Another engine wont shut off problem. - PeachParts Mercedes-Benz Forum

Mike Michalek · #1 10-13-2006, 02:30 PM

Hi-I have an 1985 300D turbo. The door locks went first, but the car would still shut off OK. Then the car started to take longer to shut off and then would only shut off by pushing the mechanical stop linkage under the hood. Then the car started to shift hard and had loss of power at times. I rebuilt the vacuum pump condersiding its age, but it did not help any. I used the search and did the following. I replaced the four way and the three way conntectors and all of the small rubber connectors. Here is what I found. There is a white vacuum valve I think it is called the vacuum control valve. It is mounted to the IP right above the shut off valve. It has two vac. lines the one on top has a green vac. damper valve and the line on the bottom had oil on the connector and a small black diam. hard vac. line that was not connected to anything and did not appear that it would of have gone through the firewall. Also I found a larger black diam. hard line at the same connector for the door locks and the HVAC broken. I believe that line goes to the reseroir tank. When replacing all the connectors the only oily one was the bottom conntector on the white vacuum control valve (?). Here are the tests that I performed. I isolated the large blk. vac. line from the pump to the brake boster connected a gauge and got a good steady 22 Hg. reading. I connected a vac. pump to the shutoff valve and the car shut right off. I also performed the same test at the ignition sw. and the car shut off OK. I isolated the yellow door lock lines & valve the green HVAC line the broken black line to the reseroir tank and the line going to the trans. mod. valve. Also isolated the white vacuum control valve (?) and the car would not shut off. Need some help please.
Thanks in advance.
Mike

vstech · #2 10-13-2006, 02:39 PM

the line with oil in it, whatever it is connected to, is leaking engine oil. it would also absorb vaccume causing the problems you are describing. give another description of the part, and maybe phil has it in stock.
John

Mike Michalek · #3 10-13-2006, 03:04 PM

It's the bottom line off of the white control valve (?). This valve is mounted to the IP right above the shutoff valve. It was leaking at the connector of the line that was broken. I had isolated the valve and the top/bottom vac. lines, but it didn't help any with shutting the engine off.
Thanks
Mike

JAM300 · #4 10-13-2006, 03:12 PM

I had a similar problem and I was told that its the brown line that comes from the ignition that needs to be tight and dry. I changed my oil once and spilled oil from the filter canister down on it and there was oil all in the line. I replaced it and got a tighther rubber fitting and the car shuts off and doesnt diesel anymore ever since. Hope you get it figured out.

Samuel M. Ross · #5 10-14-2006, 02:49 AM

Quote:

Originally Posted by Mike Michalek

Hi-I have an 1985 300D turbo. The door locks went first, but the car would still shut off OK. Then the car started to take longer to shut off [<- a leak getting worse] and then would only shut off by pushing the mechanical stop linkage under the hood. Then the car started to shift hard [<- not surprising] and had loss of power at times. I rebuilt the vacuum pump
[<- premature pump rebuild] condersiding its age, but it did not help any. I used the search and did the following. I replaced the four way and the three way conntectors and all of the small rubber connectors. Here is what I found. There is a white vacuum valve I think it is called the vacuum control valve. It is mounted to the IP right above the shut off valve. It has two vac. lines the one on top has a green vac. damper valve [<- ] and the line on the bottom had oil on the connector [B] [<- ?][/U] and a small black diam. hard vac. line that was not connected to anything and did not appear that it would of have gone through the firewall [<- a vent that should go thru firewall and terminate under dash as a clean air source]. Also I found a larger black diam. hard line at the same connector for the door locks [<- ?] and the HVAC broken] [<- "broken"?... black line or HVAC?]. I believe that line goes to the reseroir tank [<- wrong color line I think!].

When replacing all the connectors the only oily one was the bottom connector on the white vacuum control valve (?). Here are the tests that I performed. I isolated the large blk. vac. line from the pump to the brake boster connected a gauge and got a good steady 22 Hg. reading. I connected a vac. pump to the shutoff valve and the car shut right off. I also performed the same test at the ignition sw. and the car shut off OK. I isolated the yellow door lock lines & valve the green HVAC line the broken black line to the reseroir tank and the line going to the trans. mod. valve. Also isolated the white vacuum control valve (?) and the car would not shut off. Need some help please.

It's hard to follow your description of your car's vacuum line plumbing... it's almost like someone might have jumbled things up a bit in the past... so let's try to pin down the proper vacuum diagram for your car.
IF your car is a 1985 W123 with 617.952 engine in a 300D Turbodiesel that is NOT a CA car, then most likely the correct diagram is this:
http://www.peterschmid.com/vacuum/1977_1985/617_95/1984_1985.jpg
But IF it is a CA car, then it is most likely this:
http://www.peterschmid.com/vacuum/1977_1985/617_95/1985_cal.jpg
My sympathies for your Engine Vacuum system is one, if not the most, complicated system. I hope others with more direct experience will chime in and help out [ Brian Carlton we need you!].

