Draining w202 fuel tank

[television]

CPS sensors contain an iron core with a winding of copper, the expansion rates are not the same for the 2 metals so the copper wire breaks where soldered to the connection points, when hot it loses contact and as it cools the wire touches the connection and works again. To make matters worse it is potted, so in all 4 different materials.

When all good they measure between 800 and 1k ohms, when bad infinity or some silly figure up in the high K range.

It sits over the starter motor on the bell housing

 

[yorkshire1]

fuel

on the other hand how much fuel is now in the tank if not a lot and the tank was only drained and not cleaned more thoroughly it wouldnt take long to block the prefilter again as its not very big

 

[darkchild101]

on the other hand how much fuel is now in the tank if not a lot and the tank was only drained and not cleaned more thoroughly it wouldnt take long to block the prefilter again as its not very big

Put in just below a quarter of a tank

Yorkshire1, what size inline filter do i need mm wise, 8mm or what

 

[yorkshire1]

Put in just below a quarter of a tank

Yorkshire1, what size inline filter do i need mm wise, 8mm or what

yes 8mm will be fine

1/4 tank will only have nicely wet the bottom of both halves of the tank best with 1/2 has your mechanic come back withcause of fault yet

 

[darkchild101]

yes 8mm will be fine

1/4 tank will only have nicely wet the bottom of both halves of the tank best with 1/2 has your mechanic come back withcause of fault yet

No he is only saying what i already knew. I think the wvo hadnt been filtered at all and was straight out of the fat fryers because its so dirty and cloudy. Guy does it for me probably got mixed up gave me wrong one thinking was the god stuff as was dark

So best to put half a tank of fuel in yeah? So what does this do as opposed to quarter tank

 

[yorkshire1]

oil

No he is only saying what i already knew. I think the wvo hadnt been filtered at all and was straight out of the fat fryers because its so dirty and cloudy. Guy does it for me probably got mixed up gave me wrong one thinking was the god stuff as was dark

So best to put half a tank of fuel in yeah? So what does this do as opposed to quarter tank

if the waste oil was as bad as that there could be solid fat also on the bottom of the tank that hasnt drained out causing clogging etc, the ongoing problem 1/2 a tank or more just dilutes all the crap still in there further making it easier to go thru the filters

 

[darkchild101]

if the waste oil was as bad as that there could be solid fat also on the bottom of the tank that hasnt drained out causing clogging etc, the ongoing problem 1/2 a tank or more just dilutes all the crap still in there further making it easier to go thru the filters

I am really at my wits end. the stuff he drained out, he showed me and it was really bad with white sediment settling at the bottom

I need a lasting solution to this :cry:

 

[yorkshire1]

fat

I am really at my wits end. the stuff he drained out, he showed me and it was really bad with white sediment settling at the bottom

I need a lasting solution to this :cry:

yes the white stuff is animal fat ie solid at room temp and this will clog your paper main filter overnight as the filter cools down again

best solution put a gallon of petrol in the tank (helps with animal fat dissolving) and then fill up with diesel fit that clear filter inline as previously said itll catch the bigger crap particles and save youre merc prefilter blocking then keep spare fuel filters with you to change if car starts to fail prime the filter and away you go will take about 10 mins to swap a filter

you will eventually clear the tank depending on your mileage, only other way is to drop the tank and clean it out properly

 

[darkchild101]

yes the white stuff is animal fat ie solid at room temp and this will clog your paper main filter overnight as the filter cools down again

best solution put a gallon of petrol in the tank (helps with animal fat dissolving) and then fill up with diesel fit that clear filter inline as previously said itll catch the bigger crap particles and save youre merc prefilter blocking then keep spare fuel filters with you to change if car starts to fail prime the filter and away you go will take about 10 mins to swap a filter

you will eventually clear the tank depending on your mileage, only other way is to drop the tank and clean it out properly

Ordered 5 prefilters should be here Tuesday

So once i fit the bulb primer i will just need to squeeze it few times and fill the filter with diesel and start the car and it will start easily?

So fit the buld and then inline filter and connect pipe into preheater yeah?

