Internal Combustion Engine. Most engines in road going vehicles are 4-cycle internal combustion gasoline engines.

learn more… | top users | synonyms

5
votes
1answer
197 views

Reliability of water test for valve seal

I took my valves out, cleaned and lapped them and put them back together. I also put new valve stem seals. At least on one side of my V6 Tacoma. I performed several water tests to check the seal of ...
5
votes
2answers
10k views

Engine never warms up (actually: it cools down) at highway speeds

I have a 1997 Caravan (base model) and normally on my drive to work and my highway drives in rush-hour, the engine warms up just fine. I took a road trip for work, about an hour and fifteen minutes ...
4
votes
2answers
10k views

What exactly is Honda's i-VTEC technology

I see that almost all of Honda's cars have an "i-VTEC" logo at the back. I googled it and came to know that it has something to do with different cam profiles. Can someone explain? A diagram or ...
4
votes
1answer
3k views

Car Stalls When Coming to a Stop

Make: Chevy Model: Cavalier (4 cyl.) Automatic Year: 1993 Miles: 230K Normally my Cavalier drives just fine without problems. However, if I drive for 45+ minutes then it will sputter and stall out ...
3
votes
1answer
284 views

How do the bore and stroke affect the characteristics of an engine?

How do the lengths of the bore and stroke affect the performance (power and torque), and general running characteristics (e.g. redline, noise etc) of a 4 cylinder engine? Note: When asking this ...
3
votes
1answer
341 views

VW Passat B5 EPC Light on Dashboard

There is a yellow light on my dash that says 'EPC'. I have no idea what this could mean on my car as I haven't noticed any difference in the way it drives, nor are there any unusual sounds other than ...
7
votes
2answers
331 views

How do modern engines differ than older ones

Modern engines produce more horsepower with more fuel economy but with the same procedure of burning the fuel air mixture and moving the piston, but the old ones and new ones are both four cylinders ...
7
votes
1answer
1k views

Why does an engine's idle RPMs take time to settle from a cold start?

I've noticed my car's (healthy) engine will idle at a slightly higher RPM for a few moments after it's been started from cold/not run for a day. I also noticed that my (somewhat less healthy) other ...
6
votes
0answers
131 views

Once-only thud knock when open throttle

I have a 1997 Yamaha TRX850. When I open the throttle I'm hearing a thud knock sound near the left crankshaft cover. That sound does not always appears and I can't find any correlation between ...
5
votes
2answers
3k views

Effects of driving through deep water WITHOUT hydrolocking (car still bogged down and died)

So, yesterday we had very heavy rains, and unfortunately I was driving in an unfamiliar area of town. I drove through high water, which caused my car to sputter and so I turned around. The car behaved ...
4
votes
2answers
2k views

Dealership Installed “Oversized” Oil Drain Plug As Solution

In this question, we discuss stripped oil pan threads. I learned it is a result of user error - over tightening and cross threading, by the dealership I consistently go to. Many people have come ...
4
votes
3answers
35k views

What would cause a car to lose power a few seconds after starting, then run normally?

I start my 2003 Honda Civic each morning and drive to work. A few hundred feet down the road, the engine will sometimes behave as though it is running out of gas and lose power momentarily. It doesn'...
19
votes
2answers
2k views

Why do we need to cool air after it leaves a turbocharger?

When we are using a turbocharger to compress the incoming air, the air gets hotter. Usually this hot air is cooled by using intercooler before it is passed to the engine. But what is the reason ...
15
votes
3answers
35k views

What exactly is a “burnt valve” and what causes it?

I've come across this term a couple of times in the context of diagnosing engine-related issues, but don't know what it refers to. Here is an example from an automotive forum I frequent: I gotta ...
13
votes
2answers
189 views

How do I troubleshoot the source of oil in my coolant?

I would like to know the step by step troubleshooting procedure for discovering the source of oil appearing in coolant. There are several different points of failure that can be the root cause for ...
13
votes
3answers
290 views

Why does GM still insist on push rod engines?

GM continues to design and produce push rod (Over Head Valve or OHV) engines while most of their competitors have gone to over head cam (OHC) configurations for their performance engines. Is there a ...
11
votes
2answers
15k views

How much power (HP) do the components on the engine belt generally use?

