Disco 300tdi Starving;

Posted this in the 300tdi section but I'll put it here too in the hope of help.


Hi all, I'm new to the forum but not to Landys, I've got a problem that's driving me nuts.

I picked up a '97 Disco 300tdi a few weeks back, no history & I knew it needed work but it was cheap.

The problem I have is this, it fires up & idles like a sewing machine (albeit a noisy one) runs fine up to about 2500 rpm but when it hits about 3000 it jerks & cuts out momentarily, guffs of whitish smoke too.

Its got a mechanically controlled pump with EGR that looks like it's been blanked.

I'm thinking fuel starvation & it's evident that somebody else has been fiddling with the same idea as the lift pump is pretty recent & seems to flow fine, also the tank's obviously been taken out & refitted.

So I decided to start from scratch & repiped from the tank direct to the engine bay with an inline filter before the lift pump.

Having replaced all the fuel line from tank to injector pump & no improvement I've been scratching my head & swearing.

So today I thought I'd check some other stuff & ran it up with a hand on the turbo output hose, sure enough it's strangling when the boost comes on.

Checked the pipe from the turbo to the injector pump, Eureka it was blown behind the engine.

Replaced it & slight improvement but not a lot.

Any ideas?

Boost diaphragm on top of injector pump maybe.

Fuel pump still duff.

Valve clearances?

Timing belt?

Try the wire at back of fuel pump spade connector and bout 4 inch of wire.mine broke n did same as urs is now so luck for broken wire fix it and you should be running fine

Checked the boost control diaphragm, & the shutoff valve this morning & both ok.

Somebody has already had the anti-theft system off the pump as it's just got ordinary screws holding it on not shear-bolts & the pump has yellow paint marks on it, which tells me it's either been changed or rebuilt.

With no load on, from idle, if you floor it it whips straight to over 4000 before choking, if you run it up gently it starts the odd miss about 2500 & cuts in & out at about 3000.

Everything points to a fuel delivery problem, but not knowing enough about the pump I don't know where to go next.

Frankly it's the last thing I need at the moment, I've got to find a job & I can't use it or sell it as it is.

Help please.

Well good news here,

Did a bit of digging around on the web looking for replacement injection pumps & found a "how to" on Bosch pumps which linked to a pdf on servicing them.

I read through all the bits about the vane pump & the high pressure head & the advance , until my head was swimming but then I spotted a little paragraph about the pump regulator valve & it's matching outlet banjo bolt to the tank return line, which is a restrictor.

So I took out & examined the regulator which was fine, & then decided to check the outlet banjo, as I was at it.
Lo & behold it was just a bog stock banjo bolt with bloody great holes.

A trip to the local scrapper provided a restrictor bolt from an old Citroen & now it goes like it should.

All that grief because some German numpty put the the wrong bleeding bolt in!

The upside is that I now know with absolute certitude that the fuel system's good all the way through, & I found & fixed another problem that I probably wouldn't have spotted otherwise.

Thanks or the post telling us of the completed job. Nice to know when things are finished.

Good luck