Fuel problems, off the road again.

[copperbollock]

Well I've had 6 months without it breaking down but now I can't figure out what's wrong.
Out and about and the car started spluttering and then stalled, cleaned out the pre-filter and got her started again and just made it home before it did it again.
This time when I removed the pre-filter there was a hiss of air. The filter was clean so I put on a new main fuel filter. Started again and ran for 2 minutes then died, cracked the fuel filter and had the hiss of air again and then I could get it running again.
Something's causing a vacuum which is stopping the fuel flowing as it should.
Anybody have any ideas?

 

[SilverSaloon]

intank strainer blocked, as a test you could swap the IN and OUT rubber fuel lines in the engine bay over

 

[CRH71]

Blocked Tank Breather?

 

[copperbollock]

I thought that initially so I ran it from a jerrycan direct to the filter block to see if that cured it but I've the same issue.

 

[CRH71]

Could a faulty return valve in the pump cause this, I wonder? The amount of fuel that turns over it wouldn't surprise me if that'd create a strong vacuum in a short period of time and explain your symptoms. I understand it's on the very end of the return pipe and can be fairly easily replaced.

 

[copperbollock]

Well she's running (although needs a new alt) I don't know how but there was a load of crap in the return pipe which caused the problem. I don't know why I did it but I disconnected the return pipe in the engine bay and tried to draw the fuel through but had no luck, so I sucked till it was pulling my tongue down the pipe (no gayer jokes please :Oops::lol and after about 2 minutes of this I got a gob full of diesel and some pretty big lumps of god knows what (I know I'm not helping myself).
After that she fired up pretty much straight away and ran great.
I'm going to take the tank off and clean it out, I also need to sort out the saddle tank pipe because if it drops below a 1/4 it just dies of fuel starvation.

 

[spock500]

You might be confusing folk with your signature.

Car: E250D 1993 W202

If it's a C250D you can clean the tank in-situ via the two sender units when removed. No fuel strainer on W202's either.