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warm up compensator for M110 engine

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Posted 9/26/2007 2:38 AM

elevatorbernie
Expert

Date registered: Aug 2006
Location: Vancouver B.C. Canada
Vehicle(s): 1989 280GE
Posts: 1347
1000

Re: warm up compensator for M110 engine

charon_sin - 9/25/2007 2:23 PM

elevatorbernie - 9/22/2007 6:08 PM

charon_sin - 9/20/2007 5:46 PM

If you need a new regulator replace it with this http://www.unwiredtools.com/utcis.html

Have you tried it? I want one, where did you buy it? :cheers:

I called Steve at Unwired and I have talked to the shop that has installed them on a few 280's here in Phoenix and they have positive things to say about them. I think it is about the $500 or $600. I plan on getting one when my regulator fails.

I might get one before my WUR fails...having full load enrichment controlled with a map sensor is a big improvement over a stock unit with vacuum controlled rubber diaphragms and springs. I suspect fuel consumption would drop greatly due a more accurate enrichment process. The only thing that worries me is that the uniwire unit has no mesh screening on the inlet (the stock unit has) to filter out any debris that could clog it up. The last WUR I had replaced was clogged with rust; I suspect if it didn't have those screens it would have failed much sooner. I guess one could add a small inline filter, before the unit.

Edited by elevatorbernie 9/26/2007 2:43 AM

#90022 - in reply to #89976

Author

Posted 9/26/2007 8:49 PM

bram_r
Expert

Date registered: Apr 2007
Location: the Netherlands
Vehicle(s): 1984 MB 280GE, 1982 MB 300GD, 1986 Subaru XT 4WD
Posts: 1659
1000

RE: warm up compensator for M110 engine

as promised, some follow up on testing the different control and system pressures. Also, as said earlier, my warm control pressure was a bit on the low side which needed some investigation; what can I say, some questions are answered, others raised. Hopefully some of the experts can help me out here...read along!

First, results of my testing following the 5 steps I wrote about:

1. cold control pressure, at 50F I measured 14.5 psi, ok to me
2. system pressure, I measured 75.4 psi, perfect
3. warm control pressure, with fully warmed engine my warm control pressure rose to 40.2 psi with an inlet vacuum of 8.7 psi. This control pressure is too low.
4. wide open throttle control pressure, vacuum connection pulled from WUR, control pressure rose (!) to 43.5 psi. This is the correct wot control pressure, but there should be a drop in control pressure with a drop in vacuum, not a rise...
5. residual pressure maintained above 41 psi for 20 minutes, ok.

So, very strange thing here, warm control pressure too low and with a drop of vacuum it actually rises, this should not be happening. In the attachments is also a picture included from the MB manual how the vacuum should affect the warm control pressure.
Too see how curve was going, I removed the vacuum connection and plugged in a vacuum pump to similate different inlet manifold pressures, these are my measurements:

at vacuum of 0.65 bar control pressure is 2.75 bar (vacuum of 9.40 psi - control pressure 39.9)
at vacuum of 0.60 bar control pressure is 2.77 bar (vacuum of 8.70 psi - control pressure 40.2)
at vacuum of 0.50 bar control pressure is 2.80 bar (vacuum of 7.25 psi - control pressure 40.6)
at vacuum of 0.40 bar control pressure is 2.85 bar (vacuum of 5.80 psi - control pressure 41.3)
at vacuum of 0.20 bar control pressure is 2.95 bar (vacuum of 2.90 psi - control pressure 42.8)
at vacuum of 0.00 bar control pressure is 3.00 bar (vacuum of 0.00 psi - control pressure 43.5)

this doesn't make sense to me, to my believe a high control pressure should results in a lean mixture. Mine does exactly the opposite what it is supposed to do, on a high vacuum situation (idle, cruising) the control pressure reduces which will give a richer mixture. And, the control pressure rises on wide open throttle test, leaning out the mixture when it should be richer...
By the way, the MB chart also shows a drop in control pressure by increasing vacuum, but this graph shows control pressure above the 0 psi / 43.5 psi control pressure situation. At least than you'll have a leaner mixture with inlet vacuum present.

