Ignition Coil Wiring? Fuel Distributor hook up? - PeachParts Mercedes-Benz Forum

agood · #1 03-31-2009, 01:57 PM

I am working to get a 90 300SEL running again. Someone had removed the ignition coil and the fuel distributor.
I need to know how the wires go back on the coil. There are several black wires and one brown wire. I have positive voltage on one of the black wires when the ignition is turned on.

I also need to know what part I am missing on the fuel distributor. It appears to be the fuel return line....but the line I have is too short to reach the fuel distributor. I have it patched with a piece of fuel line right now as you can see in the picture.....but how is it supposed to go?

Ivanerrol · #2 03-31-2009, 07:54 PM

Some pictures for you that may Help. These are off a M103 300e - should be almost the same. It looks like you are missing the fuel regulator. I am guessing that the blue rubber hose comes from the fuel pumps and is plugged in to the wrong section of the fuel distributor. The last foto shows where the fuel line plugs into the distributor. The input point is labeled - Here it is. Where is your fuel regulator? It is the brown coloured device in foto 2, Hope you don't need to buy a new one -- $$$.

agood · #3 04-01-2009, 10:26 AM

OK, Just so I got it straight. Your blue arrow is pointing to the fuel inlet port, the hose connected there should come from the fuel pump...right?

The blue hose I have connected was so I could try and start the engine.....and until I found out what I was missing, and now I know it is that regulator. Wonder how much that thing costs..

agood · #4 04-01-2009, 10:34 AM

Seems like I have more loose wires for my ignition coil. Is there ground wire that is connected to one of the mounting bolts for your coil?
I remember seeing any red wires either....I do remember a brown wire....maybe it used to be red and has faded.

Cal Learner · #5 04-01-2009, 12:16 PM

Quote:

Originally Posted by agood

OK, Just so I got it straight. Your blue arrow is pointing to the fuel inlet port, the hose connected there should come from the fuel pump...right?

The blue hose I have connected was so I could try and start the engine.....and until I found out what I was missing, and now I know it is that regulator. Wonder how much that thing costs..

Fuel pressure regulator (p/n 000-078-03-92). OE will cost you about $425.

Ivanerrol · #6 04-01-2009, 06:48 PM

Brown is Mercedes code for ground wire. The pictures I posted are of a W124 wiring.

See if you can get a good second hand fuel regulator first -should be able to get one for around $ 30.00. Where is the original?

I will see if a M103 W126 comes into the workshop today and if one does I will get some fotos of the coil.

agood · #7 04-01-2009, 08:06 PM

The regulator and coil were missing when I got the car. It was given to me...I know it has a bad head gasket or something as there is water in the oil.

I am just trying to piece it back together enough to see if it will run. If it does then I will work on getting the water leak fixed. If it doesn't I am going to part it or crush it.

I found a regulator.....now I need a coil. I hate to buy a new $100 one.....just to test it....so I am trying to find one at a local shop. I guess all the 126 coils are the same?

pawoSD · #8 04-01-2009, 08:13 PM

The M103 engine coils all seem to be similar, I think the only change they made was the orientation of the wires.

Ivanerrol · #9 04-01-2009, 11:04 PM

Quote:

Originally Posted by agood

It was given to me...I know it has a bad head gasket or something as there is water in the oil.

Unless you can do the head gasket by yourself this car could end up costing you too much grief.

The old adage - There is nothing more expensive than cheap Mercedes Benz applies - even to free ones.

How much mileage is up on this car?

agood · #10 04-02-2009, 08:08 AM

I can do the head gasket ....no problem. I just need to know the wiring for the ignition coil so I can test it and make a decision.

agood · #11 04-02-2009, 08:09 AM

It has 168K miles

Ivanerrol · #12 04-02-2009, 08:33 AM

No W126 300 M103's in today - I will see tomorrow.

168K's is head gasket changing time. Possibly timing chain and guides as well.

pawoSD · #13 04-02-2009, 11:05 AM

I believe it was Larry Bible that said the timing chain on the M103 is practically lifetime....its very short and simple, and only runs the camshaft.....I highly doubt it needs any looking at with only 168k. The I6 engines are not like the V8's in that regard.

How long has that engine sat with water in the oil? There's a possibility of rust in the engine if it has been very long!

agood · #14 04-02-2009, 11:33 AM

It's been sitting for over a year and I am concerned about the rust thing. I have changed the oil and removed the spark plugs and turned it over several times untill it built oil pressure. I am going to do this again with diesel fuel to get out some of the milkshake. It seems to be OK, and has good compression.

But again, why I need to get a coil in it and fire it up.....

pawoSD · #15 04-02-2009, 11:37 AM

Quote:

Originally Posted by agood

It's been sitting for over a year and I am concerned about the rust thing. I have changed the oil and removed the spark plugs and turned it over several times untill it built oil pressure. I am going to do this again with diesel fuel to get out some of the milkshake. It seems to be OK, and has good compression.

That's a good sign, I bet with a new head gasket and a couple oil changes/TLC it will be good for many more miles. The M103 is a pretty rugged motor, especially on the bottom end.