Dane Ckark

Hi I know my cars idling really bad files at about 2 grand then goes down to about 1 grand and when I come to stop after driving it bounce up and down if any acc is on it'll rev at 2.5 I know its o2 related because the guy I got the car from slammed it on it's bullocks but I'm curious if there's any tips or tricks that I can do to avoid ripping the o2 sensors out and wasting the harness whenever it scrapes or bottoms out aside from New suspension I know I need one and don't really wanna cut corners but right now I don't have the 400$ for New suspension and really need to get the o2 sensors back in so the car will stop guzzling gas like an alcoholic does cheap vodka I legit getting worse gas mileage than trucks with 454s lol I was thinking if possible maybe rotating the section of the exhaust where the o2 sensor mounts are so that the wires and sensors will be getting more space between them and the ground if not that then what else can I do please help

OneJzSupra

I hate to say it but I think you have a different problem. That second O2 sensor really just measures how the cat converter is doing it would have a min. effect on how your car runs.

Dane Clarke

Doesn't have a cat on it and the code reader threw o2 sensor codes

Dane Clarke

Not too mention the downstream sensor came out completely and the upstream the harness wires were ripped out

ezone

O2 sensors have nothing to do with the idle RPM bouncing all over the place.

Any new fault codes related to IAC or idle speed?
Look for vacuum leaks, and see if the IAC valve is stuck open.

Dane Clarke

Ten four buddy and thank you does the iac have a relay or something because he did say another code but didn't mention iac from what I recall and the o2 sensors would effect gas mileage and from what I've found while Google searching and on here in the sticky threads. Say about the idle and rough idle if I remembering right I'll go back and check re-read but they give the ecu readings to regulate fuel ratios correct

ezone

what specific car do you have?

Dane Clarke

03 civic si ep3

Dane Clarke

K20a I wanna say a k20a3 it's the US model

ezone

So it's a K20 engine....different animal from the 1.7 LOL


Ok the engine will run without the O2 sensors connected, if you want to eliminate them from being any influence in the way it idles too fast....disconnecting shouldn't change anything there other than set O2 sensor codes.


Take off the intake tubing to the throttle body. Start the engine and use your fingers to block off the open hole in the side of the throttle body. If that brings the idle RPM down to a normal range or below, the IAC valve is probably stuck open. (If no change, then look/listen for vacuum leaks instead)

You might tap on the valve and see if that may jar it enough to change how it idles, that would prove it's a problem with being stuck.

The unit has a rotary valve that oscillates back and forth to change the size of the air passage. It can stick with carbon buildup. Sometimes you can soak it in carb and throttle cleaner and get it to free up, sometimes you have to take it apart to clean it thoroughly, sometimes it gets replaced.

Dane Clarke

Now will that iac issue raising the idle and bouncing the idle cause gas mileage to go down drastically or would the o2 sensors cause that or both lol I'm just confused how this things guzzling so much gas I'm even tryna stay away from the power band so I'm not using excess fuel I'm New to the Honda's and "vtec" lol and from what a buddy of mine who's a mechanic and Honda enthusiast he said stay outta the vtec powerband and the gas won't get eaten up as quick

ezone

The SI is not a real fuel efficient car to begin with.....and you didn't post any relevant supporting info that deals with an issue with economy.
Don't worry about that until you get it running right.

A catless downpipe and stuff? That missing catalytic converter can affect economy (believe it or not), so can O2 sensor faults depending on how it fails, but if you bought it this way then the previous owner probably didn't care about the CEL being on, nor economy at all....(rode hard, put away wet?)

The IAC and idle RPM issue would mostly just make it annoying as hell to drive slowly. Probably no huge effect on economy other than you tromp the gas pedal to get through the surging.

Got a scanner? What are the ST and LT fuel trims at?
Coolant temp after warmup is....?

Got new codes?
What are the codes for the O2 sensors? (standard OBD2 format of "Pxxxx" please)
Does it have stock ECM or a tuner? Kpro? Flashpro?

Dane Clarke

I wanna say something like that's stock cause the dude I got it from didn't seem like the type to do something that it's a kinda half assed Frankenstein upgrades lol

ezone

But you say cat is removed? That sounds like a typical rice racer wannabe move.

Dane Clarke

And I wanna say it's rated at like 26 or 27 highway and like around 20 city or something

ezone

Under ideal conditions.
That doesn't mean you'll ever see it in real life.
Depends on traffic, car condition, and how you drive.
Stop and go traffic kills gas mileage, bad.

