2017 Kia Optima - Bad engine

Bad engine, Does not run properly - miss fires a lot. Had it into dealers 6 times (Over 6 months) Still does not run properly even after a new engine put in. What can I do to get it fixed? KIA headquarters no help.

well, you can start by giving us more info. like what the dealers said was the problem. check engine light codes? are you having the same exact problem with this engine as the last? if so, it may not be the engine. it can be the computer, electrical wiring, or just a bad alternator or battery not producing enough to keep the vehicle running correctly.
did the dealer put the new engine in?

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If none of the Kia dealerships are able to correct the problem, and it appears they’ve tried pretty diligently, and now Kia headquarters won’t help, other than perhaps a legal remedy, hard to say what you can do other than choose a product from a different manufacturer next time you buy a car. Is there any dispute whether the car is in the warranty period or not?

As far as getting this car working correctly

  • Take it to an independent shop who specializes in Kias or at least Asian cars, see what they say.
  • Since a replacement engine didn’t help, that’s a big clue the problem is in the fuel delivery system, or the electrical system. Fuel pump, fuel filter, evap system, fuel cap, alternator, battery, wiring harness. Shops have methods to test most of those system for problems. For anything the shop has no method to test, you could try just replacing that part.
  • Grounding problem. These can produce very difficult to diagnose symptoms that may not turn on the CEL nor throw a diagnostic code. Usually caused during prior shop work done at some point, the mechanic forgot to re-connect a ground wire he removed for access, or didn’t tighten the bolt, just installed it finger-tight. Such a problem could cause the transmission to misbehave, for example the transmission might shift from 2nd to 3rd gear, shifts to 3 ok, but doesn’t leave 2, so you are in 2 and 3 at the same time. This sort of problem might make you think it’s an engine problem, but really a transmission problem. Another example, replacing something that threads into the cooling jacket, if the shop wraps teflon tape on the threads, that can cause a grounding problem. If I had your problem I’d probably just install a few of my own grounding cables. In most cases adding more grounds only fixes problems, never causes them. I’d probably install 3: from the cylinder head to chassis, engine to chassis, transmission to chassis. Also make sure the battery negative has a solid connection to the chassis. Sometimes it may appear to be a good connection from a visual inspection, but there’s really only 2 strands of a 16 strand wire making the connection, the other 14 strands have broken off.
  • Any shop work done on this car prior to the problem developing should be considered a prime suspect for the cause. Suggest to create a summary sheet showing everything that had been done by any shop you used prior to the problem developing, and give that to the inde shop to aid them in the diagnosis.
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This is more of a legal question than a car question.


I’m not exactly sure how Kia headquarters was no help . . .

When the zone rep gets involved, things typically start moving along

Remember that when an engine is replaced, lots of parts from the old engine are swapped to the new. Depending on a clearer idea of the original issue, might have just narrowed it down to the swapped parts or parts tha we’re not swapped at all. Agree though time for a private shop but I don’t think everyone will work in Kia.

Your owners manual gives you information on exactly how to bring an issue to Kia corporate. Have you followed that procedure? If not, do a restart. Start there.


It’s obviously not a bad engine if the new one behaves the same way. It could be something like fuel pressure or an electrical problem.

Has anyone checked the ignition timing with the flashing light tool?

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Are you serious . . . ?!

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LOLOL. That’s a good one. Almost made coffee come out of my nose.

Quick question, for the real mechanics here. Have any of you actually used your “flashing light tool” A.K.A. timing light on anything newer than, let’s just say the 1990 model year?

The last vehicle I owned with a distributor was my 89 Suburban. That was the last one I used my “flashing light tool” aka, timing light, on.

It’s been well over 10 years since I’ve used my “flashing light tool” at work

It’s gathering dust in the bottom drawer of my tool box afaik

Does the problem happen all the time or just when driving it or when it’s under load?

Really? Even my 2002 Daewoo has a timing mark on the crankshaft pulley, although it uses a 4-way ignition coil, and there is no way to adjust the ignition timing. I would be fascinated to know when the timing mark was eliminated from most engines. I seem to recall that when I changed the accessory belt on my 2004 Corolla, there was no visible timing mark on the crankshaft pulley.

I actually do own a fairly high-end timing light, and am looking forward to using it if/when I find the time to restore my 1993 Sundance. I know that when installing the distributor onto that engine, there is quite a range of adjustment available.

I’ve never really thought about how a shop would measure the ignition timing for a vehicle with the coil on plug configuration. Guessing coil on plug only used with OBD II vehicles, and most any OBD II scan tool is able to measure the ignition timing. I use my timing light to periodically check my Corolla’s camshaft timing too, to make sure the timing belt hasn’t jumped a cog. Can a camshaft timing check be done with a scan tool for OBD II engines?

I burned mine out about 1978. Never replaced it.

I did NOT say the timing mark was eliminated on most engines

I simply stated my timing light has been gathering dust for over 10 years

A timing light is simply not used on modern engines

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If there was a problem where the ignition timing was jumping around how would you know without a timing light?

I think the timing mark is still needed to align the cam sprockets on modern engines.

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Most scanners will read the timing.

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