Right, here I go again.
My 1978 series 3 diesel with CAV fuel pump won't prime. Starting at the beginning I have had the engine out and done a partial rebuild (only really piston rings and big end bearings and overhaul of head) for this I took the fuel pump off, now it's back in and a few weeks ago I tried to get fuel up to the injectors and at the end of the day when I was running out of time, light, battery power and the will to live, all of a sudden I had what i thought was a good flow of fuel at no1, however had no time to go any further. On returning to it today I had to start the whole process over again with no real luck. I have air free fuel at the 2 bleed points on the pump but no matter what I do it doesn't appear at any outlet from the pump. I believe it should appear at the injectors using just the hand pump as it did last time, but even turning the engine over as much as possible hooked up to my van I get nothing. Just to check I am not being daft too, the fuel stop lever should be sloping down pointing to the rear of the vehicle shouldn't it? OH and I sheered the bleed point union in the pump, the one on the flat face. So had a great day really. But really any help at all is appreciated.

As long as you have fuel to the pump body you will only get fuel out of the delivery valves when the pump is running. Bleed to pump, fit injector pipes tight at pump finger tight at injectors, turn engine over when air free fuel reaches injectors tighten them up engine should start.

Thanks Wammers, seems I was being daft, maybe when my battery is fully charged I might get somewhere, still have to get over the sheered vent screw issue, not convinced it will be easy to find a replacement.

Just thinking, is there any way to tell if the pump is actually turning when you turn the engine over, I've checked that the spigot inside the engine turns but by my measurements the spindle is only engaged in the pump by a few mm, could this mean no drive to pump?

johnboy1983 said:

Just thinking, is there any way to tell if the pump is actually turning when you turn the engine over, I've checked that the spigot inside the engine turns but by my measurements the spindle is only engaged in the pump by a few mm, could this mean no drive to pump?

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It's a long long time since i worked on anything with a CAV pump. It depends on what you mean by a few millimeters. If it's engaged it should turn it will start to push fuel past the delivery valves when it does.

With the unions cracked at the injectors the buggers usually start. That way I have never failed yet.