I researched this in the forums but could not find an answer.

My 1986 190D stays on for about 4 seconds after I turn the engine off. I am getting very good vacuum from the vacuum pump.

Also, when I apply vacuum to the shut off valve it holds and I can see the off switch drop.

I checked all of my vacuum lines and can't find any leaks. Locks are all working fine.

Does the vacuum line that is Brown/blue go to the ignition switch after passing through the firewall?

Any ideas?

Thanks!

You should have 2 vacuum lines going to a Vacuum Switch on the Steering Colum Lock. On my 84 300D there is solid brown line and a brown line with a blue stripe.

On mine the solid brown line is the vacuum supply and goes into the top nipple of the Vacuum Switch on the Steering Colum Lock and the Brown with Blue Stripe goes from the bottom of the vacuum switch to the vacuum shutoff on the fuel injection pump.

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84 300D, 82 Volvo 244Gl Diesel

If you T into the Vacuum Line between the Fuel Injection Pump Vacuum Shut off and the Vacuum Switch on the Steering Colum lock what happens with the vacuum reading?

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84 300D, 82 Volvo 244Gl Diesel

When I take the brown with blue stripe vacuum line that goes to my shut off valve, disconnect it from the rubber junction hose and apply vacuum to the shut off valve directly, the shut off valve holds for about 20 seconds and then starts to drop.
When I take the other end of the brown with blue stripe line that goes to the ignition switch and apply vacuum, I get nothing.

?

Also, I just checked the vacuum on the solid brown line going into the firewall after the yellow junction and I am getting a solid and steady 21" vacuum.

When I hook the vacuum gauge up to the vacuum pump directly I get the same reading.

I am thinking my shut off valve is bad or starting to fail?

It takes a little time for the engine to turn off, but it does eventually.

What happens to your shut-down time happens if you apply vacuum directly to the shut off valve?

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When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

When I apply vacuum to the shut off valve with a vacuum pump the car shuts down immediately.

When I turn the ignition off, I don't have enough time to get to the hand pump before it shuts down so I haven't done that test yet.
Thanks.

I can't get a infinitive idea from your description but the best guess is there is an issue with the Vacuum Shutoff Valve on the Steering Colum Lock.

I have never had any issues with my original one and when I got a new steering colum lock it came with a new one. So I have no experience with how the malfunction. Perhaps someone who has had the issue will need to speak up.

However, I think if you disconnected the line at the Shutoff Valve and squired in some WD-40 inside and removed it as you cycle the key on and off to suck the WD-40 into the Steering Colum Shut Off Valve you might find out if it is just some gunk or sticking going on in there.

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84 300D, 82 Volvo 244Gl Diesel

You most likely have a low level leak from one or more rubber connecters somewhere in the vacuum circuit.

The ones in the engine bay tend to fail first.
The connectors should really grip the hard vacuum lines tightly, and be difficult to remove.
If they are loose, replace them.

Isolate the shutdown circuit by plugging off the other vacuum consumers (HVAC, etc.) with golf tees.

If it shuts down quickly, then the leak is in one of the temporarily disabled circuits.

If it is still slow to shut down, then you have a leak in the shut down circuit.
A hard line might have a crack, the rubber connectors at the vacuum valve may need replacing, or the shutoff valve on the ignition switch may be sticking.

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78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022

So you don't think it is the shut off valve?

When I apply vacuum to the shut off valve brown/blue hose, it shuts the car off immediately but it doesn't hold the vacuum too long.

I will investigate the ignition switch vacuum circuit.

Thanks

If you connect your vacuum gauge to the line from the ignition switch to the shut down actuator, does the vacuum build quickly or slowly when the key is moved from RUN to OFF?

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When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

Unfortunately I will have to try that at a later stage. I am replacing my shift rod bushings and I believe the neutral safety switch is activated...the car won't start.

So that I understand you correctly, I will T the brown/blue vacuum line for this test?

You do have a leak in the ignition switch/shutdown circuit based on the above test.

Most likely culprit is one or both of the rubber vacuum connectors.
The brown/blue or brown hard lines might have cracks, but not very likely.

The shut off valve on the ignition switch can fail if the works get gummed up,
it is possible but not as likely as a failure of the rubber connectors.

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78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022

Correct, except that you don't need to tee it. Just remove the line from the IP and connect it to your gauge.
You could also apply vacuum to said line and see if it holds with the key in the RUN position.

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When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

I see this thread has a bit of a terminology problem...
Some reason many people on this forum have "shutoff valve" on the injection pump...
Leads to confusing threads like this (or was it just me...)

So just to clarify, the shutoff valve ("vacuum switch") is on the ignition. The governor has the shut off actuator which the shut off valve controls...

So what I'm reading the issue as, is a leak between the shutoff valve and the shutoff actuator on the engine.

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1978 300D, 373,000km 617.912, 711.113 5 speed, 7.5mm superpump, HX30W turbo...many, many years in the making....
1977 280> 300D - 500,000km+ (to be sold...)
1984 240TD>300TD 121,000 miles, *gone*
1977 250 parts car
1988 Toyota Corona 2.0D *gone*
1975 FJ45>HJ45
1981 200>240D (to be sold...)
1999 Hyundai Lantra 1.6 *gone*
1980s Lansing Bagnall FOER 5.2 Forklift (the Mk2 engine hoist)
2001 Holden Rodeo 4JB1T 2WD