W126 420 SEL 1986 won't start

[Nico69]

Hello, my name is Nicolas, I am 23 years old, I just bought a 420 SEL W126, only the engine does not start, I would like to know how to test the idle valve. Thank you for your help.

 

[star]

Idle valve will not stop it from starting, check the basics first, fuel and spark to start with.

 

[mattkh]

Wow! What a car.
Put up a picture of the engine bay.
Wet plugs. Use a metal pipe to touch the idle valve, turn the ignition ON, and you should hear it buzzing when you put the other end of the pipe to your ear.

 

[rayhennig]

check the basics first, fuel and spark to start with.

Definitely. Make sure all HT is in 1st class order.

Then start on fuel.

R

 

[DSK]

I can’t say anything than the above but have to say, what a cracking car the older SELs are!


Sent from my iPhone using Tapatalk

 

[Nico69]

Hello, I checked my 8 spark plugs, they are dirty and do not produce sparks, I changed them. My battery is HS, 6 volts when I want to start the car ...
So I will change the battery and see if the 420 SEL will start.
Nicolas

 

[grahamcol]

Do these suffer from condensation under the distributor cap /s.?

 

[rayhennig]

Hello, I checked my 8 spark plugs, they are dirty and do not produce sparks, I changed them. My battery is HS, 6 volts when I want to start the car ...
So I will change the battery and see if the 420 SEL will start.
Nicolas

Sounds like a good place to start. Then look at the distributor and ensure all contacts are bright and shiny and that the cap is clean, dry and not damaged.

And if you decide to replace HT parts, try to justify MB original parts - expensive. If you choose to use aftermarket parts, Beru may be best, then Bosch. My latest cap was installed by a pretty hopeless garage late in 2019 and is already cracked. It's a Bosch so I'm not overly impressed. In fact, the original 30 year old cap looks better!!!

Good luck.

RayH

 

[Nico69]

Hello, thanks all for your help, I have now checked my ignition head, and the metal contact points seem oxidized and not shiny, the rotor is itself at the end of its life (very worn metal), I think first of all to clean the 8 ignition head contact points.

 

[star]

Take the king lead off, put an old spark plug in the end and place on metal of engine. Crank the engine to see if spark there.