I want to compliment for the obvious effort you ahve expended... a lot of effort into trying to solve what I think are multiple problems in multiple vacuum systems. I can only fault your NOT trying earlier to isolate the various vacuum systems and thus you might have done a better job of troubleshooting the problem/cause in each system. Q - Do you have a separate electric vacuum pump in the trunk or elsewhere that serves the door-lock system? I'm guessing the answer is NO and that such electric vacuum pumps/systems are only on the W126 chassis cars.

Compare the vacuum components you have with those in the diagrams I referenced above and then report back to those of us reading/monitoring this THREAD as to which it is that you have. I'm sure other will come along and help with specific suggestions. We need to be more systematic... one system at a time!

Regards,

Shorebilly · #6 10-14-2006, 07:26 AM

G'mornin',

I began a thread a few weeks ago...search Shorebilly.....and I went thru my vacuum problem on my '85 300D-T, Federal,.....eventually I found my problem to be the "Switchover Valve" that supplies Vacuum to the Boost Dump to be leaking.....

The thread that I began has some highlighted photos and such.....

....it was leaking through the valve to the "Vent to Passenger Compartment"

There are 2 devices.....

1) Vacuum Converter.....this device has a nest of Vacuum plumbing, but basically it supplies Vacuum to the EGR Valve, to open it, and vents that vacuum back to atmosphere, to close it.

2) Switchover Valve.....this device has 3 connections, Vacuum from Supply, Vacuum to "Boost Dump", and Vent to Atmosphere (via the li'l filter , to Passenger Compartment)......

if either of these devices stick, hang up, or otherwise leak "internally" they can/will connect your "Vent" directly to your "Vacuum Source/Supply"

Read my thread.....

I have eliminated the "Vacuum Source/Supply" from both of these devices.....initially I plugged the Vacuum lines with Golf Tees......since, I have removed all of the related vacuum hoses/lines......and replaced the 4 way vacuum connector that supplies vacuum to the switchover Valve with a 3 way connector (taking the Switchover valve out of the vacuum circuit entirely) and replaced the 3 way vacuum connector with a 2 way (small piece of hose) connector (taking the Vacuum Converter out of the Vacuum circuit).......I have left the both devices mounted to the wheel well, for the time being.....because...I do not know what removal of the electrical component (solenoid coils) will do to the operation of the "Control Unit" which also outputs to the tachometer and a couple of other EGR/Pollution control items`.......

Note: I saved the whole "Vacuum Tubing Assembly" (sort of like a wiring harness) that connects both of these devices to both vacuum and vent.....just in case I decide to replace/renew the switchover valve that began my odessy thru the Vacuum System.........

Note II: this all began because I changed the "EGR Filter".......the old one was plugged solid.......

Luck to ya....send me a personal message if you have any questions, I will do my best to help you...

SB

Mike Michalek · #7 10-14-2006, 08:49 AM

Thanks Sam for the diagram and identifing the vent line. Shorebilly, I remember reading either your post or your reply to one during my search. I will revisit. I will also isolate the two valves and see what happens. I do have some other things going on this weekend, but will dap into it some. I will repost with my findings.
Thanks Again.
Mike

Samuel M. Ross · #8 10-14-2006, 05:34 PM

Quote:

Originally Posted by Mike Michalek

Thanks Sam for the diagram and identifing the vent line. Shorebilly, I remember reading either your post or your reply to one during my search. I will revisit. I will also isolate the two valves and see what happens. I do have some other things going on this weekend, but will dap into it some. I will repost with my findings.... Thanks Again. Mike

Mike,
In your “newer vintage diesel” cars, there are many possibilities as to which vacuum component(s) might be causing your problem(s)… and as I said before, I believe that you probably have 2 causes of vacuum loss and these could be in separate subsystems because they can interact with one another… especially if someone in the past might has drilled out one of the restricted “T”(s) that branches off the large, main, vacuum line between the pump and the brake booster.

You can easily waste a ton of time and effort and worse yet end up more frustrated and less confident in your ability to deal with what might now seem like “abstract” vacuum components and systems. It helps me to think of vacuum as the reverse of a supplied air system… and to quantify it just the same way. Another way is to think of a supplied air system as positive pressure and the vacuum system as a negative pressure. In reality, however, both are positive pressures in “absolute” terms… it’s just that a vacuum has less air pressure than atmospheric [or "gauge" pressure]... so a vacuum is nothing more than a pressure less than atmospheric [14.5 psi] and is expressed the same as barameter readings... in inches of mercury in reverse. E.G - 10" of vacuum is a higher absolute pressure than 20" of vacuum. I hope this helps.

After studying the vacuum diagram for the “Federal” 1985 W123 300D TurboDiesel [I hope you don’t have a CA car – and you didn’t say]… anyway I recommend you start by using golf Tees to isolate or shut off the “Remaining consumer” lines that branch off the 4-way or 5-way rubber vacuum connector… EXCEPT the line going to the “SwitchOver Valve”[#81] which is part of the engine/tranny/turbo control system that uses vacuum as an energy source and control signal.

