I did not plug anything near where the ALDA had been. Vacuum lines were just hanging.

Should I try plugging the two ports?

-John

You should but I don't think it will help much.

Why 2 ports? The ALDA only has 1 port.

Sixto
87 300D

There was one and only one vacuum line connected to the ALDA (although perhaps it split into two or something). From everything I've read that line needs to be plugged (use a screw or something).

__________________
14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 154k miles
06 E320 CDI "Rutherford", Black on Tan, 172k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 142k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

While I'm sure you're correct, I do remember being amazed how, after I replaced my pressure converters, the car was still a dog....until I noticed one vacuum line that had not been reconnected.

__________________
14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 154k miles
06 E320 CDI "Rutherford", Black on Tan, 172k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 142k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

I will plug the one port that connected the ALDA.

I will also try to spin the turbo today.

More disappointment.

I pulled the air tunnel into the turbo and saw the blades. Reached in a turned them - everything looks in good order. Very little play in any direction. A little bit of oil in and around the area but I believe this is normal.

I also plugged the ALDA port and took it for another run with the wastegate closed and the ALDA removed. No difference in 0-40 MPH (14+ secs).

I'm totally at a loss. What else can I look for?

-John

Maybe you did go over this already but in scanning the previous entries, I didn't see anything on fuel supply. Might want to set up an auxiliary fuel tank (1 liter gatorade bottle or something like that). Make a couple holes in the bottle top, one for the supply and one for the return. Disconnect the fuel line before the primary filter and put in the bottle and also put the return line in as well. Voila, a 1L fuel tank that you know if clean. (Make sure to plug off the tank supply and return lines while you do this of course. Bungy strap the thing under the hood and run the car off of this with some clean diesel in it to eliminate the fuel tank as a potential problem restricting fuel. If that still doesn't resolve it, might look into fuel pressure and/or the lift pump before damning the IP as the problem. The other thing is to install a boost gauge at least temporarily and see what the turbo is putting into the manifold, it may be pushing 13 psi and you don't even realize it, just no fuel to burn to go with the air. Just a thought and both diagnosis I mention are easy to do.

Great idea of the mini-tank. I've done something like this when I did a diesel purge the other day. I'll give it a try.

In terms of the boost gauge - I have a vacuum/pressure gauge - how would I connect this to determine the manifold pressure?

Thanks,

-John

With the ALDA removed, hook up the boost gauge to the line that goes to the ALDA. With the ALDA in place, tee into the line to the ALDA.

Sixto
87 300D

Haven't had time to work on the Turbo issue recently - but I was under the car the other day and there is a half dollar sized hole on the center exhaust box (is that the right name for it?).

Would the lack of back pressure due to a hole that size prevent the turbo from spinning up/working?

Just a wild thought.

-John

No.

Sixto
87 300D

Ok - earlier this week I connected the wastegate to the vacuum line and forced it open. Been driving it like this for the past few days and I noticed a high pitched turbine noise around RPM 1800-2200. I believe this is the turbo turning - correct?

If so - why would the turbo be spinning but not providing any additional power? We had thought it was a fuel delivery issue. My next step will be to check the tank filter as I've not been there yet and feel I should check to see if fuel is flowing correctly.

Thoughts?

-John

Do you have a leaking flex joint on the exhaust manifold? If your leaking (visible soot near the flex coupling) you are losing efficiency.

__________________
1987 300SDL #1, 1987 300SDL #2, 1980 240D, 1982 300SD, 1994 S350, 1990 350SDL, 1991 350SD, 1985 300D, 2005 E320CDI

Gone, but not forgotten: 1981 300SD, 1982 300SD, 1987 300SDL, 1983 300TD, 1980 300CD, 1981 300SD #2, 1987 300D, 1987 300TDT, 1980 300D

YES! I do have a break in the flex joint and can see exhaust out the break.

Sounds like I will be changing it.

Thanks,

John

That would be my first area of concern.

__________________
1987 300SDL #1, 1987 300SDL #2, 1980 240D, 1982 300SD, 1994 S350, 1990 350SDL, 1991 350SD, 1985 300D, 2005 E320CDI

Gone, but not forgotten: 1981 300SD, 1982 300SD, 1987 300SDL, 1983 300TD, 1980 300CD, 1981 300SD #2, 1987 300D, 1987 300TDT, 1980 300D