85 ALDA has vacuum line? - PeachParts Mercedes-Benz Forum

winmutt · #1 03-20-2007, 01:33 PM

I am starting another thread on this to see if I can catch some more eyes.

My ALDA banjo (alda side not manifold side) has a nipple on it and a vac line that runs to the vac system. Is this normal?

vstech · #2 03-20-2007, 01:35 PM

again, post some pictures.
it sounds like somebody mis connected your vacuum lines.
John

winmutt · #3 03-20-2007, 06:53 PM

and I bring you THE ALDA NIPPLE!

winmutt · #4 03-20-2007, 06:56 PM

Quote:

Originally Posted by tangofox007

Where does your ALDA line connect to the vacuum system?

Not every line that looks like a vacuum line is a vacuum line.

In the main vac line there are two nipples, one runs to the interior and the other ran to the ALDA. Now I may have made this mistake, I went disconnect happy when I got the car just trying to get enough vac to the booster. I don't suppose this was the line that fed to the thingamajig on the turbo? I guess now I have a hand hookup spot for my in the mail boost gauge.

psfred · #5 03-20-2007, 07:41 PM

There should be a line from the ALDA to the manifold and one from there to the vacuum amplifier for the transmission (blue dodad on the fender that looks like an electric horn). You must clamp the hose on.

You won't be getting any extra fuel to go with the boost as it is, the system must hold pressure.

Peter

winmutt · #6 03-20-2007, 09:14 PM

Quote:

Originally Posted by psfred

There should be a line from the ALDA to the manifold and one from there to the vacuum amplifier for the transmission (blue dodad on the fender that looks like an electric horn). You must clamp the hose on.

You won't be getting any extra fuel to go with the boost as it is, the system must hold pressure.

Peter

I had a hose on it it was just running to the vac system and was certainly getting boost. I terminated on the nipple of the ALDA (No silly vacuum amplifiers for me) and the nipple of the vac line. Things got better with the brakes but not stellar. And I'm fairly certain the turbo isnt putting out at spec, it was replace by PO. I'm going to pull the turbo and verify that it is causing some other issues I am having and then putting in a VNT. I'm still convinced the booster is shot (no shutoff with brake pressed). I am pulling the vac line and booster from my other car this weekend or so. It stopped on a dime and I sorely miss that. The bigger shoes I had on the other car are coming to. One day at a time.

psfred · #7 03-20-2007, 10:30 PM

You must have two things to get more power with a turbo -- more air (from the turbo) and more fuel. If the boost line from the intake manifold is leaking (or the switchover valve for over-boost protection leaking), you won't get more fuel, hence very little extra power. Check the boost signal line for obstructions and integrity.

If the signal line to the vacuum amplifier isn't connected, the transmission will get the wrong vac signal and shift funny -- and may slip badly on shifts, causing it to fail prematurely.

Your lack of power brakes can be a loose vacuum line or a booster full of brake fluid from a leaking master cylinder, or a bad vacuum pump (the check valves fail, or the cam is worn out).

Get a Mitivac hand pump, it has a convenient guage on it. You must get at least 11" of vac in two or three minutes idling in the main vac line -- if not, you have a major leak (which can be the booster, although I've not every seen a bad one on a Benz yet), or a cracked line, etc. That Mitivac is handy for chasing down and fixing other leaks as well, and works nicely to change the fluid or bleed the brakes.

I believe there has been a vacuum line diagram posted for your car here on the forum in the past, do a search, it will make life easier.

Peter

Peter

winmutt · #8 03-21-2007, 07:19 AM

Quote:

Originally Posted by psfred

You must have two things to get more power with a turbo -- more air (from the turbo) and more fuel. If the boost line from the intake manifold is leaking (or the switchover valve for over-boost protection leaking), you won't get more fuel, hence very little extra power. Check the boost signal line for obstructions and integrity.

Overboost already removed. The waste gate needs to be modified.

Quote:

If the signal line to the vacuum amplifier isn't connected, the transmission will get the wrong vac signal and shift funny -- and may slip badly on shifts, causing it to fail prematurely.

Please see my sig.

Quote:

Your lack of power brakes can be a loose vacuum line or a booster full of brake fluid from a leaking master cylinder, or a bad vacuum pump (the check valves fail, or the cam is worn out).

I get like 40 PSI at the pump outlet iirc. Master cylinder hasnt shown any signs of leaking yet but if the booster is fill of liquid then I will just clean it out. If my foot is on the brake no amount of revving will build enough vacuum to shutoff the engine. Which is why I am pretty sure its the booster.

At any rate my extra nipple on the ALDA that used to go to the turbo will be used for my new boost gauge.

rrgrassi · #9 03-21-2007, 09:47 AM

That looks like someone had a boost guage on there already, and took it off, but did not plug the line, so the ALDA was not able to read boost signal.

winmutt · #10 03-21-2007, 09:59 AM

Quote:

Originally Posted by rrgrassi

That looks like someone had a boost guage on there already, and took it off, but did not plug the line, so the ALDA was not able to read boost signal.

