TD4 Engine knock and black smoke

I tried this post previously, but it got sent to moderation and didn't post. Having a second attempt. Mods, if the first attempt reappears, please delete it.

Hi all,

I've been using these forums for a year or so, but these are my first few posts.

Previously I've been able to find answers to my questions without needing to post, using the wealth of knowledge on here, but I've searched a lot over the past few days and not found any posts that exactly match my current problem.

I have a 2002 Freelander 1, TD4 Auto.

I currently have an engine knock problem. The car was in a garage but they weren't able to fix it before the Christmas holidays so its now back at home with me.

The knock sounds like a diesel knock, and I also have black and possibly some white smoke.

I've been trying a few different things to nail down the problem and am now fairly stuck. These have all been gleaned from posts on here.

I'm probably repeating a load of things the garage has done already. They were also struggling to diagnose the cause and wanted to remove the head for inspection.

Rather than send the car in for unplanned diagnostic work, I'd like to have a good idea what needs doing before the car goes back to the mechanic.

So far I have:
Completely unplugged the Synergy 2 from the fuel sensor and MAF and reconnected the original sensor harness.
Unplugged each injector individually, engine misfires as each injector is unplugged, but knock is always present.
Checked the connections of all engine sensors, ok
Checked the wiring to the fuel pressure sensor, ok.
Crankcase breather has just been replaced with a new BMW cyclone breather so not blocked.
Tested the fuel sensor voltages using the info in this thread. http://www.landyzone.co.uk/lz/f9/td4-fuel-pressure-problem-help-83679.html
All ok, voltage readings match the values in post 10.

Todays work:
Removed the injectors and the camshaft cover for visual inspection. All looked ok, but traces of sealant of some kind in the injector bore of number 3. The sealant won't wipe out.
Checked and cleaned the copper sealing washers on all injectors.
Replaced the number 3 injector that was missing the top sealing O ring with a refurbished LR unit from Rimmer Bros that matches the other 3 injectors.

Added injector cleaner to tank in case dirt was present.

On start up, knock still present.
Unplugged each injector in turn, knock always there.
When the connection to number 3 is unplugged, black smoke goes away and can't see any white smoke. (Number 3 has new injector) Some white smoke and black smoke when unplugging the other injectors.

Swapped number 3 and 4 injectors over and repeated injector unplug test. Problem is still with number 3, unplugging the injector stops the black smoke, so the problem is not the injector.

Finally, continuity tested the wiring to number 3 injector, while moving the connector about. No problems, wiring tests as good.

Unplugging the maf makes no difference to anything.
All intercooler hoses are good, with no obvious holes.

I am now stuck and would be grateful for any suggestions. My theories at the moment are fuel system or something in number 3 cylinder.

I've looked at the head removal procedure on RAVE and think this is probably beyond my skillset, plus I don't have the crank and camshaft locking tools. I really don't want to shell out to have the head taken off if this is a fuel system problem.

I have found a local common rail diesel specialist who can do a leakback test early next year and probably a full check of the fuel system. Does this sound like a sensible plan or is there anything else I can try myself over the next few days?

Thanks for any and all suggestions and Happy New Year to all.

Simon

you sure it's a diesel knock and not the crankshaft damper?

the smoke could be a separate issue..

was the sealent type a black colour if so this might be desiel gone solid that has escaped as the injector was not tightened down enough you need to clean it all out and try to clean where the injectors sits if it is not sitting down enough it will make a light tapping sound as air is being pushed pass it I had this trouble took me a day of getting the old solid desiel out very very carefully hope this helps

my diesel knock (pinking) has completely gone since I started using 2 stroke oil, absolutely purrs now

Thanks for the replies.

No I'm not sure about anything any more. How can I tell the difference between diesel knock and crankshaft damper?

I was thinking diesel knock as that was the last area of the engine that was disturbed when it went into the garage. The camshaft cover was removed so all the injectors came out, when it was put back together it was fine for a while then the knocking noise started as the engine was idling.

The sealant was a black colour, I initially thought it was diesel leaking but the garage told me it was sealant. The noise is not a tapping though more a solid knock, you can hear it clearly inside with all doors and windows cold.

How did you clean out the injector bore without all the sealant falling into the cylinder?

Just an update

I've searched the forum for crankshaft damper issues and inspected mine.

It looks different to some of the photos as my car has A/C so I have two belts on the crankshaft pulley. No sign of the belts contacting the splash guard and no marks I can see on the pulley.

I've done a little bit of driving as well.

The knock noise increases with engine revs and doesn't vary under acceleration, the faster the engine is turning, the faster the frequency of the knocks. The knocks don't seem to match the engine revs when you lift off the throttle and let the car slow down with engine braking only, which is what originally made me suspect fuel system as the cause. My assumption is that the engine doesn't inject fuel as often on the overrun, so if the knocks are related to the injectors they don't happen as much.

