Td5 Discovery Revs out of control

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Ian M in France

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france
Hi our Td5 has had a hard life, today my son was driving it with trailer on back as normal, came across a junction and engine started to rev out of control, but he turned the key off and it stopped, got there a bit later checked the oil, it was a bit low, turned the key and it ran normal, he pushed the accelerator and it started to rev out of control again, turn key off and it stopped, lots of smoke, some from under bonnet but we know the exhaust manifold is leaking again! and have one ready to go on, also lots of oil has leaked from somewhere near back of engine on exhaust manifold side, towed it home but at 40°c have not had a chance to look at it what do people think ?
 
Hi our Td5 has had a hard life, today my son was driving it with trailer on back as normal, came across a junction and engine started to rev out of control, but he turned the key off and it stopped, got there a bit later checked the oil, it was a bit low, turned the key and it ran normal, he pushed the accelerator and it started to rev out of control again, turn key off and it stopped, lots of smoke, some from under bonnet but we know the exhaust manifold is leaking again! and have one ready to go on, also lots of oil has leaked from somewhere near back of engine on exhaust manifold side, towed it home but at 40°c have not had a chance to look at it what do people think ?
Ow!
What a crying shame!
Only time I have ever heard of out of control revs is when a diesel engine is burning its own oil, or summat like it.
don't think the exhaust manifold has anything to do with it.
Cannot think offhand of anything else to say about this except good luck with sorting it out. :(:(:(
 
Ow!
What a crying shame!
Only time I have ever heard of out of control revs is when a diesel engine is burning its own oil, or summat like it.
don't think the exhaust manifold has anything to do with it.
Cannot think offhand of anything else to say about this except good luck with sorting it out. :(:(:(
That is what I thought or diesel getting down in the engine oil and then into cylinder but if that would not turn off with key I think? I have had that happen more than once and had to stall the engine, think it is to do with accelerator controller
 
Its probably because of Brexit.
Apparently everything else is, so why not this too? ;)

Good Luck, I hope it is just a simple accelerator position sensor thingy. :)
thanks, me too, Brexit might not have caused the problem but getting the bits to put it right will be harder and more expensive:(
 
There are reports on the net that 300tdi engines can destroy themselves when the turbo bearings wear and allow engine oil into the inlet.....the only way to stop carnage is to block off air supply, or somehow stall the engine. . Whatever you do I guess you need to be prepared for thiS scenario....assuming it can happen to a td5
 
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There are reports on the net that 300tdi engines can destroy themselves when the turbo bearings wear and allow engine oil into the inlet.....the only way to stop carnage is to block off air supply, or somehow stall the engine. . Whatever you do I guess you need to be prepared for thiS scenario....assuming it can happen to a td5
What I am hoping is as it turned off with the key it was diesel being sent through the injectors so the problem is not mechanical but do not know what damage it may have done
 
perhaps an injector is stuck open?
when it was turned off and back on it was okay but when accelerator pushed it carried on increasing revs but maybe one sticks but at the moment think more likely to do with accelerator but not sure
 
I would check the intake from the breather to the inlet manifold for oil, they run a little damp, just to be sure it’s not the turbo seal starting to fail or oil from the breather as the oil was a little low. Fairly simple first step probably.
Think good place to start
 
If it turned off with the key then it's not likely to be oil runaway. I would get it on diagnostics and check throttle sensor readings.
Although my first thought was oil runaway like you can not see if the key turns it off it is car is with my son at the moment and I am not there but will try and find a bit of time this week to get out the nanocom see what it says
 
I have had a runaway engine fuel rack jammed in the fully open position, you cant stop them by turning off the ignition, as its self firing, but we are talking high revs 3-4-5000, until it destroys itself, I would think it a faulty Throttle Position sensor,
 
I have had a runaway engine fuel rack jammed in the fully open position, you cant stop them by turning off the ignition, as its self firing, but we are talking high revs 3-4-5000, until it destroys itself, I would think it a faulty Throttle Position sensor,

I wonder how high a TD5 would go as they are mechanically OK to nearly 6000
 
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