paradise57

Okay, I have a 99EX, and here's the deal--my car idles fine 90% of the time, but when it's fully warmed up and I turn it off--like when I stop at a store, run in and come back out--when I crank it again, it fires up and idles, but really low. I started noticing this when I installed a DC header which rattles when the engine idles low.

Adjusting the IACV doesn't help because it ONLY idles low when I crank up after it's warm.

It doesn't stall or anything, but makes my header rattle, which is annoying.
Is this normal or is it indicitive of a problem with the IACV or the charging system?

Any thoughts?
TIA

ekb18cCivic

exactly how low is it idling??

paradise57

Well--that I don't know, exactly, since I dont' trust the stock tach. I would say probably about 200-300 rpm lower than normal (650, I think, is normal).

paradise57

bump for the AM

boostin4drcivic

mine does the same. i say it just needs the idle adjusted using the idles adjusting screw near throttle body. im just lazy and havent done it yet

tbcmorris

i dont think the idle is the problem. your car warm sholud idle low...i agree with not trusting your tach. but i think the exhaust rattling comes from the fact that honda didnt use a flex pipe on the elbow connecting th cat to the exhaustmanifol. so i think yu might have to live with the rattle. i just put my foot on the gas a little if it annoys me at like a stop light or what not.

HXMan

Mine does that occasionaly also, but it happens so rarely I'm not going to do anything about it.

civ98

i just installed a dc sports header last week as well and i had the same rattle at low idle...

I finally figured out why I was getting a rattling noise at low idle or while in reverse or at a stoplight... at first i thought it was the heat shields under the car, i took them all out and i still got the noise...then i tried a new donut gasket near the cat... well on the dc sports 4-2-1 header, the tail portion on which the donut gasket fits on to is about 1/8" too long (it sticks out past the donut gasket, on the factory header, it is flush with the end of the donut gasket)...so at low idle that 1/8" of exposed header past the gasket was rattling against the inside flange of the cat...now i just need to find a 1/8" spacer to move the donut gasket out a bit so it's flush with the end of the header...either that or take out the entire header and file down the end about 1/8"...

I hope this helps out you guys who may be having the same type of rattling noise after a dc sports header installation.

paradise57

dude--you are the bomb! That is my problem exactly, I think--searching other posts about rattles, it seems the DC fitment is the main problem. I hadn't isolated it to the donut gasket, but that makes total sense. I will also try to find some remedy for the problem--

Thanks to everyone for the help--
more ideas still appreciated,

Mark