Car is 1959 Mark 1, with later 3.8 engine.The fuel pump operates fine and has that lovely ticking sound as it fills up the float bowls,then stops ticking. HOWEVER, once the car is started the fuel pump has begun to emit a rhythmatic small "boom" or "pop" - about every 3-5 seconds. Has anyone experienced this ? Any thoughts on what may be causing this ? Is the pump trying to warn me that its about to have the "schnitzel" ? should I try to fix this or just replace it with the Hardi pump that I keep as a spare ? Car runs just fine, but I'd rather replace / repair the pump in my garage than the side of the road , as I'm going on a 300 mile round trip drive in a couple weeks.
Thanks for your thoiughts !
Schmitty

 

The noise you describe is a new one to me. Noises from SU pumps, other than the standard ticking, can result from the pump touching something solid due to the mounting moving or rubbers failing, parts coming unscrewed inside the pump, or leaks on the inlet side letting air in (you would see bubbles in fuel from the outlet side). I can't think of (remember) much else.

 

Personally I would exchange it for the Hardi now and then strip the SU down on a bench to see what is wrong. Always best to be on the safe side rather than listening to a faulty fuel pump for 300 miles waiting for it to stop working.

 

Yes, I'd check the pump, out to see if there's anything noticable wrong with, it like loose mountings or connections, and, if all seems well, then change it for the spare one. The faulty one can be carried in the boot, just in case, and checked out at a later time. No doubt life will get in the way and it will be a job left for the next owner.

It may be worth while to check the fuel tank, in case there's an obstruction moving about in there. I had to remove the left-hand tank on my S Type to clean it out because there was a load of lining crap that had broken loose and was floating around. The problem I thought I had to deal with was a malfunctioniong fuel sender unit on that side, which was then fine again once I'd cleaned it all out properly. I think the previous owner had just lined the tank as a precaution or becaude he was an idiot.

Ray.