W124 slow to start

[ms500]

Sometimes, my 300TE takes a while to start; I have to hold the key in the ignition for about 3-5 seconds before it will spring into life. Once it has started, it will run fine.

There doesn't seem to be any pattern to this; the other day I started it from cold and it started right on the key, then when I tried to start it again in the supermarket it took a while to start.

The starter seems to be spinning at the right speed, and the battery is recent and seems healthy.

I don't know when it was last serviced, but the oil looks clean. I do intend to replace the filters / oil / plugs soon though.

I'm thinking it might be fuel starvation, maybe a new fuel filter is needed?

 

[grober]

Leave the ignition switch on for 10- 20seconds ( warning lights on) before turning it further to start the engine--that gives the pump time to pressurise the system.

 

[Frank O' Phile]

Mine does the same. I thought the new plugs and filters would sort it, but no.

Anyway it always starts and that what counts. For now.

 

[Dieselman]

If it's when warm it will be fuel pressure causing a vapour lock. At the fuel pump is a one way valve that can fail and allow fuel to return to the tank. Check the pressure and fit a valve if necessary.

 

[ms500]

Leave the ignition switch on for 10- 20seconds ( warning lights on) before turning it further to start the engine--that gives the pump time to pressurise the system.

I do hear a faint buzzing noise from the back of the car when I put the ignition switch on, I presume that is the fuel pump and I always wait for it to finish before starting the engine.

If it's when warm it will be fuel pressure causing a vapour lock. At the fuel pump is a one way valve that can fail and allow fuel to return to the tank. Check the pressure and fit a valve if necessary.

Sounds logical, I'll take a look at this.

 

[Big White 'Benz]

Sometimes, my 300TE takes a while to start; I have to hold the key in the ignition for about 3-5 seconds before it will spring into life. Once it has started, it will run fine.

There doesn't seem to be any pattern to this; the other day I started it from cold and it started right on the key, then when I tried to start it again in the supermarket it took a while to start.

The starter seems to be spinning at the right speed, and the battery is recent and seems healthy.

I don't know when it was last serviced, but the oil looks clean. I do intend to replace the filters / oil / plugs soon though.

I'm thinking it might be fuel starvation, maybe a new fuel filter is needed?

Possibly a faulty ignition switch?

 

[ms500]

Possibly a faulty ignition switch?

I don't think this is the problem, since the starter motor does start turning but takes a while to start.