Disco 1 300 tdi Injector issue?

Hi y'all
Firstly may I say thanks to all who set up and run this forum..I have browsed it many a time over the last 'x' years having owned a 300tdi defender for 12 years up to 2016 and a series 111 109 previously.

Sooo..after a brief affair with a 61 reg Fiat van (ending after it needed a complete overhaul of the fuel system inc hp pump, injectors etc, not cheap on a common rail diesel) I got myself a 1997 300tdi Discovery last summer. 133K miles, previous owner had done lots of welding underneath with pictures to show.
He also said he'd put on 'new turbo, new injectors' etc hmmmm...

Running wise, it seemed pretty good if a little smokey (black) on acceleration, fuel economy not too bad. However over the 9 months I've had it, the black smoke got worse and worse.

A couple of weeks ago, a couple of miles from home on the bypass, I suddenly got a boost of power which went as soon as it came, followed by distinctly rough running. It was dark so not sure on smoke output!
First thought...runaway..sh*t.
Next morning, started her easily enough but would not pull more than 1500rpm and clouds of white/blue smoke. Hmmm. Replaced air filter, diesel filter and lift pump (as the lever on the old one was 'loose' and flapping), bleeding seemed easy enough, but no improvement.
Next took intercooler & pipes off, a bit of oil but nothing untoward. No leaks or delamination.
Felt the turbo impeller and 'oh dear' lots of movement. Ordered a refurb unit and fitted it after cleaning hoses, intercooler and manifold.
No difference! Starts, won't run above 1500rpm, white/blue smoke.
B*gger

I then went on a little meander checking fuel pipes for air/ crap, swapping back to old lift pump then back again, creating a new problem, solving it etc etc you know what it's like.

Finally have a clue! But it's a bit odd. Basically I think there's no air in the fuel getting to the IP. If I crack off the injector nuts (at the injectors) they all seem fine except for no 4 which 'foams' diesel out, as if there's air in the fuel (which is why I went on my meander) BUT 1 to 3 seem fine.

I have on order, decent 2nd hand injector, new washers and new no4 injector pipe.

Sorry for the long post, but has anyone come across something like this before. Can a defective injector do this (how?) could it be the IP (hope not!)
Am I missing something?

If you got this far, many thanks for your patience!

Hello and welcome, have you done a compression test?

White blue smoke suggests oil/fuel, the fact it won't run above 1500rpm suggests something more sinister.

Hey thanks for the reply

Not using any oil, always starts very very easily (so compression reasonable?), mostly unburnt diesel, I think, smells quite strongly. Fraid I'm trying to fix it at the side of the road and have very limited tool other than spanners etc

If the new injector doesn't fix am gonna take the head off (already have gasket and new valves/pushrods) see if there's something there. Just keep coming back to the air in no 4 and none of the others and trying to 'think' why/how that could be!

Zfid said:

Hey thanks for the reply

Not using any oil, always starts very very easily (so compression reasonable?), mostly unburnt diesel, I think, smells quite strongly. Fraid I'm trying to fix it at the side of the road and have very limited tool other than spanners etc

If the new injector doesn't fix am gonna take the head off (already have gasket and new valves/pushrods) see if there's something there. Just keep coming back to the air in no 4 and none of the others and trying to 'think' why/how that could be!

Click to expand...

The timing may have skipped a tooth or two on the timing belt. It happens, friend of mine had it occur in his 300Tdi, engine would still start and run but limited rpm and little power. Check the valve and injection pump timing before going any further toward removing the head, you might only need a timing belt.

Hi
Just thought I'd put an update to this. Firstly it's becoming one of those 'how did it run' rather than 'what's wrong'.

Have now changed the sender and fuel line (for 8mm internal diameter braided hose). Someone had previously removed the sedimentor and replaced with rubber hose and jubilee clips, the rubber had seriously perished and the sender fuel connectors looked very rusty and predictably sheared whilst trying to undo.
Am awaiting some banjo's and clear hose so I can look at the engine end for air leaks (new lift pump? Filter housing?)

At this point still had the strange froth appearing out of no4 when I cracked the connector. None of the others do this. Switched engine on from cold and 'ah ha' no4 cylinder exhaust manifold very slow to heat up. So replaced no4 injector with a decent looking second hand one. Old one didn't look too bad.
Looked reasonable, smoke wise, on tickover and when I took it out there is power...oodles when the new turbo kicks in but a slight hesitation beforehand. Unfortunately there is a ridiculous cloud of white-ish smoke and this goes black when the turbo kicks in....damn also over-run on ignition switch off. So back home and crack the FIP banjo...looks ok, crack no4 again, and froth...curses

Just wondering at this point if I'm missing something, why would one port remain cold if not injector or FIP? Am I fussing too much about the air, would it be that dramatic?

Thanks for the suggestion above Gazbo, this is definitely something to look at, am also wondering if it could be the woodruff key on the crank..yikes.

Did you check the cambelt timing?

So..

Have now replaced all 4 injectors with decent looking (but untested) 2nd hand ones. Also took the time to check the pump timing which was correct with respect to the flywheel mark.

Whilst replacing the injectors took the spill return hoses off and noticed that, whilst running with the hoses off, fuel was coming FROM the IP up the spill pipe ie towards the injectors. Is this what might be expected?

Currently runs 'ok' bit of a stutter just before the turbo kicks in, plenty of oomph and smoke thereafter..wondering if I should take it down some country lanes and rag it to clear any residual carbon.

Any ideas?

Zfid said:

So..

Have now replaced all 4 injectors with decent looking (but untested) 2nd hand ones. Also took the time to check the pump timing which was correct with respect to the flywheel mark.

Whilst replacing the injectors took the spill return hoses off and noticed that, whilst running with the hoses off, fuel was coming FROM the IP up the spill pipe ie towards the injectors. Is this what might be expected?

Currently runs 'ok' bit of a stutter just before the turbo kicks in, plenty of oomph and smoke thereafter..wondering if I should take it down some country lanes and rag it to clear any residual carbon.

Any ideas?

Click to expand...

Have you done what @dieseldog69 told you to do weeks ago & do a compression test ??

White smoke to me would suggest water going down the exhaust = head gasket so down on compression
& not burning the fuel properly, then you would have black smoke for the unburnt fuel, if you've done a comp
test what was the readings.

Cheers Kev

Zfid said:

So..

Have now replaced all 4 injectors with decent looking (but untested) 2nd hand ones. Also took the time to check the pump timing which was correct with respect to the flywheel mark.

Whilst replacing the injectors took the spill return hoses off and noticed that, whilst running with the hoses off, fuel was coming FROM the IP up the spill pipe ie towards the injectors. Is this what might be expected?

Currently runs 'ok' bit of a stutter just before the turbo kicks in, plenty of oomph and smoke thereafter..wondering if I should take it down some country lanes and rag it to clear any residual carbon.

Any ideas?

Click to expand...

Have you got a boost gauge to accurately ascertain when the turbo comes on boost?

I find the stutter concerning as I do the back flow of diesel injector bound from the bleed off pipes, depending on how much fuel and what sort of pressure we are talking as to whether or not it is major cause for concern.

How was the compression test?