CK42 & jhal:

DO NOT BUY THE VDO GAUGE! I'm on my second now. the first one developed a really bad rattle, and thinking that I just got a defective one, I bought a second. Same thing. They look good, and match the other gauges in the car, but stay away!

Alex

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1983 300D (parked for four years)
2012 VW Sportwagen TDI Manual
2001 Miata SE
1962 Chevrolet Corvair Rampside

I've increased the turbo boost by adjusting the wastegate spring and did not make any changes at the ALDA. Can't really say I had anything to compare it to but you can definitely feel the turbo start working.

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Jim

For ck 42
I was not upset for your answer , i now my english it is not good because my mind it is set to speak gramatical in two diferent languages beside english but i troy to adapt to english gramatic and way of puting the words to make sense in conversation
Now about my pilar pod i adapt one from the Honda type car which has wider botom opening and smaller up opening then by aplying heat from a heat gun i molded almost to the pilar
I have to advise in one mather : IN THAT PILAR WE HAVE THE DRAINAGE HOSES FROM THE SUN ROOF SO PLEASE BE CAREFULI WHEN YOU MAKE THE HOLE i kind of have been luky with mine
Today i observed the presure does not show at all on the instrument and i believed it is my seting but logic kick in and i find out my intake plastic hose at the banjo fiting it was totaly clogt ,so my point is, whit out the instrument i will have no way to discover that at the moment notice

A gauge hooked to a T in the line from the switchover valve to the ALDA capsule will help you determine whether there might be an obstruction in the switchover valve or in the lines leading to the switchover valve. If you hook the gauge to the manifold and then get a plugged switchover valve, you might have good boost in the manifold but the ALDA capsule won't know it and won't tell the injection pump to pour on more fuel.

Does that make sense? I am just now studying this boost issue for the first time.

On your wife pushing you to get the Mazda, that is exactly how my wife wound up with a Subaru Impreza, and there is nothing wrong with that.

....sure, if the banjo fitting itself is plugged. otherwise, if the obstruction is elsewhere along the several feet of tubing leading to the injection pump - the guage won't display the diminished pressure to the alda.
I do like the Mazda quite a bit, by the way. You should have insisted that the Impreza be the WRX!

My pod was for a Ford Mustang. I belive 88-93 , used a VDO black
get 9 lbs of boost. I'll find out this week my friend installed it. Looks almost factory!

I use one that IS factory.(and stealth!)

1. Take an old fuel/temp/ oil pressure/economy gauge section from a GASSER 126 and transplant it into the 126 diesel instrument panel!
2. Remove needle from economy gauge (remove STRAIGHT up).
3. Replace needle on the ultra thin gauge shaft from where it came, but place it with the needle pointing at ~10:00 o'clock position.
4. Rotate the needle CC and lift/ bend it over the left side stop pin.
5. What used to be the economy gauge (Bourbon type vacuum gauge) is now a boost gauge (Bourbon type pressure gauge).
6. Attach with appropriate hose to "T" in boost line or to the empty intake manifold fitting.
7. I attached the hose to an aquarium gang valve in the boost line to the overboost protection switch so that I could rig a parallel hose and shop gauge temporarily into the cabin in order to calibrate (by moving the indicating needle on the shaft of the former economy gauge).
8. Full travel (left to right) is ~16 psi after calibrating. (I run ~14psi full out uphill). FWIW

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The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

That is way smart!

Do you have to use a gasser gauge from a same year car or are all the W126 years the same in this regard? I'm thinking about all the connectors on the back.

Also, I have a KKK turbo on my 1983 300SD - the archives seem to suggest that boost adjustment is much easier than on the Garrett - any thoughts? I assume I run my vac gauge connected in series with the vac line from the manifold to the overboost switch-over valve when setting it up?

I think that connection would be in parallel, wouldn't it? Also, it seems to me that the best place to connect a boost gauge is between the switchover valve and the ALDA. The following is a verbatim quote from a Mercedes technical service bulletin:

07.1-85011 Poor Engine Performance Engines 617.95 Revised 10/85 1/85

Cause:
Low boost pressure at the boost pressure aneroid caused by soot-in the switch-over valve, boost pressure lines and hollow screws on intake manifold or boost pressure aneroid.

Remedy:
Check, clean or replace parts as required.

Always check boost pressure directly at boost pressure aneroid or at the boost pressure line just behind switch-over valve. If necessary, bypass switchover valve and repeat test.

That makes sense - between the switchover valve and the ALDA - guess you see what the ALDA is seeing that way.

As for parallel or series, I guess I just interpose a T-connector in that line and run the third leg to the gauge, no?

In here?

Attached Thumbnails

 

Thomas, don't know all on the gasser gauge on the 86-89 revision; 90-91 revision. There are slight differences in the 126 for ea. of those time frames. I used a 1984? 380 SEL gauge section from the '81-85 time frame version of the 126. I have seen many others and the method (armature winding) and resistors of the fuel gauge part do look a little different on some of the newer ones, but I THINK they interchange.
PS: Hope you received (or should recieve soon) the parts info. I sent. Went out 2 days ago.


dculkin, Point well taken, but since my lines and switch over valve are pristine (tested and checked) I opted for the easiest to get to spot to add the parallel line since I am an inveterate "fiddler" and I throw a vinyl hose on the "gang" often.

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The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

Thomas, that is the location I had in mind, although I would defer to the more experienced people on the board. I was looking at my 1985 300D last night to pick a location for the tee connection and was surprised at just how small these pressure lines are. I guess the small diameter doesn't hurt anything because all these lines do is sense pressure, so there is no pressure loss like there would be in a line carrying an actual flow rate. It would be interesting to see whether a gauge connected directly to the manifold would show greater pressure fluctuations than a gauge at the location shown in your photo.

I just ordered an Isspro gauge which I plan to connect at the location shown in your photo. I think I will mount the gauge in the ashtray.

I also think jba's point is well taken.

Jbaj007 - thanks. There's a nice 380SEL at the local wrecker - that might be a good match for my 1983. I'll let you know when the package arrives - thanks again.

Dculkin - thanks for helping me think this through. This location should disclose whether either the line or the switch are jammed (or the turbo is blown!)

Thanks again for the tip - I have added a page to my transmission tuning piece and credited you with the suggestion here.

Very interesting on the economy gauge idea...was the gauge ever put on 123 instrument panels?

Even if the 126 gauge part would fit on a 123 (I'm guessing not), I don't want to lose the mechanical oil pressure gauge...

The gasoline 123s like the 280E and 280CE have the economy gauge and one of the guys out in the Bay Area who put a 4 speed 240D transmission in his 300TD rigged up the 280, 123 econo gauge as described here and it worked fine.

Ben

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www.reproduce100s.com

Thomaspin: your website is not Mozilla friendly - can't see anything but "e-mail" on the index page. Could you please post the url for the page explaining the econogauge?

thanks.

I don't have the econogauge fix done - that was jbaj007's idea.

The location for measuring turbo boost is here if that helps.

My home page uses java for the menu - do you have java script enabled on your browser? What is Mozilla, by the way?

Where are these ports?

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"If anyone knows other lessons I need to learn, please tell me. I'm tired of learning them the hard way".
by JerryBro

The Glow Plug Wait: This waiting period is a moment of silence to pay honor to Rudolph Diesel. The longer you own your diesel the more honor you will give him". by SD Blue

My normal daily life; either SNAFUed- Situation Normal... All Fouled Up, or FUBARed- Fouled Up Beyond All Repair

62 UNIMOG Camper w/617 Turbo, 85 300SD daily driver- both powered by blended UCO fuels