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Chicken Drumstick

Help diagnose 200Tdi running issue

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Posted (edited)

So we are having issues with a 200Tdi in 90. The motor has been in the vehicle for years and has always run really well. Out of the blue it has developed two issues (which must be related).

1. Loads of smoke

2. Less power

The engine still runs super smooth, but looks like a steam train going down the road. Even on fairly light throttle loads. We are talking serious amounts of smoke. And very very black if you open the throttle. Power delivery feels very "n/a". It is smooth and pulls better at higher rpm, but overall is way down on performance of even a regular 2.5TD and nothing like it was only a few weeks back.

It "feels" like there is no turboboost reaching the engine. As you can't feel or hear the turbo kicking in at all (you can feel the surge as it boosts normally) and it is lacking the fat low end torque curve a Tdi normally has. For all intensive purposes it seems like it has way more fuel than air.

 

Things we have done so far.

  • changed turbo hoses
  • by-passed the intercooler with fresh hoses from turbo direct to intake
  • ran without the turbo connected to the intake manifold
  • checked the wastegate isn't stuck/jammed
  • swapped on a 2nd hand actuator
  • Ran an injector cleaner through it and fresh diesel

We have a Boost gauge plumbed into the vac line from the turbo to the injector pump. This is showing 10-12psi with the original actuator and just under 10psi with the swapped one.

Turbo hoses are a bit oily, more than I'd like to see normally. Especially the one coming just off of the turbo outlet. 

We have also tried running it without the turbo hooked up to the intake manifold (essentially n/a). Boost gauge showed no boost under these conditions. It did smoke slightly more and was slightly slower. But felt more like loosing 5hp rather than 40 or 50.

 

Overall I think we can rule out any of the hoses, intercooler or Vac lines. I'm not convinced it is injector or even compression related. Which leaves just the turbo assembly and the injector pump.

We'd like to swap on a new actuator to rule it out. But I can't seem to find one. The 300Tdi actuator mounts differently. Anyone know what options are available here?

Any other suggestions on how we can further the diagnosis?

Short of replacing the turbo and/or injector pump (both expensive options). I'm hoping there is something else we can try for little to moderate cost.

Thanks :) 

 

EDIT:

Forgot to say, the engine is a Discovery spec one. Not that I think it will make any odds in this circumstance.

Edited by Chicken Drumstick

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My bet would be on the pump timing having jumped a tooth or two. White smoke is unburned fuel, so you're either looking at intake restriction, lack of compression or the timing being off. In your case, as its happened all of a sudden and you've eliminated the intake stuff, you can move straight to the last two. If its running smoothly, it's unlikely to be head gasket, so timing seems a good place to start. 

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split boost diaphragm in the injector pump? quick and easy to check

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If you're getting over 10psi on boost then the wastegate isn't opening prematurely, and if the arm moves freely then I would rule that out. 

If the boost pipe is attached and diaphragm is in good nick, I'd be checking the timing belt next. 

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Are you losing engine oil level?

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Nah oil is fine. Will check the boost diaphragm on the injector pump. 

We had the head off about 2000 - 3000 miles back and all looked good (had a failed oil cooler in the rad and had emptied all its oil into the header tank. Sadly we didn’t confirm the cooler until after we had the head off. But gave us chance to check). 

Checked the turbo tonight  free spinning and no play and not as much oil as I feared there would be.

Going to see if we can get a new actuator. Re-fitted the old one but seems to be making only 5psi on the gauge now. Which is a little puzzling.

 

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Boost only works when driven, checks just revving it while stationary won't tell you if it's working under load. 

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Even if the wastegate spring has gone soft, it just means the gate opens easier, you loose boost but also the extra fueling generated by the diaphragm being depressed - you just get reduced performance - maybe a little extra smoke but not pouring out.   Anyway, if you were able to get 12psi on the turbo to pump pipe, thats over 0.8 bar which means it's working.  

 

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What wastegate are you using as a spare? Mine had a hole in the diaphragm on my 200tdi and i couldnt find a new one. Its run a 19J wastegate actor for about 5 years now. 

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Oil in the intake system is more likely to be from the engine breather than the turbo seals, so I think that's a red herring.

I wouldn't think its the timing belt, as if it has slipped/jumped, I would think the engine would be fooked mechanically by now.

Does the engine sound different ? What colour is the smoke, or does it alter ?

As has been suggested, look at the boost diaphragm, but a split or hole may be hard too see. Beware of this fault though, and you may (or may not) like to try this as a test...…..

