I know there are millions of threads on here, and I have read many of them however none match my scenrio exactyly so...I'm afraid its another.
My truck started to splutter and died on idle a few days back after filling with second tank of WMo/diesle 50/50 mix, it ranthe first tank just the same as it did on 100% bio or normal diesel, so think its unrealted. but since then it's been hard to start...eventually i workd out the fuel cu toff solenoid was failing to lift when the key was turned...Now do this manually, However she still wont start easy. takes 10-20 seconds of cranking with gas on.
When the truck does start eventually you have to hold it flat out at 2500 rpm or so to keep it running and dropping much below 2 leads to itknocking loads and wanting to stall. it iwll not hold an idle for more than about 20 seconds just dies on idle.
I even plumbed ina small tank of fuel straight to the lift pump today and ranit up off that, it idled ok for almost a minute then died. the main filter was replaced first as part of the fault finding process along with cleaning the pre filter, which is out of the loop anyway running this little tank, so that leaves the lift pump and the IP... I'm hopinh its very common for lift pumps to fail, as i don't want to be taking that IP off or paying for the reapirs on it! so What are your suggestions guys?

truck is stock apart from #0 plate and boost elbow.

 

It's pretty common for lift pumps to go out. A fuel pressure gauge would go a long way in diagnosing your problem.

 

just to double check, the lift pump and primer pump are the same unit, no in tank lift pump, right?
Would one of these work ok? Cummins B series Lift Pump. 3904374 Leyland roadrunner | eBay UK

 

You're right, there is no in-tank lift pump. The pump with the primer pushbutton is the lift pump. It looks like that pump may work, but it may be best to get one directly from Cummins. I got mine a few years ago and it was about $120.

 

fair enough, that one doesn;t look as good to me either. i'm gonna rig up a electric fuel pump from a Nissan 200SX today to check it is the lift pump causing the problem, can i pump through a broken lift pump?

 

That I don't know.

 

Turns out the lift pump is fine...i cut the pre filter and and heater again today and put feed straigh tot pump off a bigger can of diesel and she ran fine. i guess the tank rana lil low last time...I then connected to main tank in this way and it worked perfectly again! before these problems I had not touched anything onthe fuel system other than the feed to the pump when fitting my plate and it started leaking air all on its own, what are the chances!

 

Hmm. Odd. Well, glad you got it fixed!