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  #1  
Old 09-16-2009, 12:18 AM
tankowner's Avatar
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Ignition Vacuum Valve Question

So I am still working on getting the 240D ready for the road and have managed to get a lot of work done, but the one thing that is really starting to bug me is that I can't shut it off with the key. Doing some vacuum diagnostics, I traced this back to the ignition vacuum valve - err, I think so anyway.

If I hook up the MityVac to the brown w/purple stripe vac line (goes to the fuel shot off valve) I can shut it down easy (~6"). It also seems as if I can get good vaccum from the pump side - well, after I removed some other lines and teed the brown vac line right into the main vac line (apparently there are some other issues in other lines -locks not working properly either - but I am bypassing that for now). So this get me back to the ignition vacuum valve (IVV - if you will).

So I pulled the instrument panel out and I am looking down onto the ignition. There's the IVV sticking out from the side with its two prongs to hook the vac lines to. With the car on and running I can hook the MityVac up to the first prong (nearest the ignition) and put my thumb over the outer prong. Trying to pull vac in this configuration produces nothing. However, if I put the Mityvac on the outer prong I can pull strong vacuum that doesn't leak down (without having to cover the other prong). I am assuming then that the line from the pump (brown vac line) goes on the outer prong and the line to the fuel shut off (brown w/ purple line) goes on the inner prong - although that is the reverse of how I found it - so, did someone else mess with this???

Okay, this is where it gets weird. With the MityVac on the outer prong and car running, I pump up a strong vacuum. When I turn the key to off that vacuum releases - presumably sucks air through the other prong (which in theory I should be able to hook the line to the fuel shut off valve to and it will shut the engine off - right?) I can confirm that this is so because I can put my thumb over the inner prong, turn the key to off and feel the suction on my thumb - remove my thumb and the vacuum releases. Okay - good. Now, I hook the vac line to the fuel shut off valve to that inner prong, start the car, then pull a strong vacuum with the MityVac on the outer prong. Turning the key to off should then open the valve and pull vacuum on the shut off valve (as confirmed with my thumb trial) - no dice - I get nothing when I turn the key to off. HOWEVER, if I pump the MityVac even once at this point it shuts the engine down. What????

Your thought please.

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'95 E300D ("Tank") - 231,000 miles
'79 240D ("Biscuit") - 197,250 miles (Sold)
'83 240D ("Ding-Ding") - 217,000 miles (Death by deer)
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  #2  
Old 09-16-2009, 12:35 AM
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I was not able to understand your test proceedure.
However, on my year and model the Vacuum Valve that goes on the Ignition/Steering wheel lock is a $25-$28 item + shipping. Some places will give your free shipping for $50 or more.
At the point you haver reached if it was me I would just buy a new Valve and some other items I need like filters, extra fuel return hose, extra Glow Plugs and so on to get the free shipping.
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Old 09-16-2009, 12:52 AM
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Quote:
Originally Posted by Diesel911 View Post
I was not able to understand your test proceedure.
LOL . . . crap . . I tried, sorry.

Quote:
Originally Posted by Diesel911 View Post
However, on my year and model the Vacuum Valve that goes on the Ignition/Steering wheel lock is a $25-$28 item + shipping. Some places will give your free shipping for $50 or more.
At the point you haver reached if it was me I would just buy a new Valve and some other items I need like filters, extra fuel return hose, extra Glow Plugs and so on to get the free shipping.
Yeah, I already looked up the part and you are right, it only costs about $25. But it just doesn't make sense to me - how exactly is mine bad?

The short version of the original post is that I start the car up (key on - obviously) and I can pull good vacuum on one end of the ignition vacuum valve that releases and sucks air in through the other side when I turn the key to off. In theory, all I have to do is hook the fuel shut off line to the that other side and it will shut the engine off when I turn the key off - but that doesn't happen. I can replace the ignition vacuum valve and see what happens, but I still don't understand while it isn't working.
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'95 E300D ("Tank") - 231,000 miles
'79 240D ("Biscuit") - 197,250 miles (Sold)
'83 240D ("Ding-Ding") - 217,000 miles (Death by deer)
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"Back off, man. I’m a scientist” ~ Peter Venkman
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  #4  
Old 09-16-2009, 01:21 AM
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Brown lines.

Hook both the brown lines up to the valve at the ignition, in the manner which you think is "correct".

Disconnect the supply line from the three/four-way connector. Make sure the line that goes to the shutoff solenoid on the pump is properly connected. Now, start the car. Hook the hand-held pump up to the supply line (the one you disconnected). Turn the key to off. Pump hell out of the mightyvac. If the car doesn't turn off, try switching the lines at the ignition and repeat.

This assuming your shutoff solenoid is 100%.

If the car doesn't turn off with the lines in either configuration (your shutoff solenoid is definitely good, ya?) then I'd feel pretty comfortable saying the shutoff valve is defective.

Also, NEVER, EVER, EVER, EVER (EVER!!) try to run the car with the line to the oil-pressure gauge disconnected. It'll fill your car with oil. Believe me.

