Glow Plug Readings:
Actually I had taken mV readings and found they were fairly consistent in comparison to one another. Right now I canNOT find the readings I recorded but ~14-17mV seems to stick in my mind... that is if I was interpreting the digital VOM readings correctly?
I do NOT have a tac but these were at whatever my idle is turning over?
I also will NOT have the car again until Monday or Tuesday.

Diesel Timing Light search:
Thus far, except for high priced shop equipment, the only thing I have found in the way of a diesel timing light is actually an accessory from Ferret that works with any standard HV ignition timing light that uses an induction sensor clipped onto the #1 spark plug wire. This piezo-electric pulse sensor [ Ferret V765-01 ] runs off it's own 9-V battery and works with either timing light or shop engine analyzer. Co$t ~ $150 +T&S. I spoke a Ferret techRep and he claimed that a newer timing light with the ability to crank in the desired timing... this way you would be able to look for the TDC mark rather than a numerical reading that is often difficult to see. He also inplied that it would be desireable to use the light/accessory first on and compare the results for a vehicle of known timing and this would give you an idea if any "fudge-factor" might be needed on other similar vehicles.
Sounds a bit "IF'y" to me... what do you guys think?
Sam Ross // Novato, CA
Sam

It's not "iffy" at all. In fact, the tech rep is right on the money.

With and adjustable timing light, you adjust the light so that you are reading zero degrees and the setting of the light is the injection timing.

He's also correct regarding comparing the vehicle to one with known timing.

As I previously explained, above, the SD was calibrated to known timing of 15°ATDC and the pulse timing was 13.5°BTDC. There's your calibration for the pulse system.........13.5° BTDC.

Older engines I personally do not think will have the same percentage voltage drop across the board. If you read some cylinders at 17mv and others at 14mv it may or may not be a permissable voltage swing percentage wise. I may have misread your post and if all were about the same mv all should be well as far as power balance of the engine is concerned.There is just not enough knowledge floating around yet but your report does add to what little is available at this stage. For that I personally thank you. The other engine I know of landed up with a straight 8mv average across the board and I considered that a perfectly indicated power balance test from what is known at present. We do not even know the sensitivity component of this test yet though. I hope to start testing this spring sometime if I can just get a little time to establish at least that rating. He started out with one cylinder at 5.6 mv with an original reading of about 9.5mv on the other plugs. When he got the low cylinder reading to 9.5 as well he set the idle down to about 8mv across the board. Engine gained lost power and smoother than it ever was as well. The more people that try reading their glow plug voltages and reporting the sooner we will perhaps have some common sense paremeters. Not even sure why your getting initial readings higher than his. Yours were at idle I assume. Could be different idle speed, different brand of glow plugs, aging of same brand plugs or newer plugs than his. Actual function of your meter for example as well. Anyways his drop of about 30% in voltage reading on that one cylinder and was signifigant power wise but it was a 240d and you need all you can get. The causes for a lower comparison reading range all the way from an abnormal glow plug, marginal injector, lower compression, Poor prechamber, Pump difficulties or sequential timing problems. Just far too early to quote really anything. Thanks for posting your results.

Thanks Brian / EngAtWork / Barry / Rhodes / Ken / and Tony for your posts on this thread and the sidebar issues such as IP timing and timing lights that were raised along with the real root problem the 80' 300D[na]'s poor power and black smoke at the high-end/rpm(s).

Well I got tired of waiting for my M-B only prival garage mechanic to return from his Hawaii vacation so I could crank him up on troubleshoot this problem... and so today I decided to fiddle with the power problem myself while I had the car to replace a burned out headlight.

What I did was to disconnect the vacuum line to the EGR. What the hay, I figure my 80' model 240D doesn't even have an EGR. So I let my son take the car without telling him I was using him as a guinnie pig. Well he just called to ask if I had done anything because the car has noticeably more power at speed where power has been a problem.

So Brian, I figure this car probably has an EGR only because it was delivered in California... AND I read in another thread where you talked about blanking off the EGR opening on the intake. Tomorrow I will have the car most of the day and will investigate things further by looking down the throat of the intake to see if the EGR is hanging opening or is partially hung open... or whatever it is doing when I pump up the vacuum.

So what do you guys think... should I :

Q1 - Replace the EGR?
or
Q2 - Remove it and blank it off ?

I'm not entirely sure when the EGR is intended to work on these diesels...
but I figure the tempurature controlled vacuum switch in the line means that the EGR is OFF until the engine has warmed up. But what then?

Q3 - Does it just remain open the rest of the time?
Q4 - Does it work only full open or full closed?
Q5 - And if mine is hung open partially then could that alone cause the high-end/RPM power loss while puffing the black smoke?

