sasquatch Posted August 15, 2004 Share Posted August 15, 2004 I have a '90 Legacy that has an intermittant idle problem. When you first start the car, the idle is unsteady and bounces up and down a little nearly stalling out the car. Once you rev the car a little it goes away. No problems at all anywhere else in the rpm band. Suggestions? Thanks Quote Link to comment Share on other sites More sharing options...
kingbobdole Posted August 15, 2004 Share Posted August 15, 2004 Yo, I'd give the generic check the engine temp sensor. I have an old XT-6 and usually before I fived it, the idle would be real low, maybe even surge and sometimes stall. Usually the connector will corode and one just has to clean it for the fix. Also check the MAF and see if its clean. Check that out, Phil Quote Link to comment Share on other sites More sharing options...
sasquatch Posted August 15, 2004 Author Share Posted August 15, 2004 sorry, I'm dumb... MAF? Thanks for the reply Quote Link to comment Share on other sites More sharing options...
sasquatch Posted August 16, 2004 Author Share Posted August 16, 2004 This doesn't seem to be an air temp problem in that the car will do it even when warmed up. The idle rpm will bounce up and down but has no problems at any other time....anyone? Quote Link to comment Share on other sites More sharing options...
Legacy777 Posted August 16, 2004 Share Posted August 16, 2004 MAF = Mass Air Flow Sensor Quote Link to comment Share on other sites More sharing options...
marcinczyk Posted August 16, 2004 Share Posted August 16, 2004 Come to think of it....this was the first symptom my 90' legacy was having....then it had problems starting when I let it sit for a few days.....then it just decided to not start at all. Turned out to be my ECU (the computer)....I picked one up at the local junkyard for about $25 and now the car runs like a champ. Quote Link to comment Share on other sites More sharing options...
sasquatch Posted August 16, 2004 Author Share Posted August 16, 2004 Come to think of it....this was the first symptom my 90' legacy was having....then it had problems starting when I let it sit for a few days.....then it just decided to not start at all. Turned out to be my ECU (the computer)....I picked one up at the local junkyard for about $25 and now the car runs like a champ. well, short of swapping out the ECU (hopefully I won't have to go that far, though that price is very good), anybody know what else it might be? My subaru has been doing this off and on for quite a long time. Quote Link to comment Share on other sites More sharing options...
sasquatch Posted August 16, 2004 Author Share Posted August 16, 2004 Thanks Josh....do you think the MAF might be the prob? Why wouldn't I see this anywhere but at idle then? Quote Link to comment Share on other sites More sharing options...
Legacy777 Posted August 16, 2004 Share Posted August 16, 2004 nah I don't think it's the MAF. I'd spray some brake cleaner in the IAC = idle air control valve tube. There may be gunk in there that's causing it to stick. Other possibility is the injectors. See if you can find some seafoam and run some in your gas. Does the weird idle thing happen without touching the gas pedal at all? Quote Link to comment Share on other sites More sharing options...
arracado Posted August 16, 2004 Share Posted August 16, 2004 Is the check engine light coming on at all? If so, check the codes out. I had the same problem in my 91, and had error codes for both the MAF and the water temp sensor. Changed them both and now it runs great. Quote Link to comment Share on other sites More sharing options...
jcniest5 Posted August 16, 2004 Share Posted August 16, 2004 It could also be the IAC (Idle Air Solenoid Controller). Quote Link to comment Share on other sites More sharing options...
frag Posted August 16, 2004 Share Posted August 16, 2004 nah I don't think it's the MAF. I'd spray some brake cleaner in the IAC = idle air control valve tube. There may be gunk in there that's causing it to stick. Other possibility is the injectors. See if you can find some seafoam and run some in your gas. Does the weird idle thing happen without touching the gas pedal at all? Josh, would you spray brake cleaner in the valve after removing it from the throttle body or just disconnect the rubber hose and go at it? I would like to clean the IAC and am looking for the easiest way to do it but I'm afraid to mess things up. Sorry for hijacking the thread but this could also be useful for the original poster. Thanks in advance. Quote Link to comment Share on other sites More sharing options...
p.monro Posted August 16, 2004 Share Posted August 16, 2004 This doesn't seem to be an air temp problem in that the car will do it even when warmed up. The idle rpm will bounce up and down but has no problems at any other time....anyone? If you have checked the codes and there are none then I suspect that your idle problem is a vacuum leak. This lets too much air in at idle. At higher revs it is not so odvious because the vacuum is lower. It should also happen with the engine both hot and cold. The usual cause is cracked vacuum hoses but also the 2 air inlet manifold gaskets may be leaking Quote Link to comment Share on other sites More sharing options...
sasquatch Posted August 16, 2004 Author Share Posted August 16, 2004 Thanks for the input guys.....the check engine light is not coming on...it will do it all on it's own w/o touching the gas. If you rev it a little bit it seems to help. Also, let's say you have to decelerate really fast like coming off a freeway and have to stop suddenly it will sometimes die. Does this help? Quote Link to comment Share on other sites More sharing options...
