Vaccuum, or however it's spelled..is a tricky word for me, and perhaps others to spell. Therefore, when I searched to no avail using all the possible spellings I could think of, I figured I'd post.

My car's doing this thing, where sometimes (more often then not) my cars idle will fluxuate up and down when braking or stopped. So, stoplights and signs, and occasionally on vehicle startup the idle bounces from like 800 to 500 over and over again. It's retarded sounding.. just wondering what if anyone has any ideas? It seems to be linked occasionally if not always with my holding the brake when stopping.. sometimes when i release the brake if im not in a rolling situation, it'll go away..

If this is something specific you all can think of I think I can tackle it myself, but if its no screw or something to adjust, guess its gotta go to the shop.

Thanks

 

Intake Air Control Valve (IACV)

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mikester_91 &raquo;</TD></TR><TR><TD CLASS="quote">Intake Air Control Valve (IACV)</TD></TR></TABLE>

You are to fast, not enough info to say that it is definetly the IACV...

Does it do it hot, cold or all the time.

Most commonly, on honda's three components will do this if you have eliminated a vacuum leak.

1. IACV (usually cold engine)
2. TPS (warm engine)
3. MAP (warm engine)

GOt a multimeter to test them?

fs

 

No, I do not have a multimeter.

Sometimes when I start the car, it'll start doing it - so i guess it can happen cold.. and definately when warm too.
and also just rolling into a stop in neutral or if I put it in neutral even rolling a decent amount and just wait a bit to put it into gear (in certain driving conditions or something) i'll hear it fluttering.

It's really messing with my head, I can hear it making the noise when im trying to sleep lol.

It never did this before my friend fixed all my CEL's, by replacing distributor and o2 sensor and vtec pressure switch, a few other things.. he thinks a vaccuum problem but doesnt have a vacuum pressure tester thing?

 

hey i had a similar thing but what happened to me was i had a air pipe somewhere under the fuel intake taken out somehow
and my car was revving from 800 to 1500 and back to 800.
this happend to me when i just bought the car and i was shitting my self so i took it to honda and they just placed it back in but i didnt find out where and witch one.
anyway now my car is still doing it like your situation 500 to 800 on stops and stuff but its not a worry to me it jsust happens to me sometimes.. so if anyone has a fix help us both.
ME i recons its got to do with somthing with the air and vacum...
good luck

 

i have got the same situation but my idle jumps are from 900 to 2000 rpm whenever i'm on neutral. And does your car lags? because my does lag especially when it's hot. I was thinking it was the O ring in my fuel injectors thats bad causing air leaks. But i havent fix that problem yet because i dont have any diagram on that yet.

 

yea thats how mine was and i was freaking it shitted me so much when i was driving on low revs about 1300 the car would jump up and down and it ws the air hose.
try plugging all the hoes in i dont know how mine went off i recon it happened when i was installing my system must of hit a hose off or somthing putting hte power wire through the firewall.

 

daym i have the same exact problem..i was think map.tps.or vaccum leak

 

No, my car runs solid..and thats a huge jump man that must be really irritating.. even a 300 rpm spur for me sounds retarded in traffic.. ppl look hah..

 

Just a thought - but could it possibly be the "fast idle thermo valve" - like a leak in that system.

you can test it by removing your Intake air duct, running the engine (when cold) and feeling for air flow from the small port at the bottom.

once the engine has warmed up - there should be no vacuum from that hole.

the reason i'm thinking this - is because a leak would *simulate* a cold engine- so your car would rev up - the computer would prob compare this to the current tps and other inputs and correct for it - draggin the rpms back down, and the process could repeat over and over? if i'm way out on a tangent here someone help me (;

check for air in your rad fluid too - because apparently a leak in the fast idle thermo valve can cause that.

I don't think it would be the IACV itself - because technically that should throw a CEL ode 14... which no-one here has mentioned. since the fast idle thermo valve is non-electrical it leads my suspicions that way.

best of luck.

 

OK now..i have got that idling problem also and if a O ring on the fuel injector is bad which has air leaking and i'm not too sure if a torn O ring can cause idle problem due to a leak. In that case it's the only problem i've found so far by spraying carburetor cleaner at it and causing it to rev up then shut-off. And thanks to you (Altilude) i may be able to disassemble and replace the O ring if it's the problem..and hopefully it isn't the manifold gasket whiches it would be the hard part. I don't ever wanna go behind there taking the manifold apart.