BX turbo diesel seriously ill

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freek
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BX turbo diesel seriously ill

Post by freek »

Hi,
This evening after driving 20 km on the highway my BX turbo diesel suddenly lacks power. It reaches at most 100 km/hr and accellerates very very slowly. At low speed blue smoke is produced, most when slowing down. Furthermore the idle speed is somewhat unevenly. A look under the bonnet shows no obvious faults: the turbo and fuel hoses are in place and there are no oil leaks. The engine seems more quiet than usual. In the past I reported the following problems on this forum: a few weeks ago I had air in the fuel system (which was solved) and some months ago at more than 120 km/hr the warning light for the turbo pressure burned. This is not solved, but when driving in Germany for 1000 km the moment when the light apeared changed to app. 150 km/hr, so it was not that serious anymore. For this I thought about a faulty sensor or a faulty waste gate. Could it be that the problem I experenced today has to do with that? Is it possible that my turbo (or waste gate) has died without any signs of oil leakage? Or could there be something wrong with my Roto diesel pump? Please give me some hints how to sort this out!
Regards,
Freek
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Kowalski
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Post by Kowalski »

The boost light coming on is a sign of a wastegate sticking which would mean your turbo could have been running too fast. It might have killed itself but I think that unlikely because when turbos die they either become very noisy or go with a fairly big bang. Could the wastegate be sticking closed limiting your boost pressure to some very low amount?
The other thing that can cause a power loss is if either the boost pipe to the fuel pump isnt' connected (or leaking) or the diaphragm in the pump has split. Either of these two faults will stop "extra" fueling being available when the turbo boost comes in, but since you've got smoke neither of these two would cause smoking.
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Post by ghostrider »

If the blue smoke is on the over run, it could be some sort of piston ring problem,which means oil in the exhaust and getting burned onto the turbo shaft, which in extreme cases if I understand correctly can cause seal failure and lack of boost. A compression test should be able to tell if there is a ring problem
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jeremy
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Post by jeremy »

Sounds as though this could be a serious mechanical problem like piston rings - but if there is a piston problem there will be a huge amount of crankcase fuming - take the filler cap off and if it chokes you - then its a ring problem. Oil will also come out of everywhere due to the excess crankcase pressure!
If its not a piston problem I think the interesting bit is that its running unevenly. Blue smoke suggests lubricating oil and uneven running suggests a cylinder problem rather than a turbo problem which is why I suggested a piston problem.
I suppose the next step is to try and judge the compressions - use the stop lever on the Roto-Diesel pump and wedge it open and then operate the starter and see if it seems even or if one or even 2 cylinders are 'missing'
I had a head gasket fail between 2 cyinders but after a couple of miles of bad running (getting worse) which enabled me to get home it could only be started with extreme difficulty.
Let us know how you get on
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Post by AndersDK »

The blue smoke is engine oil getting burnt in the combustion process. This will not be caused by lack of turbo pressure. Unless you have a genuine engine run-away (it runs on the engine oil alone).
As I read your symptoms you either have what Kowalski explains - or a simple split hose to the overfuelling device on the rotopump.
On my TRDturbo there is a rather long small dia hose running from the intercooler tap down to under the battery where the overpressure boost sensor switch is located. It's rather difficult to check this hose without removing the battery.
My suggestion is you check all these small hoses as the rubber may look perfect but be brittle and split as soon as you touch it.
Another simple test would be to remove the large braided hose coming up from turbo to the intercooler. It's rather easy to check if you have any air pressure from the turbo if you pull the acc cable while engine is idling.
Hope this gives you some roadsigns in your faultfinding jungle [:p]
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Post by jeremy »

Anders - I know the little hose you mean. If it falls off all that happens is that you loose some of the extra fuel required for maximum power - so the engine just feels a little underpower. The hose can be replaced without removing anything (As you can probably guess mine rotted and I replaced it a couple of weeks ago)
Jeremy
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Post by freek »

Goodmorning,
I'm now at the office so I have to wait until this evening, but your answers make me curious! I hope Anders is right. When searching for the boost light problem in march I looked at the switch underneath the battery. Then I noticed that the hose was quite loose and used a tyrap. It is indeed possible that the hose fell off (which is hard to see). For the blue smoke I reported: when running in my garage it smelled very much like burned diesel and not as burned oil (and dieselsmoke can be blue as well). I desperately hope that the crankcase test is negative. I will keep you guys informed!
Freek
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Post by citronut »

always look at leser things before you go getting all complicated and expensive regards malcolm
freek
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Post by freek »

Goodevening,
Well I visited the patient and I did some checks. The little hose to the boost switch is part of a hose which connects the intercooler with the overfuelling device on the pump. The hose is o.k. as well as the connections. When trying to start (now from cold) the engine reacts instantly but now and then with unstable rpms and dies a few seconds later whatever you try. By playing with the accelerator you can run it for a few seconds more but with a lot of smoke (it looks like it chokes). I think now that the turbo has nothing to do with it nor do I think of a compression problem. Could it be that the electromagnetic timing device or the overfuelling device are defect? The powersupply to the electromagnetic timing device seems o.k. though.
Best regards, Freek
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Post by jeremy »

I don't think the electromagnetic timing device does much on these engines except reduce smoke on startup. Earlier versions of the pump didn't have it and simply used the cable to the switch to open the throttle a bit when cold.
The extra fuel device doesn't seem to give many problems from postings on here. Its function is to respond to inlet pressure and increase the fuelling appropriately.
From what you are now saying it sounds to me like more air problems or altenatively there is a possibility that the stop solenoid itself isn't opening properly. If the engine is misfiring due to an inadequate charge the unburnt fuel will collect and either be partially burnt (black smoke) or ejected as vapour (white smoke)
Jeremy
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Post by vanny »

might want to try checking the fuel filter as well, its possible that there is dirt getting into the engine, probably wouldn't stop it smoking as you describe, but could be the reason why it wont idle!
freek
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Post by freek »

On 27 july 2003 there was a post from Bernie who complained about a lack of power on his BX turbo diesel. One reply said ' Assuming of course that air filter is OK, and all the hoses are on, EVERY one of these that i have ever had in my workshop with this problem has had a rotodiesel pump with a burst diaphragm on the boost/fuel device.'. Unfortunately this was not the cause of his problem, but obviously this is a 'normal' problem of these pumps. But according to you Jeremy this does not fit to my problem.
Freek
freek
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Post by freek »

Dear all,
Sad news: I have found the cause; Looking underneath the car I saw diesel on the garage floor just underneath the cam belt. Because there are no obvious leaks it should be the bearing of the pump which has died. I now have to decide what to do: changing the engine for a 'fresh' one or just replacing the pump. Depending on what I will find the difference in costs can be marginal...
regards,
Freek
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Post by Kowalski »

The bearing failing seems fairly common on the Lucas (Roto-Diesel) pump. If the engine is sound apart from the pump i.e. starts and runs OK, I'd be tempted to just swap the pump over, it won't be too bad a job. If the engine is very high mileage and worn you could swap engines over, but I'd be loath to throw away an engine if I knew there was nothing wrong with it.
The biggest cost is going to be the labour, if you can do it yourself it'll work out cheaper to swap just the pump, if somebody else is doing the job, the cost won't be much different (either way it'll be blooming expensive).
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Post by jeremy »

May be worth enquiring of a diesel specialist how much it would cost to change the seal and bearing on your own pump. These things can be fully overhauled and there is a whole industry working with them and in my experience some are not hugely expensive. If you can do it you may be able to take the pump off yourself and deliver it to them to save the cost of dismantling.
Jeremy
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