There was a line running from the turbo to somewhere I think to the ALDA. PO replaced turbo with a non whatever it was called part that the line hooked up to. I think I may have been the one to run it to the vac system.

The car is def running better, almost enjoyable to drive.

rrgrassi · #11 03-21-2007, 10:04 AM

Yeah! It's always a good thing to get the PO issues resolved!

psfred · #12 03-21-2007, 11:45 AM

Hmm.

There is a line from the turbo outlet housing to the wastegate controller. This must be intact to prevent over-boosting (else you toss a rod, not a pretty sight!). Fairly large hose, check for integrity.

The boost signal line on a 617 engine runs from the rear of the intake manifold to the ALDA, again it must be intact or you don't get added fuel.

Check to make sure the wastegate control link is installed, otherwise the wastegate will be open all the time and you don't get boost, or very little, even though the turbo is fine.

Later model turbos (85 california, 86 49 state engines) have an air recirculation valve that vents boost back into the air intake duct -- this is both to keep the turbo up to speed and for the trap oxidizer that you don't have. On the KKK it's on the front of the housing, I think somewhere else on the Garret, but I'm not sure. Just leave the vacuum line off, you don't need it in your application.

Limit boost to 13.1 psi unless you a willing to risk "greatly reduced engine life" -- on an engine with lots of miles, read hours of operation, not weeks or months with more boost. Under no circumstances exceed 14 psi, you risk very rapid rod failure, that engine just wasn't designed for that much hp.

How did you measure vacuum pump output? I thought those pumps (post 76) vent into the crankcase, not the intake manifold, so there is no accessable output. If you are getting 40 psi from the TURBO, you need to attach the wastegate control pressure hose or the solenoid to wastegate link, the engine isn't gonna stay together long!

If the engine won't shut off with the brakes applied, you have a split diaphram in the booster most likely. However, you should also make sure the check valves and plastic section in the vacuum line from pump to booster isn't cracked (they get very brittle). If in doubt, replace the entire line, they aren't expensive. Also verify that the other lines (shutoff, door locks, ACC) from the main line hold vacuum and fix or cap -- they should have restrictions in the lines (little yellow "butt connectors" or small orifices in the main line fitting) to limit the effects of leaks, but who knows.

Peter

winmutt · #13 03-21-2007, 12:49 PM

Quote:

Originally Posted by psfred

Later model turbos (85 california, 86 49 state engines) have an air recirculation valve that vents boost back into the air intake duct -- this is both to keep the turbo up to speed and for the trap oxidizer that you don't have. On the KKK it's on the front of the housing, I think somewhere else on the Garret, but I'm not sure. Just leave the vacuum line off, you don't need it in your application.

Thats the whachamacalli was talking about. Interesting about keeping the turbo up to speed. Do you think that functionality would keep the turbo spooled during gear shifts (manual remember)?

Quote:

How did you measure vacuum pump output? I thought those pumps (post 76) vent into the crankcase, not the intake manifold, so there is no accessable output.
Peter

I unhooked the main vac line and plugged the mighty vac up to it. It also seemed to go up in stages? I'll check it again when I swap the line and booster from my old daily driver. The inline check valve appear to be ok, but without the auto tranny there is no need for it right?

psfred · #14 03-21-2007, 01:34 PM

Ah, that's inches of vacuum. Your pump is probably OK.

You need the check valve so that your shutoff will work and the brake booster doesn't loose vac as soon as the engine is off, leave it in there. The only thing you don't need with a manny tranny is the shift control signal to the vacuum modulator.

The air recirc is mostly to keep the turbo up to speed on highway cruise to eliminate turbo lag and to dump boost under some circumstances to prevent overheating the trap oxidizer that you don't have (It also opens when you take your foot off the accelerator, same reason -- turbo spins but doesn't pressurize the manifold). It will increase milage a bit on the highway, but won't do a thing for manual shifts, you have to use your foot for that, as it isn't connected to the control linkage. Unless you have the computer system, it isn't gonna do anything anyway.

Peter

winmutt · #15 03-21-2007, 03:14 PM

Quote:

Originally Posted by psfred

The air recirc is mostly to keep the turbo up to speed on highway cruise to eliminate turbo lag and to dump boost under some circumstances to prevent overheating the trap oxidizer that you don't have (It also opens when you take your foot off the accelerator, same reason -- turbo spins but doesn't pressurize the manifold). It will increase milage a bit on the highway, but won't do a thing for manual shifts, you have to use your foot for that, as it isn't connected to the control linkage. Unless you have the computer system, it isn't gonna do anything anyway.

Peter

Thats what I am looking to fix is turbo lag during shifting. Wouldn't that solve that particular issue?