Suggestion that this harms the auto? Say your rolling down the takaka hill with engine on but in neutral. Fine with a manual, is it a problem with an auto?
johotech,
Mar 18, 11:40pm
You don't like your brakes or something?
bumfacingdown,
Mar 18, 11:48pm
Yeah, not something I would recommend in a manual or auto
brapbrap8,
Mar 18, 11:54pm
It would work, but why bother? Just wastes fuel and wears your brakes out.
jimgammy,
Mar 18, 11:56pm
Wont waste fuel because most auto's will idle going downhill anyway. Also, auto's have big brakes because they do not have engine braking to assist. It will be completely fine, and pointless.
tamarillo,
Mar 18, 11:59pm
Yes thanks, I didn't ask if I should do it, I wouldnt. But am looking at car that has been used like this a handful of times, and someone else claimed this was bad for the gearbox, so I wanted some knowledgable person to advice, more out of interest really. I've never really understood auto mechanics so couldn't work out whether neutral disengages the box and is therefore safe.
Thanks for advice, seems it is fine.
tweake,
Mar 19, 12:04am
not sure with current autos but with old ones was never tow an auto because the oil pump in them is on the input side and no oil would be pumped and it will wear/damage parts. i guess with engine at idle it would still be pumping oil.
i think theres bigger issues to look for than if its gone downhill in neutral.
3tomany,
Mar 19, 12:05am
modern autos and manuals will waste fuel in neutral my xr6 uses .5ltrs per hour at idle but uses 0ltrs per 100kms going down hill in gear.
lookoutas,
Mar 19, 12:05am
It's called - "Maori Overdrive"
And don't get offended! That's what it's been called for years.
bumfacingdown,
Mar 19, 12:08am
Gosh, there I wondered why they have a manual downshift in autos, silly me has been using it to engine brake on long steep downhills.
intrade,
Mar 19, 12:13am
why would you even want to do this?
intrade,
Mar 19, 12:23am
if you think your going to save fuel then your mistaken. i have a youtube video on exactly this proofing that the fuel injectors turn off downhills on over-run when it is in gear. and we all agree you use less fuel when nothing is injected as when it is injecting idle fuel amounts. i dont know if all turn off as you would need some fuel to keep the cat alive my toyota has a dead o2 sensor so it wont go in closed loop i recon it saves more fuel like this old high emission programming on carbureetor you would save fuel they dont turn off its why they splatter and cough on overrun
tamarillo,
Mar 19, 12:39am
I remember Clarkson saying that as a top gear tip!m
brapbrap8,
Mar 19, 12:47am
It does tell you that the previous owner had limited understanding of cars and mechanics though!
lookoutas,
Mar 19, 12:51am
So the engine stops?
motorboy2011,
Mar 19, 12:54am
If the engine is running at the time it's sweet. Which is say it would be, otherwise the brakes would be near non existent.
socram,
Mar 19, 12:58am
Modern autos do seem to engine brake going downhill, but as the engine is still ticking over, although ours also says 0.00, surely it cannot be correct? I would have thought the least it can use is on tickover.
intrade,
Mar 19, 1:01am
no the engine keeps rotating the gearbox is making it turn . the engine is pumping air as no combustion takes place , I should check if its also shutting off ignition on overrun its the next thing i am going to check soon. You need some fuel and some air to keep the cat going so injecting every other cilinder could be what a modern engine is programmed to do on over- run = engine is keept going by the car going down hills thru gearbox to engine to keep it rotating.
tweake,
Mar 19, 1:09am
most modern engines kill the fuel when going downhill, above a certain rpm and no throttle. (also if brake is applied.) there is enough speed and hill steep enough to keep engine turning over. if you hit the throttle or change gear (or out of gear) it fires back up. with modern electronics it does it all seamlessly.
so to save gas going down hill, select a gear that will allow you to coast at a good speed, put foot on brake slightly (not braking but enough to trip the brake light) and the ecu will turn off the fuel.
intrade,
Mar 19, 1:19am
if anyone wants to see my video i post a link as i dont want it to be seen as comercial post. I have to learn how to edit the video is un-edited . and i like to only do videos that are not on yourube or multiple wrong like i will one day do one on correctly doing a auto trans service, non video i ever seen is correct for diy.
trouser,
Mar 19, 1:47am
Jeez my diesel vw cuts the injectors just going along my flat drive when I'm off the throttle. Obvious to the ear and the readout goes to 0.0.
johotech,
Mar 19, 2:24am
Modern autos change down gears and increase engine revs when going down hills, and definitely do engine braking quite well.
Maybe not in your HQ Holden though.
sr2,
Mar 19, 4:04am
Not sure if I can think of any models that put lager brakes on the auto versions?
jmma,
Mar 19, 4:05am
They have bigger brake pedals so you can put both feet on them Lol (o:
movnon,
Mar 19, 4:27am
Haha - as we all know! OP might be thinking of downhill runs without the engine running (doesnt help the braking much without the vacuum on the brake booster or drive to the power steering pump tho!) just the same as towing any distance in most autos without a rear oil pump - lack of lubrication will do unnecesary damage.pretty smartly.
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