“Shorebilly”’s THREAD, also dealing with a 1985 300D TurboDiesel model is:
Vacuum Devices, '85 300D-T and hopefully Brian Carlton and/or others will pitch in here soon.

The main help I can provide you from this point is to encourage you to “isolate” the vacuum subsystems and NOT jump around from one component to another just because someone guesses the problem is this or that. You will have to use logic and your hand vacuum pump/gauge and find those leaks and fix them and this will eventually lead you to one or more components that might also have failed. Thanks to the experience of others on this FORUM/THREAD, you will learn how to isolate and possibly do without the EGR system, a common source of problems… and other components having to do with the turbocharger with which I have little-to-NO experience [yet].
Be methodical in your approach… don’t jump around… AND ask specific questions of those on following and responding to this THREAD.

Shorebilly · #9 10-14-2006, 05:38 PM

Howdy,

When I was having my major problem....engine would not shut down...

First I hooked up my MiteyVac to the forward most Vacuum tap on the Main Vacuum Line that goes to the Brake Booster......and then ran the car, found that my Vacuum Pump was working....I had 23+in hg.....

Then I connected that back up.....and hooked up the MiteyVac to the Brown Vacuum line as it goes to the Injection Pump Shutdown device.....ran the car....pumped the MiteyVac 1x and Engine Stopped....this proved that the IP Shutdown was/is in fact working....

Next, after reconnecting that brown line......I disconnected the other brown line that goes from Vacuum Source....a little trident looking connector....into the firewall....and to the ignition switch......ran the engine.....pumped up MiteyVac.....turned off ignition key.....had to pump the Miteyvac a couple of times and......engine shut down......proving that the Ignition switch was operating ...perhaps not as good as it should...but was working.....will renew the little vacuum valve on ignition switch sometime when I dig under the dash.

Then I disconnected the lines from the after vacuum tap on the Main Vacuum Line.....the one that the 4 way connector attaches to.....pumped up MiteyVac....had to pump a bunch as this goes to Vacuum Reservoir.....and then watched to see if it would hold.....it did.......therefore no major leaks in anything in this area......Shut Down, AC Climate Control, Door Locks.....stuff inside car or to the rear of the engine compartment.

Then I disconnected the lines from the forward Vacuum Tap, once again, this time I connected up the Miteyvac.....pumped it...and it would not hold vacuum.....proving that the leak was somewhere in the EGR system.....or under the hood......in the engine compartment

Then I hooked up the MiteyVac to each of the devices......where vacuum Supply connects to......pumped up MiteyVac......found that the Switchover Valve, that operates Turbo Boost dump......would not hold vacuum.....plugged this line where it enters Switchover Valve, Golf Tee,...and ran engine.....turned off, engine shut down......

Since I have removed all of the vacuum plumbing in this circuit......and eliminated their connections as close to the vacuum source as possible.....

This is the best that I can do for you, from here.....

Isn't Mt. Airy, MD near to Cumberland??? I am 40 miles West of Clarksburg, allong RT 50...sorta.....about 130 miles from Cumberland

Hope that this helps...
SB

Mike Michalek · #10 10-15-2006, 07:23 PM

I found the problem. I started to check the valves that Shorebilly suggested and I found a bad 90 degree connector on one of the valves. Before I was totally focus on the area around the shut off valves and the lines going into the firewall. I still have a leak in the door lock system, but I can start trouble shooting that later. Thanks Sam & Shorebilly.
Mike

Mike Michalek · #11 10-15-2006, 07:30 PM

Shorebilly-Mt. Airy is about halfway between Baltimore & Frederick off of Rt. 70.
Thanks Again!

Samuel M. Ross · #12 10-16-2006, 12:05 AM

Quote:

Originally Posted by Mike Michalek

... I still have a leak in the door lock system, but I can start trouble shooting that later...

Mike,
I canNOT say with any certainty because your Signature does not show us the YR/Model of your MBZ, but you might find this THREAD helpful in resolving your Door Lock leak/problem: W123 Vacuum InterLock Diagram
Regards,

Shorebilly · #13 10-16-2006, 07:49 AM

Quote:

Originally Posted by Mike Michalek

Shorebilly-Mt. Airy is about halfway between Baltimore & Frederick off of Rt. 70.
Thanks Again!

Now I remember....I see it on my way to Ocean City (my mom lives there), as I turn down MD 32 from I 70.......a bit far for me to lend personal assistance....but I do pass by thattaway several times annually.....usually in the wee morning hours......getting past NSA before the "rush".....

SB

Mike Michalek · #14 10-16-2006, 08:54 AM

Thanks Again Sam-Hopefully in a couple of weekends I will be able to get on it.

Samuel M. Ross · #15 10-16-2006, 11:04 AM

Quote:

Originally Posted by Mike Michalek

Thanks Again Sam-Hopefully in a couple of weekends I will be able to get on it.

Mike,
On Nov 1 I'll be off on an overseas trip for 3 weeks and return Thanksgiving day. There are others here that can help as well and I'll catch up when I return.