Aidanm332 Posted December 6, 2013 Share Posted December 6, 2013 Have 1999 legacy wagon 30th anniversary edition. Runs pretty well for 173k miles on it and pretty sturdy. Only thing I wonder about is it idles around 200 rpm and shakes just a bit. But accelerates normally, even from idle and runs fine other than that. Any knowledge on what it should idle at? Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted December 6, 2013 Share Posted December 6, 2013 Idle should be about 700 and the tachometer is misleading. The first tick above 0 is 500 rpm. These generally don't run at all below that. If the idle is low, check for vacuum leaks and clean the IACV and throttle body. That usually makes a big difference. Quote Link to comment Share on other sites More sharing options...
Aidanm332 Posted December 6, 2013 Author Share Posted December 6, 2013 Oh god that's so freaking weird, well then it's at 600 which isn't bad, and I'll clean the IACV sometime, thanks! Quote Link to comment Share on other sites More sharing options...
1-3-2-4 Posted December 6, 2013 Share Posted December 6, 2013 Idle should be about 700 and the tachometer is misleading. The first tick above 0 is 500 rpm. These generally don't run at all below that. If the idle is low, check for vacuum leaks and clean the IACV and throttle body. That usually makes a big difference. True, I noticed with the flywheel on a Ej25 maybe because of the mass I've hit that line or a tad under it fully expecting the car to stop but it was still running if you manged to clutch in quick enough, back when I had the EJ22 it would of stalled well before it got to the first line. Quote Link to comment Share on other sites More sharing options...
Bushwick Posted December 7, 2013 Share Posted December 7, 2013 Mine's been acting funny sometimes when still cold. Normally, it hikes the rpms to around 1500 for awhile (to long for my tastes to be honest), then settles around 650-700. Once in gear and warm, it's been dropping on occasion to around 500 and won't auto correct either, which is forcing me to leave the heater on front defrost as it's supposed to kick the AC compressor on as it apparently works to dehumidify the air. I've got my AC belt off for time being, but it'll still kick the RPM up to a more normal RPM. I need to clean my TB and IAC as well, otherwise I think the IAC is getting lazy. Oil pressure also gets REALLY low around 500 rpm or less which makes me nervous. If cleaning and all that doesn't help, and you don't like leaving front defrost + plus heater speed at least at "1", there are 2 ways you can adjust the idle manually. One way is there is a small idle set screw on the underside of the throttle stop. Need a flat head screw driver and an 8 mm wrench IIRC. Put car in "D" (if auto) and set parking brake or block wheel. Back the nut off, turn screw until idle moves, put foot on brake, blip the gas, recheck idle. Adjust accordingly. Once it's set, hold the screw in place with screw driver and carefully tighten with wrench. Be careful as it's easy to lower the idle again as it's sensitive while turning nut. Other option is use the throttle cable and cruise cable adjustment nuts to bring idle up, though you really should use the idle stop screw instead and just use the cable adjustments to remove any slack in the line, which can prevent fully opening the throttle blade at WOT if there is too much slack. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted December 7, 2013 Share Posted December 7, 2013 There is no way to adjust idle speed manually. The ECU will try to correct any changes you make by changing the IAC valve position to set idle speed. If it can't change idle speed it will set codes, and you could cause further idle and running problems. If your oil pressure is too low at idle you should change to the next step higher weight oil. If you run 30 weight, switch to a 40 weight. Quote Link to comment Share on other sites More sharing options...
Bushwick Posted December 8, 2013 Share Posted December 8, 2013 There is no way to adjust idle speed manually. The ECU will try to correct any changes you make by changing the IAC valve position to set idle speed. If it can't change idle speed it will set codes, and you could cause further idle and running problems. If your oil pressure is too low at idle you should change to the next step higher weight oil. If you run 30 weight, switch to a 40 weight. If you keep your foot barely on the gas pedal the ECM doesn't try to drop RPM, right? The idle stop screw on the underside is a mechanical travel limiter and a way to fine-tune idle speed by altering the throttle body valve a bit more to let more air in. As far as the ECM is concerned, you are just pressing the gas pedal slightly. I originally altered mine and could get from 500-1000 RPM (in gear with e-brake set and fully warm) and didn't get ANY codes. It needs altered again as the bigger alt is placing a slightly higher demand at cold idle and I haven't readjusted yet as I think my IAC needs cleaned anyways. My low oil pressure (as seen on the oil gauge) at fully warm idle is "low" from the lower (below 600 RPM) idle speed. If I get idle to around 650 it's 11-12 psi. 700 seems a little to high on this. Quote Link to comment Share on other sites More sharing options...
