[MRGIBR]

Hi all,

I am new to forum however I use to drive my Hyundai i30 2011 with 1.6 engine for almost a year.

When I purchased a car it was in an excellent condition, I had to change only oil and batteries.

Now about the issue:

Overall car is still in a good condition, no bad noises from the engine, I recently changed oil again and car worked fine, however recently I noticed that the car losses power especially at the evening or after driving several miles.
When saying loss of power I mean that I need to push gas pedal harder to reach a certain speed, in other words I need to get higher RPM than before to get some speed, even after acceleration. The issue appears periodically, not always.

and this loss of power is more noticeable when air conditioner is on.

Conditions:
- no check lights (not even engine)
- cheeked on computer but no errors
- To ensure that everything is ok, I replaced air filter, fuel filter and even spark plugs. (oil is also recently changed)
- No unusual noises from the engine

Can someone share own experience?
Can it be air compressor issue? Sometimes I have a feeling that engine does not get enough air for combustion.

[eye30]

Just a quick thought as there are others with more knowledge  but have you checked fuel supply is ok i.e. fuel pump and or starvation due to vacum in tank?

Sent from my ATU-L11 using Tapatalk

[MRGIBR]

Hi,

Thanks for the reply.

I did not check it separately, but thought that it was checked when fuel filter was replaced by services guy, as fuel filter is located at fuel pump. Service guy did not mention any issue.

Should I ask for separate check?

regards,

[GaKu]

If you need higher rpm for same speed, it sounds like transmission/clutch issue?
But lets wait for the experts..

[eye30]

If you need higher rpm for same speed, it sounds like transmission/clutch issue?
But lets wait for the experts..

A quick clutch check is

Car stopped and running,
Pull hand brake up as tight as possible,
Put car into 2nd,
Rev car to normal start off revs and raise clutch pedal,
If the clutch is ok the car should be trying to move forward as you increase revs and as handbrake is on tight the front of the car should be rising.
If may even stall.......

If clutch is on way out the above will not happen and to try and move forward you will be reving hard.


Another test is

Do a constant 30mph in 4th,
put foot down quick on the gas.

The car should pick up speed without revs going way to high.

If not as revs rise without an notable increase  in speed it may point towards clutch on way out.

Try 1 way then the other and see how each reacts.

Sent from my ATU-L11 using Tapatalk

[tw2005]

If you need higher rpm for same speed, it sounds like transmission/clutch issue?
But lets wait for the experts..

First thoughts that hit my mind too. There's a missing bit of info manual or auto. I'm thinking it's going to be an auto at this point at a guess. Having the AC on is always going to add load to the engine

[mickd]

@GeeKv2
Hi,
Extra revs to reach SAME speed - drveline issues - transmission slippage.
Extra throttle to reach SAME speed - performance / efficiency issues.
Pump pressure /flow or injector flow, even though filter is good.
Timing error.
"Air compressor for combustion" - is it a diesel ?,  possible loss of boost due to leak .
If you could answer the following it will help the brains trust do their thinking.
Manual or Auto? Petrol or Diesel?  Kms ?

Cheers

[nzenigma]

If you need higher rpm for same speed, it sounds like transmission/clutch issue?
But lets wait for the experts..

First thoughts that hit my mind too. There's a missing bit of info manual or auto. I'm thinking it's going to be an auto at this point at a guess.

MY first thought too.

Same RPM in / gear ratio does not change/ = same road speed out.

Possibly incorrect transmission fluid level?

Clutch slipping?

[MRGIBR]

Hi All,

Thanks for such replies.

forgot to mention:

1. it is Manual
2. Petrol
3. The car KMs is 150 000 KM
4. I don't think that clutch is slipping as speedometer arrow always moves)

So to sum up:

spark lights, fuel filter, air filter, Engine oil are replaced. No engine check light, or other check lights.
Engine has no unusual noises and I use premium quality fuel.
The car shows no errors on computer check as well. (even at Hyundai Service Center)
The RPM arrow is at 800 00 RMP when engine is on and idle. (which I think is normal)


- Mostly (on the mornings) the car drives flawlessly, in other words, when pressing the pedal, I feel, I get the appropriate power and speed from the car.

However on the evenings, after driving some KMs, I feel that car needs more effort than before to get the same speed. The car needs more effort during acceleration (take off) and after acceleration as well. (again it appears time by time and the effect is more noticeable when air conditioner is on, as it takes more power from the engine)

[tw2005]

there goes my auto theory.  dragging brakes?

[MRGIBR]

Hi,

No issues with brake system.

Based on above discussions I assume there is an issue with Transmission but not sure, as the issue appears periodically.

[GaKu]

Do you park in the shade during the day? Since the problem does not appear in the mornings when it is cooler, can you see if that helps?

(I have a weird electrical issue that occurs only in the winter)

[MRGIBR]

I park always outside garage so the car is always under direct sunlight at 30-35 degrees Celsius in Summer.

Oh and I forgot to mention that during that time when the issue appears, when car is idle, it vibrates slightly. (no unusual sound from engine)

[MRGIBR]

If you need higher rpm for same speed, it sounds like transmission/clutch issue?
But lets wait for the experts..

A quick clutch check is

Car stopped and running,
Pull hand brake up as tight as possible,
Put car into 2nd,
Rev car to normal start off revs and raise clutch pedal,
If the clutch is ok the car should be trying to move forward as you increase revs and as handbrake is on tight the front of the car should be rising.
If may even stall.......

If clutch is on way out the above will not happen and to try and move forward you will be reving hard.


Another test is

Do a constant 30mph in 4th,
put foot down quick on the gas.

The car should pick up speed without revs going way to high.

If not as revs rise without an notable increase  in speed it may point towards clutch on way out.

Try 1 way then the other and see how each reacts.

Sent from my ATU-L11 using Tapatalk

I will try above mentioned as well and get back.

[nzenigma]

I park always outside garage so the car is always under direct sunlight at 30-35 degrees Celsius in Summer.

Oh and I forgot to mention that during that time when the issue appears, when car is idle, it vibrates slightly. (no unusual sound from engine)

The problem is being associated with temperature. That usually points to an electrical problem . Time of day could be irrelevant, save the fact that you heated the engine bay during an earlier drive.

The vibration at idle is more interesting. Get out and listen to the sound from the exhaust pipe, unusual? popping sound?
I suspect you have a failing spark plug, coil, cam sensor or crank sensor.

[MRGIBR]

If you need higher rpm for same speed, it sounds like transmission/clutch issue?
But lets wait for the experts..

A quick clutch check is

Car stopped and running,
Pull hand brake up as tight as possible,
Put car into 2nd,
Rev car to normal start off revs and raise clutch pedal,
If the clutch is ok the car should be trying to move forward as you increase revs and as handbrake is on tight the front of the car should be rising.
If may even stall.......

If clutch is on way out the above will not happen and to try and move forward you will be reving hard.


Another test is

Do a constant 30mph in 4th,
put foot down quick on the gas.

The car should pick up speed without revs going way to high.

If not as revs rise without an notable increase  in speed it may point towards clutch on way out.

Try 1 way then the other and see how each reacts.

Sent from my ATU-L11 using Tapatalk

Hi again,

I made both checks.

in the first case car is trying to go forward and the nose rises

in the second case I drive at 30mph (50KMH) at 4th gear, pressing on gas pedal faster and it gain speed, not very faster, but it gains speed.