dhewitt Posted February 28, 2008 Share Posted February 28, 2008 Our '03 Subaru Outback seems to have developed a bit of an issue in regulating the engine RPMs on start-up. A few times now it has revved the RPMs up normally just after starting, but then the RPMs drop pretty fast and go too low. The computer catches the mistake and revs the RPMs way back up to like 2000 or more. The engine shudders a bit, but then the RPMs seem to return to normal idle and everything is cool. I've noticed no other issues related to normal operation. Any ideas? Quote Link to comment Share on other sites More sharing options...
nipper Posted February 28, 2008 Share Posted February 28, 2008 Our '03 Subaru Outback seems to have developed a bit of an issue in regulating the engine RPMs on start-up. A few times now it has revved the RPMs up normally just after starting, but then the RPMs drop pretty fast and go too low. The computer catches the mistake and revs the RPMs way back up to like 2000 or more. The engine shudders a bit, but then the RPMs seem to return to normal idle and everything is cool. I've noticed no other issues related to normal operation. Any ideas? How many miles please nipper Quote Link to comment Share on other sites More sharing options...
dhewitt Posted February 28, 2008 Author Share Posted February 28, 2008 95,000 Has had the timing belt and some other associated work done (water pump, thermostat). Quote Link to comment Share on other sites More sharing options...
nipper Posted February 28, 2008 Share Posted February 28, 2008 Has it been doing this since the repair? it may be as simple as loose vacume line under the air box (a common thing). nipper Quote Link to comment Share on other sites More sharing options...
dhewitt Posted February 28, 2008 Author Share Posted February 28, 2008 I would have answered No, that it has just started this, until my wife last night indicated that it did this to her occasionally when it was "her" car. I can't be sure we're describing the same thing, but she was convinced. So I'll say that it has done it occasionally for "a while". Can you explain a little more what you mean by the loose connection? I checked the plastic tube running from the grill back to the engine and all connections seem fine. What about an IACV? I've read on here about people needing new ones to solve idling issues (go figure). Maybe time to try that, since it's relatively cheap? Quote Link to comment Share on other sites More sharing options...
porcupine73 Posted February 28, 2008 Share Posted February 28, 2008 In addition to possible vacuum leak, an easy thing to try is clean your IACV. There's a good article on endwrench about how to do it. Basically get the airbox off and spray throttle body cleaner up at the IACV intake in short bursts. http://endwrench.com/images/pdfs/ISCSpring04.pdf Quote Link to comment Share on other sites More sharing options...
mellow65 Posted February 28, 2008 Share Posted February 28, 2008 this sounds like mine did, but i got a check engine light with it. mine ended up being the temp sensor. the bad thing is it really hard to get to them on these motors and just check them. are you getting any check engine lights? Quote Link to comment Share on other sites More sharing options...
dhewitt Posted February 29, 2008 Author Share Posted February 29, 2008 No CELs The infrequent nature of the thing is what's odd to me. Quote Link to comment Share on other sites More sharing options...
nipper Posted February 29, 2008 Share Posted February 29, 2008 No CELs The infrequent nature of the thing is what's odd to me. Its what we in the field call a "hiccup" Sometimes it happens, and they really hard to diagnose. Check your IAC motor to make sure its clean, the EGR valve operation, and wait for it to mainfest tiself into something else. Or you can call it "personality". Does it seem to happen with any specific weather conditions? nipper Quote Link to comment Share on other sites More sharing options...
idosubaru Posted February 29, 2008 Share Posted February 29, 2008 you didn't answer - did it do this before the timing belt change (ask wife?). i think you checked the wrong hoses "from the grill to the engine" - that's the radiator hose. the largest hose in the engine bay, from the air box to the engine is the intake hose and where you will find vacuum leaks. large black hose from passengers side fender to the engine. underneath of that hose it has a number of other hoses connecting to it. need to make sure those are not broken, leaking, or possibly not seated properly. if it has only done this since the timing belt change you might just ask the mechanic to look over it. and yes - IAC's get dirty and cause stuff like this as well. have the spark plugs and wires ever been changed? at nearly 100k i'd say it's about time. Quote Link to comment Share on other sites More sharing options...
