Problem W124 M103 .Will only run if pumps are primed .And stpps

[optimusprime]

First start this year ...Started fine, I can start it but only after priming the pumps again , but after a few seconds it stops again .When the engine cuts out i can hear the pumps running as the engine cuts out , and i think i can hear them when the car is running.Any one had this , .new pumps and filter last year

 

[Pontoneer]

Had similar issues in the past - a new set of spark plugs always seemed to fix it . These engines always seemed sensitive to plugs - both 2.6 and 3.0

 

[optimusprime]

All new ht system last year, it is not elactrical .All the pumps work, but as far as i can see, its not pumping fuel [ new Bosch pumps ] ..if i prime the pumps it will run for a few seconds and dies again.All the time engine is running i can hear the pumps and even when it stops the pumps keep running on .

 

[Will]

Sounds like the fuel pump relay is faulty.

Remove the relay and link out pins 30 and 87 and they will run continuously, which should help you confirm this to be the fault.

 

[optimusprime]

Will , iI is the best thing to do first ...but i thought the relays worked ,or the dont .The pumsps work even after the cars engine as stopped. . And i cann hear the pumps working all the time engine is running ,and i dont think they should..Dont hear them as a rule one the engine as started

 

[Will]

Will , iI is the best thing to do first ...but i thought the relays worked ,or the dont .The pumsps work even after the cars engine as stopped. . And i cann hear the pumps working all the time engine is running ,and i dont think they should..Dont hear them as a rule one the engine as started

Yes that sounds exactly like a classic relay fault.

They energise to prime the fuel system, then stop. They are then designed to energise and run the fuel pumps again once the engine is started - but if the relay is faulty it won’t.

Just link out pins 30 and 87 to check.

 

[optimusprime]

But Will i can hear the pumps .If i could not hear them i would plug for the relay .But i will give the hot wire a try later on today ...thanks.

 

[Will]

Sorry it’s a bit confusing as you say you think you can hear them running all the time but from the first post it sounded like you could hear them only when priming again (which you wouldn’t need to do if they were running already?)

Still worth ruling that relay out by linking the pins, easy and costs nothing. But if the pumps are running and you have fuel supply issues you could be looking at a blockage on the fuel side - tank strainer maybe?

 

[optimusprime]

Will,,, the strainer is my nightmare ...cant get the car moved to get it fixed .Thats if your right .Some one said it was the accumulator .And if they split inside the fuel is sent back to the tank in doung this the fuel pressure drops off ...First start yesterday, i primed the pumps until they stoped .And it strted up right away, i can hear the pumps running none stop ..

 

[optimusprime]

And i recon all this is down to ethanol in the fuel ...but last night i put some Red X in the tank., it started first time so i can fotget the accumulator idea . , . now i need a fuel tank sender its on zero , i know there is over half a tank of fuel in there I removed fuel sender last year and it was crusty on both the shafts.We will see how things go Friday..As for the strainer i will get that done as well . .

 

[optimusprime]

Back to square one .Car started first time .And when i put my foot down it stops and i can hear the pumps running after the engine as stoped i recon its not getting enough fuel ./

 

[optimusprime]

Will . New strainer on order from The SL Shop ..Thats what i recon the problem is .Car. started first time today ,,,As for the tank sender it was stuck another sign of crap in the tank . I will get a guy to change the strainer , and drain off the tank at the same time . Enjoy your week end . Trevor

 

[Will]

Will . New strainer on order from The SL Shop ..Thats what i recon the problem is .Car. started first time today ,,,As for the tank sender it was stuck another sign of crap in the tank . I will get a guy to change the strainer , and drain off the tank at the same time . Enjoy your week end . Trevor

Possibly this is all the clues for why the old fuel pumps needed replacement?

 

[optimusprime]

I recon so Will ..

 

[Pontoneer]

It sounds like a blockage if you have eliminated everything else .

Four possibilities for a blockage

Tank strainer ( relatively unusual in a petrol car but commonplace with Diesel ; have had that myself )

Fuel accumulator ( but you reckon that's OK )

Fuel filter ( in pack beside accumulator and 2nd fuel pump ; if not recently changed , worth doing , but the little banjo pipes can be well rusted up and are shockingly expensive ! )

Finally , I think there is a small strainer/filter in the fuel distributor , I have heard of these getting blocked but never experienced it .

Another test you can do it to disconnect the fuel feed pipe from the distributor and put into a large jar , then turn ignition on to observe fuel flow ; there is a specification for so many mL in so many seconds ( I can't recall what it is ) but if you use a decent size jar , or something like a 5L petrol can , you should be able to observe whether there is a healthy flow of fuel coming up to the engine .

 

[optimusprime]

All up the back end is new ,other than the tank strainer .. it starts first time, and will run ,but if i give it gas it dies .. Prime it with the key, and it will start up again

 

[optimusprime]

Having so much trouble just finding a fuel tank strainer to fit my W124 260E Even Germany dont have any .. no one has the right strainer ..

 

[carat 3.6]

Having so much trouble just finding a fuel tank strainer to fit my W124 260E Even Germany dont have any .. no one has the right strainer ..

It wont let me post this as a link, so the ebay item number is: 175197266608

 

[optimusprime]

carat 3.6 Mercedes dealers tell me this​

pert number is right -A201 470 05 06 . As do 3 other web sites Autodoc , Pelican Parts, and our local SL Shop .​

 

[Will]

I’d drain the tank down, take it off and clean it first.

Have to say though that the one in Carat’s pic looked different to I thought it would - does your one have the thread in the middle for the metal pipe that has the hose attached to feed into the fuel filter/pump package?