I destroyed my car's ability to shut off!

[JHZR2]

Hi,

Id been researching transmission adjustments because since I swapped the vacuum valves on the valve cover of my 83 300D, the trans has flared and acted funny.

I have a turbo/vac gauge in the car, so I attached it to various spots. I was getting 21" Hg at the brake booster line, and so on.

I played arouns with a few connections, checking vac here and there, and ever since, the car will not shut off.
I replaced the rubber connections on the brown lines at the key tumbler, as well as the shutoff line (brown with blue stripe I believe) that goes onto the IP near the bleeder valve.

Still nothing.

I know when the key is 'on' there is no vaccum pulling on the IP at the brown with blue line. Using my finger I felt that there was vacuum pulling on it when the key was put to the 'off/lock' position.

Door locks work fine after i reconnected the vacuum and had the car running.

Its not a matter of stored up vacuum. the car was running for 15 minutes, everything connected, key off before I shut it off manually

What was there that I could even have broke? besides the vac lines being setup wrong, the car worked 100%

Please help!

JMH

[psfred]

Brown line from the main vac line to the keyswitch.

It's not with the other lines, it's separate, I think, and is usually pretty brittle.

If you cracked it while working, it won't shut the car off.

Also, see if you can shut the engine off with the MitiVac at the IP. If the servo is bad, it won't matter if you have vac or not!

Peter

[JHZR2]

ok, tested it before on my way home...
key on: 0"
Key off: 10.5-11"
Is that too low?

I drove 40 miles and then tried to turn it off when I got home it turned off very slowly, but it did turn off.

I think if either of the brown shut off lines were cracked or leaky, the locks wouldnt work after a while, right? The vacuum pump side of the key/valve is plumbed into the same circuit as the door locks and vac reservoir.

Thanks,

JMH

Hi JMH.

Don't forget to check the rubber connection
pieces.
Since they are rubber,they might be dry and
brittle and you might have cracked some.

Louis.

[JHZR2]

Ive replaced all of the ones corresponding to the shut off circuit, including the ones on the ignition cylinder under the dash... That rubber had swelled up 3x its size and was really soft because of oil getting on it...

JMH

[JHZR2]

Hi,

Does anyone know the threshold or minimum vacuum required to activate the door locks vs. activating the shutoff valve? I ask this because my locks work 100% and hold plenty of vac in the reservoir, whereas the shutoff valve all of as udden stopped working when I was testing the vacuum levels on OTHER components.

Seems quite odd.

Any info would be great.

JMH

[psfred]

Replace the shutoff solenoid, it's bad. That's where the oil at the keyswitch came from.

Peter

Your SHUTOFF VALVE is suspect. Test it with your Mity Vac and see if it will shutoff the engine. Also, oil in the vacuum line suggests a faulty shutoff valve and will require replacement without delay. See thread:

Would a leaking Shutoff Valve at IP cause a quicker Loss of Vacuum to Door Locks?

[JHZR2]

I will replace the shutoff valve... That oil has been down there for some time, I just never researched the cause.

Its just so odd... the car shut off instantly until I started pulling vac hoses. Now it shuts off really slow if at all. I wish I hadnt broken whatever I broke, so I could do the valve swap at my convenience... But I guess this is for the best anyway, so it gets done.

Thanks,

JMH

[JHZR2]

Well, I went out to check it this morning with the mityvac. Pushing the stop lever didnt allow me to feel anything as per the 'finger method' psfred suggested in the archives. So I guess it was pretty bad.

I then checked the vac at the shutoff line, by pulling it from the IP and attaching my vac gauge in there... 21" Hg with the key off. So Im pulling all the vacuum that my pump is making.

Then I tried pumping my mityuvac to get it to shut off... No mattert how fast I pumped, it wouldnt shut off. If I really pumped furiously, it would slow the engine, but not enough.

I just wis I could understand why the valve failed so instantly, and just when I was testing the whole vac system.

Thanks for the help,

JMH

[psfred]

It didn't fail suddenly, it's been leaking for a while (the oil in the keyswitch). It just got so bad it wouldn't shut the engine off.

Peter

Make it absolutely certain that you have a very thorough idea of what to do when replacing the shut off valve. Larry Bible, one of the long term members and an excelent tech here blew his rebuilt 300D last year after replacing the shut off valve. The little hook on the end of the vacuum shut off assembly does not get where it should and will force the IP to work as if wide open.
The problem is that if not installed correctly, after your start the engine it will build up revs until the turbo kicks in and then run away until it blows up.
The way it was explained to me, and has worked so far, is to carefully remove the old one and note the position you need to turn it to unhook the lever from the inside of the fuel injector.
It just pulls out and then needs to be twisted slightly to get it loose.
Then carefully put the new one on there, and get it to hook inside. Pull the shut off away slowly while hooked and you should feel the slight springiness of the internal part resisting your pull. With that it should be safe to bolt it in and start the engine.
But keep wrenches at the ready to loosen injector lines if it starts to run away from you. Nothing else will stop the engine until it is left in pieces on the garage floor.

[unkl300d]

If one needed to stop the engine in such a case, could you cut the

fuel line at the secondary filter??

It would be messy but perhaps faster than undoing the injector lines.

Clues??

[JHZR2]

I plan to be very careful removing it, attempt to install it in the exact postition as the one I pulled out, and then fully test it before ever starting the car. I will use the pull trick as well as pump on the valve with the mityvac to ensure that the stop lever moves as is required. Ill also manually push the stop lever and check for pressure/vac at the shutoff valve orifice as an extra check.

Thanks for the tips!

JMH

[Rick Miley]

Originally posted by unkl300d
If one needed to stop the engine in such a case, could you cut the fuel line at the secondary filter??

All the options were discussed in LarryBible's thread here.