Revving the engine when cold
Discussion
Hey guys,
My neighbours seem to rev the engine as they start up their cars; they both do it and in both cars, theyre middle aged people with kids and they dont exactly have racing cars, quite the opposite. Im curious as to why they do this? I can hear it no matter where I am in the house and it just seems a very strange thing to do as ive never seen or heard anyone else ever do it. They do it as they start the engine, so you hear the ignition and then it suddenly revs up pretty high for a few seconds and then theyll reverse off or whatever.
Any ideas to why they do it or are they just idiots?
My neighbours seem to rev the engine as they start up their cars; they both do it and in both cars, theyre middle aged people with kids and they dont exactly have racing cars, quite the opposite. Im curious as to why they do this? I can hear it no matter where I am in the house and it just seems a very strange thing to do as ive never seen or heard anyone else ever do it. They do it as they start the engine, so you hear the ignition and then it suddenly revs up pretty high for a few seconds and then theyll reverse off or whatever.
Any ideas to why they do it or are they just idiots?
My old Honda has a blown head gasket and idles much better from cold if started and then revved to maybe 1,800 rpm for a second or two. Maybe I'm your neighbour? Is that you Gary? Your Christmas lights are shining through my side window all night - can you switch them off at midnight or something please?
Thrash said:
Hey guys,
My neighbours seem to rev the engine as they start up their cars; they both do it and in both cars, theyre middle aged people with kids and they dont exactly have racing cars, quite the opposite. Im curious as to why they do this? I can hear it no matter where I am in the house and it just seems a very strange thing to do as ive never seen or heard anyone else ever do it. They do it as they start the engine, so you hear the ignition and then it suddenly revs up pretty high for a few seconds and then theyll reverse off or whatever.
Any ideas to why they do it or are they just idiots?
Lazy people with lazy feet who rest their foot on the throttle and treat it as a foot rest. My neighbours seem to rev the engine as they start up their cars; they both do it and in both cars, theyre middle aged people with kids and they dont exactly have racing cars, quite the opposite. Im curious as to why they do this? I can hear it no matter where I am in the house and it just seems a very strange thing to do as ive never seen or heard anyone else ever do it. They do it as they start the engine, so you hear the ignition and then it suddenly revs up pretty high for a few seconds and then theyll reverse off or whatever.
Any ideas to why they do it or are they just idiots?
jamieduff1981 said:
TankRizzo said:
Is this not a feature of modern cars which raise the revs automatically when the engine is very cold for a few minutes?
Mine idles at 1500rpm-2000rpm when very cold for a minute or two.
Some, certainly. My newest car does it.Mine idles at 1500rpm-2000rpm when very cold for a minute or two.
TankRizzo said:
Is this not a feature of modern cars which raise the revs automatically when the engine is very cold for a few minutes?
Mine idles at 1500rpm-2000rpm when very cold for a minute or two.
I don't think it's a modern thing. My 1994 MR2 Turbo did it, as did my 1998 106 Rallye. The 106 was particularly noticeable due to it's exhaust. Mine idles at 1500rpm-2000rpm when very cold for a minute or two.
A high idle when cold is pretty normal.
Many newish cars start with a hefty rev before settling to a high idle like this:
https://www.youtube.com/watch?v=A5w3W0Fal_M
Apologies for the cack video - I was just playing with that MS movie editor
Many newish cars start with a hefty rev before settling to a high idle like this:
https://www.youtube.com/watch?v=A5w3W0Fal_M
Apologies for the cack video - I was just playing with that MS movie editor
After I had my GTR remapped it idled at around 2750 for about 15 seconds when started from cold. Not sure what the reason was for as it never did it standard but I'm sure it pissed a few of the neighbours off as it had a decatted zorst!
Currently got a R8 and when that starts cold it idles slightly higher but also must have some kind of valve that opens on the exhaust for around 20 secs as it is loud as fook! Again,no idea why.
Currently got a R8 and when that starts cold it idles slightly higher but also must have some kind of valve that opens on the exhaust for around 20 secs as it is loud as fook! Again,no idea why.
Petrol or diesel? If it's an older diesel, sometimes a dodgy glow plug will mean the engine will start with only 2 or 3 cylinders firing. Increasing the revs will cause the missing cylinders to fire & clear the smoke screen that will have been emerging from the exhaust. The correct solution to this, of course, is to replace the glow plugs, but some people won't think of that...
dme123 said:
Old cars often wanted a little blip to get them up and running from cold, even when new, so it's very possibly just an old habit that they haven't realised has been unnecessary for 20 years. Muscle memory and all that. Probably does get oil pressure up pretty quickly though 
I had an uncle who would always prime a cold engine by pumping the throttle before turning the key. Same reason, just a really old habit. Spectacularly unnecessary on a common rail diesel.... 
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