So, time to investigate again this warm up regulator. The only logic explanation I could come up with was that was something wrong with the lower chamber plunger. If this part would have been stuck or something, than a high vacuum would just pull down the regulator plate which would explain my drop in control pressure at higher vacuum. Basicly same as it does in the MB chart. The mebrane of the lower chamber is already at its upper stops, any increase in vacuum in the top chamber would just pull down the pressure regulator, decreasing the control pressure.

Anyway, please see pictures of disassembly of WUR. A lot of things comply to the instruction posted earlier. Most interesting point with a significant change in the earlier posted drawing/schedule of the WUR is the lower chamber. I noticed when putting a little vacuum on the side inlet, the plunger of the lower chamber was rising, when according to that drawing nr. 30 on earlier post, you should suck it down to the lower stops. Funny.
So I also split the lower two segments, to indeed find out there is a second membrane, under which a third chamber lies. I kind of drawn this design in one of the attached pictures. The good point is that this phenomenom perfectly explains the altitude correction; with a lower pressure on the side inlet, the plunger of the lower chamber rises, increasing pressure on the regulator and leaning out the mixture, perfect! The vacuum required to get this plunger to its upper stops was very little, I trust that the Germans will have their calculations right...
Maybe Bernie has got a good official picture of this WUR in one of his books.

The next step for me to do is to get the warm control pressure quite a bit higher so that it is above the 0 psi value and back in the 45 - 55 psi range. Just contemplating what's the best thing to do, tapping the pressure regulator inwards as instructed by linked document or try to find some fitting shims and shim the springs to the correct warm up pressure. Will keep you posted, any input is again greatly appreciated.

Bram

pic 1. partnumber Bosch warm up regulator: 0 438 140
pic 2. split top (vacuum) chamber from lower segments. Bi-metal strip is visible, both springs, pin and cone have fallen out.
pic.3. remove bi-metal strip and pressure regulator is visible
pic.4. these are the parts you'll have when you remove the four screws holding the pressure regulator together
pic.5. split lower two segments and what we find? Middle segment is closed on both sides by a membrane, lower chamber is a closed chamber with 1 bar pressure (no inlet or outlet)
pic.6. when you suck on outlet, you can see plunger rise, this must be compensator for altitude
pic.7. this should approx. be the schematic as my WUR is contructed.
pic.8. for reference, this is the MB G chart of inlet vacuum against warm control pressure

(pic1.jpg)

(pic2.jpg)

(pic3.jpg)

(pic4.jpg)

(pic5.jpg)

(pic6.jpg)

(pic7.jpg)

(pic8.jpg)

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pic1.jpg (80KB - 17 downloads)
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pic2.jpg (54KB - 9 downloads)
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pic3.jpg (63KB - 9 downloads)
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pic4.jpg (42KB - 10 downloads)
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pic5.jpg (53KB - 12 downloads)
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pic6.jpg (49KB - 9 downloads)
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pic7.jpg (64KB - 8 downloads)
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pic8.jpg (76KB - 10 downloads)

#90135 - in reply to #84730

Author

Posted 9/27/2007 8:41 PM

bram_r
Expert

Date registered: Apr 2007
Location: the Netherlands
Vehicle(s): 1984 MB 280GE, 1982 MB 300GD, 1986 Subaru XT 4WD
Posts: 1659
1000

RE: warm up compensator for M110 engine

today I planned for getting my warm up pressure up to spec. With different ways to raise pressure of the regulator (to increase my warm control pressure), I thought extending the small pin between pressure regulator and cone would be the easiest way for starters. So I bought about 10 inch of 2.4mm stainless steel welding wire. The original length of the pin is 21.7mm, increasing the length by 1mm seemed like a good starting point.

However, before I could get to this, I wanted to start my car on this day to get a benchline reading. Witth all gauges still attached, I noticed that my warm up pressure would not rise any further than 2,3 bar while yesterday I was having approx. 2.8 bar. Basicly, nothing had changed on the WUR, I only tried to disassemble the middle chamber membranes by turning some hex screw. Apparently, it turns out, that you can lower and raise the height of the plunger on which the inner (small) spring rests on.
So after disassembly of the WUR today, I turned this hex screw fully in so it was level with housing. After connecting WUR back on car, warm up pressure rose to 4.2 bar. Too much, but at least I knew I could vary the control pressure from about 2 bars to about 4.5 bars.
Then I turned screw two turns out, which gave a pressure of 3.6 bars which I settled for. So at least my connections are now correct and my control pressures are in spec, probably is my cold control pressure also a bit higher now.

