I pulled it from a 1985 280CE Euro. I know about how some convert it into a boost gauge, but I figure if I were to keep an eye on my boost, I'd just get the real deal VDO gauge. What I'm going to do with this is tee into the vacuum line running into the VCV and have it operate like it would on the gassers. It's purely for eye candy purposes and conversation starters at MB GTGs (say, why does yours have that economy gauge? Does it really work?) After I got it, I noticed the folks at the Pick-A-Part marked the gauge with some yellow paint for warranty purposes. They put the paint on the white backing, I'm hoping that won't affect its operation, will it? Sorry for the blurriness.

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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.

what would doing this achieve? So you can watch your vacuum fluctuate when you give it throttle???

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1981 300SD 512k OM603

Exactly. The vacuum moves and works like it would in a g@sser's intake manifold so it will still work as an economy gauge.

I always thought those gauges were pointless. As if you need something to tell you how far you've opened the throttle.

But kudos to you for doing something different to your diesel.

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1985 CA 300D Turbo , 213K mi

I just recently got one too....Maybe I will do the same thing! I agree it makes for a conversation starter at meetups.

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

that aint gonna work, there is NO vacuum in the intake manifold on Diesel engines, the gauge is just going to sit just like it is all the time.

Paul

Vacuum gauges are good for detecting failed valves. On a gasser they flutter with the inconsistency in vacuum that a bad valve causes. I once bent a pushrod on a Ford straight six and the vacuum gauge picked it up right away.

In this particular instance, I think the vacuum gauge is a great tool for keeping a permanent diagnostic eye on the vacuum system. You'll know your engine is not going to shut off before it actually doesn't shut off.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

most of us know that.. but by t'ing into a vacuum line... you can see how much vacuum the pump is putting out... or with some clever tinkering make it work with the turbo

I agree. It would seem useful for early diagnosis of vacuum related problems and just give info about the operation of your car. I'm going to put a voltmeter on both of my cars as soon as I get the charging problem solved on the 300D. The more info the better. I just wonder about the operating range on the econ gauge and how much it will move with the vacuum seen at the main line. Is there a big difference compared to the intake on a gasser?

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Kevin

1978 300D
1979 240D

Isn't the amount of vacuum pretty much the same on our diesels regardless of rpm????

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Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

if you put it after the VCV it should act the same as a gasser, if you have your VCV and system tuned correctly

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1982 300CD Turbo (Otis, "ups & downs") parts for sale
2003 TJ with Hemi (to go anywhere, quickly) sold
2001 Excursion Powerstroke (to go dependably)
1970 Mustang 428SCJ (to go fast)
1962 Corvette LS1 (to go in style)
2001 Schwinn Grape Krate 10spd (if all else fails)

So you would in fact be monitoring vac to the tranny, but you would at least maybe see the gauge move I guess??

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Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

probably impossible... but extremely cool to make it a boost gauge.

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Cheers,
Robert

There is information on this site about converting it to a boost guage. Can't find it right now. Needle gets moved to new position on shaft.

Pry the needle off the shaft, install it in the 10 o'clock position, move it over the stop peg and bingo, you have a 5-12psi gauge. It worked for my gauge.

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