Do you turn off engine at lights to save fuel?

[cavalier1990]

Hi

Just wanted to find out if any of you do this when your out and about, and does it save you fuel?

I tend to do at lights I know take a long time to change but I think it's pointless at lights that stay red for less than 20 seconds or so.

Was always wondering if the energy used from the battery to turn starter causes the engine to use more fuel to recharge the battery or if fuel saved is still more than that used to replenish battery from restarting. I certainly think I am using less doing this.

[HAIRIBO]

I don't. Not sure old engines are designed for that.

[btcctroy]

Pointless exercise costs £1.50 to have the engine idle for an hour.

[humbucker]

You use more fuel starting the engine than you do sitting in traffic for half hour!

[Cavalier342]

They reckon 3 minutes of idle time equates to a mile of urban driving, so on that basis I only shut the engine down if there is a major gridlock and there is no sign of movement for as far as I can see, but not at the lights, as been pointed out you use more gas restarting the engine rather than letting it tick over for a minute or 2.

[TurboDan]

Yep a waste of time on old engines like cav ones. Allot of new cars will do it these days but they are designed to do this and also they will only do it once the car is upto temperature and not before that.

[Lowrider Dave]

I do on the Peugeot as I know the lights I get stopped at regularly won't be changing that quickly. I also put on the handbrake which, just like indicators, many drivers seem unable to use, content in the knowledge that their modern bright brake lights are burning MY fudgery RETINA OUT.

[Cavalier342]

Yes, all them poxy new cars with LED brake lights, great for visibility, unfortunately not great if you're stuck behind them at eye level!!

[iancav6]

Had a look on the net, general consensus is any idling longer than 10secs (or up to 60secs depending on whose report you read) will use more fuel than switching off and restarting.
Thing is , unless you are at a set of traffic lights,how do you know how long you are going to be stationary?
Need some hindsight glasses.

Seems its illegal in some areas to sit in a parked car with the engine running?

[Cavalier342]

I tell you the one thing I do, is when I pull up at a gas station, if the pumps are busy and I have to wait behind someone, I shut the engine off, then when the car ahead moves off, I get out and push it to the pump. Everyone thinks I ran out of gas but is there really a point in starting it just to move 15 feet?

An old guy in a Jag once asked me if I ran out, I said the above, then when I went, I saw he did exactly the same...

[TurboDan]

You really are amazing andrei

[Cavalier342]

That's what she said...

[TurboDan]

[Mk3alan]

I can imagine it puts unnecessary extra wear on starter and battery.
I only turn off if there is a total non movement (jam/accident)

Alan

[planetc]

The latest stop start technology uses starters and batteries that are designed to cope with the different characteristics.

[Envoy CDX]

Can't say I have really.

[Ads]

really carnt believe what i am reading here, LOL

[cavalier1990]

I have noticed a rise in my MPG, not significant but it's something, so what I might do is next tankfull I'll not turn of at lights and see what happens. I need at least two full to empty tank MPG figures to do a comparison between them (one 2nd just now) and then 2 full to empty runs when not turning off at lights.

I only turn off at lights that I know on my daily run stay red for a long time. Is it true that my Single Point injector injects more fuel to start the engine? I know this kind of action is usually pointless on old carb cars but I wouldn't think the cavy chucks fuel in to restart since it's injection?

Anyway my MPG figures will tell

Andrew

[Cavalier342]

SPi isn't great, it's only a carburetor with an injector which replaces the jets, and more electronics to control it. I would think it does need more fuel to start as it's not as efficient as MPi. It still chucks the fuel in with the air, like a carb.