My own car is rated at like 38 or 39 mpg highway.....I'll be damned if I can get anywhere near that at real interstate speeds.
More like 34-35 mpg @ 70-75 mph
32ish or lower @ 80+ mph.
85+ mph gets me down to 29 mpg or less LOL

Wait, never mind...I do the speed limit at all times. Yep, that's me. Law abiding citizen here!

I can get over 40 mpg (I've seen it hit over 50mpg too on factory LRR tires) if I go rock steady 50-55 MPH without slowing or traffic, but who really ever does that?

Dane Clarke

Yeah he riced it out dude slammed it on its ***** and wasted the ball joints tie rods ends sway bar linkages cv axels he put lowering spring on stock struts/shocks in the rear and lowered the **** outta the front with wheel wells removed so the tires fit with the rear with a noticeable camber so I'm basically using it as a learning platform reverting back to it's formal potential and some when the serious funds are acquired I'm working on getting raceland coilovers preferably the Ultimos if I can and when I save up the money I would like to put a jdm type r k20 in it for ***** and giggles lol get rid of the camber get a proper exhaust cause it's kinda rigged up luckily the motor seems to be strong and reliable aside from the idle issue which isn't major do need motor/torque .mounts which when we did the stage 2 street clutch the mounts really got messed up they were old and worn so when we took it out they kinda went to **** so I gotta little work ahead a me more than I anticipated but I was really unfamiliar with lowered cars and the issues if nit done properly and just so happens it was one of those cut corners rice type Honda owners not a do it right so it's respectable build and I learned a lot after I got it unfortunately but it'll give me a lot to learn in the process so I guess that's the positive of it my first Honda I always like hatches and seen the ep3 and fell in love with the ugly duckling of the bunch lmao I'm excited to take something all riced out and restoring to it back to a respectable Honda build even muscle heads are like Damn ok lol or at least make em eat there trash talk lmao

Dane Clarke

Well good sir you were correct I borrowed some spanner wrenches from my buddy lifted the front about an inch now she's riding 100 times better even with the bad ball joints and linkages lmao and I had to plug about a half inch hole in intake pipe cut some of the pipe and get New filter they straight rigged it up with an intake for another car but when I was doing all this I plugged the hole in the maf intake and it dropped instantly so now I'm searching the web for a cheap replacement iacv because all the parts stores tell me I need to go yo manufacture for the part lol will the high idle effect the gas at all

ezone

A hole (air leak) between the MAF sensor and throttle body might mess with fuel delivery calculations, and gas mileage.


\Did you try tapping on the bottom of the IAC valve to see if it may start working again?

Did someone leave the IAC valve unplugged?

Dane Clarke

Where's it's located there's not really any room or angle to get in there to tap it its literally on the bottome of the maf/intake manifold I try spraying the heck out of it with throttle body cleaner to no avail the way the cars been treated and maintained I'm thinking it'll be better to just replace it the person I got it from really didn't do things the right way he did them the easy half assed way the intake pipe was almost plugged by the inside of the actual filter it was inserted like 4-5 inches into the filter almost bottoming out on the back end or the top of the filter I'm shocked the car runs as strong as it does with some of the stuff this guy has done to this car I naturally assumed someone with a si ep3 would've taken better car of the vehicle since the so is more or less the civic enthusiast based vehicle but I also should've known it isn't impossible for some ricer guy to get his hands on one and waste it really appreciate the help btw thank you

Dane Clarke

Oh an the hole that I plugged was like for a vacuum line or some kind of plug in sensor like I said the air intake pipe isn't even for this vehicle it was for lack of a more accurate word "modified" to work with vehicle and since it wasn't specific to this car he left. Hole in the intake between maf and air filter

ezone

My mistake, you said 03...I think that has a MAP sensor not a MAF sensor.

An open hole could let trash get in and block open the IAC valve?


Maybe you can remove the throttle body off from the intake manifold so you can work with the IAC valve on a work bench?

Dane Clarke

I think that's exactly what happened because when I got it the engine bay was stained heavy with limestone dust like he lived on a limestone road and it was all over in there because he took wheel wells out to fit the tires when he lowered it he didn't even adjust or set the rollovers the adjuster nute on the coilovers weren't even threaded on they were resting all the way at the bottom right where you start to thread them on to set height so the springs weren't even doing anything you could literally move them up and down because they didn't have any pressure on them smh which also explains why even on minor bumps the entire car would feel it extremely hard like a big slam on a tiny one inch high one inch wide bump where they fille a crack or gapped the road a little I ran outta time when we were tinkering on her today had to get ready for work but I'm prolly gonna take the iacv off come Fri and try and clean it super good cause somethings causing me to get real bad gas mileage filled her up for the most part it was on full but didn't fill it till she wouldn't take any more lol and used a Qtr and a eighth a tank on 70 miles of driving based on specs I've read if I'm remembering correctly it has a 12 gallon tank so on 70 miles I used about 6 gallons around 11 mpg lmfao and that's staying outta the vtec power band for the most of the driving and the only things I can conclude it to be is the iacv causing the high revving resulting in more gas usage and or the o2 sensors not giving ecu proper exhaust readings to regulate the fuel ratio mixture

