270cdi hard start when hot

I drive a 2002 C270 CDI,
Recently the car switched off while accelerating. and would'nt start afterwards. Had to use a cloth dipped in petrol to get it started.
The mech replaced injector № 5 (2ⁿᵈ hand) it then started but now it takes about +\-5 tries before it starts. I've noticed that it starts ok in the morning.
It doesn't smoke when accelerating so i don't think it could be the injectors. it doesnt cut out when i floor it and power still seems to be good.
PLEASE HELP!!!!
It still could be fuel related, is there visible air bubbles in clear pipes? Often pipes brittle when doing some other repair. Do the injector leak test. Fuel problems are often temperature related. If you can plug it in star, you can see fuel pressure, read possible codes, check injector correction values etc.
All tests should be done in exact condition where problems occur!

My Mech is generally more acquainted to sprinter Buses/vans then he is to sedans which use the same 611 motor(could be different in other countries). I think the difference between the 2 is that the sedans are more electronic than the commercial vehicles.
He doesn't have a diagnostics system. So before replacing the injector he did the overflow test which showed that № 5 had more fuel than the others and therefore replaced that one. I didn't know that it has to be adapted to the rest of the car. I assume this means putting it on the computer and reseting the values ??
all the injectors have the same part numbers. would that mean they're the same?
I noticed the at night it starts much quicker than it did during the day. My logic says its most probably the crank sensor and/or the fuel filter.
I had replaced the fuel pipes so i can't really see whether there's air bubbles in the system. There is a sought of spraying sound i hear when i turn the key on, but dont see any leak anywhere. is it possible for the Primary pump to leak into the engine??
In fact in the previous months i've replace quite a bit concerning the fuel system (4 2nd hand injectors, refurbished HP pump, Air Mass Sensor, fuel Pressure regulator, Turbo Actuator, installed electronic pumps in the tank & bi-passed pick pump on the engine.
You really should get your car in place where star diagnostic tool is used (by skilled mechanic), no point to throw money to new parts... and yes, injector need to be coded to ecu, they have either 1-digit or 6-digit IMA coding (codes found in top if the injectors)...

so now it doesnt switch off but instaed take forever to start.

It turns out that its was the Fuel pressure regulator.
The FPR has seals on it, that need replacing after some time. what happens is that they leak and the preasure takes a long time to build up.
So before replacing it, check the seals
http://www.mbpartsworld.com/showAsse...=0&modelYear=0
on the diagram its parts № 14 -Preasure regulator
Parts № 15&16 -the seals.
thanks guys for all the suggestions
Trending Topics
The Best of Mercedes & AMG

Told him what i was thinking it was and he said more often than not, its the seals on the Regulator.
The crank & cam Sensors almost never pack-up. with diesels its almost always the fuel system.



sorry just didn't posted all regular culprits, pressure regulator and o-rings are one of them...)! How you found it?