Few issues involving air mostly

SON240sx Automotive
1

Hey guys,

My car is getting worse mileage than it should right now. About 400 in the city, sometimes less which bugs me.

One thing I notice alot recently is that my idle is wacky… doesnt ever dip below 700 although sometimes it chills at around 1000-1500 then slowly drops back to 700 and very VERY mildly fluctuates in that area which I think is normal. there is barely ANY change thats not my concern. My concern is why it is sitting at 1500 for a while. That is for sure wasting gas.

Next thing, I know I need a tune up. I did put all new fluids in everything in the car. Although I noticed a rip in my air intake right near the intake manifold/throttle body. I believe air is either escaping or leaking in. If it were leaking in and bypassing the MAFS then that would mean I should be running lean, which is not the case, I believe it’s running slightly rich due to higher fuel consumption rates. And because of teh pressure of the air being inducted through the intake I do believe that air would only escape and not enter therefore still getting a wrong reading from the MAFS and causing it to run rich.

The problem also persists under breaking. When I shift to neutral I can see that the RPM is at 1000-1500 and stays there then eventually drops.

Also, occasionally when I see this I try to revv a bit to see if it’ll go down. But whether in gear or not, when I rev it’ll come down to around 1000-1500 and stay there just as before.

Just a side note if it matter or helps you picture it in your head, it is an SOHC motor.

Another problem I have been encountering is while braking and coming close to the stopping point, doesnt matter if im in gear or neutral the car seems to virate alot in different areas enough for me to vibrate myself a bit in my seat while deccelerating between 2000-idle (700) or it does that stupid thing where it chills at 1500, either way I get the vibrations.

Another sidenote is that my motor mounts are in pretty bad shape and I am sure that causes some vibration in the cabin aswell.

I think thats pretty much it for now.

Any and ALL help is appreciated. I know there are plenty of tech guys who I’m sure over the years have encountered this problem, so please post and try and help me out here.

p.s.- Sorry for the loooong post, I just like to be as descriptive as possible.

Thanks,
Dan

2

It might be the o2 sensor for the rich mixture

3

Fix your rip in the intake, its most likely the cause of the strange idle issue.

4

Ya, i was thinking that while I’m at it, I may aswell clean my throttle body and MAFS.

Anyone know any good brands of cleaners to use for either or both of these parts?

5

Any throttle body cleaner will work, not carb clean though.

Or you can try some sea foam… thats good stuff as well.

6

will work for MAFS aswell?

7

try some Gunk “intake medic”

8

after you do that, disconnect the positive and negative on the battery for 12 hours, then plug it back in when u get into the car the next day. and start it. BUT don’t touch the gas until its at idle. i say this is because you can let the ECU learn a new curve becuase you are fiddling with its air consumption, it remembers to do this and that. erase its memory, so it can start fresh. i did this when i had a peice of newspaper stuck in my intake filter. i cleaned it out, and it was still dipping like a whore while driving, and idle. reseted the ecu, and it idles and drive great (previous KA).

about the vibration when stopping, it could be your brake rotors being warpped, shit in the brake pads or you pads have too much play on the shims. check those out.

hope this helps steve.

9

The vibration on deceleration only occurs between 40-30 km/h and my second gear bog occurs in the same rpm and speed range where i get bogging between 2000-2500rpm = 30-40 upon acceleration in 2nd gear.

10

I don’t think it’s my brakes, because I don’t even need to be braking for this vibration to occur. Plus I just got all new rotors and pads.

11

for the bogging it could be your 02 sensor as well from the rich mixture, i dunno just an idea.

12

i would suggest you try and clean your IACV.

13

I had a similar bogging problem in my coupe and vert. The TPS was the problem in both cases.

14

I also thoughi Intake Air Control Valve (correct?). Never thought about throttle position sensor though… it makes sense though as if my throttle thinks its closed to the computer, however in reality it’s actually still slightly open.

How do I clean my IACV, and would the TPS require replacement?

15

I’m going to do all this stuff very very shortly!

16

take off the tube running to the iacv ( i dont know where it is on a sohc ka exactly but its pretty self evident)

get some throttle body cleaner or idle air cleaner (crappy tire has that shit) and spray away into the tube

i can help you with this later today if you want… just holllaatchaboyyyy

17

Are you back home Mike? I’ll call you tommorow, ok?

18

Mike, I went out and bought the TB cleaner and some injector fluid/cleaner for the nozzle because some old person at the store was explaining to me about how the the TB works and that it can leave drips in your combustion chamber or on the nozzle of the injector and it will spray innacurately. So I got some of that, it is suposed to be poured into the fuel tank with about 1/2 tank of fuel in there and run through.

Mike, I’m going to call you as soon as I get my hands on another intake since i have a tear in mine.