OK - I give up ! And I thought I understood diesels !!!

I found an old thread on here suggesting talcum powder as a guide to finding trace leaks. Simple and will make the engine bay smell nice.

No response from PB Asher which is very disappointing.
 
Hi
Just seen this thread and not been on here for sometime. I had a very similar problem which caused the same none starting as you have experienced. It turned out to be a rubber O ring at the bottom of the diesel lift pump . I found it impossible to believe that was cause if all the trouble, but it was. Good luck
 
scoty said:
Steam,,cracked head,cracked manifold,faulty head gasket, restriction in exhaust.also what make of engine?
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Whereas I appreciate your pessimism, the few bubbles that form then arrive in the central chamber of the pump within 1-2 seconds of a start, and no other deleterious issues elsewhere with the engines, which are Cummins 6BT5.9M. This is definitely a CAV DPA pump issue, just trying to pin it down and thanks for all the direct experiences reported.
 
Fuel return line of the rail check valve would be a strong suspect to me, if fitted. Assuming all filters are well sealed. On suction side.
 
Off to the chemist this morning for some talcum powder. The CAV manual sets down a 20 PSI pressure test, so I have just got to work out how I can achieve this with the pump in situ. Should be a simple adaptor onto the inlet with a gauge on the low pressure return connection or bleed point. A bike pump will achieve 20 PSI.
 
superheat6k said:
Off to the chemist this morning for some talcum powder. The CAV manual sets down a 20 PSI pressure test, so I have just got to work out how I can achieve this with the pump in situ. Should be a simple adaptor onto the inlet with a gauge on the low pressure return connection or bleed point. A bike pump will achieve 20 PSI.
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Trevor I’ve read all this , in past years from my Perkins days the CAV pumps did this especially on the phaser 1000 engine.
Low transfer pressure inside the injection pump causes bad starting , maybe your pump shop isn’t on the ball as I recall you have had it into Ashers , I’ve never used them so can’t say how good they are .

A simple test is to use an injector from the other engine , split the 6 injector pipes so you can use one attached to an injector outside the head , bleed up and crank the engine over , see what kind of spray pattern you get .
 
volvopaul said:
Trevor I’ve read all this , in past years from my Perkins days the CAV pumps did this especially on the phaser 1000 engine.
Low transfer pressure inside the injection pump causes bad starting , maybe your pump shop isn’t on the ball as I recall you have had it into Ashers , I’ve never used them so can’t say how good they are .

A simple test is to use an injector from the other engine , split the 6 injector pipes so you can use one attached to an injector outside the head , bleed up and crank the engine over , see what kind of spray pattern you get .
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Thing is once the engine gets started all is just fine, decent power and turbo pressure etc. Today 6 days from last start off she went without an issue, although I did have Paul "Rocksteady" of this parish stood by observing.

I did however notice a couple of small fuel drips on two injector banjos, so maybe these need to come off and be replaced, although all are blue marked from Asher's rebuild in 2017.

However, for now I have decided to live with the occasional need to bleed, and if it persists then next Winter I will take the pump back off for further attention.
 
superheat6k said:
Thing is once the engine gets started all is just fine, decent power and turbo pressure etc. Today 6 days from last start off she went without an issue, although I did have Paul "Rocksteady" of this parish stood by observing

You can guarantee with any observer present to see the fault it will not go wrong. Just let me know every time you want to go out I will stand there and watch, to make sure she starts ok
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