What happens is, if the engine idles for a long time (off boost) and the diaphragm leaks, fuel from inside the injection pump gradually fills up the pipe that runs from the top of the pump to the turbo inlet housing. Then, when it reaches the top, it is sucked onto the turbo fan and vapourised, causing the engine to run away with itself with insane amounts of white smoke, and very loud diesel knock. the engine cannot be turned off with the key, and must be stalled with the clutch/gearbox, otherwise it will blow up.

The old 19j engine suffered with this a lot, and as its essentially the same setup, but with a different pump, its worth a look.

It could also be an injector. Unlikely on these, but don't rule it out.

Good luck 

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15 hours ago, smallfry said:

I wouldn't think its the timing belt, as if it has slipped/jumped, I would think the engine would be fooked mechanically by now.

One or two teeth and it will run as described with no mechanical damage.  The valve and injection timing become retarded and they smoke heavily.  The other possibility is if the pump timing bolts come loose.  It becomes heavily retarded and the fuel is injected too late producing lots of smoke.

My question on the engine oil is to do with a failed turbo turbine side seal.  This causes lots of smoke.

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On 8/6/2019 at 2:16 PM, L19MUD said:

split boost diaphragm in the injector pump? quick and easy to check

I don’t think so - that would result in the opposite fuelling problems.

 

Thick black smoke is either massive overfuelling or an induction air restriction, both give the same result of far too much fuel for the amount of air.

Check the air hoses for delamination (you’ll have to remove them), the air filter and inter cooler for blockages and the turbo spool for free rotation.  With the whole lot reassembled, check for air leaks downstream of the turbo.

Timing could be excessively retarded, but to be so bad on performance and smoke as you say, it’d be a pig to start and would sound and feel really rough.

 

 

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21 minutes ago, Red90 said:

One or two teeth and it will run as described with no mechanical damage.  The valve and injection timing become retarded and they smoke heavily.  The other possibility is if the pump timing bolts come loose.  It becomes heavily retarded and the fuel is injected too late producing lots of smoke.

My question on the engine oil is to do with a failed turbo turbine side seal.  This causes lots of smoke.

A bad turbo seal should cause blue/grey smoke rather than black.  My understanding and experience is that only a bad air-fuel ratio (too little air/too much fuel) causes black smoke, which bad timing can do by injecting the fuel before the completion of the induction process.

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enough engine oil in the intake will give black smoke although it usually happens just once ....

It does sound like fuelling issues at both ends of the scale - no power or smoke , too little fuel and lots of dark smoke , way too much fuel  . Still somewhat puzzling bearing in mind the checks/changes you have done

cheers

Steve b 

  • Haha 1

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Have you done a compression test to rule out the head gasket?

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Not done a CR test yet. It’s on the list to do. HG is only 2000 miles old though. 

 

Smoke is very thick black over fuelling diesel smoke. Not oil. And is directly related to the amount of throttle input or load. 

It is definitely a fuelling issue. Too much fuel and/or too little air. I’m just not sure which. 

Engine is known and has been great for past 40,000+ miles. This problem appeared out of the blue. 

Engine starts easy. Really well in fact. And sounds like a peach and is super smooth. It is just lacking the turbo fed torque curve it should have. It “feels” like an NA power delivery. Not like a Tdi normally does. Despite what the boost gauge is showing. 

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I'm 100% with Snagger on this one. Oil getting in to the cylinders by what ever route would be causing blue/grey smoke not black. If it were my engine, I'd be going straight to the injection pump and checking the security of the mounting of it followed by its timing. Small differences to the timing of the injection pump can have profound effects on general running and performance of the engine, not to mention smoke either clouds of white smoke that sting your eyes (unburnt diesel) or thick black smoke from incomplete combustion (particles of carbon). 

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To echo what Mike and Snagger said: Injecting fuel way after tdc makes hideous black smoke as the cylinder pressure isn't high enough and the charge isn't dense enough to burn the fuel completely. The net result is similar to a restriction in the intake. 

If I recall correctly, the pulley isn't keyed to the pump and relies purely on the taper fit to maintain the timing, so that slipping is also an option. 

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Easy starting is associated with retarded injection, and while that reduces performance, it results in a smoother engine and white smoke, not black.  Unless the injection pump or the sprocket are floating and the timing changing between start and running, I don’t think it’s a timing fault.

Bad injectors could do it as the engine over fuels to compensate for poor spray pattern and slower, less complete burn.  The turbo would mix the output from each cylinder to a point, so it could look relatively continuous even with one bad injector.  A good dose of injector cleaner is worth a try on the off chance, but I suspect it’s something on the air induction side.

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It would explain the excessive smoke, but not the lack of performance.  It’s getting the fuel, but isn’t getting the air.

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When you say 'steam train' I think white smoke?, only turning black when you boot it, ? just wonder if its worth checking the valve caps/clearances????

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