Thread: Measures to combat a runaway diesel engine

What has you concerned about engine runaway? It's quite rare. Do you have some extreme modifications or existing problems that increase the chance of it happening?

I had an air cut-off system on my D2a when I had it. I had the EGR butterfly valve solenoid wired directly to a (fused) 12V supply that was operated by a red button switch mounted in a dash switch blank and also operated electronically if engine oil pressure was lost to cater for a roll-over.

I used the dash-mounted switch as an anti-theft facility too. It allowed the engine to start because the butterfly requires vacuum to operate but then the engine would only idle, cutting-out if the throttle was opened. If the switch was operated with the engine revving, the engine stopped regardless of how wide the throttle was opened trying to supply more fuel.

Edit: The shut-off when no oil pressure was also in case the oil pump bolt let go, in order to immediately cease all engine power.

Originally Posted by Graeme

I had an air cut-off system on my D2a when I had it. I had the EGR butterfly valve solenoid wired directly to a (fused) 12V supply that was operated by a red button switch mounted in a dash switch blank and also operated electronically if engine oil pressure was lost to cater for a roll-over.

I used the dash-mounted switch as an anti-theft facility too. It allowed the engine to start because the butterfly requires vacuum to operate but then the engine would only idle, cutting-out if the throttle was opened. If the switch was operated with the engine revving, the engine stopped regardless of how wide the throttle was opened trying to supply more fuel.

Edit: The shut-off when no oil pressure was also in case the oil pump bolt let go, in order to immediately cease all engine power.

Graeme, sounds great and exactly the kind of thing I'd be keen on doing.
I have no EGR anymore, it was gone before I bought the car, but I suppose there is another way of doing it.

Did you ever have to use it in an emergency?

[ame=http://www.youtube.com/watch?v=Fw2r_lIRgpY&feature=related]epic diesel engine fail - YouTube[/ame]

Visit a cheapie wrecking yard with your intake hose, find an EFI throttle body that looks like it might fit, remove the closing spring and operate the butterfly with a choke cable.

just carry a book or piece of thick rubber cut to the size neede to jam in under air filter.

it does not take much to stop a screaming engine.
while working in a workshop they were converting a gm8v71 diesel truck engine into a blown version for a road stabiliser.
a 350hp monster, it would make the workshop rattle.
well on the test run it ran away and was stopped buy covering the air intake with the detroit service manual..
it turns out the govening system was installed wrong, thats apprentices for you.

a couple pages were chewed but not eaten.

No, mine was not used in any emergency but I proved that it worked by trying to run the engine at various revs, throttle settings and loads to see if the engine could keep running.

I suspect you could pick-up the throttle body and valve modulator either from someone who has removed them or from a wreckers, either here or ex UK.

Originally Posted by bee utey

Visit a cheapie wrecking yard with your intake hose, find an EFI throttle body that looks like it might fit, remove the closing spring and operate the butterfly with a choke cable.

Great idea. Thanks.