Only thing that still puzzles me is when checking the WOT pressure according to MB procedure. When removing vacuum connection, the control pressure now rises to 4 bar, instead of dropping to the 2.8 to 3.2 bar range as it should according to manual. I don't know exactly how much force of the vacuum is affecting the pressure regulator (pulling it down) or working on the lower chamber (raising plunger and increasing inner spring pre-load).

Anyway, for now it's time to verify if any of my testing did improve my starting, mileage and reduces my somewhat sooty exhaust.
Will be receiving some K-Jetronic books soon, hopefully also my last questions will be answered soon!

bram

(pic9.jpg)

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pic9.jpg (114KB - 7 downloads)

#90206 - in reply to #84730

Author

Posted 9/29/2007 10:45 PM

elevatorbernie
Expert

Date registered: Aug 2006
Location: Vancouver B.C. Canada
Vehicle(s): 1989 280GE
Posts: 1347
1000

RE: warm up compensator for M110 engine

bram_r - 9/27/2007 5:41 PM

Only thing that still puzzles me is when checking the WOT pressure according to MB procedure. When removing vacuum connection, the control pressure now rises to 4 bar, instead of dropping to the 2.8 to 3.2 bar range as it should according to manual. I don't know exactly how much force of the vacuum is affecting the pressure regulator (pulling it down) or working on the lower chamber (raising plunger and increasing inner spring pre-load).
bram

Sounds like you have the vacuum hooked in the port. You indicated that you have hooked it on the side. Your testing is now giving you reversed results. Try hooking the vacuum in the top port.

Edited by elevatorbernie 9/29/2007 10:49 PM

#90498 - in reply to #90206

Author

Posted 9/30/2007 8:55 PM

bram_r
Expert

Date registered: Apr 2007
Location: the Netherlands
Vehicle(s): 1984 MB 280GE, 1982 MB 300GD, 1986 Subaru XT 4WD
Posts: 1659
1000

Re: warm up compensator for M110 engine

Bernie, vacuum connection is on the top connection, atmospheric connection is on the side, just as it should. I've connected everything by the book now, and all pressures are now within spec, only the test of pulling of vacuum connection doesn't give expected results...

Somehow I'm not totally clear on this test. If you look at the MB chart of vacuum against control pressure, than it is quite clear that how higher the vacuum, the lower the control pressure is (just as I'm measuring). When you extrapolate the chart to the right, it would be logical to me that if with 0.2 bars of vacuum a control pressure of 3,7 - 3,8 bars is present, that you'll get approx. 4,0 - 4,1 bars of control pressure with no vacuum. This is also exactly what I get on my gauges.
So why does MB give a test expectation of 2,8 - 3,2 bars when the vacuum disappears, I don't know.

bram

p.s. when engine is stopped and no fuel flow is present anymore, than the control pressure actually drops to about 3.1 bars and gradually leaks to about 0 bars (over 40 minutes or so)

Edited by bram_r 9/30/2007 8:57 PM

#90581 - in reply to #84730

Author

Posted 10/1/2007 1:48 AM

elevatorbernie
Expert

Date registered: Aug 2006
Location: Vancouver B.C. Canada
Vehicle(s): 1989 280GE
Posts: 1347
1000

Re: warm up compensator for M110 engine

bram_r - 9/30/2007 5:55 PM

Bernie, vacuum connection is on the top connection, atmospheric connection is on the side, just as it should. I've connected everything by the book now, and all pressures are now within spec, only the test of pulling of vacuum connection doesn't give expected results...

....So why does MB give a test expectation of 2,8 - 3,2 bars when the vacuum disappears, I don't know.

My manual says if 2.8-3.2 bar overpressure is not reached, with vacuum removed, renew warm-up compensator. Maybe the springs are weak and it should be replaced?

#90604 - in reply to #90581

Author

Posted 1/4/2009 7:37 PM

DesertStar
Expert

Date registered: Apr 2006
Location: San Diego, CA USA
Vehicle(s): 85-280GE/95-G320/08-G500
Posts: 2156
2000

W460 Warm up compensator proper vacuum connections

After reading Elevatorbernies and Bram_r 's threads/posts concerning the proper connections of vacuum lines to the WUC, I thought it appropriate to start another thread since I have read and reread the posts with still no definitive answer. This leads to my question:

Which is the proper connection of vac lines to the WUC of the attached photos/diagrams?