Jay.
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  #5  
Old 09-16-2009, 02:35 AM
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There could be another issue.
The Valve is moved by some sort of cam; I believe the sameone that move the Steering Wheel Lock into position. I suppose it is possible to have a good Valve and something wring with the Cam. But, have not read of even one occasion of this happening.
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Old 09-16-2009, 02:47 AM
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Originally Posted by babyjames View Post
Also, NEVER, EVER, EVER, EVER (EVER!!) try to run the car with the line to the oil-pressure gauge disconnected. It'll fill your car with oil. Believe me.

Jay.
Jay,

Where were you two days ago when I started the car up after finishing my valve adjustment??? Oh yeah, started it right up, got out and listened to the engine, walked around for awhile humming a tune, finally decided to go back and shut it down only to find a small lake of oil forming on my floor mat!!!!!

Panic mode! Panic mode!!! Must shut car off - turn key, oh wait, that doesn't work!!! Run around to the engine and lay on the shut off lever . . oh wait, that doesn't work unless I turn the idle way down . . run back and turn the idle down (notice that the lake has grown) . . . back to the shut off lever and kill the engine . . . run to the garage for massive amounts of shop towels.

Yeah, forgot that i had disconnected the oil pressure gauge the previous week and hadn't bothered to reconnect before moving on to the valve adjustment. Luckily it all stayed on the floor mat and mostly on the rubber part. The mat is also pretty filthy any way. I have learned my lesson!
__________________
'95 E300D ("Tank") - 231,000 miles
'79 240D ("Biscuit") - 197,250 miles (Sold)
'83 240D ("Ding-Ding") - 217,000 miles (Death by deer)
______________________________________

"Back off, man. I’m a scientist” ~ Peter Venkman
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  #7  
Old 09-16-2009, 03:05 AM
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Quote:
Originally Posted by babyjames View Post
Hook both the brown lines up to the valve at the ignition, in the manner which you think is "correct".

Disconnect the supply line from the three/four-way connector. Make sure the line that goes to the shutoff solenoid on the pump is properly connected. Now, start the car. Hook the hand-held pump up to the supply line (the one you disconnected). Turn the key to off. Pump hell out of the mightyvac. If the car doesn't turn off, try switching the lines at the ignition and repeat.

This assuming your shutoff solenoid is 100%.

If the car doesn't turn off with the lines in either configuration (your shutoff solenoid is definitely good, ya?) then I'd feel pretty comfortable saying the shutoff valve is defective.


Jay.
Thanks Jay. Let me review what you have here. I can try it as you have said it, but I think I have already tried this. I have hooked the lines up the way i believe they should be (I can only pull vacuum on one side of this valve and then it releases when turn the key to off - so I figure that has to be the supply side - yes?). Then I disconnected the supply line (but I did so right at the injection vacuum valve and hooked the MityVac on right there. I connect the other line that goes to the fuel shut off solenoid to the other end of the ignition valve.Then I start the car.

At this point you say to turn the key off and pump the MityVac - i can do that and it will shut the engine off, but that doesn't really solve my problem. So, what I have dones is to follow the above up to the point where I start the car, then I pump the MityVac on the supply side to simulate the vacuum pump - it holds vacuum. If the ignition valve is operating properly, then turning the key off at this point should kill the engine - yes? But it doesn't. So, I think to myself - well, the ignition valve is bad. However, if repeat the above but just disconnect the the line to the fuel shut off solenoid and place my finger over the valve outlet, i can verify that that when i turn the key to off the valve opens and it pulls air through which should effectively kill the engine . . . but again, it doesn't kill the engine when I have that line (to the fuel shut off solenoid) attached.

I know that the fuel shut off solenoid is good because I can hook my Mityvac up to the brown line (w/ purple stripe) while the car is running, apply a small amount of vacuum and instantly kill the engine.

I don't know, i guess I am completely missing something here, but it seem like each of the indiviudal components is working properly until I hook them together and it no longer works.

Not sure if this makes sense - it is difficult to explain. I appreciate your help though.
__________________
'95 E300D ("Tank") - 231,000 miles
'79 240D ("Biscuit") - 197,250 miles (Sold)
'83 240D ("Ding-Ding") - 217,000 miles (Death by deer)
______________________________________

"Back off, man. I’m a scientist” ~ Peter Venkman
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  #8  
Old 09-16-2009, 11:52 AM
tankowner's Avatar
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Quote:
Originally Posted by Diesel911 View Post
There could be another issue.
The Valve is moved by some sort of cam; I believe the sameone that move the Steering Wheel Lock into position. I suppose it is possible to have a good Valve and something wring with the Cam. But, have not read of even one occasion of this happening.
Yes, I also considered that but, as you suggest, I don't think that is the problem. When I have the engine on (Key turned on), I can pull a vacuum on one side of the valve (the only side that will hold vacuum) and then, when I turn the key off, the vacuum releases (pulls air from the other side of the valve), so it seems as if the cam from the ignition switch to the valve is operating properly.

I am going to look it over again - maybe over luch - I am hoping for one of those "Why are you such an idiot?!" moments that will clarify everything - just doesn't make sense right now.

__________________
'95 E300D ("Tank") - 231,000 miles
'79 240D ("Biscuit") - 197,250 miles (Sold)
'83 240D ("Ding-Ding") - 217,000 miles (Death by deer)
______________________________________

"Back off, man. I’m a scientist” ~ Peter Venkman
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