Fuel adjustment - '74 240D - Page 2 - PeachParts Mercedes-Benz Forum

Diesel911 · #16 05-27-2008, 12:58 PM

I am glad the other member remembered about what type of governor you might have!!! Because I thought you had a mechanical governor.
If you have a Butterfly type valve in your intake manifold abd linkages going to it you have a penumatic Governor. The Governor diaphragms get stiff and sometimes develop cracks and do not perform correctly. There is also a passage exposed to the out side air that gets plugged.
Here is a site with info on your governor if you have this type; a pic with a cross section of the governor is on page 2.
http://www.pauldrayton.com/uploadfiles/merc/Service/W123/w123CD2/Program/Engine/615/07-010.pdf

#10 is the Diaphragm and #3 I believe is where the Diaphragm attaches to the fuel rack. Important: there is also some shims and a spring here as well as other places. #14 are the shims I believe the other member is talking about.
I have changed 3 of these Diaphragms (one of them on the car) but that was back in the late 70s. But I worked in a Fuel Injection shop at that time and if I had problems I could as my Boss what to do.
The Diaphragm can be changed but you need to be extremely careful when you take it apart to be sure to note where all the parts, shims and springs go.
Draw pictures and take pictures if you have a digital camera.
Back then the Diaphragm was made some sort of thin Chamey material (the soft leather that people wash their cars with) which is soft and suppel when new but a it gets older it gets stiff. Since it works of vacuum there is not much pressure (-) or (+) to move it when it is stiff. The replacement is made of something else.
Also you Fuel Injection Pump is not lubricated by the engine oil has its own oil reservoir

BathCity · #17 05-27-2008, 08:05 PM

Thanks all, especially Diesel911, for all the help. I did find the pauldrayton.com link earlier today and it helped a lot.
I have removed the IP & torn down the diaphragm, there was oil in the diaphragm. (soaked) so I removed, being careful of the shims & springs.
I have cleaned the diaphragm to remove the oil & blotted it dry. There are no rips/tears/holes so I decided to seal it with a very diluted coating of 100% Silicone to seal the pores of the leather. I am going to try this tomorrow after it dries a day, mainly because the cost of a new diaphragm is $200.00. I may put a smudge of silicone on the outer metal ring of the diaphragm, on the vacuum side, during re-assembly.
I also checked the control rod fro free operation and it is good. I am hoping the silicone sealant will work well. We'll see tomorrow.

Diesel911 · #18 05-28-2008, 01:17 AM

You did not say if the origional diaphragm was stiff or not. I would think that silicone sealant would only make it stiffer. Becareful when you start the car you may need to shut it down manually.
Also what company had the $200 price on the IP diaphragm?

Diesel911 · #19 05-28-2008, 02:47 AM

You might want to start a thread in the; Vintage Mercedes forum and ask if anyone knows where you can get the Governor Diaphragm and at a cheaper price.
I did some internet searches and the cheapest I could find was $218.
There is a fuel injection place in Texas that sells SPACO (made in Italy) parts. He is the USA authorized distributor. They make the part but I do not know the price. Also if he dose not have it in stock that pretty much ends it. I waited for 4 months for Boidiesel compatiable gasket kit for my Volvo Diesel Fuel Injection Pump, they never arrived and the Italians would never give any delivery date. I was not required to pay for the kits until they actually arrived so I was not charged but it was still frustrating. The other stuff I bought from him was OK.

BathCity · #20 05-28-2008, 06:20 AM

911....the leather was supple, it just was soaked with oil. I checked the drying of the diaphragm this morning and it is very flexible. I diluted the silicone with lacquer thinner to almost a liquid when I applied it so that it would soak into the pores of the leather. I have great expectations for this repair. I will be ready at the "kill flap" at the intake when I start it up, just in case though.
I also have a spare IP that came with the car and the other diaphragm is in the same shape.
As for your Volvo, I purchased a complete rebuild kit from dieselvw(dot)com and 2 shaft seals for my Volvo when I got it a year ago April because the shaft seal was leaking like a stuck pig. All I did was replace the shaft seal, on the car, without removing the IP and it has been running great since. I have a pictorial instruction pdf for the rebuild of the IP when I get ready to replace the seals.
I run all my diesels on B100. I have a seperate, removeable, tank (a 5 gallon cubie) set up in the back of the wagon with some 3way ball valves to run the B100 during the winter. I run straight diesel in the regular tank. This way I can swith to diesel, run the engine for 10 minutes, and remove the cubie to bring in from the cold at work or over night. This works great so far.

BathCity · #21 05-28-2008, 02:09 PM

Diesel911.....I'm waiting on USDiesel to quote on the diaphragm. Found the web site after you suggested them.

Diesel911 · #22 05-28-2008, 04:25 PM

Quote:

Originally Posted by BathCity

Diesel911.....I'm waiting on USDiesel to quote on the diaphragm. Found the web site after you suggested them.

Good detective work! Again back in the late 70s the fuel injection shop I worked in used SPACO gasket/seal kits for Fuel Injection Pumps. It usually takes Brad at US Diesel a day or so to answer back. Seems like he looks at he E-mail at the end of the business day and answers at the end of the next day.
I hope he can save you some $$$. I forgot to add he took my payment with PayPal when I bought stuff last year.

Diesel911 · #23 05-28-2008, 04:47 PM

Quote:

Originally Posted by BathCity

I also have a spare IP that came with the car and the other diaphragm is in the same shape.
As for your Volvo, I purchased a complete rebuild kit from dieselvw(dot)com and 2 shaft seals for my Volvo when I got it a year ago April because the shaft seal was leaking like a stuck pig. All I did was replace the shaft seal, on the car, without removing the IP and it has been running great since. I have a pictorial instruction pdf for the rebuild of the IP when I get ready to replace the seals.

