200tdi loss of power

[Diablo]

Hi there, had a search, but nothing really matches my issue.

I have a 1985 90, with a 200tdi in it. It has been converted [properly, using a smartveg system] to use veg oil.

For the last few months [been on veg oil for almost a year now], when I sit in a traffic jam or similar for more than a minute or two, a puff of white smoke [with maybe a hint of blue] comes out. This only happens on veg oil, not diesel.

As well as this, I have experience a loss of oomph from the engine. Previously I could manage a cruising speed of 75/80, now it is more like 65/70, and if there's any sort of hill, this drops to 55/60. This is on both diesel and veg.

I asked on a veg oil forum, and they said this often happens with old injectors. So I took them out and the local diesel injector man had a look at them, and said that they were fine. I put them back in and now it appears to have slightly less power than before!

Have also taken out the air filter [only a few months old], to check the air hoses are clear, and they are. There is a small amount of oil in the turbo pipe, more than I'd expect. Could this be the/a problem? Not noticed any odd noises from the turbo before.

Any ideas as to what it is/where to go next?

[scube]

You don’t mention anything about changing the fuel filter..

I’m no expert in Diesels or Veg power for that matter. However when I owned a diesel I found it loved a clean fuel filter.

I have read that veg power clogs up the fuel filter though I would of expected that problem to of cleared up after a years driving

[Diablo]

Both fuels have their own filter, so I wouldn't have thought that would cause this problem. The veg filter [which uses the original one] was changed at the weekend too, with a Bosch filter, as a 'just in case it's that' measure.

[Aragorn]

i'm only guessing here, but when diesels are idling they tend to cool down, perhaps the heat exchanger isnt quite heating the veg oil enough in this state, causing the white smoke (unburned fuel)

Does the heat exchanger have any sort of electrical assistance? or is it solely run from the cooling system?

As for the lack of performance, as it exists on both fuels i'd ignore the veg oil and treat it like any normal diesel engine.

Check for boost leaks, clean the intercooler and check the turbo wastegate is free. Might also be an idea to install a boost pressure gauge to see whats going on.

[Diablo]

The heat exchanger is purely run from the cooling system. And I don't think that there would be enough time for it to cool down in a minute? Could be wrong there of course.

Had been thinking of the boost gauge before, perhaps this is the excuse to fit one...

[jimmy_neutron]

Hi ...

The answer to the smoke after sitting in traffic a while is .. 'They do'. I tried to work out why but gave up, so if you do ever work it out then i'll be very interested.

I do long journeys and very rarely stuck in traffic so it doesn't really bother me that much.

1) It seems worse when its dark and theres car headlights behind

2) The longer you sit at idle the worse the puff of white smoke

3) If you sit at idle for long enough then a bit of smoke will develop then big puff when acelerating away.

4) Starts to build with no turbo boost.

5) Starts to clear slowly (small amount of smoke for an extended period) with a small amount of turbo boost.

6) Clears in one large plume with 1 bar boost.

My thoughts on the matter ..

1) Oil attracts water so if leaving veg oil stored for a while, it will absorb water like a sponge especially if you use an ibex container. This can be seen when you change the oil in your chip pan and first heat it up. There are always some bubbles etc which is the water releasing from the oil. This also happens in your engine and could be part of the smoke problem.

2) You are running a smartveg system which is nearly as good as mine so any changes in the characteristics of your driving will have a large effect. Meaning if you were doing realitively short runs then the % of diesel in your veg tank will be increased due to the amount of time the system was on 'flush to tank'. If you suddenly change to longer runs then the % of diesel will be much less.

3) From above make sure you don't run at a greater concentration than 80% veg and 20% diesel and this will help.

4) There is an additive that you can put in your veg which will help with its cetane value http://www.vegetableoildiesel.co.uk/veggiboost.html This is also available on ebay.

5) If your injector pump setup isn't correct or you have tampered with it to give your truck more oomph (Like mine B) ) then this may also be part of the cause. When adjusting the pump, the first thing you will have probably done is turn the cone thing 45 to 90 degrees. This is reasonable only if you back off the idle mixture on the top lid. Failure to do this will cause a rich mixture, smokey on veg, and if really bad will cause bad dash board vibrations at tick over.

6) The other likely cause is the distance that the fuel has to go from the heat exchanger to getting burnt. Its all the way from the heat exchanger through the fuel pipe, through the fuel pump, then through them long metal pipes up the side of the engine. At tick over the fuel delivery rate is very slow so therefore cools alot more. Again thinning to 80/20 or 75/25 will help this. One test i was going to do with this is monitor the return fuel temperature. However i lost interest as i did the things mentioned above.

Other thing to do is get a 4 tank redex diesel treatment and run it through the veg tank for then next few fill ups.

