the line going OUT the bottom of the little blue widget that has a couple of green-widget modified vacuum lines going into it and one going down to the transmission... it's on the drivers side mounted to the inner wheel well fender area... and only read 7 inches or so, that doesn't seem to vary with RPM at all.. what's my problem? Think I read I was looking for 10-12 inches going down to the transmission.

Climate control leaks are completely fixed, as near as we can tell, just for the sake of "ruling out" things. Engine shuts off with the key every time and all door locks work. (Although that's due to the electric pump I think).

Any ideas about any of this would be appreciated.
Thanks... it's a lot to make sense out of.

I deeply apologize for all the "widgets" and various references but that's the only terms I've got for this stuff. I'm trying...

__________________


~Michael S.~
Past cars:

1986 300SDL
1987 300SDL
1982 240D
1982 300SD


Current:

1987 300SDL

None of the vacuum lines are required on the right side of the engine. There should be a wastegate hose that runs from the intake to the wastegate actuator but that's it. No vacuum of any type is needed.

7 inches is a bit low. What's the shift quality? Does it bang into any gears or does it bang on downshifts?

Unless it's an EXTREMELY good day, all upshifts break peoples' necks if they don't brace for it. I do have good days however when it feels like a normal car. But that isn't consistent at all. When it's being bad, about 90% of the time, all upshifts are neck breakers and most downshifts are. 4-3 isn't too horrible but the rest are a little rough. In general, upshifts are much worse than downshifts.

__________________


~Michael S.~
Past cars:

1986 300SDL
1987 300SDL
1982 240D
1982 300SD


Current:

1987 300SDL

I just did the road test that I should have done before I asked my question. Here's the results.

When the MityVac is measuring the signal that would normally go to the transmission, after all the mutations, the transmission is NEVER seeing more than 7.5 inches. That does indeed drop down to zero or one, properly, when I accelerate hard. Nothing is wrong there. It's doing what it's supposed to perfectly.

I then put the mityvac on the line to the transmission, and controlled it myself. I'm thinking about that as a long term solution

Seriously, when I gave it ten inches manually with the mityvac, shifts were smooth as glass. 8.5 to 9 I could live with, and 12 produced a slight "slip" feeling even on the lowest RPM shift I could make.

So... the only problem I have, whatsoever, is that my transmission never has the chance to see more than 7.5 inches. Where's my missing vacuum? How do I find it?

__________________


~Michael S.~
Past cars:

1986 300SDL
1987 300SDL
1982 240D
1982 300SD


Current:

1987 300SDL

Hook up the Mityvac to the output line from the VCV. It goes to the vacuum amplifier. Drive the vehicle and see what this line reads during typical operation.

It would be best if you could T into this line so that the vacuum amplifier remains operational and the transmission still sees some vacuum.

Are you positive that the amplifier is properly connected with four lines (two on top and two on the bottom)?

How do I identify the VCV? Will try to test it this afternoon. On fall break now and headed back to college Sunday, we were just working on some of this stuff while we had the chance.

The amplifier has two lines on the bottom and two lines on top, yes. But I can't vouch 100% for what's at the other end of those lines. I know the line to the transmission is in perfect order, because when I control the transmission manually with that line, things are perfect. Other than that, any of the other 3 lines are suspect. They're intact, but who knows if they're hooked up right. Probably.

__________________


~Michael S.~
Past cars:

1986 300SDL
1987 300SDL
1982 240D
1982 300SD


Current:

1987 300SDL

Also, while I've got help... we made an interesting discovery about the turbo I've been complaining about. In lieu of a real boost gauge (which is more accurate, I know) we used a tire pressure gauge and hacked together a way to check boost just briefly. I know, we had leaks and everything else probably. But... we removed the little plug from the intake manifold (The little screw in plug on the left side of the tube before it divides the air into the cylinders) and checked there, as well as a few other places. Even considering the inaccuracy of our test, the potential for leaks, and everything else... I think I've got a problem. What boost should I read there? We NEVER got the car to show more than 5 psi, and that was at nearly "redlined" rpm. We can easily cover the hole with fingers and... it's blowing SOME, but not nearly what we estimated it should feel like for 10 psi or whatever the engine is used to.

Our new theory: Can a wastegate get stuck open? And cause the turbo to never get enough exhaust gas to make full boost out of?

part two of that theory: IF the turbo isn't making enough boost because it's not getting enough air... then it's not sending the "ideal" amount of boost signal to the rest of the system... would that have any influence on my vacuum lack? In other words... you said the VCV takes input from the turbo as part of its decision making process. Well... could a lack of boost pressure cause the transmission to not ever quite get enough vacuum?

We couldn't quite tell what we were looking at, but regarding your way to tell which brand of turbo we have, my dad: "The best I can tell, whatever parts of the wastegate and actuator and whatever's down there are all on what I'd call the bottom of things instead of on top"... I think that's how you said you could recognize a Garrett vs a KKK.

Anyway... could that be related?

__________________


~Michael S.~
Past cars:

1986 300SDL
1987 300SDL
1982 240D
1982 300SD


Current:

1987 300SDL