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#1
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My '77 240D has no butterfly in the air
intake(can that be called "intake manifold" since the fuel is injected?) & the '83 parts car has a butterfly. The same is true for the plastic unit on top of the valve cover('83 has it, '77 does not). Will someone please clue a newbie diesel owner in....
One more - why do they have a pump for vacuum when I am cautioned to not try to stop a run away by placing my hand over the air intake(I read that you can lose body parts!). |
#2
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Can't a runaway engine be stopped by the stop lever?
-Joe
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'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate Sooner or later every car falls apart, ours does it later! -German Narrator in a MB Promotion Film about the then brand new W123. |
#3
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A normally aspirated diesel has only a little vacuum and a turbo frequently has positive pressure in the intake. The amount of vacuum necessary for existing vacuum operated devices is not available off the intake, hence the pump. Gasoline engines develop significant vacuum below the throttle plate in a carburated engine. Ever watch vacuum operated wipers slow down when the car is climbing a hill? Throttle open, low vacuum and you are at least as old as me. A runaway diesel isn't stopped by the stop lever because it ran away in the first place because something isn't right in the mechanical feedback mechanism in the injection pump. It can be stopped by THOROUGHLY blocking the air, which isn't always a sure bet depending on how its executed, using a fire extinguisher in the intake (a carbon dioxide one is clean and will displace the oxygen necessary for running) or removing the high pressure fuel at the injectors, by loosening or cutting the lines. Some have mentioned the possibility of an engine with a lot of blowby running away by aspirating crankcase oil too.
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'82 300SD - 361K mi - "Blue" "Good judgement comes from experience. Experience comes from bad judgement." listen, look, .........and duck. |
#4
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I doubt I am as old as you, but I have seen vacuum-operated wipers on Dad's 56 International pickup. Used to annoy the hell out of me when I drove it in the rain. Took him a long time to get it through my head why they slowed down like that.
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Keep everything as simple as possible-but no simpler--Albert Einstein |
#5
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The plastic box on top of the 83 is related to emissions equipment that the 77 doesn't have. I'm not sure about the butterfly, but suspect the same.
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Rick Miley 2014 Tesla Model S 2018 Tesla Model 3 2017 Nissan LEAF Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro Chain Elongation References |
#6
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Its the EGR OM616 style...
The exhaust goes from a hole/port in the exh manifold, through a vaccuum controlled valve (I think) through a tube through that butterfly and into the intake stream, decreasing emissions (and power...just read here a while to see what most think about functional EGRs...). Wedge that butterfly shut and decrease youe egr flow. The black plastic box is either vacuum switching for the auto-trans (if you have one) and/or the vacuum switiching that disables egr at idle and full throttle. -John
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2009 Kia Sedona 2009 Honda Odyssey EX-L 12006 Jetta Pumpe Duse (insert Mercedes here) Husband, Father, sometimes friend =) |
#7
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Thanks for the replys - and Pete, I'm old enough
to even remember the hand lever on those wipers that could be used to give them a boost if needed....
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Jim '49 170?(donated to church in Darmstadt '58) '58 220S(crusher, after '73 fire[San Antonio]) '72 280SE 4.5 '77 240D '81 300SD '83 240D parts car |
#8
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Quote:
Anyone know why I was backing up the hill?
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'10 Chrysler T&C Stow-N-Go White. Grandpa's ride. '13 Chrysler 200 Touring Candy Red. Grandma's ride. Age and cunning will always over come youth and vigor. |
#9
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About out of fuel?
......
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Jim '49 170?(donated to church in Darmstadt '58) '58 220S(crusher, after '73 fire[San Antonio]) '72 280SE 4.5 '77 240D '81 300SD '83 240D parts car |
#10
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Quote:
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'10 Chrysler T&C Stow-N-Go White. Grandpa's ride. '13 Chrysler 200 Touring Candy Red. Grandma's ride. Age and cunning will always over come youth and vigor. |
#11
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There had been so much rain that the unpaved road was
so muddy the A would not go up in forward gear?
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Jim '49 170?(donated to church in Darmstadt '58) '58 220S(crusher, after '73 fire[San Antonio]) '72 280SE 4.5 '77 240D '81 300SD '83 240D parts car |
#12
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Quote:
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'10 Chrysler T&C Stow-N-Go White. Grandpa's ride. '13 Chrysler 200 Touring Candy Red. Grandma's ride. Age and cunning will always over come youth and vigor. |
#13
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Answers
Quote:
The run away is over revving, sheer momentum will keep it cycling as a giant multi cylinder vacuum pump, this is one of the few times when it can build hard vacuum in the intake manifold, hard enough to suck your blood through skin and in some diesels, break the bones in your hand, followed by sucking it in. Here is an article I wrote. Run away diesel, why does it happen? Note: A dry chemical fire extinguisher does a wonderful job of junking a run away diesel…
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ASE Master Mechanic asemastermechanic@juno.com Prototype R&D/testing: Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician. Noise Vibration and Harshness (NVH). Dynamometer. Heat exchanger durability. HV-A/C Climate Control. Vehicle build. Fleet Durability Technical Quality Auditor. Automotive Technical Writer 1985 300SD 1983 300D 1984 190D 2003 Volvo V70 2002 Honda Civic https://www.boldegoist.com/ |
#14
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Quote:
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'10 Chrysler T&C Stow-N-Go White. Grandpa's ride. '13 Chrysler 200 Touring Candy Red. Grandma's ride. Age and cunning will always over come youth and vigor. |
#15
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I believe some 240s had mechanical governors instead of vacuum governors, so they won't have a butterfly in the intake. If there is a vacuum line to the back of the IP, you have a vacuum governor. If not, it's mechanical and there won't be a butterfly in there.
Don't mistake the vacuum throttle for the anti-backrunning plate. As for stopping a runaway engine, the safe (although messy) way is to loosen the injector lines. You can also discharge a CO2 fire extinguisher into the intake. The main reason not to use your hand is that the suction will cause serious bruising and might even rupture the skin. On turbos, you would have to remove the air filter housing and cover the turbo intake (else too much air gets in and it won't stop), and the turbo will cheerfully munch off most of your hand it if touches the turbine. Not funny. Peter
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1972 220D ?? miles 1988 300E 200,012 1987 300D Turbo killed 9/25/07, 275,000 miles 1985 Volvo 740 GLE Turobodiesel 218,000 1972 280 SE 4.5 165, 000 - It runs! |
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