300Tdi revs to the max when starting - and won't settle down

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Deafening-Defender

Member
Posts
38
Trying to recommision my neglected Defender after a good many years sitting idle (the Defender... not me... well, not much).

It now starts... but it seems to want to rev to the max (and I'm not awfully keen on that - as I suspect the old timing belt may object). Had a quick look under the bonnet - and it looks (to my untrained eye) like the throttle mechanism is working OK. So... what could be causing it to rev so much? Is there something else that could be stuck?

I tried starting it about 10 times... but each time it almost instantly tried to rev itself to destruction (so - most times - I cut the ignition fairly sharpish. A couple of times I kept my fingers crossed and let it run for a short while - in the hope that it would settle down - but it didn't... it still wanted to rev its bits off).

Any advice would be most welcome. Thanks.

(I mentioned the above (new) issue at the end of my previous thread... but thought it might be useful to start a new thread on this specific problem - so it's easily searchable in the future (for anyone that has the same over-revving problem.) Hope it's OK to do that.
 
Henry_b said:
Or an injector that is stuck open..

Especially if there is crap in the system.

What is the tailpipe like?

Any smoke?
Click to expand...


Masses of smoke the first time I got it running.
Not sure about subsequent times. I'll give it another go tomorrow and observe.

The diesel is pretty old (about 10 years)... so does that qualify as 'crap in the system'?
 
Deafening-Defender said:
Masses of smoke the first time I got it running.
Not sure about subsequent times. I'll give it another go tomorrow and observe.

The diesel is pretty old (about 10 years)... so does that qualify as 'crap in the system'?
Click to expand...

Personally, I would get rid of the old diesel, modern diesel is much less stable than the old stuff, and contains a good deal of rapeseed oil, which can gum things up.
I would try new fuel, remove filter, fill the new filter with fuel and a bottle of Comma diesel magic, or a splash of petrol if you don't want to spend a couple of quid on diesel magic, then try again.
You might find that that will free up the works of the pump.
If you have a suitable space, try starting it in gear, and driving it around, the drive train and vehicle will act like a governor.
If the clutch won't separate, and you can't get out of gear, you can always just switch off at the key.
 
(copied over from your other thread when @Turboman pointed this one out to me :))

Where is the throttle quadrant ? - might be worth posting a pic up of the throttle quadrant - we can tell you if it is the right place for tickover .. though you may know this already - Does the accelerator pedal work as expected - or it is stuck down ?

It does sound like a seized governor - though it might simply be the fuel/boost pin - you should find the rebuild manual online for the Bosch VE pump - which will point you in the direction of the bits that can stick - and where to tap the pump body gently to aid release ;) - or whether, as Turboman says, above - the actual governor can be got at from outside the FIP.... .....

:)
 
Disco1BFG said:
(copied over from your other thread when @Turboman pointed this one out to me :))

Where is the throttle quadrant ? - might be worth posting a pic up of the throttle quadrant - we can tell you if it is the right place for tickover .. though you may know this already - Does the accelerator pedal work as expected - or it is stuck down ?

It does sound like a seized governor - though it might simply be the fuel/boost pin - you should find the rebuild manual online for the Bosch VE pump - which will point you in the direction of the bits that can stick - and where to tap the pump body gently to aid release ;) - or whether, as Turboman says, above - the actual governor can be got at from outside the FIP.... .....

:)
Click to expand...
Thanks for the info.
I'll get some photos up tomorrow - when there's some light.

The accelerator pedal does look like it's in a semi depressed position (However, I haven't driven the car for so many years... so I could be wrong).

(Again, sorry for starting new thread... thought it was the right thing to do! Maybe not!)
 
Turboman said:
Personally, I would get rid of the old diesel, modern diesel is much less stable than the old stuff, and contains a good deal of rapeseed oil, which can gum things up.
I would try new fuel, remove filter, fill the new filter with fuel and a bottle of Comma diesel magic, or a splash of petrol if you don't want to spend a couple of quid on diesel magic, then try again.
You might find that that will free up the works of the pump.
If you have a suitable space, try starting it in gear, and driving it around, the drive train and vehicle will act like a governor.
If the clutch won't separate, and you can't get out of gear, you can always just switch off at the key.
Click to expand...

Thanks again.

I'll get some diesel magic when the shops open again.
 
Dippypud said:
Pint of petrol is cheaper ....
Click to expand...

It is, and works well. But if you fill a fuel filter with petrol and start up, as I have done on occasions, it is recommended to leave the engine on idle while the petrol goes through the pump.

His engine doesn't idle, it revs up uncontrollably.
 
Deafening-Defender said:
Masses of smoke the first time I got it running.
Not sure about subsequent times. I'll give it another go tomorrow and observe.

The diesel is pretty old (about 10 years)... so does that qualify as 'crap in the system'?
Click to expand...

Definitely lol

You can Jerry rig something under the bonnet straight into the ip if the fuel tank is rubbish and full of mould or rust, just as a temp measure to assess further,

The fact it starts is a good thing though, the boost pin might be seized but I am not sure this would cause excess revs, but rather a lack of power when on boost (underfuelling). They tend to get stuck in the ‘not on boost position’
 
flat said:
Definitely lol

You can Jerry rig something under the bonnet straight into the up if the fuel tank is rubbish and full of mould or rust, just as a temp measure to assess further,

The fact it starts is a good thing though
Click to expand...

That is what I think too. With anything that hasn't run for ages, the main thing is to get it running, and keep it running.
 
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