2010. Automatic with 140k. My sons Accent revs too high at cold startup and the valves sound like they are oil starved. After 3 to 5 seconds, the noisy valves go away. I have tried, Hyundai oil filter, clean IAC , thicker oil 10/30.

i,d love to get the rpms lower at start up

any tips or tricks? Mike

 

Idle speed is controlled by the PCM.
What you might try is to remove the negative battery cable from the battery negative post and hold the cable end against the positive cable at the battery for aprox 15 seconds. This should erase any learned idle speed. Then reinstall the negative cable back on to the post. Go in and start the engine WITHOUT touching the throttle pedal and see if the idle speed comes down to the programmed speed. This will take a minute or so.

If that doesn't get rid of the problem, start looking for a large vacuum leak , and possible problem with PCV valve and hoses. Let us know what you find, thanks.

 

Good Info Hanky,
The car is in another state currently, Last week, we changed to original timing belt at 140K, the teeth were falling off it.. it was a close call. It actually broke when he tried to start it in the morning.

I'm going to order PCV .

Whats your Opinion on Oil for these engines. 5w20 seems too thin for the south. Does it need thin oil for the variable valves?
The engine uses oil but is not smoking. Seems to be common for these engines.

 

We try to stick with the owner's manual as far as oil recommendations.
Did you gents ever check compression on that engine ? It is an interference engine and just cranking it over with a damaged timing belt could open the door for valve damage.
Just trying to cover all the bases.

 

With the new timing belt on , I hand wrenched the engine a couple turns and it did not whiff a low compression noise from a valve not closing. The kid has drove it about 600 miles since the job. It runs and idles fine. It sounds better with new belts and idlers etc.. I think we dodged a bullet. The alternator is howling a bit. I’ll see if I can find brushes for it.

 

Usually anytime you get a running noise from an alternator the bearings are talking back There can always be a first time , but I have never seen worn brushes provide noise just no or spotty output.