Hi,, I've been battling a cylender #4 misfire for over a week now. Started off as a low rpm misfire upon acceleration (for a couple years like that).. Now the misfire occurs when the vehicle is fully warmed up & at a low idle (700rpm). Diving along all cylinders fire normally, engine power normal. Back to an idle and it starts missing again always on #4 according to the code.
Things looked at so far : -New spark plugs installed
- inspect and clean injectors , moved #4 into the #1 position (no change)
- Swapped ignition coils , no change.
- Installed new O2 sensor (primary /#1 sensor) - no change.
- Reinspect spark plugs , #4 smells of fuel
- Check & cleaned idle air control motor, - no change , no error code , IAC appears to be working.
- Check and clean MAP sensor , appears to be working , live data is responding.
- Fuel trims appear equal , adjusting minor bits up and down in unison.
- Sprayed MAF cleaner down the intake - no change
Vehicle will idle normally for a minute or 2 sometimes, but starts missing within a few mins of idling.. spitting and sputtering out the exhaust during the miss. Soon as the throttle is applied, evens right out again... Some detonation can be heard while driving , like a tick or ping,, not a knock but more of a ping.
No signs of contaminants in the oil, not consuming coolant, . ... Not sure what else to try except compression test.. but if that is indeed the last thing ,, the car is almost certainly toast then. Just wanted to see if there's anything else it could be before another Hyundia ends up in the scrapyard. Thanks.
2009 Hyundia Accent 5sp hatchback
cylender #4 misfire (...) spark plugs , #4 smells of fuel
If compression is fine,
You need to connect a fuel pressure gauge, turn key to position II, wait 4 minutes, see if it has dropped.
If the pressure dropped - replace cylinder #4 injector.
only under load /acceleration does it make that noise tho.. super weird
(You have the Hyundai Alpha engine - their first entirely in-house design)
They're very well known for having lifter tick, and the lifters/tappets are a known weak spot!
A bad tappet can cause a valve
Can't say I'd ever drive a Hyundia again after this
"The Manufacturer's Suggested Retail Price (MSRP) for the base 2009 Accent (...) around $10,500"
And no one paid window sticker for these.
This 13 year old super budget car's competitor was bus tickets - not driving, a corolla was 50% more.
Don't keep disposable super budget sub-compact cars for over 10 years or 125k miles, it's not built for that.
Check intake manifold for vacuum leak near #4. I had one crack just at the engine block. Repaired it with JB weld.
Bear in mind it is a 13 year old Hyundai.
Scotty has videos on doing a wet & dry compression test, I think that's your next step.
Also, a leak down test to isolate a bad valve, if that's the cause.
Thanks for the info... Ill inspect the valves and get a compression tester at the least. I hope it is something in the top end then with the clicking/ticking/popping type noise,, only under load /acceleration does it make that noise tho.. super weird,, one day the car was normal, & the very next start up , this issue happened right from cold. Can't say I'd ever drive a Hyundia again after this nightmare lol.