Whitty

Hey guys, I installed a 2.4 mani on my car this weekend and something weird has been happening since. Its not a rough idle like jumpy RPMS but it just seems to take its time to settle to the usual 8 - 900 RPM idle. It will sit at about 1400 for a sec then come down in about 200RPM intervals before it levels out at between 8 - 900... is this normal? on my 2.2 mani i never noticed this (doesn't mean it didn't do it) however i might just be paying more attention to it where it is a fresh install. Other than that everything is great! It pulls awesome and feels like it should just that semi strange idle. Any Ideas?

Thanks!

oldskool

Vacuum leak? I guess electronic throttle bodies don't have IAC's so that's probably not it...

Whitty

almost sounds like a hissing like a leak when i pop the hood i wrote this off as normal cuz the MAP isn't throwing any codes out for low pressure or n e thing... i could be wrong tho and it could be leaking how would i know for sure ?

DoMiStIc_RuSh_06

iTrader: (1)

so its acting wierd is it.....hmmmm thats kinda odd...and we put in all new gaskets too. Let stu have a look at it tomorrow and see what he says but from what i understand im pretty sure we did everything right

Whitty

yeah for sure, i just noticed it when i was sitting in traffic on the way into the city this AM, with all the stop and go, not really worried about it cuz no CEL's and its running great / pulls hard (for a 2.2 :P lol) just want to know if this is normal or not...

XM15

I would guess that the higher idle is just the ECU adjusting for the slower air velocity down low. I can't remember if I experienced anything like that when I had the 2.4 manifold on, but compared with the issues I've had during cold starts with the comp cams your problem doesn't sound too bad.

Whitty

So i guess this is normal then, can anyone with a 2.4 mani confirm ? and the fact that it does level itself out in like 10 secs to 800 ish RPM and stays there with no fluctuation tells me that it must be sealed or it would be going all crazy with low mani pressure.

CobaltLs_14

i have a 2.4 mani on my car and it ideals at 750-850... and when i first start it up it hits 1200-1100 just for a quick sec the goes in into ideal but never drops that low

also reset the battery if you havent already...

Whitty

battery was disconnected all through install and i let it idle for about 15 mins after doin the install just to be safe. does yours spike to 1400 or so when u first stop before it levels out ? thanks again for teh responses guys!

blackbolt89

mine does that too.

its called warming up. most cars i've been in sit high right after being cranked then it settles down to its set idle point.

im not mocking you, i'm just saying its most likely in your head. mine does the same thing after the 2.4 install. starts at like 1200
drops like a hundred every few seconds down to the 700~750 idle.

its in your head man.

DoMiStIc_RuSh_06

iTrader: (1)

it did sound like there was an air leak after we installed the manifold but the car ran perfectally normal

CobaltLs_14

Just double check for leaks but if its clean dont worry about until you see the problem get worse or if another pops up otherwise you should be fine...

mrsilent13

if you hear hissing you got a vac leak somewhere

you dont want unmetered air going into your engine...

Mregan

I have a stock 2.2 and on start up it idles at 1400 ish for a while then slowly goes down. Should be normal

DoMiStIc_RuSh_06

iTrader: (1)

the hissing noise was a vacuum leak. It was leaking around the maf sensor....His car was idleing bad and he threw a cel which was a lean code. I figured all of this was where it was getting unmetered air by then sensor

Whitty

also should note as well (going to PM Maven on the how to ) guy that helped me determine the prob (bigstu thanks again! ) said that when borring the hole out for the map sensor remove the o-ring on the MAP sensor and fit it that way. that way when you put the o-ring back on it seals. when i bored the hole out i did it with the o-ring on so it wasn't a tight tight fit like is needed to make a good seal. hench the crappy idle. After building up the oring with a little silicone it sealed no prob and idles perfect / runs perfect.