81 240 won't start when engines cold
 

Ok 81 240 hard to start when engine is cold. It's not even cold outside.


New glow plugs.
New starter

start with a valve adjustment. then a compression test. DO NOT USE ETHER!!!

Check the strip fuse in the GP Relay. Pull the cover and you will see it.

Was it starting ok and now a no start condition?


Mercedes Diesel Glow Plug Repair


Charlie

Are the glow plugs getting 12 volts with the key in the start position? Do you have series or parallel plugs?

A busted 80 amp glow plug fuse was enough to strand me on a cool day. I walked to Canadian Tire and McGuyvered in an fuse.

Valve adjustments are critical on these cars. My 78 300D had none for 12 years before I got it. Having one done, it was like I got a new engine

I'm getting power to all glow plugs. Just started this over night. Valves do need adjusting. I'm having trouble finding a .004 feeler my only goes to .008 and all at parts store go to .006

Series pencil plugs

When this condition occurs on indirect injection engines. Usually the first prime suspect is the glow plug system. Some indirect diesel engines do not like to start with even one glow plug bad.

I even had one oddball indirect injection diesel engine that still was fairly tight. It would not even light off hot without a little glow plug action first.

Something very odd there. Series are always loop plugs and pencil always parallel. That could the problem.

Huh. They each have there on wire going to them. Not looped together

They're parallel then.

When you replaced the glow plugs, did you ream out the carbon?

Did you use Bosch plugs? Not autolite

When was the last time you replaced the fuel and air filters?

Ever clean the fuel tank?

Does it have the newer style primer pump?

I lost my .004 feeler gauge, when I do a valve adjustment....I use the .006 one.....I figured .002 over isn't enough to cause any issues....if the valve is tight using that gauge or to lose.....that can cause more of an issue......I would use the .006 and check your valves...

I used the cheap auto lite plugs. I did ream the holes out

If it just happened overnight, I doubt it's tight valves. More likely malfunctioning glow plugs or lack of fuel.

Get the feeler gauge set from Sears, it has the sizes you need.



Mercedes Diesel Valve Adjustment Procedure