I think of the effort involved in all the possible tests and it seems like the best thing I can do is just swap the pump out and see if solves the issue. I have a spare here somewhere and I made a tool to get the tank lid off last time I did it so I can swap the pump out in 20 minutes.

Thank you all for the good advice and knowledgeable tips. I will get a fuel pressure gauge for the shed now so I have one ready next time.

Regards

Frank

im pretty sure the pumps are a rotary vein or meshed gear pump, was your walbro a cheapy??
if and when you remove the pump look into the pick up hole in the bottom of the pump, if you see plastic its a walbro rip off.. if you see metal its a proper walbro..

just a thought, did you use proper submersible fuel hose linking the pump outlet to the line on the carrier??
if not the fuel hose may have perrished..

In your case of course it's simpler.
You need to remove tubliner and floor panel to get to an XH pump, so it was easier to do a SST on the in situ pump - waste of effort accessing it if it tests to spec.
Other thing is it is useful to actually test pressure and leakdown - your spare could be marginal as well.
The basic vacuum/pressure ones I've seen don't measure the pressures required for EFI - and ones that do were pretty expensive, hence the old oil pressure gauge - and considering the amount of use, it surprisingly did the job well.
If you do find one for reasonable $$$, let us know - I couldn't.

I have one here Sanp from just a general tool/welding/farming shop... 0 to 60psi I think it is... And Collier & Miller in girffith were doing all std positive pressure gauge (not diagnostic gauges) for like 40 or 50 bucks from memory...

Cheers,
Tim

Yeah, that's not too bad a price Tim.

Troyman has the winning bid..

I pulled the pump out and took a look.. the hose was mostly gone.. It was proper hi pressure fuel line hose, but apparently not submersible. It disintegrated and coated everything with sludge. (I learned something today... I didn't know the hose had to be special submersible grade)



Repco were having a 25-40% off after xmas sale so in the interests of not doing this again any time soon I bought a fuelmiser pump. with a 2 year warranty. Since my Walbro is fine, it goes back in the cupboard. The Fuelmiser had all new proper hoses and pickup filters so it should all be spot on for the foreseeable future. (Car runs like a dream again on lovely expensive 98 premium unleaded.)

While I had the car on stands to put the filter in.. I figured I might as well put the Gabriel Ultra's that have been floating around the boot for 6 months in too... makes a huge difference so I am glad I was put in a position where I was forced to do it.

On the subject of fuel pressure guages.. the cheapie ebay rising reg I bought ages ago has a fuel pressure guage on it and I think I only paid $50 for that.... it looks like this:
{DESCRIPTION} but as i said, I don't think I paid that much for it. Might be worth putting it in just for the benefit of a permanently connected guage.

Now that my petrol situation is stable for a while... My second Blos carby has just arrived.. so now that I have two I can start figuring out how to do the plumbing for them.. I was thinking of using the section of an old EF fuel runner intake pipe where it splits into 2 2.5 inch runners... If I can get two of those (have one here already) I can modify the intake to split into two for each BLOS gas carby and then back to 1 and into the intake. Spose I have to look for a y splitter for the hose from the converter too. good fun.


Thank you to all of you for your help and suggestions... this place is a better resource than either of my manuals.