dhewitt Posted February 29, 2008 Author Share Posted February 29, 2008 I did answer about the history of the thing, but the result was that my wife says it's been doing it "for a while" and wasn't sure if it was before or after the timing belt change. My guess is no; she's tending to forget the old Soob now that she has a new vehicle. And... At the timing belt change we had the IACV cleaned because the mechanic was trying to sort out that vibration-at-idle axle problem. I just spoke with him and he said it was cleaned thoroughly, so I doubt cleaning it again will fix it. I'm leaning towards just ordering a new IACV and trying that first. And I checked the right air tubes... I'm not THAT bad. The plugs are pretty new... changed at the indicated intervals (initially with platinum, which underperformed and were then replaced with good 'ol regulars). New IACV make sense as a starting point? Quote Link to comment Share on other sites More sharing options...
idosubaru Posted February 29, 2008 Share Posted February 29, 2008 I did answer about the history of the thing, gotcha, i saw your response but didn't understand. And I checked the right air tubes... I'm not THAT bad. oh sorry, i wasn't trying to poke, trying to get one more thing checked off the list. you said: tube running from the grill back to the engine i assumed you meant the front of the car where the grill is and that's where the radiator hoses are and they go "back". so you checked the other smaller hoses plumbed into the bottom of the air intake tube? mounted on the front side of the passengers side strut tower should be some small mechanisms that have very tiny vacuum hoses attached to them. follow those hoses and make sure they are properly seated. there's one in particular that makes a bee line straight across towards the engine and has a small round filter in line with it - about the size in diamter of a quarter roughly. it's about 1/2" thick with a sponge around it. this one can easily get pulled out even with just about any engine work, spark plugs, air filter, etc. other than that - the IAC might be worth a shot. i would start here, but throwing parts at something can also be very frustrating when it doesn't work. maybe there's a way to test it? you might want to consider a used one. they very rarely fail. most 1980's subaru's still have the original IAC valves on them, if cleaned they almost never need replacing. so used isn't a bad option here at all. Quote Link to comment Share on other sites More sharing options...
dhewitt Posted March 1, 2008 Author Share Posted March 1, 2008 so you checked the other smaller hoses plumbed into the bottom of the air intake tube? mounted on the front side of the passengers side strut tower should be some small mechanisms that have very tiny vacuum hoses attached to them. follow those hoses and make sure they are properly seated. there's one in particular that makes a bee line straight across towards the engine and has a small round filter in line with it - about the size in diamter of a quarter roughly. it's about 1/2" thick with a sponge around it. this one can easily get pulled out even with just about any engine work, spark plugs, air filter, etc. Gary, thanks for the help and for bearing with me. Now I'm starting to wonder if I DID check the right things. I am assuming that the air intake tube is the the big black plastic tube that starts at the front attached to the frame and sits over the radiator top. It's flattened top-bottom at that point and goes back along the passenger side toward the air filter box. I followed that tube back and didn't find any little hoses. In fact, until you get to the box for the air filter there are no "hoses" that aren't hard plastic. In front of the strut tower is a couple black plastic boxes that connect up to the main tube, but they're big. What I am I missing here? I did notice that there is a small round hole (looks original) on the backside of the main tube about a foot back from the entrance point near the fender, which seemed odd. For what it's worth, the big tubes all seemed well connected. I didn't find the "beeline" hose you referred to. I searched around for photos on here but wasn't able to clarify for myself. While I was in there, I checked on the passenger side axle that we had replaced (with MWE). I can still smell the grease that had leaked out of the bad one burning off (which is normal I understand), but was curious to see that all was well. I found a boot on the driver's side on a connection from the wheel to the engine that was leaking. It's not the driver's side axle, but a straight bolt type connection that's below and forward of the axle connection -- tie rod?? The boot (different looking than the boot on the axle) is leaking a thin grease/oil and it's slung out on the exhaust pipe and other parts. I'm thinking this is a source of the smell. Does a tie rod have a boot? Is this serious? Quote Link to comment Share on other sites More sharing options...
porcupine73 Posted March 1, 2008 Share Posted March 1, 2008 Your setup (ej25 sohc phase ii) doesn't have the ton of little hoses connecting to the bottom of the air intake snorkus like earlier soobs did. There are only the two breather hoses from the valve covers, and those connect to the bottom of the airbox itself, the part that attaches to the throttle body (which you wouldn't disturb even changing the air filter). That other boot you describe does sound like the inner tie rod end boot. Do it look like this? Quote Link to comment Share on other sites More sharing options...
