3L black smoke under load (94 LN106 2.8D)

[Old n Slow]

Hi All 😁

I have a 94 LN106 with the 2.8D 3L non turbo engine - my cars only done 156k, the engine was replaced 10yrs ago at 149k and it has only covered 7k since. The car spent  the last 10yrs garaged after its previous owner fell ill, sadly he recently passed away and the car was put up for sale, I bought it a couple of months ago.

She was running perfectly well, until last week. I had to have the fuel lines changed as they had perished, I also decided to have the timing belt and water pump done at the same time.

I picked her up from the mechanic after the work was done and all seemed good. Next day I drove her on the freeway and noticed a decent amount of black smoke when under load (constant). I’m 100% certain it wasn’t doing it before the work. 

I took it back to the mechanic for them to double check the timing and no issues found. They checked the valve clearance, they are out so I’m having new shims put in to adjust back to spec...

I have my fingers crossed that this will resolve the problem but if it doesn’t where next? 

I thought maybe fuel pump (over fuelling?) but there was no hesitation when driving and no recent adjustments. 

Id really appreciate any advice anyone can offer, it seems odd that it’s happened after the work was done but she’s literally been sat still for 10yrs so anything could happen! 😉

Thanks in advance! 

[campbeam]

Never had a diesel so the following is based upon a Google search.

Following article suggest a few cuases e.g. dirty air filter, not using the right engine oil, over-fuelling due to worn fuel injectors.

https://www.lubrizoladditives360.com/black-smoke-cause-impact-and-prevention/

[Ndeb]

Hi there,

As you said valves out that you got fixed doesn't fix smoke.

But fuel lines has perished depends what you mean. If old rubber from lines

or pieces of metal got into the fuel pump that will make your engine smoke like hell mate.

Look at how clean your fuel is to run is one good thing to do. Your are looking at replacing the fuel

filter first, before you pull the Injectors and then the fuel pump out. The reason is fine bits can easily block the injectors fine holes.

But I will get it diagnosed properly step by step to a diesel workshop.

In case you need some good advise on fuel issues look up to www.cornells.com.au

Good luck!!

Noel

 

[Old n Slow]

Thanks guys, it was the rubber fuel lines so there’s a chance of contamination - I will keep you posted as we progress! 

[GC_AUS]

Steve,

You’ve done the right thing certainly with the timing belt & valves.

 

Do the obvious things first - IE: sitting around for 10 years = all the crud that was in the tank has gone through the system to the filters or to the pump &  injectors if it got past the filter.

My guess is the filter will be clogged with gunk out of the tank. Diesel grows mildew over time when sitting so this cloggs filters real quick once its shaken up.

 

1.       Drain tank & fresh fuel (you have probably done this by driving it)

2.       Replace all filters = fuel, air -  assuming you changed the oil & filter already.

3.       Run a decent quality tank cleaner & injector cleaner through  & then replace the fuel filters again. This might sound excessive but a set of filters is cheap compared to injectors or pump.

                                The Liqui moly diesel purge is a good product - there are others of course. See here = https://youtu.be/Bgg3Y2vzWes  - add to the filter when changing. - a good set of instructions here - https://liqui-moly.com.au/how-to-clean-your-diesel-fuel-system/  - ( I have no affiliation with liquimoly so use whatever brand you like the look of)

 

Once you know the air, fuel & oil is all getting to the engine clean go for a drive & give it a bit! - diesels like to work so being driven soft with no load will create glazed bores & smoke. A good hot work out will usually get a smoky motor running clean again but don’t thrash it until you are sure you can do so safely.

 

It’s a simple elimination process = clean fuel, air, oil & if its still bad then start investigating the pump & injectors.

rgds G.

[Old n Slow]

Thanks G - Will give that a go this week 👍

[Old n Slow]

Okay.... hopefully this is the final installment!

Firstly I have to say a massive thank-you to West Coast Automotive Repairs in Wangara, Western Australia. They have been absolutely fantastic and have managed to get my old Lux sorted. 

So... after the timing and valves were done the smoke was unfortunately still there, next came new injectors and still she smoked. Last resort, Dyno and fuel adjustment. This did the trick and my old car was much improved so I collected her and drove her home. Unfortunately this isn't the end of the story...

Later that same day I went out to the car and noticed liquid on the ground under the engine, I thought it was probably water from the air-con I had running earlier in the day but checked it anyway. Sadly it was oil, and a lot of oil at that. I managed to limp the car back to West Coast for a diagnosis, hoping that it was perhaps something not done up properly after the recent work. Unfortunately this wasn't the case and a failed head gasket was identified.

West Coast took the engine apart (again) and here's where my luck changed! The damage wasn't terminal, the head was checked, confirmed as good (after a little leveling). A new gasket fitted and she lives again! (this is a much shorter version of the story of course).

Now she's back home, just in time for Summer beach runs!

:)