Dead Fuel Injection Pump? - Jazzmag
Hello Back Roomers?

I?m sure this?ll be an easy one for the experienced guys out there!

I had cause to disconnect my fuel tank on my Peugeot 309 GLD 1.9 diesel (1988), creating an almighty air lock in the feeder pipe to the fuel injection pump. I reconnected the tank but the engine sort of half spluttered but never actually fired. After flattening the battery, I left it on charge overnight.

This morning, after similar rather disappointing splutterings, I decided connect a plastic fuel tank I have directly into the fuel pump, the tank balancing rather precariously on the engine. With fuel now flowing into the pump under gravity, the engine at last fired and ran!

Great I thought - progress at last. Until I noticed a firm and steady drip of diesel from the pump. It looks like an internal seal has gone, judging by the quantity of fuel leaking. Apart from that, the engine revs and sounds normal.

The only thing I can think of was there was a potential situation where the vent line back to the tank was partially crushed closed for a minute of two before I noticed it and un-jammed the pipe.

Any ideas ? would a large air lock, or closed return pipe actually knacker the pump?

Is the pump repairable or am I looking at replacement scrapyard pump time?

Any help / advice very much appreciated ? thanks in advance guys.
Dead Fuel Injection Pump? - RichardW

These pumps return quite a lot of diesel to the tank, so it is possible that you have caused some damage if you ran the engine with the return line blocked. Can you tell where the diesel is coming out? You may just have sprung a banjo seal, or one of the leak off hoses from the injectors.

These engines were fitted with either a Bosch or Lucas pump - easy to identify by where the cold start cable from the termostat housing goes to - rear of pump if it's Bosch, front if it's Lucas. Lucas pumps are known to be a bit weaker, and the front seal can fail leading to diesel leaking out around the cambelt area. This seal and bearing can be replaced, but you have to remove the injection pump, and it's a specialist job to repair. There are tons of these engines in the scrap yards, so getting a new pump shouldn't be too dear, but fitting it will be interesting no doubt!

However, I would make sure that it is not something like a split / disturbed hose first - much cheaper and easier!


Is it illogical? It must be Citroen....
Dead Fuel Injection Pump? - Jazzmag
Hi Richard,

Many thanks for your reply.

I have a Lucas pump and the leak is definately coming from the top of it. It look like its pushing up around the spring that holds the accelerator level in place. Putting a large wad of tissue here, stops the drips!

Is it poosible to fix in-situ? It looks like the top of the pump can be accessed by removing the top cover - or am I vainly clinging to the hope of a 'simple' repair?!

Many thanks for your kind help. Much appreciated.
Dead Fuel Injection Pump? - RichardW
Ah, I THINK there is an o-ring around where the shaft comes out of the pump, and it MAY be possible to change this in-situ. I would be very circumspect about trying to dismantle the pump without good knowledge of what is going to happen in case all the guts jump out. Your best bet is probably to ring up your local diesel injection specialist and have a chat to them - they should know if it's possible, and what it will cost.


Is it illogical? It must be Citroen....
Dead Fuel Injection Pump? - Jazzmag
Thanks Richard. To it is then, to find my friendly diesel injection chaps...
Dead Fuel Injection Pump? - 659FBE
I'm afraid blocking the fuel return, even momentarily will apply full transfer pressure to the pump body, including the governor assembly on top, blowing the seals. The seal for the fuel control lever can be changed in position on the CAV pump, but make sure you know exactly how to do it, and get everything spotlessly clean before you open the pump.

You should then remove the timing belt cover and check the shaft seal with the engine running, over a period of time, because this will have been overpressurised too. As has been said, the pump needs to come off to renew this seal - use only the correct puller on the drive wheel, and set the pump timing very carefully when you have finished.

Dead Fuel Injection Pump? - Jazzmag
Thanks for that, From what I can work out, it's only leaking from the top control lever. So I'll change this seal first, as you recommended. But I guess if the saft seal has been weakend, this will show up once the top seal is holding pressure.

I have a friend who's an experienced mechanic, so the offer a few beers and a curry should secure his masterful help!

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