Does this sound like I am on the right track?

I put a bolt down and the carefully cleaned with a long thin screw drive not scraching the sides although this would not matter then I pulled the bolt out after I had put the hoover nosle down and finished the bottom and then got the hoover and the tube on the hoover was just a nice tight fit and left it on for about 5 mins and just hoped that all the bits were out I can not see why sealent should be down there unless they put some on the injectors which is a big no but some people will hope this helps

Great, I'll give it a try.

Maybe if I can get the black goo out the injector will seat properly which may sort the black smoke issue.

Thanks!

There's no logical reason to use sealant on an injector.

Any blow by on a cylinder will make that cylinder overfuel whatever injector is in place.

You can test with soapy water.

If you find there is blow by you could try a new annealed copper washer, if that doesn't work you will probably need to recut the seat.

Have a look for "glitter" around the crankshaft pulley too, my woodruff ended its life like this and the dampered pulley was knocking like mad, got louder with engine revs, but quiet under braking, ie no load on the engine. Smoke might be the intake hoses,like mine was. while its all off clean right up. Also when i spayed wd40 on the crank pulley area, the knocking stopped completly for a bit.

teddywood1 said:

was the sealent type a black colour if so this might be desiel gone solid that has escaped as the injector was not tightened down enough you need to clean it all out and try to clean where the injectors sits if it is not sitting down enough it will make a light tapping sound as air is being pushed pass it I had this trouble took me a day of getting the old solid desiel out very very carefully hope this helps

Click to expand...

How did you get it out? I have had an injector tube full of hard diesel and it is really difficult to clean out well.

when doing this job make sure you do not over tighten the 2 little bolts on the each side of the injector - one each side they are about £25 each and a devil to get out

Just an update after some time with the car today.

Have checked the crankshaft pulley again for glitter, no signs of that.

I have a couple of photos I can post once I've worked out how to get them hosted.

I removed number 3 and 4 injectors again. While cleaning the sealant/solid diesel from the bore of number 3 injector, I realised that a copper washer was still at the base of the bore, which would prevent the injector sealing.

As it couldn't get it out, I removed the washer from the number 3 injector and finished cleaning the top surface of the washer and the chamfer in the bore. Once it was all back together, no more smoke!

The hoover down the bore idea worked really well, good tip.

When refitting I gently tapped down the saddles of the injectors to get them to seat properly. Made refiting much easier.

Unfortunately, the original knock is still there, so I will be getting the injectors tested asap next week.

great on getting that sorted is it a heavy knock or light

Its a light knock, but solid. Not light and tappety.

Doesn't sound like bottom end.

I haven't been able to narrow it down to a single cylinder using the "screwdriver in the ear method" but it does sound like its at the top of the engine.

Had the fuel injection system checked today. The system tested as all ok, no blockages in the injectors and everything working well for the age of the engine.

This is not good news, as that leaves mechanical as the only possible cause of the knocking noise, and the only way to fix it is to start stripping the engine. The alternative is a replacement engine. Either way looks like big bills.

Has anyone taken the head off a TD4 without the special landrover tools mentioned in RAVE? I'd like to at least look at the engine before I spend a lot of money on a replacement lump.

Thanks for any and all suggestions...

Could it be a hydraulic tappet? Try pouring some special hydraulic tappet cleaner through it - I found it improved the sound of my engine.

I was going to say that next it might be tappets I would go for a compleat engin flush there may be bits around that are either stoping one tapet getting its oil or the bit is stuck on the tappet head probably you would not see with the naked eye
hope this helps

Thanks for the replies.

Sorry, should have mentioned in my earlier post, that the diesel mechanic said that the noise definitely didnt sound like tappets. He thought the noise was more mid engine, not big ends, maybe a piston pin.

The noise can be heard when you drive the car with all the windows closed. I dont have enough experience to be sure, but I thought tappets were fairly quiet and can't always be heard inside the car.

Currently planning on a replacement engine, as the cost to get the engine stripped means it isnt viable. Taking the engine apart I could do, but getting it back together and working is probably beyond what i can do and I don't have the cam alignment tools. Had a good read of the BMW TIS for this engine on the web last night. It looks rather tricky.

Rather than getting a new / replacement engine right away I would be paying a visit to a BMW agent. Don't tell the receptionist anything other than you want to speak to the workshop manager.

The workshop guys are usually pretty decent types - who live in the real world. It's the salesmen with the smart suits that need to be avoided.

I would tell them you have a BMW M47 engine and ask for a couple of minutes of the workshop foreman's time just to listen to your engine and get the benefit of his great knowledge and years of experience. The M47 is one of the most popular engines BMW have made - well over a million of them!

They like to hear that 'knowledge & experience' kind of thing - ha ha. I know - I've picked their brains for a few things over the years - they're nice enough guys in my experience.

You've nothing to lose - possibly your engine will rumble on for years yet.

Good luck, Singvogel.