[reb78]

Change the lift pump - that may well improve the top end - it worked on mine and is cheap and easy to try first. I reckon these fail more often than people think and are not considered often as we all think they should last longer than they do (longevity of this part will depend on the quality of the part previously fitted)

[TheRecklessEngineer]

i'm only guessing here, but when diesels are idling they tend to cool down, perhaps the heat exchanger isnt quite heating the veg oil enough in this state, causing the white smoke (unburned fuel)

A common misconception. A HX merely lowers the viscosity of veggy which allows it to be pumped more easily (or in the case of a Lucas pump, stops the pump self destructing). When injected into the cylinder the veggy will be at the temperature of the injector ('ing hot!).

AFIAK, white smoke is caused by the cylinder temperature decreasing under idle. Fuel condenses in the cylinder rather than burning as a side effect of a DI engine- this results in white smoke. When the cylinder temperature increases again, the white smoke will clear (under load and boost). For this reason, if sat at idle for a while it is generally wise to switch back to diesel.

As far as the loss of power is concerned - I suggest you look towards the possible problems mentioned in this thread before looking at the veggy system. It might be worth checking how heavily the engine is breathing - it isn't unheard of for veg to gum piston rings.

[Diablo]

@james: correct with the ring gumming, though it shouldn't happen with a twin tank system. If I was just chucking it in the tank or mixing it, then I'd expect this. Interesting what you say about the cylinder temps, don't know masses about diesels. I also agree with the switching over if idle for a prolonged period, but still wouldn't expect 30secs to one minute to puff out smoke.

@reb: the lift pump only pumps the veg oil, so I'm ruling that out at the minute.

@jimmy: what I've read, from those who have been doing this for years, is that this smoking issue we experience often occurs when using injectors that have done more than 60k. He suggests a full service and new nozzles. When I had them checked at the weekend the bloke said they were fine. But perhaps it's worth a second opinion?

Redex probably isn't a bad idea. Next time I'm passing Halfrauds...

[howard14]

Hi ...

The answer to the smoke after sitting in traffic a while is .. 'They do'. I tried to work out why but gave up, so if you do ever work it out then i'll be very interested.

I do long journeys and very rarely stuck in traffic so it doesn't really bother me that much.

1) It seems worse when its dark and theres car headlights behind

2) The longer you sit at idle the worse the puff of white smoke

3) If you sit at idle for long enough then a bit of smoke will develop then big puff when acelerating away.

4) Starts to build with no turbo boost.

5) Starts to clear slowly (small amount of smoke for an extended period) with a small amount of turbo boost.

6) Clears in one large plume with 1 bar boost.

My thoughts on the matter ..

1) Oil attracts water so if leaving veg oil stored for a while, it will absorb water like a sponge especially if you use an ibex container. This can be seen when you change the oil in your chip pan and first heat it up. There are always some bubbles etc which is the water releasing from the oil. This also happens in your engine and could be part of the smoke problem.

2) You are running a smartveg system which is nearly as good as mine so any changes in the characteristics of your driving will have a large effect. Meaning if you were doing realitively short runs then the % of diesel in your veg tank will be increased due to the amount of time the system was on 'flush to tank'. If you suddenly change to longer runs then the % of diesel will be much less.

3) From above make sure you don't run at a greater concentration than 80% veg and 20% diesel and this will help.

4) There is an additive that you can put in your veg which will help with its cetane value http://www.vegetableoildiesel.co.uk/veggiboost.html This is also available on ebay.

5) If your injector pump setup isn't correct or you have tampered with it to give your truck more oomph (Like mine B) ) then this may also be part of the cause. When adjusting the pump, the first thing you will have probably done is turn the cone thing 45 to 90 degrees. This is reasonable only if you back off the idle mixture on the top lid. Failure to do this will cause a rich mixture, smokey on veg, and if really bad will cause bad dash board vibrations at tick over.

6) The other likely cause is the distance that the fuel has to go from the heat exchanger to getting burnt. Its all the way from the heat exchanger through the fuel pipe, through the fuel pump, then through them long metal pipes up the side of the engine. At tick over the fuel delivery rate is very slow so therefore cools alot more. Again thinning to 80/20 or 75/25 will help this. One test i was going to do with this is monitor the return fuel temperature. However i lost interest as i did the things mentioned above.

Other thing to do is get a 4 tank redex diesel treatment and run it through the veg tank for then next few fill ups.

I have seen the night-time car-headlight/smoke effect with normal diesel exaust.

I belive it is because of the narrow wavlength of the light emitted from the following car's headlamps (Maybe H.I.D.s).

I also belive that it's not just a matter of the smoke, but of the normally invisable exhaust gases (maybe carbon dioxide) refracting, or absorbing, the visible light.

So it maybe the distorted light we are seeing, rather than extra smoke.

I dont realy know for sure, but I think this maybe how 'gas-cromatography' works.

I'm prepared to be knocked down on this, but I would like to know a bit more about it.

