Knn intake issues

[Mallardsx2]

Hello All,

I just had my muffler removed and had an 16" stainless muffler put on last week. I then followed up this with installing a KNN cold air intake. I installed it and it ran good but my fuel mileage is really sucking now. I lost 3 miles/gallon...Also it seems to be not using the MDI cylinder shutdown mode nearly as much. (Probably causing the ****** gas mileage) Is there any advice you can offer? Oh and before you say re-install the stock intake...Its gone..dad stopped by and lit the burn barrel on fire and everything around it...

I followed the instructions to the T and installed everything correctly. I only let the truck idle for a few minutes after installing the new KNN... should I have let it idle for 15 minutes?


Any help would be greatly appreciated!

 

[JJP71584]

I think that there is going to be an adjustment period for the computer. Try disconnecting the battery for 20 mins and let the computer reset or just drive it more. Last intake I put on stated that you should drive it for 100 miles because it takes the computer time to learn the new setup.

It's a guess but it might work for ya...p.s. it's MDS not MDI and I'm not sure that would really cause that drastic of a drop.

 

[quietpeen]

did you reset the computer

 

[Mallardsx2]

I unhooked the negative terminal while I installed it. Is that what you mean? I dont have a programmer hooked up to it.

 

[quietpeen]

it will take the computer time to readjust. I wouldn't worry yet.

 

[Mallardsx2]

I have put about 200 miles on it so far since the CAI and it seems to be staying right at 17... I was getting 21 on the highway....then I changed the oil to synthetic 5w-20 Pennzoil and changed the exhaust and put the CAI on it and not it gets terrible mileage...

Ok I'm done wining! Waaaaaaaaaa!

 

[Joshwaa]

Wait a sec... What muffler did you put on the truck and what did you do to the rest of the exhaust?

If you say Flowmaster that's your problem.

 

[Mallardsx2]

Its not a flow-master. But it sort of looks like one. I'll snap a picture and post it.

 

[Joshwaa]

These trucks are picky on their back pressure when it come to fuel mileage. Are the cats still on?

 

[Mallardsx2]

Yes The cats are still on it. The only thing I changes was the muffler. Here are a couple pictures of the muffler.

 

[Mallardsx2]

This muffler has packing in it. Its not too loud. Its just about perfect. I didnt notice the decrease in mileage until I put the CAI oi it.

 

[Mallardsx2]

Should the seal on the KNN filter box be touching the hood when I close it? Maybe I am getting too much air?

 

[Joshwaa]

What about the temp sensor on you CAI tube. Is that still connected and working?

 

[quietpeen]

Should the seal on the KNN filter box be touching the hood when I close it? Maybe I am getting too much air?

you can't get too much air. that seal is more to try to keep the hot air from the engine from getting into the cai.

 

[Mallardsx2]

How would I know if the sensor is working? Yes it is connected using the supplied harness and fitting.

 

[quietpeen]

i would think it would throw an error code if it wasn't working

 

[Joshwaa]

Well it is possible to bend the little sensor (it's touchy). Could give an inaccurate reading. Just throwing out Ideas. My be a heavyier foot on the pedal due to the new toys.

 

[Mallardsx2]

How much does that stupid little sensor cost?

 

[blackout11]

ya your k&n should not cause bad gas mileage unless you keep your foot into it lol, and you can never get to much air infact i made a tube for mine which give it 100% more air and it runs better,

 

[Mallardsx2]

Hmm..we have a stalemate...could it be my synthetic oil that I just put in it causing the problem?