Won't start after parking with nose uphill

[Highmileage]

Hi again! My trusty 270CLK (250k and counting) is still misbehaving. In did a leakdown test and replaced 2 injectors which makes all 5 done over time. No more leakdown issues. I've also re-sealed the HP Pump. She starts well on the flat (first turn of the key) but left overnight nose uphill, I end up flattening the battery (new) and need a boost charge again before she will start. Also, while she goes well I can't put my foot down hard without the engine cutting out instantly; so no overtaking and a couple of stick situations already! My own feeling is that the uphill issue suggests poor fuel delivery from the pump? Any suggestions?

 

[Jim2]

OBD scan? Done when she's refusing to start?

 

[davidsl500]

Somewhere in the back of mind this issue was usually caused by worn O rings in the fuel lines letting air in and allowing the fuel to drain back to the tank. If it starts easily with the nose downhill that would probably confirm it. It's an issue on some mercs hopefully yours is one of them...

 

[mersum1es]

Most probably like davidsl500 says. Very common problem. And finally even nose downhill won't help.

You also may see air bubbles traveling in clear low pressure lines when engine running. Change all lines too, they will brittle over the age.

 

[DREAMER NO2]

electric pump or engine driven ?

 

[Highmileage]

I've resealed the engine driven pump. I suspect the electric pump, but now I have other suggestions regarding O ring seals etc. (thanks guys!). I've owned the car since 80K miles, so the pump is at least 170K miles old!

 

[Jim2]

Have you ever had any other with it since you bought it?

 

[Highmileage]

Have you ever had any other with it since you bought it?

Did you mean 'any more trouble'? Answer no, not really! Apart from worn suspension parts etc. The only expensive problem was a knackered alternator, followed by a second replacement after 3 years (£50 from a scrap yard and still running fine!). It's probably been the best car I've ever owned in terms of trouble free running and still manages over 50mpg on a run, doesn't use oil and the drive train is fine. At 251K (I just looked) I can forgive it beginning to creak (no pun intended), but the engine stopping or not starting is bugging me. The only other issue I have to deal with is the well known failure of a nylon gear in the complicated air con/vent system which entails removing the entire dash..... Has to be done before the Winter. The car is relatively worthless in the market place and so I've decided to just keep fixing it until something major occurs (or I sell my farm is Spain!).

 

[LostKiwi]

Symptoms are exactly what would be expected from an air leak in the low pressure side of the pump. If the pump supply is higher than the tank air will be drawn past the o-ring seal and back into the line. This is difficult to shift once there so flat battery results.
If parked with pump lower than fuel level no air drawn in so easy to start.

 

[Highmileage]

Symptoms are exactly what would be expected from an air leak in the low pressure side of the pump. If the pump supply is higher than the tank air will be drawn past the o-ring seal and back into the line. This is difficult to shift once there so flat battery results.
If parked with pump lower than fuel level no air drawn in so easy to start.

Thanks, sounds logical. Are we talking about the electric pump? (I've resealed the engine driven pump).