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Discussion Starter · #1 ·
A few days ago I began noticing that my VVT seemed to be a lot less aggressive than it used to be. Before, I could feel it kick in around 4k, but now I barely feel it-if at all. The engine also seems to make more noise (gurgling and popping) when I shift, which it didn't do before. The oil was changed a few weeks ago at a local shop and I don't know what they put back in, but I do know that the VVT system is driven by oil pressure, which makes me wonder. I've heard someone had their OCV replaced, but that was to address a SES light (mine is off).


What do you guys think about changing the oil again (myself) with a KIA factory filter?

Any other ideas?

Thanks in advance!
 

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Discussion Starter · #2 ·
I should add the car only has 13k mi, a tk cai, and a rrm pulley. I also scanned it and found no codes. I know I could be blowing this all out of proportion, but it just doesn't feel right and it's my first new car.

How do you guys feel about seafoam? Should I run it with seafoam before changing the oil?
 

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No need to Seafoam at 13k, direct injected engines benefit from the valve cleaning when induced into a vacuum line since the valves on those don't see any fuel. Ours do.

If you really think there is an issue, you can replace the oil & filter but I'll bet you are just getting used to the power. If there was a VVT issue, you'd pop a CEL.
 

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Discussion Starter · #4 ·
Thanks for the reply! I was actually tallking about adding a detergent to the oil before changing, not the fuel system.

I scanned it and there were no trouble codes, so you might be right about the power thing.
 

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The power bug has hit! It never goes away, you always want MOAR!

Even then, I still feel the CVVT kick in at certain RPMs. A small amount at 3k, then full force at 4k. It's definitely noticeable.
 

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Discussion Starter · #7 ·
That's exactly what I'm talking about. I don't feel anything at 4k anymore. I've owned the car since October and for this to be happening now, makes me worry.
 

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The power bug has hit! It never goes away, you always want MOAR!

Even then, I still feel the CVVT kick in at certain RMPs. A small amount at 3k, then full force at 4k. It's definitely noticeable.
CVVT works at low RPMs.
 

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Discussion Starter · #9 · (Edited)
I was under the impression that cvvt was constant, meaning that it was always being adjusted, despite the rpm.

Whatever the case may be, the boost in power that I felt so strongly at 4k is no longer there and it has me scratching my head.
 

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Discussion Starter · #10 ·
Ok, I just hooked my ultragauge up and while the timing adjustments are continuous, the most significant changes are at low rpm's. Most of the vvt engines I've dealt with in the past also had lift, which was actuated at higher rpm's.

I went ahead and did the seafoam and oil change anyway, but I'm gong to attribute this to a combination of the change in temperature and the fact that I'm getting used to the power.

If by chance my SES light does come on and I have issues down the road, I'll be sure to post.
 

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^ true, it's constant but it focuses on lower rpm's. It will adjust at higher RPM's given it a situation when it's needed.
 

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^ I always notice it when at partial (1/2 to 3/4) throttle. Around 3-4K is when it really hits. Full throttle it's not really as noticeable.
Unless the sudden surge of power isn't the CVVT and instead a little spritz of nitrous.... so what am I feeling then? Is my butt dyno broken?
 

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You just answered it. At a dead stop, the CVVT will engage extremely early at WOT, and stay engaged as long as the driver is still keeping WOT. This is why you don't feel a jump in the higher RPMs since CVVT is already engage.

Now if your just cruising at ~3500 rpms, and you get on it, you will feel the CVVT engage, giving you the extra power sensation.

It's only engaging at 4,500 rpm's because more then likely you are at a roll and CVVT wasn't engaged until you got on it. Same goes when you are a COMPLETE stop, you feel the initial pull, but don't feel anything after since CVVT was engaged from the moment you were at WOT. Get it?
 

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Discussion Starter · #14 ·
Update:

I think I found the problem. It appears that the tech who changed my oil used the wrong filter. It fit, but it was tiny and didn't have a built-in pressure regulator.

The car seems to be back to its old self again. I just hope there was no damage done to the internals.

I lost faith in the dealer techs shortly after I bought the car, now I've lost faith in a private shop. You know it's sad when you feel like you're the only one who can repair your car correctly. It makes me feel bad for the people who depend on mechanics, but lack the knowledge to catch the bad ones. Ugh.
 

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Sorry to hear that bro. Glad you figured out the problem early. I'd just buy the OEM filters in bulk (cheaper) and just give it to whoever it is that's servicing your car each time you need to change the oil. Just so you know they're using the right part.
 

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You just answered it. At a dead stop, the CVVT will engage extremely early at WOT, and stay engaged as long as the driver is still keeping WOT. This is why you don't feel a jump in the higher RPMs since CVVT is already engage.

Now if your just cruising at ~3500 rpms, and you get on it, you will feel the CVVT engage, giving you the extra power sensation.

It's only engaging at 4,500 rpm's because more then likely you are at a roll and CVVT wasn't engaged until you got on it. Same goes when you are a COMPLETE stop, you feel the initial pull, but don't feel anything after since CVVT was engaged from the moment you were at WOT. Get it?
Obviously I'm going to feel a surge of power when I stomp on the gas. What I mean is when I'm coming from a full stop, or even a rolling start, holding it in gear with shift-tronic, I can very clearly tell at certain RPMs that there is more power. It's not noticeable WOT, but at partial throttle (and hold it there) when the engine labors a bit in one gear (4spd has a very long 2nd gear) it will kick a little at 3k and 4k as the timing adjusts to get better power/efficiency under the higher load. Or do I have the only Forte in existence with this unique gift? Do I have a super Forte? I know I'm not imagining it. Friends feel it too.

@OP: I'm glad you figured it out! That's exactly why I change my own oil, incompetent mechanics (trained monkeys)
 

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I do my own oil changes now that I don't have a warranty to worry about :p
 

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Discussion Starter · #18 ·
Haha. Thanks for the replies, guys. There definitely is a noticeable change in power at about 4k and half throttle. Actually, I start at wot, but when I hit 2nd (6-speed) I always back out to half throttle just before 4k to feel the extra power. That was how I noticed the issue originally. That surge disappeared completely (even at half throttle).

I suppose the turbo might cure a few things. I doubt I'd crave more power and that whole lame warranty thing would no longer be an issue. Lol
 

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Obviously I'm going to feel a surge of power when I stomp on the gas.
OK
What I mean is when I'm coming from a full stop, or even a rolling start, holding it in gear with shift-tronic, I can very clearly tell at certain RPMs that there is more power.
Thats cause of CVVT engaging and the cars normal power-band.

It's not noticeable WOT,
The reason why you don't notice the drastic change in power at ~4,500 rpms when you are at WOT is because CVVT is already engaged, so your engine has already adjusted duration and timing on the cams.

but at partial throttle (and hold it there) when the engine labors a bit in one gear (4spd has a very long 2nd gear) it will kick a little at 3k and 4k as the timing adjusts to get better power/efficiency under the higher load
When you are at partial throttle, CVVT won't engage until there is a situation when it's needed.

Or do I have the only Forte in existence with this unique gift? Do I have a super Forte? I know I'm not imagining it. Friends feel it too.
I've never denied the car being able to adjust timing and duration at higher rpms, find a statement where I have.
No, you don't have a super Forte, you just don't understand CVVT, let alone basic VVT.
 

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Yes I know how CVVT works, and why it works.
I'm just gonna back out of this now, no flame wars are needed.
 
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