dhewitt Posted March 2, 2008 Author Share Posted March 2, 2008 Thanks for the clarification on the air intake tube... makes sense now. Mine looks like what you describe. And YES, that's the tie rod end boot that's the culprit. Does it make sense for that to be leaking? Is it serious? The grease/oil is coming from the "cupped" end closest the engine. Quote Link to comment Share on other sites More sharing options...
nipper Posted March 2, 2008 Share Posted March 2, 2008 Thanks for the clarification on the air intake tube... makes sense now. Mine looks like what you describe. And YES, that's the tie rod end boot that's the culprit. Does it make sense for that to be leaking? Is it serious? The grease/oil is coming from the "cupped" end closest the engine. Check your power steering level. Let us know if its low, you may be leaking fluid, and thats a used rack. nipper Quote Link to comment Share on other sites More sharing options...
dhewitt Posted March 2, 2008 Author Share Posted March 2, 2008 It's a touch under the full mark, but nothing dramatic. I'm not sure if it's lower than usual, as I don't tend to add milliliters of fluid to keep everything right at full. For the amount of "wetness" around the area near the tie rod end, it seems like there would be more of a leak. Maybe I'm looking in the wrong place. Quote Link to comment Share on other sites More sharing options...
nipper Posted March 2, 2008 Share Posted March 2, 2008 It's a touch under the full mark, but nothing dramatic. I'm not sure if it's lower than usual, as I don't tend to add milliliters of fluid to keep everything right at full. For the amount of "wetness" around the area near the tie rod end, it seems like there would be more of a leak. Maybe I'm looking in the wrong place. Thst the only fluid that is in that boot, PS fluid. Do yourslef a favor, go to a do it yourself car wash and wash the entire underside of the car. This will help and let you know where the leaks are. And if you are trying to find a leak, well yes you need to check levels and keep them full. nipper Quote Link to comment Share on other sites More sharing options...
dhewitt Posted March 10, 2008 Author Share Posted March 10, 2008 Hope its not too much trouble to revisit this old-ish thread... I think the rack's gonna need work... it was the tie rod boot leaking. Glad we found that now before we leave on a 4,000 mile road trip. On the idle surges, it seems to have turned into a little something else. No more big surges, but now when it starts up it tends to jump around subtly. Jump up to 2000 or so, down to 1500, then kicks up a few hundred, drops back, etc. If I tap the accelerator to break the routine, it drops down to 1000 or so, but still ticks up and down at intervals of 5-10 seconds. Seems not to find its comfortable "place". Any ideas? Quote Link to comment Share on other sites More sharing options...
nipper Posted March 10, 2008 Share Posted March 10, 2008 Well since we sort of ruled out the IACV, how about the EGR valve? nipper Quote Link to comment Share on other sites More sharing options...
dhewitt Posted March 11, 2008 Author Share Posted March 11, 2008 I haven't gotten a P0400 CEL code yet, and other than that I don't know anything about an EGR. Quote Link to comment Share on other sites More sharing options...
nipper Posted March 11, 2008 Share Posted March 11, 2008 I haven't gotten a P0400 CEL code yet, and other than that I don't know anything about an EGR. Egr can be sluggish or dirty. nipper Quote Link to comment Share on other sites More sharing options...
screwbaru2 Posted March 11, 2008 Share Posted March 11, 2008 Surging idle which is what it now sounds like is commonly caused by vac leaks. Get a can of carb cleaner and spray the any vac hoses you can find. Also any intake connection ie; manfoild to block. If it is a leak and you hit it with the cleaner the idle will drop for a few seconds because air is no longer being sucked in, the flammable cleaner is, once the cleaner is burned/dried the idle will increase and begin surging again. Make sure you have no ignition leaks (sparks) as it can ignite the carb cleaner. I check for spark leakage and keep a fire extin. near by. Quote Link to comment Share on other sites More sharing options...
dhewitt Posted April 17, 2008 Author Share Posted April 17, 2008 Sorry so late getting back to this (a new baby at home, free time approach zero). Just trying to wrap this up for future readers. In attempting to figure out the erratic idle surges, we replaced the PCV valve and the spark plug wires and all seems well now. Not sure which it was, but my mechanic showed me where both needed replaced. The PCV valve was sticking open or close and one of the spark plug wires was arcing. All seems well now. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.