 

[yorkshire1]

bulb

Ordered 5 prefilters should be here Tuesday

So once i fit the bulb primer i will just need to squeeze it few times and fill the filter with diesel and start the car and it will start easily?

So fit the buld and then inline filter and connect pipe into preheater yeah?

if you fit a new filter prime it with the bulb keep squeezing until you feel resistance to squeezing to purge as much air thru as possible engine should then start relatively quickly may run rough for a few seconds as all the residual air is eliminated

 

[darkchild101]

When a car engine is running does fuel go to the engine and some of it returned to the tank like i some kind of loop? I am just curious about this vis-a-vis the Mercs saddle tank design

 

[hotrodder]

Generally yes, more detail in this thread including principles of the venturi/syphon pump that's used to transfer fuel from the passive side of a saddle tank and/or keep the in tank swirl pot/splash bowl full... http://forums.mercedesclub.org.uk/showthread.php?p=1044961#post1044961

Don't need the engine running to flush the tank through, back at the bottom of page 2 i mentioned disconnecting a fuel line and energising the pump so you can flush the tank through into a suitable container

 

[television]

When a car engine is running does fuel go to the engine and some of it returned to the tank like i some kind of loop? I am just curious about this vis-a-vis the Mercs saddle tank design

The return to tank takes off at the fuel distributor, what is not passing through to the injectors is returned to the tank.

 

[yorkshire1]

pump

Generally yes, more detail in this thread including principles of the venturi/syphon pump that's used to transfer fuel from the passive side of a saddle tank and/or keep the in tank swirl pot/splash bowl full... http://forums.mercedesclub.org.uk/showthread.php?p=1044961#post1044961

Don't need the engine running to flush the tank through, back at the bottom of page 2 i mentioned disconnecting a fuel line and energising the pump so you can flush the tank through into a suitable container

wont work as the lift pump is mechanically driven via the engine

 

[yorkshire1]

loop

When a car engine is running does fuel go to the engine and some of it returned to the tank like i some kind of loop? I am just curious about this vis-a-vis the Mercs saddle tank design

yes the return fuel is fed into the opposite side tank to the engine feed line this is where the problem occurs with the merc saddle tanks and veg oil; as the tank approaches around the 1/4 tank area

partially due to viscosity and the different fuel temps on each side of the saddle tank the balancing pipe which normally equalizes the fuel levels in both sides of the tank fails to do so, the feed side of the tank runs dry whilst there is still fuel in the return side

the faster the engine is run due to the mechanical lift pump the quicker the rerturn side of the tank fills up hence on long motorway journeys the car will run out of fuel with the guage still reading nearly 1/2 full

 

[yorkshire1]

return fuel

The return to tank takes off at the fuel distributor, what is not passing through to the injectors is returned to the tank.

the fuel return pipe on this engine comes off the back of the fuel filter housing where the injector leak off pipes join it aswell as the fuel return from the actual fuel injection pump and then straight back to the tank

 

[television]

the fuel return pipe on this engine comes off the back of the fuel filter housing where the injector leak off pipes join it aswell as the fuel return from the actual fuel injection pump and then straight back to the tank

Thank you and it shows that on the EPC drawings

 

[darkchild101]

Generally yes, more detail in this thread including principles of the venturi/syphon pump that's used to transfer fuel from the passive side of a saddle tank and/or keep the in tank swirl pot/splash bowl full... http://forums.mercedesclub.org.uk/showthread.php?p=1044961#post1044961

Don't need the engine running to flush the tank through, back at the bottom of page 2 i mentioned disconnecting a fuel line and energising the pump so you can flush the tank through into a suitable container

How do you do this

 

[darkchild101]

Mechanic now informs he is going to remove sender unit and try fix that way. he says the prefilter was clogged again when he tried to rev the engine by pulling lever next to engine he noticed very little fuel and bubbles and suspects the block is at the tank

So did we agree whether the c250td has a tank strainer or not. Thats what he also mentioned :-(

 

[hotrodder]

How do you do this

Sorry, i was mistaken. Thought the lift pump was leccy but...

wont work as the lift pump is mechanically driven via the engine