A Class A170 Diesel WONT Start HELP!

[turbobello]

Hi All,
i need some help my a170 wont start, i have been trying to do a leak test with no luck, i have replaced the high and low pressure fuel pumps and fuel filter and still doesnt start, diesel is getting to the rail but seems not enough pressure to open injectors i have been told it should be 100bar PLUS , i spoke to a diesel injector specialist if the injectors need power to open and he said no as long as the engine is turning i should be able to do the leak test,

Have i missed something? is there a fuel cutoff between the fuel filter and fuel tank? any ideas Please

Details

Mercedes A170 Turbo diesel CDI
Year 2000
Automatic

Any help Please

 

[Xtractorfan]

You may have air in th system, especially if you have replaced the pumps..were the others faulty... try loosening one of the injector pipes and getting someone to turn the engine over, there should be quite a spray of fuel, if everything is ok, if not check for leaks ..does your car have the dreaded O rings in the pipes..change those and try again..

 

[turbobello]

Hi, i tried to do a leak test the other day with no luck, i had very low pressure coming from the high pressure pump to the injector rail, so both pumps were replaced including the filter, once filter was fitted it failed to bleed its self so i primed the filter and still low pressure, i found out today that theres a fuel pump inside the tank but i want more info on this issue before i spend another £150, if anyone know how to test them and fit, I also noticed unusual fuel possible biodiesel looks a bit cloudy? i drained and filled with clear green diesel

 

[Xtractorfan]

Try some injector cleaner in the tank, if bio diesel and or chip fat etc has been used it may be waxing up in the system, the cleaner should free up the intank pimp..have u any means of blowing back thru the pipes to ensure free flow of fuel..

 

[turbobello]

i think my best bet would be to remove the tank clean it with petrol and then replace the pump/sender unit as the tank is off, this car is becoming a pain in the (you know where!) is it possible for the under floor pans to be removed without a car lift as working on the floor, thanks

 

[piestore]

a 170 cdi

HI

The cdi engines are usually quite good to diagnos, although a star machine or similar are very useful, as you say you need rail pressur if this is not present its either pressure reg or exces leak of from injector/s

 

[Bolide]

AFAIK the injectors on all CDi diesels are controlled by the ECU. In other words, they don't (and won't) open till told to

On older diesels (the ones I'm used to) the injectors open when the pressure reaches a preset point. Not so with the CDis, I'm told

Nick Froome
www.w124.co.uk

 

[colechelle]

once the ecu sees that the press has reached 240bar-320 bar it will then tell each injector when to open, untill the rail pressure sensor tells the ecu that yes the pressure is correct only then will it all work, sound to me like you really need it hooked up to see what all the actual values are showing!!!

 

[turbobello]

Excellent advice Called Mercedes today, and they know what the problems is, BUT the cant tell me! unless i book it in

 

[rf065]

Excellent advice Called Mercedes today, and they know what the problems is, BUT the cant tell me! unless i book it in

If they really know what the problem is, surely they can tell you over the phone how much they will take to fix it too?

Russ

 

[colechelle]

Chances are they are guessing, turbobello would have only spoken to a service adviser and not a tech, there way off reeling you into the workshops!!

 

[rf065]

Good point

Russ

 

[turbobello]

Hi they wont give any advice over the phone (their new policy) and i have contacted 2 main dealers and both said the same thing

 

[turbobello]

and your right they just want my hard earned cash!

 

[turbobello]

Dont know how much, i know its going to be mega money it usually is, if i dont get any luck from the forum (i hope i can) its booked for half hour diagnostic tomorrow with main dealer, and will get the shock then! i need to get this car started. what else can i do

 

[turbobello]

Hi, i went to main dealer this morning for a quick diagnostic test to my surprise spoke to tech and was honest enough to say i be wasting my money on a diagnostic test as this will not tell me anything but would need to book for at least 2 hours to perform a leak test, he didnt want to know any tests that had been done other than he had to start from scratch and diagnose but he also stated that it could be kept in longer than 2hours, anyway he also said that the complete system would shut down if there was a leak somewhere. i told him i done a pressure test from the high pressure pump to the rail but he said that wouldnt work, so basically do the test i have already done pay over £200 and still get nowhere,

would anyone have access to fuel diagram to show where all joints and return valves are located,

I got the impression from the service guy today that they know what the problem is and seems a be a silly one but they are making a big deal from it.

So i turned my trailer around and went home.

If there is a techy here on the forum that doesnt mind a telephone call please PM me with tel number, im sort of losing faith in mercedes... shame

 

[colechelle]

try this, http://www.detali.ru/cat/oem_mb1.as...722.701&GM=716.500716.502&CT=M&Cat=66M&SID=07 cant pm you due to you not having 25 or more posts,

 

[colechelle]

had a chat with a few of the lads today and the answers we come up with is first, injector leaking by into the spill rail,( most common ),2nd, rail presure sensor, 3rd blocked lines/filter, 4th, wiring/ecu fault, 5th, your not cranking it for very long to bled fully, these cdi engines take a awful long cranking time to bled!!

 

[turbobello]

hi, i have tried to crank for at least 30/60 seconds once i changed the filter it failed to bleed completely so i had to fill the filter first to get any fuel in the pipes, as of leak/drip test no diesel was coming out of any of the injectors, it just seems to not suck fuel as it should, i know they take alot to bleed air out but not till the battery is almost flat, it was booked for a diagnostic to cover the ecu but the techy said i shoukd have pressure at the injectors, please send a email as i have less than 25 posts to ftautos@hotmail.co.uk and i will call you Kind regards...

 

[colechelle]

sent you mail!