Howard.

[jimmy_neutron]

I had a bit of a play this morning to remind myself of this issue ...

I've got a full set of guages which helps a bit.

Sitting at idle it starts white smoking after a few minutes.

Also can start smoking if driving in 3rd gear at 20mph which is about 1500rpm and 0.05bar boost in mine. At this the bar on the side of the turbo has not started to move. As soon as i creep up the to about 0.18 bar the smoke slowly starts to appear. If i hit the throttle to get a sudden say 0.6bar then i get a quick plume and the smoke is all oer and done with.

I honestly do believe that its to do with a small amount of unburnt fuel residue reaching the turbo/exhaust (fairly normal with engines in general anyway). With no boost only a trickle of exhaust gas will go into the compessor and may cause a condensing buildup. When increasing the boost (allowing more exhaust gas to be diverted from the exhaust to the turbo compressor via the wastegate then this buildup will be vapourised and hense released as white smoke out of the exhaust.

I seem to remember coming to this conclusion last time i looked at it and therefore just ignored it as i don't sit in traffic often.

[Aragorn]

With no boost only a trickle of exhaust gas will go into the compessor and may cause a condensing buildup. When increasing the boost (allowing more exhaust gas to be diverted from the exhaust to the turbo compressor via the wastegate then this buildup will be vapourised and hense released as white smoke out of the exhaust.

All the gas flows thru the turbine, until the wastegate opens, and it only opens once you've reached your desired pressure. The wastegate is a bypass valve, which allows the exhaust flow to bypass the turbine once the turbo is producing the desired boost pressure.

Its more likely happening inside the cylinder itself, rather than fuel reaching the turbo. When you give it more throttle, the cylinder temps start to increase and the fuel sitting around in the cylinder thats not been burned properly gets shifted out the cylinder by the higher gas flow/temperature etc.

Its this effect that causes the gumming of piston rings with veg oil. The fuel doesnt burn cleanly, as its more viscous and the injector cant properly atomise it as it can with diesel. The badly atomised fuel ends up sticking to the cylinder walls, gets into the rings, and gums them up.

The point of the heat exhanger is to ensure the veg oil is less viscous when it reaches the injector, so it atomises better and burns properly, and this is why the twin tank setups are designed to start the motor on diesel for proper atomisation when the engine is cold, then once its warm enough, it switches over to the veg.

[jimmy_neutron]

Hi there, had a search, but nothing really matches my issue.

I have a 1985 90, with a 200tdi in it. It has been converted [properly, using a smartveg system] to use veg oil.

For the last few months [been on veg oil for almost a year now], when I sit in a traffic jam or similar for more than a minute or two, a puff of white smoke [with maybe a hint of blue] comes out. This only happens on veg oil, not diesel.

As well as this, I have experience a loss of oomph from the engine. Previously I could manage a cruising speed of 75/80, now it is more like 65/70, and if there's any sort of hill, this drops to 55/60. This is on both diesel and veg.

I asked on a veg oil forum, and they said this often happens with old injectors. So I took them out and the local diesel injector man had a look at them, and said that they were fine. I put them back in and now it appears to have slightly less power than before!

Have also taken out the air filter [only a few months old], to check the air hoses are clear, and they are. There is a small amount of oil in the turbo pipe, more than I'd expect. Could this be the/a problem? Not noticed any odd noises from the turbo before.

Any ideas as to what it is/where to go next?

Think i have just sorted mine

My water pump started to leak badly 2 days ago so i ordered a new one from beamends. When it came it was a britpart one but looked suprisingly ok.

Fitted it this morning and heater is now like toasty and my veg oil temp is now warmer and more importantly the temp does not drop off when at idle and thus does not seem to start smoking after ticking over for a few mins. Not done any proper tests but its looking good so far.

Incidently the water pump that i removed was one that i bought from paddocks a couple of years ago. There was a 3mm gap between the pump paddle wheel and the front face. (was like this when i bought it but semmed to work so i wasn't upset by it). The new one from beam ends is much better made and there is next to no gap between the paddle wheel and face. Thus better pumping at low revs to keep the Heat exchanger hot.

[Diablo]

Hope you're engine hasn't been gummed up because of that poor heating then!

Had a decent drive today and got no smoke whatsoever. Not a thorough test as there weren't any major traffic jams, but I usually see the odd puff.

Still think I'm going to get a proper Bosch place to service them and whack some new nozzles on though. Even if it's £200 I probably save that every few weeks/months.

[Diablo]

Had a good few sits in traffic jams yesterday and no smoke! Hurrah. Clearly that free clean did the trick [temporarily at least!].

So I guess the power issue is related to the turbo or something... It does seem to be kicking in later than usual

[Phil Hancock]

3mm gap between impellor and casing!!! the spec on a 2.25 pump is 0.5mm to 0.63mm clearance.