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25 votes

How slow ( not zero) can a car engine run without hurting engine and saving on fuel

You are right in the thinking of using less gas and that's exactly what the purpose was to have the start/stop feature. The main goal of doing it (at least here in the States) is for zero fuel ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
21 votes
Accepted

How slow ( not zero) can a car engine run without hurting engine and saving on fuel

The oil problem You can run any engine speed you want as long as you keep the oil pressure up. Because of the impossibility of getting a roller bearing down a crankshaft, engine bearings are "...
Harper - Reinstate Monica's user avatar
8 votes

How slow ( not zero) can a car engine run without hurting engine and saving on fuel

The engine needs a minimum rpm to idle smoothly - a v8 can idle smoothly about 500to 600rpm but a 1 litre 3 cylinder needs around 700 to 900rpm... It is not the companies that really decided to do ...
Solar Mike's user avatar
  • 34.6k
7 votes

Idling motor and running AC for 4-8 hours in 100 degree heat?

It shouldn't cause the vehicle any issues. Realistically, all you'll be doing is burning fuel. The wear will absolutely be minimal, mainly because at an idle, there is very little stress put onto the ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
6 votes
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Yamaha Seca - Motorcycle Idle problems

More than likely, you have an air leak If you haven't cleaned out and rebuilt a bunch of 4 carburetor banks in your life there is a good chance you have accidentally created an air leak in the system....
DucatiKiller's user avatar
  • 32.9k
6 votes

Engine start is OK but dies when applying throttle

The triple carbs were serviced 2019. I have had this 4 years and only managed 1000+kms every year (very poor for me). It's not always clear what "serviced" means. But for a bike this old ...
jwh20's user avatar
  • 12.1k
5 votes

Car dealer taking more time to repair. Is it ok to leave car idle for long time?

Cars don't like to sit. There is an inside joke among mechanics, they call degradation due to sitting "lot rot". The biggest impact to a sitting car is the rotors. They rust. Rotors rust even ...
vini_i's user avatar
  • 16k
5 votes

2001 Ford Explorer High Idle

The P1506 code is an idle air control overspeed error. From autocodes.com: The P1506 code means that the engine idle is out of factory specification. Sometimes the Idle Air Control (IAC) may have ...
anonymous2's user avatar
  • 5,235
5 votes
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Is it bad to idle the car for 5 min or restarting the car?

As long as the vehicle is well maintained.. turning the engine off, or leaving it running would not really make any difference to engine wear and tear. Well unless this was being done 50 times a day ...
Orb's user avatar
  • 5,067
5 votes

How slow ( not zero) can a car engine run without hurting engine and saving on fuel

From physical point of view, lowering the RPM means that you need to store the energy required to keep the engine running (and overcome friction) with a smaller angular speed. And the kinetic energy ...
Dmitry Grigoryev's user avatar
4 votes
Accepted

Idle dipping and rising when headlights are on - not Idle Air Control Valve

Check that your alternator belt is tight and in good condition. Also check that your battery is fully charged and in good health. There is a real possibility that the fault is being cause by the ...
Steve Matthews's user avatar
4 votes

Is a +/- 10-15 rpm idle fluctuation normal?

Completely normal. Nothing to worry about
cano's user avatar
  • 823
4 votes
Accepted

TSI engine, shaking at idle

I finally find the reason why my car is shaking at idle when the car at uphill. It was a piston failure and repair cost is around 2000$ and also that failure damaged compressor( which is combined with ...
kaan yılmaz's user avatar
4 votes

How slow ( not zero) can a car engine run without hurting engine and saving on fuel

Car companies focus on stop/start of the engine simply because There's a minimum RPM the engine can run at. You can sort of extend it using dual inlet/exhaust variable valve timing, but there are ...
juhist's user avatar
  • 14.6k
3 votes

2001 Ford Explorer High Idle

This condition can be caused by a vacuum leak. Use an automotive safe spray such as carb cleaner to try to find the leak, both visually, and by noting changes in the idle speed depending where you ...
kmarsh's user avatar
  • 2,159
3 votes

