Rough idle

IshaanIan · Sun Mar 09, 2014 6:24 am

Everyone seems to be under the impression that this has something to do with the CVT units and their hill hold or creep function? Well I remember this happening a year back in my 6 speed manual. The problem only lasted a day so I just assumed it was fine to carry on because the issue never came up again. What exactly causes this? The K&N filter reason doesn't really make sense to me, plus I have the stock one in my car. Someone mentioned something about the alternator? Can anyone shed some light on this?

Bizzenn · Mon Mar 10, 2014 11:53 am

I just put a drop in K&N in and there is really no change. I will say when coming to a stop, it doesn't drop revs as bad as it did before. Its not the hill hol function causing it as I have tested that by disabling it accidentally. It only does it in Drive, not reverse. Its gotta be a programing issue, tranny or Torque converter. Thats the only thing I can think of. However, I don't think the car is necessarily malfunctioning, it just is what it is.

Mon Mar 10, 2014 12:10 pm

Last week the outside temperature was much colder (single digits) than previously when I had taken notice to the conditions in my earlier posts. The low idle rumble was much more pronounced last week vs. earlier. Outside temps have much to do with A/F mixture which obviously affects idle.

btw, I run stock Suzuki air filters in both the Kiz and The SX4.

Bizzenn · Wed Mar 12, 2014 1:53 pm

I was thinking about disconnecting the battery and cleaning the MAF just to see if there is any change. Worth it or not?

Wed Mar 12, 2014 4:47 pm

Bizzenn wrote:I was thinking about disconnecting the battery and cleaning the MAF just to see if there is any change. Worth it or not?

I would clean the MAF sensor just for the reason of using a K&N filter alone. Been there, done that. K&N filters are great for air flow, but they don't filter better than OEM/traditional filters.

~tc~ · Thu Mar 13, 2014 3:53 am

The big issue is if you over oil the K&N, the oil will foul the MAF

Bizzenn · Sat Mar 15, 2014 7:13 pm

I've always used them and never had an issue with the MAF. As far as filtration, I have wiped the box with a rag after 10k miles and the box was clean.

Sun Mar 16, 2014 12:04 am

It's been proven that K&N filters don't filter nearly as well as paper filters. Whether is causes any problems or not depends

http://www.nicoclub.com/archives/kn-vs-oem-filter.html

Sun Mar 16, 2014 1:45 am

bootymac wrote:It's been proven that K&N filters don't filter nearly as well as paper filters. Whether is causes any problems or not depends

http://www.nicoclub.com/archives/kn-vs-oem-filter.html

I've read similar things in other sources. K&N is a good product, but they are really intended for maximizing air flow, not filtration. They got started in Riverside, California where the dirt biking, offroading, and sand dune vehicle scene is big. I'd know: the Inland Empire (Riverside and San Bernardino Counties) is where I'm from in California. It's also where the whole "Bro" phenomenon originated.

The whole idea that got K&N started was to have a filter that wouldn't suffocate so quickly from dirt kicked up on dirt trails. The oiled cloth filter media was ideal because it trapped dirt particles while it allowed more air to pass through. It was also more economical as they could be washed, re-oiled, and re-used. This was especially important if you were constantly exposed to dirt and buying new air filters frequently was a burden. Basically, these filters were initially intended for offroad vehicles like dirt bikes, offroad truck, dune buggies, etc.

They then became more widespread in other vehicles because of the higher airflow qualities they have however, when you look at their history, you can see how filtration quality was never their main goal. It was about performance, especially when caked in dirt. The compromise for better air flow was the quality of filtration. K&N filters can't filter smaller particles as well as OEM filters. Tests like the link above have proved this for years.

I used to have both a K&N panel drop-in filter and also a K&N-like Short Ram Intake in my Impreza. I went for the SRI because I felt that the drop-in had no noticeable performance improvement. I definitely noticed an improvement in performance with the SRI, however, deemed it wasn't a must-have for my future cars. I now use traditional OEM-grade air filters simply because I care more about filtration quality than air flow.

Basically, I see it like this:
If you want better performance (airflow), go for a K&N or similar filter.
If you want better longevity (filtration), go for an OEM-grade filter.

Sun Mar 16, 2014 3:04 pm

Had a fresh, properly oiled one in my 2000 Dodge RAM. Went wheeling at Paragon in Hazelton, PA which is an old coal strip mine property. a bulk of the access road type trails (green stocker level) are extremely dusty in the summer. Throttle body was caked black with oily coal dust. One Saturday of light wheeling caused me many weekends of tearing apart and cleaning the entire intake system. Not to mention what the ingested coal dust did to the engine.

K&N = race and performance applications, not daily driver duty. Paper is proven in that arena.