aa8jzdial Posted January 3, 2006 Share Posted January 3, 2006 One of the 6 subarus I am charged with maintaining recently became hard to start. No cel. I think the bulb is ok. 5 speed manual. Cold start, idle jumps up to about 2500 rpm, holds for a second, drops almost to stall, back up to 2500 for a second, drops to near stall and back up and then down for the count. Suspected fuel filter but after a few go arounds of this I held the idle near 2000 or so for 45 seconds and then seemed to idle fine. Test drive seemed ok at acceleration, but slower speeds seemed to lurch about. Tomorrow after it has cooled will change plugs but am dubious. It is my oldest daughters 60 mile per day commuter so I can't take my normal plodding pace. Thoughts?? tnx rick w. mi. Quote Link to comment Share on other sites More sharing options...
e4620 Posted January 3, 2006 Share Posted January 3, 2006 Make sure the bulb is in fact good first, just turn the key to on but don't start the engine. The bulb should light. Sounds like it could be the idle air control valve. It could be a vacume leak though. Quote Link to comment Share on other sites More sharing options...
Legacy777 Posted January 3, 2006 Share Posted January 3, 2006 You may want to replace the coolant temp sensor. How does it run when it's all warmed up? Other possibility is the idle air control valve. Quote Link to comment Share on other sites More sharing options...
aa8jzdial Posted January 13, 2006 Author Share Posted January 13, 2006 One of the 6 subarus I am charged with maintaining recently became hard to start. No cel. I think the bulb is ok. 5 speed manual.Cold start, idle jumps up to about 2500 rpm, holds for a second, drops almost to stall, back up to 2500 for a second, drops to near stall and back up and then down for the count. Suspected fuel filter but after a few go arounds of this I held the idle near 2000 or so for 45 seconds and then seemed to idle fine. Test drive seemed ok at acceleration, but slower speeds seemed to lurch about. Tomorrow after it has cooled will change plugs but am dubious. It is my oldest daughters 60 mile per day commuter so I can't take my normal plodding pace. Thoughts?? tnx rick w. mi. finally getting back to the poor idle issue. I noticed just now I didn't mention this is a 1990 legacy. Changed plugs and wires. Seemed to help the missing at low engine speed. Still very funky at cold start. Good friend looked it over and has a decent track record for fixing such things but he is at a loss and suggested I try another post here. The CEL light is indeed functioning, as it lights when ignition switch first turned on. But, again the light is not on during run. Any suggestions on what to check? How about a fuel pressure/pump issue? Would it be worth doing the read memory check? The car is presently 20 miles from here and maybe able to get to it this weekend. Is the Read memory mode the best source of info? I am not sure of how to use the D-check mode. tnx rick w mi Quote Link to comment Share on other sites More sharing options...
sasquatch Posted January 13, 2006 Share Posted January 13, 2006 I vote vacuum leak if it is always having a little trouble at idle, IAC if only when cold. Quote Link to comment Share on other sites More sharing options...
tunered Posted January 13, 2006 Share Posted January 13, 2006 keep in mind no sensors work or react till the engine temp is up to normal,im not sure about air sensor,i agree on the vacum leak,or fuel pressure. Quote Link to comment Share on other sites More sharing options...
AussieIan Posted January 13, 2006 Share Posted January 13, 2006 Try a tank of premium fuel Quote Link to comment Share on other sites More sharing options...
beezer Posted January 13, 2006 Share Posted January 13, 2006 Like Legacy777 said, look at the coolant temp. sensor. Seems to be a fairly common problem and it also seems to rarely throw a code. For $30 it is probably worth a shot. Tunered I 'm pretty sure most of the sensors are working before the engine gets up to temp.(except for the o2 sensor for a brief time when cold) Since the engine is controlled by the computer it is probably essential that it is receiving info from the sensors to make it work. Good luck Beezer Quote Link to comment Share on other sites More sharing options...
Legacy777 Posted January 14, 2006 Share Posted January 14, 2006 Yes, most definitely check the ECU for codes. Quote Link to comment Share on other sites More sharing options...
aa8jzdial Posted January 16, 2006 Author Share Posted January 16, 2006 Thanks all of you for the info. The prize goes to the guys with the idle air control suggestion. Robbed one off a 1990 awaiting more attention. Works like a trained pig. A couple remaining questions. Why no cel? Because the motor is cold and runs in open loop? Diagnostic connectors all disconnected = U check mode. Just blacks hooked up = read memory. Just green = D check mode. Is this right? What to heck is D check?? tnx rick w. mi Quote Link to comment Share on other sites More sharing options...
Legacy777 Posted January 17, 2006 Share Posted January 17, 2006 No diagnostic connectors is nothing....it's just normal. Black connectors is u-check green connectors is d-check both black & green connectors clears the trouble codes. D-check basically provides a more thorough diagnostic. 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.