Gloyale Posted December 8, 2013 Share Posted December 8, 2013 If you keep your foot barely on the gas pedal the ECM doesn't try to drop RPM, right? The idle stop screw on the underside is a mechanical travel limiter and a way to fine-tune idle speed by altering the throttle body valve a bit more to let more air in. As far as the ECM is concerned, you are just pressing the gas pedal slightly. I originally altered mine and could get from 500-1000 RPM (in gear with e-brake set and fully warm) and didn't get ANY codes. It needs altered again as the bigger alt is placing a slightly higher demand at cold idle and I haven't readjusted yet as I think my IAC needs cleaned anyways. My low oil pressure (as seen on the oil gauge) at fully warm idle is "low" from the lower (below 600 RPM) idle speed. If I get idle to around 650 it's 11-12 psi. 700 seems a little to high on this. Well the ECU doesn't interfre when you slighlty depress gas, because it knows you are pressing the gas via the TPS You are not supposed to mess with the stop screw. It isn't the idle adjust. This is stated clearly in the FSM, and why the screw has paint to indicate when it's been tampered with. If you open it up more, you can actually risk jamming and damaging the throttle butterfly and the inside bore of the TB. If you do adjust it, you likely need to reset the TPS (throttle pos. sensor) so that the idle switch is closed at the precise right time. You may not get a code, but you might have odd running behavior at low throttle cruising. Fuel cut at wrong time cause TPS is saying idle switch closed while throttle is still open slightly cruising. Quote Link to comment Share on other sites More sharing options...
1-3-2-4 Posted December 8, 2013 Share Posted December 8, 2013 I wonder why every once in awhile these topics always come up, I would for sure check for vacuum leaks first, better yet get a vacuum gauge, a lot of lines near the throttle body get brittle with age, I replaced my lines early this summer so I wont have to deal with it, during the winter and cold weather it's just a hose waiting to break. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted December 8, 2013 Share Posted December 8, 2013 If you keep your foot barely on the gas pedal the ECM doesn't try to drop RPM, right? The idle stop screw on the underside is a mechanical travel limiter and a way to fine-tune idle speed by altering the throttle body valve a bit more to let more air in. As far as the ECM is concerned, you are just pressing the gas pedal slightly. I originally altered mine and could get from 500-1000 RPM (in gear with e-brake set and fully warm) and didn't get ANY codes. It needs altered again as the bigger alt is placing a slightly higher demand at cold idle and I haven't readjusted yet as I think my IAC needs cleaned anyways. My low oil pressure (as seen on the oil gauge) at fully warm idle is "low" from the lower (below 600 RPM) idle speed. If I get idle to around 650 it's 11-12 psi. 700 seems a little to high on this. This is exactly what causes driveability problems and sets codes. You'll get TPS codes and probably IAC codes as well, then the ECU will go into limp mode. Quote Link to comment Share on other sites More sharing options...
Bushwick Posted December 9, 2013 Share Posted December 9, 2013 (edited) Like I stated already, I haven't gotten any codes and only bumped the loaded RPMs by about 75 RPM as there seems to be a "hole" in idle rpms where it goes from too low to too high when using this method. The set screw is just a stop. I agree the IAC probably needs cleaned and although the vacuum lines are OK on mine, it wouldn't hurt replacing them. Either way, doing this corrected the idle speed originally to something I was more comfortable with as a far as a warm idle. I'd love more than anything to just reflash the ecm to have a slightly higher loaded (in gear) idle rpm but since no one has reverse engineered the Subaru brain in these nor supplied an adapter to run modern USB into a back door port, you are sorta limited with options. Leaving the throttle blade a tad more opened (in my case) hasn't hurt anything. The throttle never fully closes anyway. That screw might not be a true "idle speed" adjustment, but it is there from the factory. No idea why it'd hurt the bore or throttle blade?? I've got a mechanical wire, not electronic. It's a factory adjuster after all. The TPS just reads where the blade is it at, and sends signal to the ECM. I'd just have to tell you to try it before stating it doesn't work. Edited December 9, 2013 by Bushwick Quote Link to comment Share on other sites More sharing options...
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