I'll let you know what state of failure [if any] I find with the EGR !

Sam

Well, I'm not an expert on these, but all the normal people are sleeping, so I'll give it a shot. Most people have defeated the EGR by either blocking the vacuum line (a BB does nicely) or removing the EGR completely. Removing it makes the engine look nicer, but may be a problem for emissions inspections. Blocking the vacuum line is completely effective unless the thing is stuck open. From your post, it sounds like blocking the line works for you.

I think I understand how these are designed to work. You are correct, vacuum opens the EGR. The temperature switch keeps it closed until the engine reaches some minimum temperature. The position of the EGR is then controlled by the amount of vacuum, which is controlled by the vacuum valve assembly on top of the valve cover. This engineering masterpiece somehow controls the vacuum based on throttle position (and who knows what else). It sound to me like you EGR is either opening too much or too soon, causing problems at high rpm. You seem to have three options:

1. Fix/replace the EGR system, which will do nothing for your car but will reduce the amount of NOX and prevent the end of the world.

2. Remove the EGR and install a plate over the hole in the manifold, making your engine more pleasing to the eye, and making it obvious that you have defeated your emissions system (may be a problem if you have any type of emissions inspection now or in the future, so keep all the parts).

3. Install a BB (or similar object) in the vacuum line to the EGR. Unless it's stuck open, this will defeat the EGR's function without changing the appearance of the engine. It also takes about 15 seconds (including opening the hood) and costs about $0.00001.

Being both cheap and lazy, I selected option 3.

Seriously, it sounds like you've solved your problem. Try diving for a while with the vacuum line blocked and see if it's OK. I'm sure others will chime in.

Yep, Craig has the three options right on the money.

The BB is perfectly fine to defeat the EGR but keep the original look of the engine compartment for passing any type of government inspection.

I sell a kit to remove the valve completely and replace it with a stainless steel plate, if a cleaner underhood environment is desired.

If you do keep the valve, definitely remove it, make sure that it is operates properly the diaphragm and piston fully close, and then reinstall it with a new gasket.

Yep,

My Son brought the car back this a.m. and sure enough when I drove it out on the freeway it was like a totally different car... cruising at 70mph I can punch it and she clearly still has more to give ya!!... AND no more black smoke !

I now remember... it was during the pre-purchase inspection that my mechanic found the "BB" and almost gleefully[sp?] acting as though some idiot had committed a sin doing this to such such a well engineered German car... and of course we have been struggling with the power problem ever since. The car had been so poorly maintained and was running so badly that I guess I never noticed the loss of power until later and never made the connection. Boy do I have a few tactful words when he returns Monday. I think I will start out by just saying that I found and solved the lack of power problem and just see if he is inquisitive enough to ask how!

Brian,
I like your SS plate(s) kit idea so please forward info direct to me via an e-mail... Q - would I also remove the flex pipe that connects to the exhaust manifold and cap it off?

Sidebar - While starring down the throat of this beastie’s intake I see what appears to be exhaust residue that extends up into the throat of the air intake which is plastic and designed to receive the gases from the blow-by system. My California model has what looks like an oil/gas separator chamber that the output of the blow-by pipe passes through. This separator appears to be designed so the oil drains out the bottom and returns to the oil pan through a small drain pipe... and the gasses pass into and out of the plastic throat thingie into the intake manifold directly above and around where the EGR discharges it blast of exhaust! I have already cleaned the oild drain line to insure it is clear.

The main point of this sidebar is to speculate that the excess exhaust might be what has caused oil to splatter out of the joints of the separator and onto the new air filter to hee rear side of the air breather. With the EGR shut down, I'm speculating [and hoping] that this problem will be deminished if not eliminated.

Thanks again guys,
Sam Ross

The oil splatter on the oil filter seems to be a separate (common) issue. I assume your oil separator is within the air filter housing like my 300D? At the suggestion of Brandon314159, see post # 16:

617 oily air filter

I took mine apart, cleaned it, and sealed the joints with silicone "glue." It seems to have reduced the amount of oil splatter on my filter considerably. Give it a try.

Sam, it is always a pleasure to hear some sort of good conclusion was reached and how it transpired. Great going. The only question left in my mind now is if you get to bend the mechanic over . If he removed the ball bearing or bb was it a legal requirement? He should have been aware it was not in your best interests to do so. Egr disablement has always been better for the customer generally unless of course it upsets a computor that is reading the flow. Lets say that was not even a question with your car and that much he had to know. Sometimes excess troubles are undertaken to defeat the egr.. Computor then thinks air flow is present even if not.