If I had another pump and it is not to hard to change I think I would try the other pump to see if changing it has any effect on your problem. Before, I buy a Govenro Diaphragm. I am not entirely convinced thet the Diaphragm is the problem as it has been so long ago that I do not remember what the symptoms are when the Diaphragm is getting bad.
My Volvo IP was leaking as you said. I sat for over 1 year and I got it running again about 2 months ago. I had bought a seal kit for the IP on Ebay but wanted a boidiesel proof one. I tried to get the SPACO ones from US Diesel but 3-4 months later no luck. In the mean time I had bought my Mercedes and was bussy fixing it.
I should have also only replaced the IP Drive Shaft Seal only but inside of the IP ther is 2 kidney shaped rubber cushions that dampen the governor and I wanted to change those thinking that they might have hardened (as it turned out they were soft). This led to me taking the whole IP apart.
I took pictures but forgot to mark the cold starting advance lever and the throttle lever (it is hard to follow my own advice I guess).
Put the IP to geather and on the engine; which started but blew out billowing white smoke (late timing). I tried retiming the pump several times with no change.
I orderd the Bosch book on the pump and the dial indicator set up for timing and also figured I must have assembled something wrong. So, I took the pump apart again and started over (found a site with VW pump tear down pics also). When I opened the pump up I also found I had pinched off part of the rubber cover gasket wich I found in the bottom of the pump.
Put IP back to geather back on the car retimed everthing; this time with the dial indicator. Much better but still too much white smoke to suit me.
Checked everthing again and found that I had not tightened the timing belt enough. Retimed again and now it is going great.
Please give me the PDF site; might need to do this again some time.

BathCity · #24 05-28-2008, 09:15 PM

I got the pump back together. The diaphragm turned out great it looks like anyway.
So I took her out for a spin after reinstalling the IP and reconnecting everything, timing the IP. It ran slow at idle so I lengthend the rod going down to the back of the IP, on the inboard side of the IP and she ran more smoothly at idle. Now the smoke from the tail pipe looks mostly light blue, except when the accelerator is mashed, then there is some black smoke mixed in.
I may need some valve stem seals. So I took her for a spin to see if the smoke would lessen with some hi-way driving at speed. About 3 miles from home, I heard a loud poping sound from under the hood and she jest died on the freeway, with blue smoke coming from under the hood. Thought I had blown her up!
Pulled to the apron, poped the hood, saw oil on the IP breather cap, but couldnt see where it was comming from. Tried to start her and found I had left the manually switched glow plugs on! Turned them off, checked under the hood again and found one of the glow plugs had the end blown off, right next to the IP breather cap, #3 cylinder. Sheesh.
So I called AAA, had her flat bedded home, and have a single glow plug on order from Murrays, sposed to be here in the morning.
While she was running on the freeway, seemed like she was smoking less but still more than normal, and it is blue, so that tells me I have oil getting into the cyliders. Gonna check the stem seals tomorrow night.

nhdoc · #25 05-28-2008, 10:02 PM

I'm curious as to how you check the valve stem seals? My 240D burns quite a bit of oil and I suspect mine are bad.

Diesel911 · #26 05-29-2008, 12:54 AM

BathCity I think this is one of the more interesting threads.

BathCity · #27 05-29-2008, 06:09 AM

In looking at the valve stem seal replace ment proceedure, it looks to be very straight forward. I saw the proceedure at the pauldraytom(dot)com site that you has forwarded to me and that I had found in my searches of the web. The seal kit is less than $25.00 and look very easy to do in principle.
I am hoping that the filament comes out with the blown glow plug on mine tonight. I have a replacement comming in today from Murray's, and I hope that the one they ordered is the correct plug.
Gonna keep the blown one and weld the hole up to keep as a emergency plug in case this happens again. Might just get 1 spare as well now that I think of it.

BathCity · #28 05-30-2008, 06:13 AM

I replaced the glow plug last evening. The one that I removed still had the filament in it, what a relief. You can see right through the tube where the filament passes through in the center of it.
I pulled all the injectors, disassembled, cleaned all of the pin holes in the tips of the pintles and reassembled them. After installing them, fired her up and I am still getting excessive smoke.
I'm going to put the other IP in this weekend and see what the effect is. I've held off on new injector nozzles until I've exhausted the other possibilities.
- Swap out the IP with the other one I have.
- New valve stem seals to be installed this weekend.
- New heat shields, won't get them until next week.
- Remove exhaust to check the effect on the blow by pressure, may be plugged causing excessive back pressure to engine. (it looks to be newer, not rusted in any respect)
The engine starts up well now, bout 15 seconds to fire up after 25sec glow cycle.

nhdoc · #29 05-30-2008, 06:41 AM

Quote:

Originally Posted by BathCity

The engine starts up well now, bout 15 seconds to fire up after 25sec glow cycle.

Do you mean you have to crank for 15 seconds to get it to start??? If so there is something wrong. If you glow it for 25 seconds, even with the old style loop plugs you should be able to start a correctly operating OM616 within a second or two of cranking. If you have to crank for 15 seconds you are either not getting fuel immediately and have to reprime (due to a leak), have bad compression or your glow plugs aren't working right I would say. I have owned MB diesels since the 70s and never had to crank for more than a second or two on any engine that was operating properly. Even my current '74 which has a great thirst for engine oil cranks right over and starts on the second rev of the engine every time.

BathCity · #30 05-30-2008, 06:55 AM

I'll have to actually time it, but she starts up MUCH better now. Once warm, she'll start right up after sitting for a few minutes without glow. After an hour sitting, starts right up after 15 sec glow.