[Frantic222]

Hello all!
I am owner of 99' Kia Sephia 1.5 16v LS
Recently I have a problem with my Kia. When I'm driving in 5th grade on 90 km/h I had almost 3000 RPM. (100km/h = 3.500 RPM, 120km/h = 4000 RPM)
Earlier at a speed 100km / h I had 2500 Km/h
What could be causing of such high RPMs?
Thanks for all answers
Regards, Frantic

 

[DavesSpectra]

You didn't state if your Sephia is an automatic or manual transmission.
Gears don't "slip" clutches do..
The only variable from engine to wheels would be slipping items, (clutch disk,pressure plate,flywheel on manual transmissions and a bad lock-up torque converter and/or internal clutches in the automatic transmission. Newer automatic transmissions don't normally slip like trannys from 20 years ago. After the car gets moving the torque converter "locks-up" removing the "slip" that was common in older transmissions. It then releases the "lock-up" as the car comes to a stop. A changed RPM to vehicle ratio would indicate something is slipping and allowing higher RPMs.
Dave

 

[Frantic222]

I have manual transmission.

 

[DavesSpectra]

Well if the RPMs are higher than what they were the only thing that can cause that at the same speed is a slipping clutch.

 

[lycanthrope]

if your rpms are that high when cruising, it should be difficult to get up to speed because of the slipping. while in gear, whenever you see your rpms advance and your speed is not increasing proportionally, it usually is a good sign that your clutch is toast.

is this what you are experiencing, or just incorrect rpm levels?

next time out, romp on the accelerator when you get into third. you should speed up very quickly. less us know what happens...

 

[Frantic222]

Thanks for help. When I was on third grade I speed up very quickly and RPMs goes high but speed not really.
Btw. Do You know what RPMs should I had on 5th grade on 90/120 km/h?

 

[DavesSpectra]

It's going to get worse the more you drive it. The RPMs in 5th really doesn't matter.
Because the clutch is slipping the friction material WILL wear off much faster than normal and it will strand you soon somewhere.
The only "cure" is the replacement of the clutch parts. Start checking on costs now.
Dave

 

[Dr Bob]

Thanks for help. When I was on third grade I speed up very quickly and RPMs goes high but speed not really.
Btw. Do You know what RPMs should I had on 5th grade on 90/120 km/h?

I does sound like a slipping clutch; it would be very easy for a mechanic to diagnose. Could be the pressure plate (internal clutch spring), but if it's been slipping for a while you've probably worn the clutch plate badly. You would probably want to replace it while the job was being done anyhow.

In the OP, you previously had 2500 RPM @ 100 km/h in 5th Gear (Not "Grade"), so 90/120 should be 2250/3000 RPM. It's a linear relationship.

Not sure about the exact gearing of your car, but 2500 RPM @ 100 km/h is about right for a 4 cylinder 5 speeder.