HELP... W123 Not starting! - PeachParts Mercedes-Benz Forum

Timlewak · #1 03-04-2008, 08:40 AM

My 1984 Mercedes 300d had sit for about 2 months... I got in it and turned the key... It started fine... I let it run for a few mins. and then backed out. When I put the car in drive it just shut off... It cranks and cranks and black smoke putters out the back but it wont turn over... I have replace the fuel filters and battary... I just don't understand why it isn't running. Please help me!

Timmy

vstech · #2 03-04-2008, 08:55 AM

sounds like you ingested some air to me.
I would put a bottle of fuel on the supply and return fuel lines and pump and pump and pump the primer handle then try to start it again.
the black smoke has me thinking your air filter could be plugged up. pull it and see if it starts.

pawoSD · #3 03-04-2008, 08:57 AM

There's a possibility that the tank strainer is clogged. Its a metal mesh in the fuel tank that filters the fuel before it leaves the tank. This could cause the exact symptoms you describe....enough fuel to sputter and make smoke, but not enough to run. You might have fungus growing in the fuel tank from sitting if there was any water in the fuel. Try disconnecting the fuel line before the pre-filter (little plastic one) and holding the downward into a can (as low as you can) and see how much comes out, it should flow by gravity if the tank is fairly full. If it only comes out in a trickle than thats your problem, restricted fuel. The fuel should flow pretty quickly that way if there's no restriction.

Also, make sure all connections are tight and not leaking any air into the system.

When you replaced the filters did you use the little primer pump for a while to get all the air out of the system?

bobodaclown · #4 03-04-2008, 09:02 AM

Sounds like a fuel related problem.

Did you fill the fuel filters? Did you prime the pump?

kerry · #5 03-04-2008, 09:25 AM

Although it doesn't seem likely, I wouldn't completely rule out malfunctioning glowplugs.

jkoebel · #6 03-04-2008, 09:27 AM

A good way to test for plugged tank strainer is to swap the feed and return lines from the fuel tank in the engine bay. Return fuel will blow out the strainer, incoming fuel will come from where it normally returns.

If it works good on this setup, its a problem in your tank.

Timlewak · #7 03-04-2008, 10:46 AM

When I try to use that little pumper it has very little fuel coming out... but seems to be mostly air. I know some about a car but not a lot... I am so confused.

Bajaman · #8 03-04-2008, 02:27 PM

If your not getting free flowing fuel from the primer pump, you've likely got a plugged tank strainer. See above.

vstech · #9 03-04-2008, 03:13 PM

http://www.dieselgiant.com/injectorcleaning.htm
this pictorial will explain how to bypass the fuel tank in your car.
get a 3 liter soda bottle or something similar *(I've used milk jugs...) cut two holes in the lid, and get some 5/16" fuel line and hook up like the pictorial. fill the bottle with diesel, or even add a bottle of Marvel Mystery oil to it. prime the primer until good solid fuel sprays back into the bottle, then try to crank up the car. if it works this way, there is a problem with your tank.

rrgrassi · #10 03-04-2008, 03:14 PM

That or the tank is experiencing vacuum. Also remove the filler cap and see if you get a "whoosh" sound.

It could also be be lots of air in the system from a cracked rubber fuel/return line or a leaking primer pump.