I have posted photos of from the EPC,WIS,Haynes manual and Probst Bosch fuel injection and engine management.

Mike

(WUC from WIS [800x600].JPG)

(WUC from EPC [800x600].JPG)

(WUC from Probst book [800x600].JPG)

(WUC from Haynes [800x600].JPG)

Attachments
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WUC from WIS [800x600].JPG (83KB - 4 downloads)
Attachments

WUC from EPC [800x600].JPG (40KB - 4 downloads)
Attachments

WUC from Probst book [800x600].JPG (70KB - 4 downloads)
Attachments

WUC from Haynes [800x600].JPG (76KB - 5 downloads)

#139936 - in reply to #84730

Author

Posted 1/4/2009 10:11 PM

Inkblotz
Expert

Date registered: Apr 2006
Location: Georgia
Vehicle(s): 90 300GD "Thundering Turtle II", w/ 603A turbo
Posts: 3186
2000

RE: W460 Warm up compensator proper vacuum connections

Mike

see below

Edited by Inkblotz 1/4/2009 10:14 PM

#139951 - in reply to #139936

Author

Posted 1/4/2009 10:13 PM

Inkblotz
Expert

Date registered: Apr 2006
Location: Georgia
Vehicle(s): 90 300GD "Thundering Turtle II", w/ 603A turbo
Posts: 3186
2000

RE: W460 Warm up compensator proper vacuum connections

Mike

Here is an illustration from my 280GE factory paper Manual. Looks like the vacuum line on the side runs to a tube that is attached to the aux air valve.

Mark

Edited by Inkblotz 1/4/2009 10:14 PM

(WUC.jpg)

Attachments
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WUC.jpg (134KB - 7 downloads)

#139952 - in reply to #139936

Author

Posted 1/4/2009 10:26 PM

DesertStar
Expert

Date registered: Apr 2006
Location: San Diego, CA USA
Vehicle(s): 85-280GE/95-G320/08-G500
Posts: 2156
2000

RE: W460 Warm up compensator proper vacuum connections

Thanks Mark. The info I posted shows the same, with the exception of the Bosch Engine Management book which shows opposite. I switched mine to be like what you posted to see what transpires. A few years ago I had my head done and installed a new fuel regulator/damper(which was leaking). Since then, my MPG seems to have always been poor from when I first bought my G and I question whether the mechanic connected the WUC correctly. I assume if not connected correctly, I would be running rich most of the time and thus consuming more fuel ? I seem to now be averaging 8.5-9.5mpg and cannot pinpoint whether it is because of the oxygenated fuel I use this time of year, the cold weather yielding longer idle times to warm up or WUC connections. Maybe a combination of all three? The G seems to run fine as far as I am concerned....but I have never driven another 280 to compare with.

I find it hard to believe the EPC,WIS and Haynes would all be wrong simultaneously which leaves the Probst book in error.

Mike

Edited by DesertStar 1/4/2009 10:30 PM

#139954 - in reply to #139936

Author

Posted 1/4/2009 11:07 PM

Woody
Extreme Veteran

Date registered: Feb 2007
Location: Bend, Ore.
Vehicle(s): '84 280GE -> 300GD turbo, '84 300SD veg, 06 Navion
Posts: 570
500

RE: W460 Warm up compensator proper vacuum connections

Guess one can never have too many manuals for the G

#139960 - in reply to #139936

Author

Posted 1/4/2009 11:14 PM

DesertStar
Expert

Date registered: Apr 2006
Location: San Diego, CA USA
Vehicle(s): 85-280GE/95-G320/08-G500
Posts: 2156
2000

RE: W460 Warm up compensator proper vacuum connections

Woody - 1/4/2009 8:07 PM Guess one can never have too many manuals for the G :biggrin:

Yeah...and your G is probably one of the few unmolested ones around. If you ever get around to crawling under your G, let me know how your WUC is connected. Your info could very well be the missing link to this great mystery.

