8
votes
4answers
26k views

Automatic transmission: Is shifting to neutral while approaching stops bad?

This is not with the intention of saving fuel (as I have seen many answers assuming savings in fuel while doing this). But I have this habit of putting the vehicle into neutral before approaching ...
7
votes
1answer
52 views

What is the effect of changing rim diameter while keeping wheel width constant?

Which advantages or disadvantages would I obtain by changing the rim size while keeping the overall diameter of the wheel and the thread width constant? For example, in ...
7
votes
1answer
2k views

Why doesn't my rev limiter bounce?

I have a BMW 630i Steptronic from 2007. If I floor the pedal in neutral the RPM is of course limited, but it doesn't "bounce" like regular rev limiters. Instead it keeps a constant and "clean" RPM. ...
7
votes
3answers
638 views

Calculating MPG from MAP sensor (or converting MAP data to MAF data)

My 2002 Honda Accord V6 has a Manifold Absolute Pressure sensor (MAP). I understand that this sensor gives out information in pressure units (psi or equivalent). After doing a bit of research, I ...
7
votes
3answers
6k views

Why don't FWD cars have rear differentials?

This confuses me. The point of a differential is to make it so the wheels don't slip when one needs to be turning faster than the other, such as during turns. So if the rear wheels are directly ...
7
votes
3answers
3k views

Cleaning fuel injectors?

I took my car (2006 Honda Civic) to firestone to get an oil change and they told me I should get the fuel injectors cleaned. I was in an Advanced Discount Auto Parts store the other day and I noticed ...
6
votes
2answers
189 views

Which knob setting best cooks the mold inside HVAC?

I am trying to eliminate odors inside HVAC by cooking the mold that is presumably causing them, as suggested in http://mechanics.stackexchange.com/a/146/15334 (which got 39 upvotes) However, I don't ...
6
votes
2answers
6k views

What happens to a car engine when giving max throttle while not in gear

I was driving (well standing still actually) during rush hour, and I was suddenly wondering what would happen to a car engine when I would push the accelerator pedal all the way down while the engine ...
6
votes
1answer
433 views

Oily Sludge in the Intake Manifold

When taking off the throttle body to clean my IAC, I noticed that there was a thick layer of oily sludge coating pretty much everything inside the intake manifold: I have two queastions: How did ...
6
votes
2answers
12k views

Oil pan threads stripped?

EDIT Helpful links on how threads got stripped and by who: http://tl.acurazine.com/forums/showthread.php?t=878261 Seems to be a common problem with some shops, where they don't take good care. ...
6
votes
6answers
20k views

Uneven rotation sounds when my car gets to 50-60 MPH

My 2005 Mazda 3 with 73K miles (roughly 20K on the tires) on it starts to make a sound, just like your washing machine does when all of the clothes go to one side and its still spinning, when I get to ...
6
votes
4answers
24k views

Cheap way to fix peeling clear coat?

The coat on my car is peeling away something like as shown in following picture which I just pulled up from google as an example: This is my first car and I have never done any car work myself ...
5
votes
1answer
82 views

How can torque converters fail?

In what ways can a torque converter stop working properly? Are there any symptoms that indicate failure, or simple tests one could do to determine a malfunctioning TC?
5
votes
4answers
23k views

Low beam headlights don't work, High beam headlights do

The vehicle is a 2003 Chevrolet Trailblazer. The low beams aren't working. High beams are. The fuse is perfectly fine (tested and swapped out). The bulbs are fine too. A mechanic told me it could be ...
3
votes
3answers
63k views

Possible reasons for loss of power, engine shaking, and smell of liquid fuel (not burning)?

The car (Renault Megane 1998 1.6e hatchback) lost power (about 500rpm in a bursty rhythm) after I re-ignited on a traffic light, the engine started shaking, and I could smell liquid fuel. There was no ...
2
votes
0answers
2k views

Fuel Consumption and other Fuel related data from basic OBD-II parameters [duplicate]

I want to know how can i obtain the values of Fuel Consumption, Fuel Economy and other fuel related information from basic OBD-II parameters like Vehicle Speed, RPM, TPS etc. I have noticed that not ...
2
votes
1answer
22k views

Change language of Toyota HDD Navigation (NHDN-W56) from japanese to english

I have an imported Toyota from japan with Toyota Genuine HDD Navigation and music system(NHDN-W56). The problem is that the whole thing is in japanese,can anyone help me how to change the language ...
1
vote
1answer
89 views

Supercharger calculations

How to determine safe supercharged pressure and CFM for a motor cycle engine (fuel injected 149cc (9.31 cubic inches) 12.9 bhp?
1
vote
2answers
209 views

Does torque decrease mathematically?