Dane Clarke

Also another issue is going into 5 and reverse is hard as heck not going in to gear but getting the shifter over to the right to be put in gear and also it's not wanting to shift into gear while driving which at first I chalked up to it being a New car and me not familiar with the location of shifter on the dash and that it had a short throw installed it started off with me seeming like I was missing second which it was like it just wouldn't go in but ia assumed it was me being unfamiliar now since I've drove it quite a bit its been behaving the same but now going into forth like when I go from third to fourth it'll do it could they have messed up putting the linkages back together when installing short throw or are these symptoms or issues with short throws I'd imagine this isn't a normal problem with short throw shifters or has anything to do with short throw shifter itself and I've looked at the linkages on the tranny and doesn't look like anything in the way of them there's almost absolutely nothing around them

ezone

STOP ! You're killing me here.
Learn how to calculate fuel economy correctly.

Get a notebook (or note on your phone, whatever) and get into this habit, do this every time and you have to be very consistent about filling to the same point every time or else you throw off the calculations.

Fill tank until the pump clicks off by itself
write down odometer (or reset trip meter to zero)
Drive it until tank is nearly empty.

Fill tank until the pump clicks off by itself
write down gallons of fuel
write down odometer (or note miles driven and then reset trip meter to zero)

Calculate: Miles driven divided by gallons it took to refill = MPG for that tank

Drive it until tank is nearly empty.
Fill tank until the pump clicks off by itself
write down gallons of fuel
write down odometer (or note miles driven and then reset trip meter to zero)

Calculate: Miles driven divided by gallons it took to refill = MPG for that tank

Drive it until tank is nearly empty.
Fill tank until the pump clicks off by itself
write down gallons of fuel
write down odometer (or note miles driven and then reset trip meter to zero)
Drive it until tank is nearly empty.

Calculate: Miles driven divided by gallons it took to refill = MPG for that tank



If you do this consistently, you can average out those times your pump doesn't click off at the exact same time, and you can spot trends

Dane Clarke

Ok lol this way I get a lot more accurate of an idea than doing it this one time lol now that aside do you think that I used an eighth a tank shy if a half tank on 70 miles is kind a off or am I just bugging out lmao and this is totally unrelated to what were talking about but I know the jdm k20a type r with the 6spd lsd trans makes around 212hp but I hear the type r and the k20a3 I have function differently and don't quite perform like each other most of what I heard is the vtec power band isn't like the k20a3 I'm just curious because I was kind a wanting to do a swap in the long run but I was under the impression aside from hp an tq differences and the 6spd lsd trans they behaved the same powerband wise but with what I've read Idk which is better I assume the type r is but I'm a Honda noob so wth do I know lmao again thanks for all the help dude and your patience of a saint dealing with my stupid questions lol

ezone

You're buggin on the gas mileage---until you can actually prove what it really is on paper. Every time.


Unpunctuated run-on sentence posts make English teachers cry.
The wall of words shiz is effin hard to read.
Break that down, put lines of space between different thoughts.
kthxbai

I don't need to know or really care much about all the little differences between engine versions, I deal with mostly stock stuff.

Google K20A3 (or whatever engine you want)...Find and check the wiki entries for Honda K engines. There's probably a few answers there.
Maybe temple of vtec has some answers too.

OneJzSupra

= ) Spoon feeding!

Dane Clarke

Lol sry about that.my phones a pos and punctuation is a pain. And I suck at punctuation as well lmao. But when I first got the car when going to shift into second gear. It was like it didn't want to go into gear i assumed it was me being unfamiliar with it. But drive it yesterday when I put that 70 miles on there that I was using in my mpg equation lol. And it's doing with fourth gear now. Did it about 4-5 times last night. Could it be the linkages were reinstalled incorrectly when the previous owner put the short throw in it? Or could it be something worse? I really hope it's an easy fix. Also moving the actual shifter over to the right to put into 5th or reverse its like someone's pushing it back towards you. What could cause that? Btw hope this may be easier to read even tho I'm sure the punctuation isn't very good still lol.

Dane Clarke

Lol nothing wrong with giving some help. I've done a good deal a research. All the relatable issues are on forums and none were exact to my issue only somewhat similar. And with engine the only differences ppl note are the internals and the hp/tq output. nothing really on how it behaves compared to it's baby brother k20a3 lmao