In general, how much power (HP) to the components on the the engine belt actually use? I'm trying to come up with an estimate of how much horsepower an engine wastes on things like the AC compressor, ...
8
votes
3answers
643 views

What do these compression figures mean

This is a follow up question to What are the causes of fluctuating intake manifold vacuum I have a 2005 Honda CBR600 F4i which suffers from occasional hesitation at low rpm when accelerating. After ...
8
votes
3answers
274 views

What do the terms “combined port” & “direct injection” mean?

I heard these terms recently as part of the description of a new car. I know that there are intake and exhaust valves in the engine that are controlled by cams on the camshaft (if that helps you ...
8
votes
5answers
13k views

Doing my own fuel induction service - how to, and how difficult?

I was recommended to get a fuel induction service for a 2002 V4 Camry, and am considering doing it MYSELF. The reasons for considering this are: My car idles a bit rough, especially when the AC is ...
8
votes
2answers
421 views

Fiat Punto Wont Start. Fuel Light & Three warning lights flashing

My Fiat Punto 1.2 Year 2000 MK2 (I believe) will not start. The engine turns over but the car won't start. The fuel light is flashing and petrol gauge says empty which isn't the case. There are three ...
7
votes
3answers
17k views

What is a rod knock?

What is a rod knock? What causes a rod knock, how bad is a knocking rod, and how can I tell if a rod is knocking?
6
votes
1answer
144 views

Electric water pump control

Electric fans are now common on cars, both aftermarket and stock. The advantages in horsepower, faster warmup, and hence emissions are well documented elsewhere. The same reasoning can be applied to ...
6
votes
1answer
2k views

Heater smells like sulfur

I drive a 2006 Toyota Sienna. When driving with the heater on I often smell sulfur. This is more common when I am driving up a hill, but if I turn the heater off, the smell goes away. What causes this ...
5
votes
2answers
1k views

Royal Enfield Classic 350 - Motor Break-in Best Practice

How many km's should be driven with a lower speed to setup the bore for a Royal Enfield Classic 350, what is the minimum speed for that duration and how many km's should we maintain that lower speed?
5
votes
3answers
1k views

What exactly is a clutch?

I found out recently that the flywheel, driven by the crankshaft, is connected to (or part of) the clutch. I have a basic understanding of what a clutch does due to the fact that I know how to drive a ...
5
votes
1answer
1k views

Importance of engine compression ratio

Please explain the importance of Engine Compression Ratio. In Text books I could find the following importances Engine Cold starting Characteristics Torque Generated Fuel Consumption Noise ...
5
votes
3answers
4k views

Ford Taurus common oil leak area?

On my last oil change, the technician noted some oil around top and side of the engine block and said there is a small leak. The only way to find where it is coming from is doing the whole dye test, ...
4
votes
2answers
214 views

Is it reasonable to charge the customer $1000+ to assemble the top of the engine?

I recently have an engine overheat issue and see my previous post for details: How long does items in the engine last in general for standard size cars? This is an interesting follow up on that at ...
3
votes
2answers
12k views

High-pitched squealing coming from engine

I've been told that a wet serpentine belt causes this. Is that true? If not, what else could it be? How can I fix this? This is a 2004 Chevy Trailblazer (4.2L 6-cyl. engine). I hear the noise ...
3
votes
2answers
9k views

Gas pedal not responding

It just doesn't work, as if I weren't even pressing it and it happens regardless of the speed. I have to turn the engine off and on again and it'll work for another 3 or even up to 20 minutes ...
2
votes
3answers
326 views

Is my mechanic ripping me off?

My 2002 ford focus (built after may 23) died and the AAA and tow guy both said that it needs a new fuel pump. Anyway I went to the mechanic and he said it'll be 350 for the pump and 200 for labor. I ...
2
votes
3answers
4k views

92 Civic engine won't start after replacing head gasket

I just replaced the head gasket in my 1992 Civic. Started it up before putting everything back together (just a second since it had no coolant, exhaust wasn't connected, etc.) and it ran fine. But now ...
17
votes
4answers
1k views

What is regenerative braking and why don't we use it?