There are 2 cars, car A and car B. Car B is 20% heavier than car A. We all know that this means that these 2 cars will have same power if car B at the same RPM (revolution) has 20% more Nm. Can the ...
20
votes
3answers
31k views

Is starting your car with the A/C on bad?

I was always yelled at by my father when I was first starting to drive when I left the A/C on when I turned off the car, and then later turned it back on, with the reasoning that I was ruining / ...
17
votes
12answers
53k views

Should I pull my wipers away from the windshield when parked during a winter storm?

When we are expecting snow storm and the vehicle is parked, do we pull out the wipers so they don’t touch the glass to avoid the freezing to the windshield? Or would that hurt the springs in the wiper ...
17
votes
10answers
174k views

How do I loosen stuck lug nuts in order to change a tire?

How do I loosen car tire lug nuts (so that I can change a tire) when they are really really stuck? I have tried turning the provided wrench, even standing and jumping on it. This worked for 4 of the ...
16
votes
8answers
2k views

Will having a radiator full of engine oil do damage to the motor?

I've got one question; I was looking over this car that I was going to buy and there was engine oil in the radiator. I asked the guys why it was in there and he said he didn't have enough coolant to ...
16
votes
2answers
1k views

Should a mechanical “click” Torque Wrench be set to zero when not in use?

I have a standard click torque wrench. I was told I should set it to zero when not using it in order to keep the accuracy high. Is this true? Secondly, I have not been doing this since I purchased ...
15
votes
6answers
2k views

Why or why not increase engine efficiency by running the car “fuel-lean” (using a turbo or supercharger)?

Everyone wants their cars to use less fuel, right? I read the following passage about running the car fuel lean from this website: Run the engine fuel-lean, that is, use excess air. It is well ...
15
votes
2answers
12k views

Why would a new gas cap cause the “check engine” light to shut off?

This happened to a friend of mine: The "check engine" light came on in his truck (Toyota). He replaced the gas cap and the light shut off. Then I also had a "check engine" light come on in my 1994 ...
15
votes
1answer
6k views

Where can I find my car's colour code?

I'm currently shopping around for a touch-up pen to repair some very light scratches on my car. I've found out that our local hardware automotive store can mix the exact colour for any vehicle. ...
14
votes
3answers
1k views

Are there any advantages of idling a vehicle vs. turning it off and back on again?

I was sitting outside, eating my lunch the other day, and a small bus (you know, one of the short ones) pulled up to the sandwich shop I was eating at. I noticed that the driver got out of the bus, ...
14
votes
6answers
13k views

How to fix leaky tires after 2 shops couldn't

I have an SUV with factory 16" steel wheels and P235/70R16 tires. The tires have just under 30,000 miles of gentle driving on them. Two of the tires have been leaking quite a bit (about 10 psi per ...
13
votes
4answers
11k views

I drove with my Parking Brake on for 30 mins: should I be worried?

Yesterday, I was driving my car for about 30 minutes on the highway at speeds of up to 60 mph. I felt my brakes weren't really working and looked down to notice my emergency brake had been on the ...
13
votes
3answers
16k views

What can cause warped rotors?

I have a forward rotor on my '04 Chrysler Sebring causing a lot of pulsation when braking. I replaced the rotor- but within about a month the problem had re-appeared. The guys at Monroe noticed my ...
12
votes
6answers
1k views

How to deal with a hot turbocharger

A piece of advice that seems to be widely accepted is that after a long high-speed run, when the turbocharger is thoroughly hot, you should let the engine idle for a while before stopping it. The ...
11
votes
1answer
229 views

How do lambda sensors work?

