On my '84 300D Turbo I found the switchover valve did not have any vacuum lines connected. Thought after wading through several posts and partial diagrams I found one line connects via banjo fitting to the intake while the other to the top of the ALDA. The ports on the switchover valve are numbered 1, 2 & 3. Would someone be able to share with me the correct configuration? ALDA to the bottom port or the one on the side of the switchover valve?

Thanks.

__________________
Steve
'87 300TD - 132K - Soon 4-Sale
'84 300D Turbo - 122K - Driving
'77 VW Type II - 77K - Restored
'08 250EX Ninja
English Bulldog (Brier) - My best friend. Passed away 12/02/04 while in my arms.

There are no vacuum lines to that valve. Those are pressure lines. The intake is pressurized when the turbo spools up and the line coming from that banjo bolt carries the pressure to the ALDA. When it reads the pressure signal it dumps more fuel through to the injectors.
The best way to check the operation and sort out which ports go where is to remove it and set it up in a vise, then blow through the ports and track where the air goes through. Should pass directly through from the left to the right side. Then connect 12v to the two leads there. The blown air should divert to the third valve. If you cannot get air to blow through, it is plugged and will need to be cleaned. Keep cleaning until air will pass through the and will also blow out the third port when charged with 12 v. The third port does not connect to anything, it is a release point.
Check the banjo and the line, they are even more likely to get plugged.

Thanks for correcting me on the terminology. I should have realized it since there is no vacuum source connected. Intake manifold pressure only. I guess I should have pointed out I was referring to the type of line . . .

Lines are not plugged, cleaned the switchover ports, applied 12v and all seems to be working fine.

It did surprise me to find the PO/shop had bypassed the switchover and connected the line directly together.

__________________
Steve
'87 300TD - 132K - Soon 4-Sale
'84 300D Turbo - 122K - Driving
'77 VW Type II - 77K - Restored
'08 250EX Ninja
English Bulldog (Brier) - My best friend. Passed away 12/02/04 while in my arms.

Have heard here where that is done often. Seems there is a limited understanding of what that part does.

Too lazy to clean it.

I used Brake Kleen last night and again this morning. Seems to be clear now. I often cringe using the stuff since it may interact with certain materials adversely. Time will tell.

__________________
Steve
'87 300TD - 132K - Soon 4-Sale
'84 300D Turbo - 122K - Driving
'77 VW Type II - 77K - Restored
'08 250EX Ninja
English Bulldog (Brier) - My best friend. Passed away 12/02/04 while in my arms.

Try using some "ether" also called "starting fluid" instead of brake-clean sometime! I find that it cleans much faster, and it cost about .50 cheaper too! Also may be safer!

Steve, I'd be real careful on the Brakekleen around plastic parts. The overboost valve might be damaged by the Brakekleen. I'm not sure how much plastic is inside it.

Brian, I misspelled "ether" and re-edited. I agree, I think the stuff is a killer! At least, I think the worst thing ether can do is put you to sleep, temporarily that is!

Steve........

..........and I do believe that you are not going to do any damage to any plastic with it.

I've been buying the stuff for a while now and have sprayed it on just about everything including plastic, paint, and it doesn't seem to touch it!

If you ever want to see how fast of a reaction you can get with products containing hydro carbons, such as acetone, take a piece of 1/4" plexi-glass, give it a little bend in your hands and have someone pour a little bit of acetone on it and it will crack and snap in your hands instantly!

Never thought of ether . . . haven't used that since I had my service station and even then, didn't think to use it as a cleaner. Without a doubt it would work better. Thanks for the extremely useful tip. Ether

Hard, somewhat delayed shifting on the '84 up to third gear. Been raining here since afternoon so my work time got cut short. Any ideas on the best places to start. I have already started the vacuum checking. 24 at the main line and -0- at the distribution block (haven't checked for the correct name yet) attached at the top of the valve cover. I know I have something going on . . . yet I wouldn't think the lack of vacuum there would cause/contribute to hard shifts. I'm certain I'll find it however . . .

__________________
Steve
'87 300TD - 132K - Soon 4-Sale
'84 300D Turbo - 122K - Driving
'77 VW Type II - 77K - Restored
'08 250EX Ninja
English Bulldog (Brier) - My best friend. Passed away 12/02/04 while in my arms.

Without a vacuum hook up from the vac amplifier to the transmission modulator valve your trans. will bang!

Steve, the hard shifts and the delayed shifts are two different issues.

With regard to the hard shifts, setup a vacuum gauge so that you can read the transmission vacuum while you drive it. If you do not have sufficient transmission vacuum at low and moderate power settings, you will get hard shifts. This could be due to blockage, or leakage in the EGR system, or a bad trans modulator valve. I don't have the data off the top of my head on the values for the vacuum at different points along the load curve, but, I think that there is data in the archives. The main thing to look at is whether you have a high vacuum at light throttle positions as it shifts. The vacuum should drop at greater pedal positions and then drop to nearly zero at full pedal.

The delayed shifts may require an adjustment in the Bowden cable, which I believe that the '84 still has. You want to get a little more slack in the cable so that is shifts earlier.

Also, I'm not sure of the vacuum routing on the '84, however, if the black box on the valve cover has three plastic tubes running into it, it is likely controlling only the EGR. If this is the case then you should disconnect the black box completely.

The black box has a supply vacuum, a vent, and an EGR supply. Remove the EGR supply completely (goes to the temperature switch near the thermostat).

Find the supply vacuum and remove the entire plastic tube, right up to the three way "T". Cap the "T" where you removed the plastic tube (might need a screw here until you can just get rid of the "T" completely).

The final tube is the vent. It should be a black tube. You can ignore it or remove it. Your choice.


Just be sure, before you do any of the above, that there are only three tubes going into the black box and that one of those tubes goes to the temperature switch for the EGR valve.

My advice is based upon the routing for the SD, which, I presume, is the same.