Wondering what's happening here. I have a 2014 Hyundai Veloster Turbo, and about a year or two ago it went to limp mode. No engine light or anything, I stopped the car, checked under the hood, and when I started back up it was fine. I was driving up a mountain pass that day and it was in the middle of summer so it was pretty hot. Never used to happen, but I was passing some cars so I thought it was just that.
However, few months later the car started to run bad and an engine code finally showed up. Long story short, it ended up being an ignition coil that was going bad. Eventually got all new plugs and coils in and the car has mostly run great.
Yesterday I was driving home, I was doing about 70mph and needed to speed up. I downshifted to 5th gear, which only puts me in around the 4k RPM range on a flat road, and my car instantly went to limp mode. No engine light again, and once I stopped, turned the car on and off again, it was fine. It was around 90-95 degrees which is pretty hot, but I've had the car in 100+ degree weather and not had it happen.
With the coils and plugs changed, what could it be? If it's just heat soak, then I understand there isn't a whole lot I can do accept upgrades, but I wonder if there's anything else that could be going bad and this is the early warning sign.
Get a deep scan to check for any stored codes. If you used after market instead of OEM coil packs, they could just be malfunctioning above a certain temperature. Have you ever changed the fuel filter or checked the fuel pump pressure?
I've seen this happen in Mercedes. It's usually using cheap aftermarket parts instead of dealer OEM or non dealer OEM parts.. Just to give you an example you can buy OEM Mercedes Brand coils or get Bosch which is oem. Since Bosch makes Mercedes coils. There is no difference between the 2 expect price. A clogged fuel filter/ failing pump is another cause. It usually will only happen at high rpms or when under heavy acceleration. It also can happen when it's hot out and the pump starts to heat up. . I agree with @doc check parts and have a full diagnostic done. The difference between the 2 is simple standard scan just gives you the basics.. codes and standard live data maybe a few other things. Deep scan or full diagnostic pulls data from every single module and everything connected to it. You can also manipulate different sensors.
Finally got my car in today and the dealer did a deep scan. Got some interesting results too.
Basically looked like everything on the turbo and fuel pump was working exactly as they should. I asked specifically and they mentioned some specific diagnostics that indicated there wasn't a problem. I forgot the exact terminology for the turbo, but the voltage for the pump motor was exactly where it was supposed to be.
The mechanic said he thought it would probably be a dirty fuel system and to use a cleaner. I told him not only that I used ethanol free gas, but I was using Redline S-1 fuel system cleaner. He told me that for starters, the ethanol gas works better for the turbo Veloster. That works out because I recently started using Costco gas. I didn't want to sacrifice quality, but when I found out they were top tier I decided it was worth the 20%+ savings over ethanol free.
Next, he recommended I use the BG 44k cleaner. I figured why not try it since the can was only $25. I drove 30 miles back home and couldn't believe it! The weird hesitation and choppy acceleration is completely gone already. I still have a full tank to get through.
This was strange because I've used Seafoam, Gumout and Redline frequently in my cars just to try and take care of my engines. That said, I never felt like I noticed any difference. My hope was I was preventing carbon build up. The BG 44k is the first time I've felt a noticeable difference.
I found this post from Scotty and I agree, the prices are ridiculous on Amazon. https://carkiller.com/scottykilmer/qa/scotty-you-should-promote-bg-44k/#post-111586
That said, maybe it was just a fluke but I'm pretty happy I can just go to my local Hyundai dealer in Idaho Falls and get one for $25 plus tax. I haven't tried out that one Scotty recommends from that company in Arizona, but the BG 44k is the clear winner in my book.
Hope that story helps out, glad my car is feeling back to normal again.
Get a deep scan to check for any stored codes. If you used after market instead of OEM coil packs, they could just be malfunctioning above a certain temperature. Have you ever changed the fuel filter or checked the fuel pump pressure?
Gotcha, I didn't realize there was a difference for getting a scan or a deep scan done. Should I expect a deep scan to cost up front or is that something a good shop wouldn't do?
I haven't changed the fuel filter or had the fuel pump pressure checked. That sounds like something to ask about. I have an extended warranty, but the company isn't very good so I usually need to do my own homework before taking it in.
Take it to your local auto parts store, and ask them if they’ll scan your vehicles for codes, for free. If they refuse, find a professional mechanic in your area and pay him for diagnosing the issue with a fancy scan tool. Please post the codes and/or diagnosis here, once you have it.
I had to take my car to a dealer due to the warranty and my warranty only allows OEM parts. I would hope the ignition coils aren't bad already, but who knows with these mechanics nowadays.
I'm gonna try to schedule with the Hyundai dealer in Idaho Falls now that I work in the area, see if they can do a better diagnostic. Not my first choice, but might as well use up my warranty for as long as I can. I'll reply again when I find those codes.
Quick correction, looks like Amazon does have the BG 44k at a good price. When I searched on Amazon itself, I got some really high price listings. Google searching it brought me to this Amazon link. My Mother-in-law's Rav4 has a slight rough idle so I'm gonna dump some of this in her car.
https://www.amazon.com/BG-44K-System-Cleaner-Enhancer/dp/B00DDVU6EI