Another Warning: Run away Diesels

[con67]

Over the years Ive repaired 1 or 2 that women have got out run away from lol runaway derv + runaway woman = fail

[Mitch]

My turbo let go the other night, it ran up on itself and was knocking quite badly but stalling it in 5th seemed to do the trick

[RePT]

Witnessed a transit runaway on the m40 a week or so back. It was smokey as hell. Went right through the smoke like a boss

[trog34]

When I was doing my apprenticeship we had an oil line break on the diesel generator set, the oil was spraying up to the ceiling and then into the air filter and even though the fuel was cut off it kept running until we managed to get a bucket over the end of the oil line to stop the oil getting to the filter. Not as easy as it sounds as the outside of the generator was on fire by this time and the area was like a skating rink. The generator was about 14 feet high by about 40 foot long, I wouldn't have wanted to be around if it threw itself apart.

[Atterz]

The ole two stroke engines used in 432 armoured personnel carriers had a habit of doing this due to crews not checking the hydraulic governors.

[daveylennon93]

This happened to me after using egr cleaner down the intake on a hdi.

Did it properly like the instructions said then when i got to the part where your meant to rev it up a bit the engine just took off, turned off the key and it went for a good few seconds after.

This ever happen to anyone whos used wynns egr??

[Piggy]

however with that EGR cleaner, once its burnt it off, it will stop revving...as opposed to runaways that will just keep going on and on and on and .....BANG!

[kelvsere]

Thats hectic , sure everyone coughed a bit that day

[ADV_93]

Did a turbo change on an ML V6 derv. Before though i blipped the throttle, then it went all the way to 6k, turned key off and took it out, then engine ran on it's own for 3-4 seconds then cut out. Quite scary and unexpected.

Culprit was the turbina shaft had snapped.

[nominous]

Happened to me on Sunday.
Rag was on standby and TBH I was expecting it.
Was starting the car and solenoid under the bonnet.

She picked up slowly then suddenly Blam ! smoke generator.

Still panicked, ripping off the wiring, before remembering what the rag on my shoulder was for
The fuel lines were also loosely inserted into a jerry can. So pulling the feed line and having it suck air no doubt helped a ton.


I note some modern diesels do have throttle bodies.
I guess for other reasons, but assume they snap shut if the engine goes off so the problem is lessened ?
Seems to me a mod to add a TB into the manifold might be worthy mod, actuated open with ign on.

[andywhy]

My Passat has a throttlebody (just replaced it actually, POS...) and that only closes for 3 seconds before opening again when you turn the key off (it's electronically controlled). 3 seconds might not be enough to kill an over-revving engine. Some other cars might be different.

[Poodle]

Happened to us at work today, a CO2 extinguisher was closer at hand than a big enough rag (merc 416 luton and we weren't expecting it), did the job though lol.

[JTaylor2005]

As far as I am aware the PD engines have whats called an Anti-Shudder valve. This is controlled through vacuum and an ECU solenoid. When you turn the car off it snaps shut to stop the engine running on any diesel left in the fuel system and weirding people out that don't know why its running on.

The throttle plates that are in the more modern diesels are to help control how much EGR flow there is back into the engine. They can close slightly meaning that more is drawn from the exhaust gasses rather than fresh air to control emissions

[bashbarnard]

It does indeed have a valve that shuts when the key turns off. Its a good idea. Saying this i personally have overran a pd so they dont always work!! To be fair the pipes were full if oil and my friend said its just smoking a bit.

[cully]

be warned over filling the oil on a hdi will cause it to run away too
had this experience going up haldon hill nr Exeter on full boost then it took off filled the whole hill with thick black smoke behind .
throttle peddle did nothing. it eventually eased off towards the top of the hill, cars been running fine ever since

think i was lucky the engine was under load or it would be toast

[Toms306]

As far as I am aware the PD engines have whats called an Anti-Shudder valve. This is controlled through vacuum and an ECU solenoid. When you turn the car off it snaps shut to stop the engine running on any diesel left in the fuel system and weirding people out that don't know why its running on.

From experience, PDs sound bloody awful on shut-off when you bypass the ASV/EGR with a race tube lol. I didn't expect the shudder to be so noticeable, instantly makes it feel like you've got a knackered DMF lol.