does anyone know what this vaccum line is for and why would someone tie it in a knot. i found it tonight on top of my valve cover while doing a valve adjustment. i had never noticed it before. any help?
thanx

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1980 300D

vacuum control valve on top of the valve cover for the transmission IIRC. guess they didnt know about golf tees.

Hows your transmission shift?



But it also looks like its for the vacuum cruise control. Hows that work.. or not work.

On that vehicle, the function of that valve is not so clear. The valve regulates something.........either transmission function or EGR function. What the PO did was to close off the vacuum coming to.........or from........the valve.

Check to see where the connected hose runs? Is it the supply vacuum from the vacuum pump?

The transmission shifts fairly well. no real flaring or hard shifting that i have noticed. sometimes it will want to stay in a lower gear when i floor it either for passing or and italian tune up.
now the cruise control is another thing. maybe one of the only things on this car that doesnt work. besides the sun/moonroof.

That is something i will have to check into one day/night when i have more time. for now im just gonna put everything back together and run with it. i just find it strange its just tied off.

on a different subject, if you look just below the shut off lever, you will see two cables. well only one. the other one is laying on top of the bracket beside the shut off lever. this was also noticed the first time tonight. im assuming it goes into the empty socket below it. but what is this cable?

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1980 300D

I've got this type. That line is supposed to be plugged. A vac cap works nicely. attached is diag. 1980 style

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What Would Rudolph Do?
1975 300D, 1975 240D, 1985 300SD, 1997 300D, 2005 E320 , 2006 Toyota Prius

Thanks for the diagram.

However, I read that that valve functions in conjunction with the vacuum control valve for the transmission. With one of those hoses disconnected and plugged, the VCV is effectively disconnected from the transmission.

I'm not sure of why they switch the vacuum with the throttle linkage, but, disconnecting it doesn't seem the perferred way to go.

It may be the idle speed control cable that should be connected to the idle knob on the dash. Does your idle control work, does the cable seem to move when the knob is turned?

How so. The line from the other outlet of T's off to the transmission. I believe that that does effect my transmission shifting. I 've tested it various ways and that configuration in the diagram gives me more or less smooth, no flare, not to hard (very often) shifting.

But i never really studied how the thing works. Would be fun some time when i have time.

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What Would Rudolph Do?
1975 300D, 1975 240D, 1985 300SD, 1997 300D, 2005 E320 , 2006 Toyota Prius

The vacuum control valve, item 65, provides a controlled bleed for the transmission depending on throttle position. You'll note that the vacuum to the vacuum control valve passes through the switch on the valve cover. If you plug one of the lines from the valve cover, you have effectively disconnected the vacuum control valve from the transmission and the trans gets full pump vacuum. The resulting shifts will be softer than desired, especially when the pedal is further down.........when the shifts are desired to be firm.

well i will have to deal with that another day. i will have to get the full diagram for this car and go over it until i understand it better.
Craig, thanx. you were correct. that rogue cable is my idle control. i hadnt noticed that it had stopped working, how often is it rarely used anyway, you know. but, i guess i will have to find the plastic grommet and reattach it so it will be functioning better.

so tonight i adjusted the valves....all of them were way tight. put on a new valve cover gasket and air filter. cleaned up the air filter housing and a little gunk on the intake manifold. checked my timing chain slack and put it all back together. the car starts easier(it was smooth starting before too, but its better) and it shuts off much faster now as well. but its smoking more. i dont think its too much, i havent taken it out for a spin yet, but in no time at high rpms, my garage was kinda thick. what could be the problem. it didnt smoke like this before. what could i have done wrong?

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1980 300D

Uh oh, that is kind of how The Flash started out in it's smoking saga.....


Brian,
If his car is like mine (Rest in piece Flash), there is no item 65, vac control valve. (From my pic below, which is crude) The valve receives vac via line C. One outlet is plugged, A on mine, and the other outlet , B, goes straight to the modulator on the passenger side of the tranny. Somehow that vac valve decreases the vacuum to the tranny modulator as the throttle movement increases. Then you adjust the pin inside the modulator to effect "when" it shifts. No real adjustment for firmness.
My valve started out the same as his, as far as the blocked line being on the outlet I have labeled "B", but in trying to get it to shift correctly, moving that and adjusting tranny modulator got it shifting perfectly. Had very little power, but bless it's heart it shifted correctly....

**edit**
I just remembered, that valve has an actuator, a replaceable 'flap', and mine was worn off. I installed a new one that I ordered, and it wouldn't shift correctly with it, so I removed it and all was well....
I miss that weird wagon.....

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Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

[quote=JimmyL;1378894]Uh oh, that is kind of how The Flash started out in it's smoking saga.....




Jimmy, what happened to The Flash. and why did you have to put "uh, oh" in there. now im all paranoid.

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1980 300D

I'm afraid the answer is in my sig........
Never found the cause of the smoking. But it smoked like it was on fire.....

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Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

yeah sorry, i read your sig after i posted that. what rpms was that car runnning when those pics were taken? luckily mine is not smoking that bad.

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1980 300D

It would smoke like that at idle. Didn't really smoke during acceleration or high rpm's on the highway. Also didn't even smoke at idle running on diesel purge.
I'm glad you aren't smoking like that.

__________________
Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John