Diesel Fuel lift pump problem?

[Guest]

Have just finished converting my Series III Landy to a Montego engine & got it on the road today - at first everything seemed fine though power seemed somewhat lacking - then after about half a mile it began to run rough, lost all power & cut out

Seemed like a fuel problem - so undid bleed screw on filter & tried priming lift pump - seemed to be very little resistance on priming button, but by pushing hard to the very bottom several dozen times I eventually got fuel to the bleed screw & tightened off & engine re-started - Got about a mile this time when deaccelerating for traffic lights it did it again also noted it had begun to smoke badly as it lost power, though exhaust was clear just after starting. After a further three repititions of this procedure I got back home & called it a day

Now I did have problem with said pump during rebuild & opened it up to check - outlet non-return valve had dropped out, so put it back & center punched four spots to secure - also checked diapraghm which seemed a bit aged but looked OK - put it back together & all seemed fine

To me the pump is the obvious culprit, but I have never liked the system of repair by "keep replacing items til its fixed" - I like to be sure! Can anyone confirm my suspicions or is there anything I have overlooked?

Regards - Nick

[G Force]

Hello there, if you have a good supply of fuel from the pump outlet when you use the priming handle then I would say the pump is probably fine. If you just get a feeble squirt then fit a new pump.

It does sound like you have an air leak in the feed pipe up to the fuel pump causing air to enter the system.

Cheers Gary

[Guest]

Thinking along the lines of air in the system. Not sure if this part is still present after the conversion, but the flexi fuel pipe which runs to the injector pump feed, comes up and round the back of the pump. On one of my Diesels, this pipe hardened at one end, and caused a crack to appear, which once long enough, caused a small amount of air to creep into the pumps fuel supply causing the same problems you describe above.

This happened shortly after I disturbed said pipe to replace the glow plugs, where the split was hidden underneath the pipe, it could have taken me a while to find it, and was the luck of seeing a drip of fuel come from it that I found it.

The only time i ever replaced a lift pump was beacuse it was leaking, and Diesel was running back over the head, then over the manifold

HTH, Rich

[Guest]

New pump

Thanks for the advice - have looked at the pipe from tank to pump & can't find any leaks - when it cuts out it is because it has emptied the filter, so I assume the fault is on the pump side, but I know the pipe you mean & will take a look as well - putting car back in the garage tonight (means moving several vehicles ) to have a proper sort out & fit new pump which I have gone ahead & bought as I am not happy with my repair to the non-return valve in it.

Regards Nick

[Guest]

Fixed! :-)

Well we were both right - fuel pump was decidedly feeble, though not actually leaking - priming lever was barely working at all, hence the problem re-priming. Lever had excessive wear on pivot & thre was damage under the diaphragm as if a previous one had come out (or not been fitted correctly) perhaps the lever was even bent?

However on fitting, although there was an improvement, all was not right, so re-checked all pipes and fitted a piece of clear tubing on vacuum side of pump & found excessive air being drawn up. fitted piece of 2 meter pipe direct to tank - no air! So renewed pipe & re-routed further from exhaust whilst at it. All running perfectly now & smoke from exhaust all but gone as well Certainly transformed the Landy & glad I fitted the brake servo now! Not checked fuel economy yet - will have to wait until my driving calms down a bit first!

Thanks for all help / advice - Nick

[E_T_V]

Glad to hear it is all sorted. If you want extra go then there are certain things you can do to improve performance a bit too. When I get a free hour or so then I'll try and write up a how to... article on it.