A Class starting fault

[Wingnuts]

A150 W169 2006 Manual Petrol

Help please, Happened out of the blue, car was fine until I turned it off, it sat in a rain storm for 10 minutes when I went to start it it wouldnt start.

It turns over and tries but gives the impression there is no fuel then after about 10 attempts it will start and at once settle to a normal happy tickover and run perfectly. It will then restart OK until it has been stopped for some time (say 1 hour) when the whole problem repeats.
As I say it is as if it is taking time for petrol to get through until it has been cranked.
Where do I start? Its not as if it is only when cold.
Is the fuel pump a contender and difficult to replace?
Would MB diagnostics be likely to find it if its intermittent as it might start OK if I took it to them?

Thanks for looking.

 

[Steve@Avantgarde]

I did a fuel pump on monday on an A Class for almost exactly the same fault. However I diagnosed it by measuring the fuel pressure, I would suggest you do the same.

 

[Wingnuts]

Thanks for that, dont know how to do that so may have to ask local MB although not too happy with them. Seems odd that once it starts it immediately settles to normal slow running and runs perfectly whatever the journey.

Gave the fuel pump relay a tap today after reading somewhere that that was another possibility (sticky) (Had to ask another nice member of this forum where it was, yet another terrible DIY feature of the car, have had thirty five cars and twelve motorbikes never known the relays to be hidden before and not even mentioned in the handbook & buried under thick reinforced carpet and plastic trim, virtually a day spent searching & getting access.)

Thanks again

 

[Alex Crow]

Could well be the relay, had a relay causing starting problem on a w169 last year.

 

[Wingnuts]

Found the relay and reseated and gave it a little tap, car has been OK since but not counting my chickens, going to replace the relay tomorrow if they have one but may have to wait for one from UK. If its not the relay that will go back to the pump as number 1 suspect.
Thanks for replies.