Legacy777 Posted August 17, 2004 Share Posted August 17, 2004 Josh, would you spray brake cleaner in the valve after removing it from the throttle body or just disconnect the rubber hose and go at it? I would like to clean the IAC and am looking for the easiest way to do it but I'm afraid to mess things up.Sorry for hijacking the thread but this could also be useful for the original poster. Thanks in advance. You could do it either way. By just spraying down the tube, or by taking it off. Taking it off might get things a little better, but spraying down the tube works fine. Quote Link to comment Share on other sites More sharing options...
Legacy777 Posted August 17, 2004 Share Posted August 17, 2004 Thanks for the input guys.....the check engine light is not coming on...it will do it all on it's own w/o touching the gas. If you rev it a little bit it seems to help. Also, let's say you have to decelerate really fast like coming off a freeway and have to stop suddenly it will sometimes die. Does this help? I'm really leaning towards the IAC valve. Do the brake cleaner thing, and then reset the ECU. Quote Link to comment Share on other sites More sharing options...
sasquatch Posted August 17, 2004 Author Share Posted August 17, 2004 I'm really leaning towards the IAC valve. Do the brake cleaner thing, and then reset the ECU. I'll give it a try tomorrow...to reset the ECU, do I just pull a fuse, wait and then reinstall? What is the fuse typically labeled? 'motor'? (I'd check before I asked, but it's dark out) Quote Link to comment Share on other sites More sharing options...
sasquatch Posted August 17, 2004 Author Share Posted August 17, 2004 I'll give it a try tomorrow...to reset the ECU, do I just pull a fuse, wait and then reinstall? What is the fuse typically labeled? 'motor'? (I'd check before I asked, but it's dark out) nevermind, I checked your website...thanks! I'll report back. Quote Link to comment Share on other sites More sharing options...
sasquatch Posted August 21, 2004 Author Share Posted August 21, 2004 I did the brake cleaner thing, reset the ECU....no dice. There might be a bit of an improvement but when the car starts up it still does it's little idle dance between 0 and 1k until it settles down around 500. The car didn't stall out when coming quickly to a stop but.... What next guys? Any more suggestions? (please) Quote Link to comment Share on other sites More sharing options...
SuperRallyRoo Posted August 21, 2004 Share Posted August 21, 2004 I think thats normal my legacy does that every morning when its cold for about 20 seconds then its fine. Idles perfectly the rest of the day when warm at 500-650rpms Quote Link to comment Share on other sites More sharing options...
jcniest5 Posted August 21, 2004 Share Posted August 21, 2004 I did the brake cleaner thing, reset the ECU....no dice. There might be a bit of an improvement but when the car starts up it still does it's little idle dance between 0 and 1k until it settles down around 500. The car didn't stall out when coming quickly to a stop but.... What next guys? Any more suggestions? (please) Have you tried the IAC yet? That may be the real culprit. Quote Link to comment Share on other sites More sharing options...
sasquatch Posted August 21, 2004 Author Share Posted August 21, 2004 Have you tried the IAC yet? That may be the real culprit. you mean replaced it? No....I just tried to clean it out with brake cleaner then reset the ECU Quote Link to comment Share on other sites More sharing options...
jcniest5 Posted August 21, 2004 Share Posted August 21, 2004 you mean replaced it? No....I just tried to clean it out with brake cleaner then reset the ECU Yeah, replace it. Also check your PCV valve. Quote Link to comment Share on other sites More sharing options...
sasquatch Posted August 29, 2004 Author Share Posted August 29, 2004 would a problem with the IAC cause a problem with the idle even after it's warm? I think tomorrow I am going to check the middle terminal on the connector to make sure it's getting power and then pull the IAC after it is warm and see if the valve is closed. won't hurt to hunt around for problem hoses as well eh? Which hoses would y'all recommend? Quote Link to comment Share on other sites More sharing options...
jcniest5 Posted August 29, 2004 Share Posted August 29, 2004 would a problem with the IAC cause a problem with the idle even after it's warm? Certainly to my knowledge. Quote Link to comment Share on other sites More sharing options...
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