Mike

#139964 - in reply to #139960

Author

Posted 1/4/2009 11:21 PM

Woody
Extreme Veteran

Date registered: Feb 2007
Location: Bend, Ore.
Vehicle(s): '84 280GE -> 300GD turbo, '84 300SD veg, 06 Navion
Posts: 570
500

RE: W460 Warm up compensator proper vacuum connections

I'll try to get a proper photo tomorrow. Of course it will not look pretty this time of year.

#139966 - in reply to #139936

Author

Posted 1/4/2009 11:29 PM

DesertStar
Expert

Date registered: Apr 2006
Location: San Diego, CA USA
Vehicle(s): 85-280GE/95-G320/08-G500
Posts: 2156
2000

RE: W460 Warm up compensator proper vacuum connections

Woody - 1/4/2009 8:21 PM I'll try to get a proper photo tomorrow. Of course it will not look pretty this time of year. :boink:

Do not sweat a photo...I just need to know if the port sticking out (towards driver fender) has a hose that connects the intake manifold above and the side port which faces or points to the front of the G has a small "regular" vac line going to it.

Thanks dude.

Mike

#139968 - in reply to #139966

Author

Posted 1/4/2009 11:48 PM

Woody
Extreme Veteran

Date registered: Feb 2007
Location: Bend, Ore.
Vehicle(s): '84 280GE -> 300GD turbo, '84 300SD veg, 06 Navion
Posts: 570
500

RE: W460 Warm up compensator proper vacuum connections

Okey-dokey. Thanks for the layman's explanation - you know me

#139969 - in reply to #139936

Author

Posted 1/5/2009 12:00 AM

DesertStar
Expert

Date registered: Apr 2006
Location: San Diego, CA USA
Vehicle(s): 85-280GE/95-G320/08-G500
Posts: 2156
2000

RE: W460 Warm up compensator proper vacuum connections

Woody - 1/4/2009 8:48 PM Okey-dokey. Thanks for the layman's explanation - you know me

:biggrin:

Gosh. now I feel kind of bad. Hopefully no offense taken.

Mike

#139971 - in reply to #139969

Author

Posted 1/5/2009 12:06 AM

Woody
Extreme Veteran

Date registered: Feb 2007
Location: Bend, Ore.
Vehicle(s): '84 280GE -> 300GD turbo, '84 300SD veg, 06 Navion
Posts: 570
500

RE: W460 Warm up compensator proper vacuum connections

Of course not. I was chuckling as I read that knowing what you know about what I (don't) know. I do know how to use the search function to answer my questions, though. Most, if not all of mine have already been answered!

Sometimes I feel like a spectator watching a bunch of motor-head gladiators that use WIS and EPC scans instead of swords and shields!

Love this place!

#139972 - in reply to #139936

Author

Posted 1/5/2009 12:25 AM

elevatorbernie
Expert

Date registered: Aug 2006
Location: Vancouver B.C. Canada
Vehicle(s): 1989 280GE
Posts: 1347
1000

RE: W460 Warm up compensator proper vacuum connections

Here's some info to add to the confusion.....my G has the manifold vacuum connection going directly to the base on the side of the WUR and as you can see from the sectioned drawing (2nd pic from my bosch instruction manual) that would be the bottom diaphragm at port A. Also I have a hose on the top at port B which could be a vacuum connection given it's location on the WUR. The hose that is hooked up, I have no idea where it goes, but it doesn't have any vacuum present when the engine is running. When I hook a vacuum pump to the #A port, I can not enrichen the mixture by applying vacuum. However I can when testing at port B. To confuse things even more I'm including a section drawing of a WUR from the G manual (3rd pic). Look closely at the bottom diaphragm and compare it to the 2nd pic....there's a 3rd spring and an extra port there. The manual doesn't give any explaination to correspond with the #'s on the drawing, but I can see it's not the same as I have. I think that the extra spring and port are the altitude compensation. Finally pic #4 which I borrowed from Bram's post, this is exactly how my WUR is connected..."A" port to the bottom of the manifold. I would guess the problems with my WUR are...#1 I have the wrong WUR for the G (the one I have has no altitude compensation...an extra spring and 2 ports on the bottom) and #2 my manifold vacuum connection hooked on the wrong port for the WUR I have now to give full load enrichment. or #3 something is broken in my WUR.