LONO100 Posted December 23, 2012 Share Posted December 23, 2012 hi all, im trying to diagnose a high idle in my 97 wagon 2.5. let me preface this by saying i just had it smogged and it passed with flying colors, and no CEL. i have an OBDII scanner and did a scan on top of that and no codes. i checked the throttle linkage and it looks to be in order. i just put in a fresh PCV valve, i bought a new fuel filter and plugs and wires, but havent put them in just yet. ive checked for vacum leaks, but none to be found, i would also think that if i had some sort of vacum leak through the manifold or hoses, i wouldve failed my smog inspection off the bat. anything else i should be checking on? any help would be great, thanks in advance. Link to comment Share on other sites More sharing options...
Stang70Fastback Posted December 23, 2012 Share Posted December 23, 2012 Have you looked at / messed with the Idle Air Control Valve? What exactly is your vehicle idling at? Does it waver, or does it keep steady? Either way, start with the IACV. If it's dirty or grimy, it could be getting stuck. If it's incorrectly adjusted, it would give you the wrong idle speed. Link to comment Share on other sites More sharing options...
LONO100 Posted December 23, 2012 Author Share Posted December 23, 2012 it idles right at under 1500 RPM, its steady for the most part, but sometimes itll drop down back under 900 RPM. ill start with the IAC and see what i happens. Link to comment Share on other sites More sharing options...
Stang70Fastback Posted December 23, 2012 Share Posted December 23, 2012 IAC sounds like a good starting point. Also, note that 1500 is NOT an abnormal idle if it's cold outside. These cars are particularly aggressive in how they handle cold weather. Idle speed is significantly increased in order to warm up more quickly, and the transmission will hold gears MUCH longer for the same reason. If it's 1500 even after it's warmed up, though, then something is definitely up (in addition to the idle, lol.) Link to comment Share on other sites More sharing options...
LONO100 Posted December 23, 2012 Author Share Posted December 23, 2012 thanks for the good knowledge. I'm going to clean out the IAC and see what that does. Any tips on cleaning it? Link to comment Share on other sites More sharing options...
Joaks Posted December 26, 2012 Share Posted December 26, 2012 I had something similar where it would idle fast but if I turned the car off and restarted it was fine. In my case I replaced the TPS with a used one from ebay and that fixed it. I think there are videos on youtube to cleac the IACV as well as the MAF (might need cleaned also). Link to comment Share on other sites More sharing options...
LONO100 Posted December 28, 2012 Author Share Posted December 28, 2012 i cleaned the IAC and the idle (when warm) went down to under 1000 RPM. it still idles at over 1600 RPM when started cold, but once it gets warm, it goes down considerably. thanks for the help fellas. Link to comment Share on other sites More sharing options...
subikid90 Posted December 28, 2012 Share Posted December 28, 2012 On cold starts you should have a higher idle -Subikid90 1997 Legacy GT 5spd & EJ251 w/EJ25D heads ~10.5CR 1998 Legacy GT Limited waiting for EJ22T hybrid swap Link to comment Share on other sites More sharing options...
LONO100 Posted December 28, 2012 Author Share Posted December 28, 2012 yeah, i figured that. all my other vehicles that i own seem to idle at a cold start at just over 1000 RPM, so when i noticed my subie revving at 1600, i thought it wasnt normal, but after talking to a lot of membet is a pretty normal rs on the forum, ive come to find out that that is fairly normal when cold. since the cleaning, it idles cold at 1500 RPM, and it now idles when warm much lower now. Link to comment Share on other sites More sharing options...
monkeyposeur Posted December 28, 2012 Share Posted December 28, 2012 Initially it will idle high upon startup. As it warms up the idle will drop. Completely normal operation. Link to comment Share on other sites More sharing options...
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