Merc.190 will not start

[peterlball]

Can anyone help. I have a 190 2.0 petrol which will not start if it is not used for three days or more. If used everyday it is perfect. So far, it has had new plugs, new leads, new distributer, new fuel relay. When it does start it runs perfect. There is no pattern to it starting :cry:

 

[flyingtech55]

Isn't it the non-return valve next to the pump/fuel filter that causes that?

 

[joe bloggs]

Check the supply to the cold start injector (blue plug, sprays into manifold), when the engine is cold pull the plug off, stick a test lamp in the 2 pins (not a meter) put the lamp somewhere you can see it, sit in car and try to start as normal i.e. from an ignition off state. The lamp should light up for 2-4 seconds during cranking. Post back results.
Unlikely to be any non return valves as the fuelpump should prime up when the ignition is switched on.

 

[peterlball]

Merc 190 not starting

Thanks for the help, but at present the car is starting perfect after the upper voltage re.lay was replaced. It looks as though damp had got into the connection and was causing the fault