Occasional trouble idling

Why would the car stumble occasionally? Based on what's been described, I'd say it's probably because the air-fuel mixture isn't right. It's either running too rich or too lean. If it is running ...
Zaid's user avatar
  • 39.2k
3 votes

Rough idle problems on 93 Miata

list of things to check and some questions the IAC valve might be giving the correct readings but is it stiff or sticking? does any of this happen when it is warm outside as in during summer? when ...
Cc Dd's user avatar
  • 2,879
3 votes
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Vibration at idle, much worse after warm

Although, your point about cold engine mounts applies, I would doubt they heat up enough to significantly affect vibration transfer to the interior. Instead, what you might look at is increasing your ...
Alexus's user avatar
  • 550
3 votes
Accepted

Idle speed is wrong after replacing battery (2006 Camry)

You need to clean the throttle and perform an idle relearn. Unfortunately there isn’t a reset function in Techstream or other software, you can only do it manually. This is the way I do it, some ...
Ben's user avatar
  • 10.7k
3 votes

Unable to accelerate after jump starting

The failure to accelerate sounds very much to me as though the car has gone into "limp home" mode. This usually happens when the Engine Control Unit (ECU) detects a problem (or thinks it's detected a ...
motosubatsu's user avatar
  • 10.1k
3 votes

Engine start is OK but dies when applying throttle

Carbs have multiple fueling circuits. One circuit is for idle. Another is enrichment, which gives extra fuel when you twist the throttle. Another circuit gives it fuel while at a steady state above ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
2 votes

1987 Dodge D150 High Idle and Dieseling

My first mechanic post. But were struggleing here many comments no answers. Maybe it doesn't apply to this vehicle. Dieseling run after shut off is sometimes caused by the vacuum switch on the air ...
danny117's user avatar
  • 197
2 votes
Accepted

Idle gets stuck at 2000RPM

I eventually got this problem fixed. For an unrelated issue, both the throttle position sensor and air flow meter were replaced on the car. When the same idle sticking issue persisted after that, we ...
Elliot B.'s user avatar
  • 211
2 votes
Accepted

What should the idle speed of an engine be based on?

Here is the method I used on some vehicles to set the minimum idle speed. The cars I did this with did not have a MAF, so I am not sure how that will effect things. Get the engine warmed up. Just ...
rpmerf's user avatar
  • 8,403
2 votes

Engine missfires when idling, but only when hot

If the problem is entirely related to coolant temperature, it is probably actually a head gasket problem. The head gasket may seal properly when cold, but when the engine heats up it no longer seals. ...
Eric Urban's user avatar
  • 1,286
2 votes

High vacuum pressure on idle after timing gear and chain replacement

First, verify the vacuum gauge and the port you are connecting to. 5in is very low vacuum and I suspect the car would idle like crap. Vacuum is produced by the engine efficiently trying to pump air ...
Con FUse's user avatar
2 votes

Oil pressure light and vehicle idle

WARNING: Using it in this condition could cause server internal damage to the engine, cause complete engine failure and/or strand you somewhere. Anytime the oil pressure light comes on, it means the ...
CharlieRB's user avatar
  • 9,015
2 votes
Accepted

Why do tow truck drivers never turn off their engines?

Emergency services vehicles are often kept running because they contain lots of electrical equipment that would quickly drain the battery if the engine were off. Climate control is another reason ...
Hobbes's user avatar
  • 4,412
2 votes

Why do tow truck drivers never turn off their engines?

One reason is that it could under very specific circumstances damage the engine. Every modern diesel has a turbocharger. Under prolonged heavy load the turbocharger get hot, really hot: Red glowing ...
Martin's user avatar
  • 8,458
2 votes

Chevrolet Lumina making a ticking noise below 1000RPM

The noise you've presented in the video is quite a lot more noisy than what I'd consider to be valve train noise. With it going away with you revving the engine past 1000rpm seems to me to be an oil ...
Pᴀᴜʟsᴛᴇʀ2's user avatar

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