Virtually every modern passenger vehicle today utilizes lambda sensors from the factory. How critical are they to a vehicle's operation? How do they work?
11
votes
5answers
123k views

Why would there be transmission fluid in the water overflow reservoir?

The car is a '98 Buick Lesabre with the 3800 engine and about 170k miles. It appears as though some oil was in the radiator, but I haven't seen any signs of coolant in the oil. The water pump recently ...
10
votes
1answer
369 views

What are Tappets?

I have been looking into a tapping noise after a cold start on my 2003 Opel Agila, and apparently it is caused by "tappets". What are tappets? What is their purpose? Why are the necessary? Will my ...
10
votes
6answers
10k views

Why does a diesel sound like that?

My car is in the shop for a repair, and they gave me a loaner. It's a Chevy Cruze Diesel. Sitting on the driveway, my wife said, "It sounds like a truck". It does. So what exactly it is about ...
10
votes
6answers
18k views

What is the purpose of plastic engine covers?

I have a 2010 Toyota Corolla. What is the purpose of the large plastic cover that stretches over my valve cover? Does it have a particular function? Are they just for looks? Or are they designed by ...
9
votes
1answer
115 views

What are the various kinds of tappets / lifters and the advantages / disadvantages of each

A previous question about tappets found here: What are Tappets? covers the basics of tappets. If we go the next step, here are my questions: What are the various kinds of tappets / lifters? What ...
9
votes
2answers
571 views

What's the cause of Diesels' typical clatter noise?

I guess it's related to their basically running off knocking, but if I were to explain it to someone like this, it wouldn't convince me neither. [Edit] From ...
9
votes
1answer
228 views

How does intake manifold runner length effect the power curve of a car?

Recently I learned that a number of things such as the cam profile, compression ratio and the intake manifold runner length and volume can all effect the power curve of the engine. Here is an ...
9
votes
3answers
1k views

What actually happens when there is way too much oil in a car engine?

I saw the answers to a question I posted recently highlighting the disadvantages of having too little oil in an engine, but that got me wondering what if the complete opposite were to occur! I know ...
9
votes
1answer
100 views

What is Lobe Separation Angle (LSA)?

What is Lobe Separation Angle (LSA) and how is it used in camshaft design? How is it measured? What difference does a long or short LSA make?
9
votes
3answers
29k views

Switching from Reverse to Drive - always stop completely?

I've been told by a couple people that it's really bad for a car to be shifted from Reverse to Drive while the car is still moving backwards. Is this true? In my experience: On automatic cars, this ...
8
votes
1answer
59 views

How to check if spark plugs are firing? Coil-on plugs

While trying to diagnose a tricky car not starting problem I was asked to check if the spark plugs were firing at all. I've found plenty of resources on inspecting the condition of spark plugs after ...
8
votes
2answers
402 views

Why is the engine on my Royal Enfield Classic 350 shutting down?

After travelling 7-8km on my Royal Enfield Classic 350, the bike acts as if the fuel is finished & the engine shuts down, but it starts again when I pull the accelerator. What could cause this ...
8
votes
2answers
721 views

My Ignition Timing is Retarded, no seriously, it's really screwed up

I logged some test data to try and help me figure out why my 98 Mazda 626 GF 2L ATX has a rough idle and is suffering from hesitation. (Speed k/h),(TPS_v),(MAF ...
8
votes
2answers
11k views

Is topping up the oil enough of an oil change?

If you use synthetic ester-based oil in a relatively new petrol engine, top it up regularly, and the engine runs very quietly and basically without any noise whatsoever (especially after another top ...
8
votes
3answers
9k views

Bad to run the car for a short duration, turn it off, and start up again?

Is it bad for the car to start it up in the morning, spend 10 seconds driving it out of the garage, then shut it off while I go close the garage door and then a few seconds later get in and start it ...
8
votes
4answers
9k views

Is Paint Protection worth paying for?

I've just bought myself a new car, and as expected the dealer is trying to sell me extra items. The two options they are trying to push on me are Paint Protection nano technology paint protection ...
8
votes
1answer
1k views

Car Suddenly Decides To Not Crank

Today I turned the key to start up my car and all the lights (headlights and instrument panel) came on bright and normal, but the engine made absolutely no sound. It wouldn't start, it didn't even try ...

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