Hi all,

I recently purchased a brand new Tucson Ultimate 2020 from a dealership in Calgary, Alberta. I'm really enjoying the vehicle except that I occasionally get a misfire when cold-starting. The problem is sporadic and hard to replicate. I have a video of the misfire that can be seen HERE.

Has anyone encountered this problem with their own 2016-2020 Tucson?

I took the vehicle into the dealership and they did the following:

1. cleaned the PCM ground;
2. disconnect both battery cables and connect them together for 10 minutes; and
3. perform a high RPM road test.

Unfortunately, that did not fix the problem -- the Tucson misfired the very next morning after I collected my car from the dealership.

This is the description of the problem I have given my dealership:

• Occasional/sporadic misfire when cold-starting.
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      • Tucson has not shown an error code;
      • Misfire ONLY occurs during initial cold-start;
      • Misfire does not consistently occur - it happens once in every 10-15 cold-starts.
      • Tucson struggles to start and stutters/shakes momentarily;
      • Tachometer flickers below 1000 RPM;
      • Engine takes a few seconds to start running properly at normal idle; and
      • Misfire does not occur at any other time while idling or driving.

• Even if misfire initially occurs, the engine operates normally afterwards.
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      • If misfire occurs, it will not occur again even if engine is immediately shut off and restarted.
• The vehicle has to have sat over night or for a period of several hours before the misfire presents itself again. Even then, the misfire does not always reoccur.

 

Please correct me if I am wrong.
In watching and listening I noticed the engine RPM does not falter as it would if it was misfiring. There could be something else going on that makes it feel like it is misfiring.

I would think a questionable crank sensor might do this , but the RPM should show this unless it is filtered.

 

I have had the same thing happen to me, yes you are experiencing what I believe is a cold start misfire. I have a 2017 Tucson with the 2.0L. I first noticed it after the car had been sitting in the garage for 2-3 days. What is the cause I’m not sure, I have begun to notice an oil consumption issue. Vehicle has 71,000km on it and has had the oil changed every 6000km with synthetic oil. The dealership near me is currently doing a consumption test. In 1400km they said it used 0.6L however the dipstick was at the add mark,I believe the add to full mark is 1L however I may be wrong. Ether way even .6 of a litre over 1400km is too much and may be contributing to excessive carbon in the combustion chamber and on the valves. I noticed in the video yours only has 2300km on it so that isn’t likely the issue.

 

In looking at other manufacturers with direct injection motors having cold start misfires here is a video I found
My second vehicle is a 2014 Xterra, it also has a cold start misfire however it occurs at every start up under 5 degree Celsius ambient air temperature. Every time I start it it stumbles for a second or two then operates normally. I can turn it on off and on again and it will miss while cold everytime I do that. Once the engine had warmed up it will not misfire again unless very cold out that day and engine has had a chance to “cold soak”. My truck spent 1 month at the dealership at 99,000km in order to get this fixed before the warranty ran out and it was it’s second time there for an extended period. They replaced the plugs (because it’s a v6 have to remove the upper and lower intake), pcv, did a compression test, cleaned the throttle body, and checked all the engine parameters. They agreed the engine misfired but could not figure it out short of just throwing parts at it. I have 178,000 km on it now and it still runs and drives as it has since I first experienced the problem.

The difference in these motors in terms of oil usage is shocking. I changed the oil on my Xterra right before I towed my 3000 pound tent trailer 1500km north past Peterborough to some crown lawn. I have a lift on it, 33” tires, steel bumpers and skid plates and it’s not geared down towing especially with the bigger tires. 6500km since that oil change (I use 10k intervals with 0w-40) and have not burned a drop of oil, and it’s still a darker gold colour but still very much see through. 2000km on the Tucson’s oil all highway miles and it is black as night.

So this misfire may that because of EPA requirements manufactures rely so much on sensors to give good readings to constantly change the parameters of the engine in order to heat the cats up faster it allows some fuel to burn downstream by retarding the timing at idle. Maybe there’s a Hyundai tech on here that could better explain it.

have you had any luck with yours?

 

This appears to be one of the better videos. He did a nice job explaining and showing. Thanks for the info.

 

I just had the same problem yesterday! It started fine in the morning, got to work- went to leave work and boom! vehicle started shaking/ CEL came on- i threw it in park and turned off the engine... let it sit, turned it back on- revved it a few times, and its been completely fine all day today... had my mechanic diag it and it was showing a cyl misfire.... It was so spontaneous and weird... Gunna have to keep an eye on it for a while and see if it happens again. I'll update you if anything changes. Please feel free to do the same.
2020 Hyundai Tucson