iboughtas2k

im desperately in need of finding a solution to this idle problems im having
my car idles perfect with AC off or headlight off, it runs like a dream

but whenever i turn on the AC or headlights, the idle goes up to 1200rpm
i believe there is no vacuum leak since it idles fine when they are off
further more the idle starts to surge when AC is on like dropping down to 600 and then jumps up to 1200 as the compressor kicks in
this makes my car vibrates, it wasnt a big deal before but now that the weather is getting hot, i often turn on the AC and its getting really annoying!
just with headlights on, idle is stable at 1200rpm but it is still high and i hate to hear my engine idling so high
AC blows cold consistently whether car is running or stop
IACV is clean, new spark plugs gapped at .51, no over heating or coolant leak

i have a HID and fog light, no after market stereo but i do have some alpine speakers
im leaning towards the altenator that is bad, can i just take my car to autozone for them to test the alternator instead of taking it off the car and take it to them for a test?
or possibly the battery but battery seems to be good with visual observation
one more important fact, i just noticed when i was running low in gas, the fuel indicator light came on then it dimmed to the point i almost thought the light went away i dont know if this problem is related to my idle problem if it is, then it explains that there is something wrong with charging system that is causing this high rpm issues

or maybe my AC compressor is bad


any help would be appreciated
this is driving me crazy!

iboughtas2k

Please help!! I bought this car to DD so I could keep the mileage low on my s2000 CR
And now it's making me wanna DD the S

Former User

Use the service manual procedure for your engine to adjust the idle speed.

iboughtas2k

thank for the reply ron
you have been very helpful with my cruise control issue last time
so you are talking about the idle adjustment which u have to take out the IACV(not completely but off the intake manifold) ?

but i dont see how this would help my problem because my idle is steady at rest with them off, perfectly at 750 or so..
so if i adjust the idle lower with headlight and AC on, wouldnt this cause my car to idle lower than normal with the AC and headlight off?

Former User

Important information is missing ---> What car and engine do you have?

iboughtas2k

^^^^^
sorry I have a 2000 civic si with B16a2

that_boy_sammy

Have your alternator tested it may be going bad. When turning your headlights and a/c on those units are taking up a bit more power and your iacv unit/connector is not getting enough power, but when your a/c and lights are off it has enough power to support your iacv. That's what im thinking, sounds like its the problem.

Former User

https://honda-tech.com/forums/showpo...8&postcount=12

iboughtas2k

I Checked the alt
Seems a liittlebit to over charge
Voltage was measured at 12.9
So it's fine. So is my battery
What else could it be?
I'm running out of ideas now

MrNastyEj2

Your iacv might be clean...but that doesn't mean your IACV motor isn't bad. In that case cleaning it won't make a bit of difference. Use an ohm tester and put both the wires to the terminals on the iacv motor. If you get between 10-15 ohms than the iacv motor is okay.

that_boy_sammy

I think battery voltage is supposed to be at 14.5?

iboughtas2k

Ok So I found out the problems. It was one of the vacuum line that running through to the fuel tank was lose. It's connected back and now the problem is gone

Former User

This should have affected the idle speed regardless of whether the A/C and headlights were turned on.

iboughtas2k

^^^
it really idled perfectly with AC or headlights off
but i have another problem, my CEL came on for P1456 so i took it to the dealership and thats when they found out about the vacuum leak

now idles problems are gone, but CEL just came back on for same code...
this Honda technician said everything is good and no parts have to be replaced but now CEL is back on so what do i tell the dealership so they wouldnt screw me over
i already paid over 320 for this P1456 issue and they gave me the car saying everything is good but CEL came on after 20 miles