Jamied

Okay i have a 2000 Civic SI

my car is throwing a check engine light. i work at a acura/audi dealer and i got a acura tech to scan it and he said it was the Idle Air Control Valve. so i replace it, get the code cleared and it came back on the next day.

I dunno what it could be. When im at idle and my temp guage gets close to half way, my idle goes up and down..and when i give it gas, it kinda bogs out..

so then i just turn my car off and on and it is fine until it gets back up to that temperature again. i dont understand what is wrong with my car. i just bought it like a month ago and its pissing me off already!

someone help please!

Jamied

bump

Jamied

someone help me!

Hockey27925

could be numerous things like a bad tps, a coolant pocket, bad throttle body gasket, or bad wiring to the iacv

Jamied

what about a bad o2 sensor? would this be the result?

symph0ny

An o2 sensor that was bad enough to make your engine rev up and down would throw a code every time you run the car. When they go out, the reading is too far to one side, but it doesn't go back and forth.

My guess would be the cooling system... my car started doing that when it blew a hose.

Jamied

yea well i got the code cleared right after i put in the valve, and the next day it came back on, and now it just stays on all the time. my idle is messed up all the time, the light is on all the time, but when it gets mid-temp, it starts bogging out..

Jamied

anything else guys?

Jamied

any other ideas? come on

Hockey27925

try replace the tps, cleaning the throttle body n see if you have a vacuum leak or a cracked evap canister, if u need a tps or a map sensor i have them 50bux each

djsire

i would check the coolant. open up the radiator cap(while the car is cold) turn it on and let all the bubbles come out, add coolant if nesascry. shuold take about 10 mins

Jamied

how would the TPS have to do with the problem?

and the coolant thing didnt work

EgGriff

is the check engine light throwing the same code? you said it lit up again, but never said it was the same code as before..

Hockey27925

well if you tps spring was bad it could cause an irratic idle ive had this personal experience

Jamied

yes its throwing the same code..

ima put it on the lift tomorrow here at work and see if i see any wires or bad hoses somewhere.

EE_Chris

You really do sound like you air bubbles in your coolant. Had you done anything recently concerning the coolant system? How did you bleed the coolant?

It's like this: When the car is cold (ECT says so) and you start it up, the idle should raise to keep the engine going and get it warm. When the engine is warm (ECT says so), the idle is brought down to normal speed. If you had air bubbles in the coolant, it'll have the ECT sending signals back to the ECU saying the engine is cold/hot and you get a surging idle.

Aside from that, vacuum leaks cause this problem too. Honda uses a fuel cut on decel strategy to cut off the injectors when coasting to save gas. The only two inputs needed to activate it are RPM and TPS. If the TPS shows the throttle to be closed (like during decel) and RPM is above 1100rpm, the fuel injectors are cut off. I make no mention of vehicle speed because it doesn't matter. So if you had a vacuum leak, which causes engine speed to increase in speed-density systems, and the engine speed got above 1100rpm and the throttle was closed, the ECU cuts the injectors off. Engine speed falls back below the threshold, ECU cuts injectors back and in addition to the vacuum leak, the process is repeated over and over.

But mentioning that this happens when your temp gauges gets to be about hot...seems pretty coincidental to me.

Jamied

so what do you suggest i do Chris?

EE_Chris

Tell us how you bled your coolant, step by step, so we can at least be sure it was done correctly.

You may have mentioned earlier, but have you tried shooting some throttle body cleaner into the IACV hole after the engine has warmed up?

On my stock 99 hatch, back around the 160k mile mark, my IACV froze up on me. After driving around with that bullshit to get the engine warmed up (and hoping warming up the IACV would allow the cleaner to work easier), I went ahead and sprayed it liberally with the cleaner. Eventually it just freed itself up and hasn't given me a problem since.

Is the engine stock? Have you messed the idle adjustment screws at all?

Jamied

no i havent messed with the adjustment yet.

i JUST bought a new IACV...thinking that was the problem, because my old one was so dirty. and it didnt fix it..

i havent bled my coolant at all. i dunno how to do that

EE_Chris

Starting with the engine cold and the heater contols to full hot (without the fan being on), take off the radiator cap and start the car. Just let it sit there and idle till the cooling fan kicks on once....or just wait till the temp gauge has gotten hot. No, coolant will not spill out. It may burp a time or two, but it's not going to spew out as if the engine was real hot and then tried taking the radiator cap off.

You need to make sure to put the heater controls to full hot because coolant needs to be allowed to circulate through the heater core too.

DO NOT mess with the idle screws until all hope is gone and you've done everything you possibly could to remedy the situation. Just about all of the time the screws are fine but people mess with them and THAT really puts a bind in trying to troubleshoot idle problems.

Jamied

alright ill try to give it a try

Jamied

okay another question, how long should i leave the cap off for? from when the motor is cold until the cooling fan comes on? then jus put the cap on? and turn the motor off?

EE_Chris

10-15 minutes should do it. Shut the engine off and put the radiator cap back on. I mean, I did it once in the winter time and the cooling fan never kicked on but eventually you start to see a little steam and you look at the clock and whadaya' know..it's been about 10 mintues or so.

EM199dcs

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hockey27925 &raquo;</TD></TR><TR><TD CLASS="quote">could be numerous things like a bad tps, a coolant pocket, bad throttle body gasket, or bad wiring to the iacv</TD></TR></TABLE>

I agree with the throttle body gasket. I put it on backwards on my 99 si and it fucked it up when i turned it on. Then realizing i turned it back around. lol. maybe its the gasket??? Thats weird though.

ZipTieGUy

stop giving him these stupid suggestions like throttle body gasket.. this dude seems like he doesnt know much about cars so you think the throttle body gasket will be the problem

thats what i hate about hondatech when someone has a problem people start pointing to some crazy *** ****

start simple first, you might have a vacuum leak, or on of the hose around your intake manifold is plugged into the wrong thing