I know that many electric cars use regenerative braking to enable the car to become more efficient by converting what would otherwise be lost heat energy in to a more useful, reusable form of energy. ...
16
votes
1answer
529 views

What is the difference between a 180° V4 and a true boxer motor?

Reading this thread which talks about V4 motors, I am wondering what exactly is the difference between a 180° V4 motor you'd find in a Subaru and a true boxer (or horizontally opposed) flat 4 cylinder?...
14
votes
1answer
3k views

Why does diesel engine need a warm-up before the start-up?

When starting up, diesel engine needs approximately 5s before turning the key for ignition. Why is this neccessary and what can be damaged if you don't do that?
11
votes
1answer
709 views

Brake Specific Fuel Consumption of 2-stroke vs 4-stroke

How much fuel do various types of engines burn per power output? I'm especially interested in naturally aspirated piston engines, and comparing two-stroke to four-stroke. The wikipedia article gives ...
11
votes
2answers
322 views

Diesel Engine Runaway - What is it?

I was watching some youtube videos and diesel engine runaway videos started to pop up where apparently the diesel engine runs out of control until it destroys itself. My Question What is diesel ...
10
votes
4answers
5k views

Why did V4 engines never take off?

I read that Ford Taunus (not to be confused with Taurus, it was a small model for German market) used to be made with a V4 engine but that's about it. How come V4 never became more used in modern ...
9
votes
4answers
3k views

What happens if unsuitable oil is used in a vehicle engine?

I recently heard an urban legend-like story about a guy in a developing country who decided engine oil was too expensive and so used some vegetable oil instead. The story says the car ran for some ...
9
votes
2answers
241 views

What are Performance Camshafts?

I read the following question recently: What is it about performance cams that make engines produce more power when they are installed? I know there are a few components for cars that have "cam" ...
8
votes
1answer
83 views

Pneumatic Valve Spring Operation in Formula 1

In the 2006 Formula 1 World Championship the rules allowed for pneumatic valvesprings. These engines were required to have a 90° V8 engine with 2.4 liters of displacement, 4-valve-per cylinder layout ...
8
votes
2answers
375 views

How to test if oil is leaking into combustion chambers?

How can I test whether oil is leaking into cylinder combustion chambers and getting burnt in case of oil level loss? As opposed to, for example, leaking through the oil pan or the timing chain cover.
7
votes
2answers
498 views

What are all the different types of fluid in a car and a short summary of their use?

A fluid is defined as anything that flows, hence for our purposes a gas or a liquid. I know that there is fuel, engine oil, engine coolant and brake fluid. Also air is normally taken in through a ...
7
votes
5answers
75k views

Cold start squeaking noise in engine

I just purchased a used 2010 Corolla 3 days ago. I've only now noticed that when I start the car, there is a squeaking sound coming from the engine. It lasts no more than a second. Sounds like it ...
7
votes
3answers
454 views

Why don't all diesel engines have throttle plates?

I learned recently that many older and some newer diesels don't have throttle plates to control airflow. I was also quite shocked to learn about a condition called diesel engine runaway. Apparently ...
7
votes
2answers
566 views

How can I be sure that a rod knock is actually a rod knocking?

I have a 2005 Ford Escape 2.3 L engine, there is a knocking type sound as soon as the engine is started and the speed of the "knocking" follows the RPM. How can I be sure that it is in fact a rod ...
6
votes
1answer
90 views

What is spark plug heat range

I was watching a show and their project was adding a bolt on turbo kit. In the process they mentioned that they needed a colder spark plug. What does a hot or cold spark plug mean? What changes ...
6
votes
2answers
27k views

Coolant/antifreeze leaking out of engine block (See photo/video)

I'm not sure exactly what is going on with my vehicle ('98 Wrangler, 4.0L), but it's pretty obvious something is wrong. I think I might have had some minor coolant leaking after the past few times I'...
6
votes
1answer
133 views

What is the effect of the throttle body on the power curve produced by the engine?

I heard from another member of this community that the throttle body, among other things, has the ability to change the power curve of the engine. What exactly is a throttle body? How might the ...