Why you should always park in gear

Nitefly

I used to drive FX4 taxis for a living. 

Turning the ignition off in those didn't stop the engine, there was a separate switch to stop the engine - it would die with a horrible clattering noise, like a bucket of spanners falling down stairs.

BenSirAmos

tone1 said:

So how do you switch your engine off then if it won’t stop the Engine when you take the keys out?.... maybe worth phoning your local garage or main dealer and get back to me....

I stop the engine by pushing the start/stop button. 

A diesel engine does not need external source of ignition; the ignition is by compression.

tone1

No, sorry to be calling you out on this but the compression only raises the ambient air temperature to the required temperature so that the diesel Will self ignite when injected. So if no Fuel is injected, then compression on its own will not still run a Diesel engine. All vehicles have electrical means to switch off the high pressure diesel pump and therefore stop injection... if you are talking about a diesel in over-run when the engine will still turn over by being driven by the road wheels through the transmission without keys in the ignition, then that is a different matter... but the facts are that a diesel engine will need a source of fuel and not just compression to run... and that diesel source is switched on and off by electric means... Sorry to be pushy, but please call an engineer to confirm, if you won’t take my very considered opinion 

Danny1969

BenSirAmos said:

Danny1969 said:

BenSirAmos said:

Except if you leave a diesel in first gear facing down a hill, it could bump start the engine if the handbrake fails.

The engine won't start with no ignition

Really? I thought they worked solely on compression. They don't need a spark

Yep, diesel does fire on compression and there is no HT ignition system but as others said you need fuel

 On a typical diesel van the fuel rail is driven by a mechanical pump but the injectors are piezo operated ... basically a voltage applied exerts a mechanical force to open the injector. This needs to happen very, very fast to spray a fine mist of fuel in at exactly the right time. As it's hard to make piezo injectors exactly the same each one is generally slightly different so has to be coded to the fuel pump before the engine will run right. 

BenSirAmos

tone1 said:

No, sorry to be calling you out on this but the compression only raises the ambient air temperature to the required temperature so that the diesel Will self ignite when injected. So if no Fuel is injected, then compression on its own will not still run a Diesel engine. All vehicles have electrical means to switch off the high pressure diesel pump and therefore stop injection... if you are talking about a diesel in over-run when the engine will still turn over by being driven by the road wheels through the transmission without keys in the ignition, then that is a different matter... but the facts are that a diesel engine will need a source of fuel and not just compression to run... and that diesel source is switched on and off by electric means... Sorry to be pushy, but please call an engineer to confirm, if you won’t take my very considered opinion 

Of course it needs a source of fuel to run. What it doesn't need is electrics to continue to run - compression provides ignition. These days most (but not all) diesel vehicles cut off fuel electronically. But many older vehicles and trucks and boats need a mechanism for cutting off the fuel / stopping the injectors. 

https://www.quora.com/Why-does-a-Diesel-engine-stop-when-you-turn-off-the-ignition

ICBM

Regardless of all that, if you park a diesel with it in gear in the opposite direction that it could move in, it will not start.

fob

ICBM said:

This is a particularly sad case... it may have been in 3rd.

https://www.independent.co.uk/news/uk/home-news/kiara-moore-death-inquest-wales-car-roll-river-handbrake-cardigan-a8654776.html

That was heart-breaking.

Maynehead

Another reason why I stick to driving autos

axisus

Wow! glad to hear he is OK. 

The handbrake is there for a purpose and should be fully operational or your vehicle shouldn't be on the road.

EricTheWeary

fob said:

ICBM said:

This is a particularly sad case... it may have been in 3rd.

https://www.independent.co.uk/news/uk/home-news/kiara-moore-death-inquest-wales-car-roll-river-handbrake-cardigan-a8654776.html

That was heart-breaking.

It's not hard to imagine that happening ( well, if you are as chaotic as me) and 99.9% of the time nothing untoward would happen, even on a bad day the car would just roll and hit something else and there would be tears and an insurance claim. Sad story.  

digitalscream

EricTheWeary said:

fob said:

ICBM said:

This is a particularly sad case... it may have been in 3rd.

https://www.independent.co.uk/news/uk/home-news/kiara-moore-death-inquest-wales-car-roll-river-handbrake-cardigan-a8654776.html

That was heart-breaking.

It's not hard to imagine that happening ( well, if you are as chaotic as me) and 99.9% of the time nothing untoward would happen, even on a bad day the car would just roll and hit something else and there would be tears and an insurance claim. Sad story.  

You'd think so, but twice now I've been walking to the shop next to ours with inclined parking spaces outside, and had to catch a car without the handbrake on, rolling towards the busy road with kids in the car and the mother in the shop. The second time, I didn't even get a "thank you"...I did get shouted at for putting a dent in the tailgate, though. I even ended up with her at my door claiming that I should pay for the damage.

crunchman

dazzajl said:

Wow!! Glad that worked out as it did. 

Ive always done this. Lots of people don’t and have got a great shock when going to drive my car. Possibly because I’ve always done this, I always start a car with the clutch down too. 

You have to put the clutch down on my car, otherwise it won't start.  Quite a good feature.

ICBM

digitalscream said:

You'd think so, but twice now I've been walking to the shop next to ours with inclined parking spaces outside, and had to catch a car without the handbrake on, rolling towards the busy road with kids in the car and the mother in the shop. The second time, I didn't even get a "thank you"...I did get shouted at for putting a dent in the tailgate, though. I even ended up with her at my door claiming that I should pay for the damage.

Sadly, you can't fix stupid.

relic245

Glad your son is ok.

Another reason. Last summer I was driving my wife's pride and joy Audi. Parked on a hill at a friend's house, ensured handbrake was fully engaged.

Came out an hour later, car at bottom of hill wrapped around a lampost. If it were not for the lampost it would have crossed a dual carriageway, apparently it was moving quite fast.

Mechanic said it's very common in summer, hot day, brake metal expands, you apply handbrake. As the metal cools it contracts which effectively releases the handbrake.

Lesson learned for me.

boogieman

Glad to hear your son is ok, he must have been cacking himself!!