Ask MetaFilter questions tagged with rpm

What's wrong with my truck?

geoff. — Wed, 21 Oct 2009 10:37:21 -0800

I have a 2001 Dodge Ram that I use when I need to haul things. It runs great, except in the morning after it rains. The truck will not want to rev beyond 1800-2000rpm. If I idle it or drive for for about 10 minutes the problems go away. Any ideas? This has been happening for about a year but I don't use it very often so I sort of ignored it. I've been using it a bit more and I sort of want to get it taken care of if it is causing damage, if it is not I can just ignore it. It is also an automatic so I'll try to explain gear changes as best I can, but I could be wrong. Keep in mind this only happens in the morning after a rainfall. It did occur once without rainfall, but in that instance I parked it in a field that was very dewy; there's definitely a moisture connection. I haven't noticed the problem if I drive it on a dry day and it rains in the afternoon. Here's the best description I can come up with:

It will make the transition from first to second at about 1800rpm so I don't initially notice it. From second to third, on normal conditions, it'll get up to 2400rpm before changing gears. When it is experiencing problems it won't go above 1800rpm or 2000rpm and if I apply more pressure on the accelerator the engine sounds like more power is coming out of it but the tachometer doesn't seem to want to move up. It is as if I hit a ceiling or there's a hole at around 2000rpm. If I accelerate slowly I can get up to the speed I want without any problems. This is really noticeable when getting on the highway and I need a lot of torque to get up to speed. If I push it when I hit this "wall" , and I only did this once, it gives up and drops down to like 1600rpm. I don't know if I would describe it as a popping sound or just a cessation of power? When I did this (just once!) the engine light came down, when I let off the accelerator the engine light went off. It has yet to come on again.

It is most definitely every single morning it rains the night before, I've been driving it everyday this last month to isolate the problem and to make sure the rain thing wasn't a red herring. I'm really confounded as to what it could be.

How did turntable speeds develop into 33 1/3 and 45?

kensington314 — Sun, 13 Sep 2009 00:33:45 -0800

Why are standard turntable speeds 33 1/3, 45, and 78 RPM? Why did the industry standard for RPM develop from 78 to 45 and 33 1/3? Why not 81 RPM, 42 RPM, and 34 1/6 RPM? Is there some math or logic or was it just arbitrary?

Why does my C2D Macbook Pro fan run constantly?

crazyray — Sun, 21 Oct 2007 22:19:15 -0800

I have a 2.33 Core 2 Duo Macbook Pro 15 inch laptop. Recently, I have noticed that both fans on it constantly run at the maximum 6000 rpm's. The noise is driving me nuts, and the battery seems to run out much sooner. My question is in two parts: (1) would anything in the system logs help explain why this is happening? and (2) how can I make it stop? Here are the steps that I have taken to try to diagnose the root cause:

(1) reset PMMU per these instuctions
(2) setup new blank user account to see if it was software related (it wasn't- the fans actually kick in at full blast even on the login screen)

Please help me understand what is causing this. The bootup temp is 106 degrees F, so I really do not think it is temperature related.

Help finding Apache 2.2.4 x86_64

hummercash — Tue, 20 Mar 2007 11:03:39 -0800

I can't seem to find the rpm for Apache 2.2.4 x86_64 for RedHat 4 and/or CentOS 4.4... does anyone know where it is or if it even exists? Gracias.

Diagnose My Ride

hippugeek — Wed, 08 Nov 2006 09:13:20 -0800

Why is my Mazda losing power? I have a 2000 Mazda Protege (1.8 L, automatic, 43K mi, a lot of that in the past 18 months). I had a lot of work done on it in May including brakes, new radiator, and transmission flush. Jiffy-Lube check-up in late August. Oil's fine, fluid levels are good.

A couple months ago it started having trouble with acceleration. I press the gas and the engine revs, but not all of that power is getting to the wheels. Once it gets up to speed, it will stay there, but the process is slower than it ought be. The engine sounds healthy--no knocks, no rattles, no skips--it's just working too hard.

I haven't been able to afford to take it to the shop, and the problem has been worsening slowly. There's a slight delay in response, and the RPM are high even when I'm not accelerating--if I cruise at 70 on flat ground the engine will rev at 3000. The car is eating gas, of course, and I worry that I'll damage the engine further by running it high so constantly.

I'm all but broke, and don't want to spend a penny more than I have to on diagnostics and labor. At worst, I'd like some scenarios to present to the mechanic. At best, I have DIY-car-repair friends I can work with. So tell me, (1) what are some likely problems, and (2) could a team of very intrepid laymen repair them?

Slowing down an mp3 from 45rpm to 33rpm

the fire you left me — Tue, 15 Jun 2004 07:39:01 -0800

What would be the best way to convert the speed of an mp3 so that it emulates slowing from 45rpm to 33rpm? The speed change would be around 0.733. SoX doesn't seem to work very well.