phillys14 Posted July 8, 2009 Share Posted July 8, 2009 1997 Subaru Impreza Outback Wagon, will start up and idle just fine, run fine, after 5-10 min., will start to idle slow and fast, eventually dying, if giving gas, sounds like it is being starved or not running smooth and then die, the exhaust also seems to smell a little different when it does this (only when running strange). Can't say that the exhaust smells liek fuel, but maybe. If I shut off and let cool down, will start up and run fine again for a while. If driving, can only go about 5 miles from cold start, then it dies, try to restart a couple times, then runs fine for a few more mile before repeating. Mechanic check fuel pressure and was fine. Check engine lite codes for knock sensor, but multiple mechanics have said this will not affect much. Code is cleared and comes back to same code. Stuck in very remote location, possible oxygen sensor, ignitions module, maybe? Any help greatly appreciated. Quote Link to comment Share on other sites More sharing options...
nipper Posted July 8, 2009 Share Posted July 8, 2009 How many miles? Check the obvious things first, like loose vacume lines. Does it idle at all? The exhaust sound like rotten eggs? How old is the timing belt? When was the last tune-up? nipper Quote Link to comment Share on other sites More sharing options...
davebugs Posted July 8, 2009 Share Posted July 8, 2009 I'd check vaccum lines first. The line that goes to a T almost under the aribox at the the throttle body on the passenger side that is a 1/2" or so hose that's hidden is a good place to start but often if it's not plugged in properly the car dies immediately. Then check all the little vacuum lines for cracking, etc. A knock sensor will cause it to be sluggish but I haven't had one cause what's happenning to you. Perhaps others have. Other things could be fuel filter. He's checking pressure at startup - not after it's been run a while. Even a catalytic converter. But often you can smell them being hot, sometimes they even glow red. Hopefully others will have some idea's for you. Quote Link to comment Share on other sites More sharing options...
Log1call Posted July 8, 2009 Share Posted July 8, 2009 The knock sensor being faulty won't cause the problems you have but, those codes are intended as an aid to diagnosis. In this case the code could be telling us that the engine is knocking as the problem is occuring. So what can cause knocking? Oil consumption, carbon build-up causing localised hot-spots in the combustion chamber, general overheating, too much boost from a turbo, ignition timing being too advanced, wrong/bad fuel. Do you know what knocking sounds like and have you heard any? Is the motor running hot? Is the motor smoking, using oil? I'd check the cooling system first. You don't say how long you have to leave it after the five mile drive but I assume till it cools off a bit. If you had to wait for the whole engine to cool it could be the thermostat or radiator not working correctly, if it only takes a couple of minutes to cool then it could be locallised heat, like carbon or the water pump not circulating the water evenly. Quote Link to comment Share on other sites More sharing options...
edrach Posted July 8, 2009 Share Posted July 8, 2009 The exhaust sound like rotten eggs? nipper Don't you mean smell like rotten eggs? Quote Link to comment Share on other sites More sharing options...
nipper Posted July 8, 2009 Share Posted July 8, 2009 Don't you mean smell like rotten eggs? picky picky picky Quote Link to comment Share on other sites More sharing options...
EVOthis Posted July 9, 2009 Share Posted July 9, 2009 (edited) How many miles on the vehicle? Any recent maintenance? sticking IAC? shot in the dark...but carboned up TB? ignition coil?..all easy things to check...worth a peak at..As mentioned, I would take some gum cutter (2+2) and with the engine running spray around all intake gaskets/vacuum lines etc etc..and see if anything changes with your idle... Also..MAF sensor...with the engine running tap on the MAF with a butt end of a screwdriver and see if the idle changes or the car dies.....Personally though...I would replace the knock sensor before you go any further with trying to diagnose this idle problem.. Edited July 9, 2009 by EVOthis Quote Link to comment Share on other sites More sharing options...
phillys14 Posted July 11, 2009 Author Share Posted July 11, 2009 The impreza has 160k, recently tuned and appears great. When the problem starts, it will usually idle sith just a slight up and down to it. If you try to increase the rpm over 1000, then it sounds like it's choking and eventually dies. Will start again and die if you increase rpm. Eventually, if will run smooth for undetermined time, then repeat issue. One suggestion was water in fuel, these problems didn't start until topping off tank one day with 4 or 5 gals. With it running well somtimes after poor without cooling down, I'm not thinking vacuum, good thought or bad? No knock sound to engine. It doesn burn a very slight amount of oil, but not noticable to the point of ever needing to add oil between changes. As for rotten egg smell, not really, just not a normal exhaust smell. Thanks. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted July 11, 2009 Share Posted July 11, 2009 No CEL? Sounds like a bad O2 sensor to me. Unplug the upstream sensor and see if that fixes it. Quote Link to comment Share on other sites More sharing options...
Log1call Posted July 11, 2009 Share Posted July 11, 2009 Or a fuel blockage? Vacuum in fuel tank? Quote Link to comment Share on other sites More sharing options...
nipper Posted July 11, 2009 Share Posted July 11, 2009 The impreza has 160k, recently tuned and appears great. When the problem starts, it will usually idle sith just a slight up and down to it. If you try to increase the rpm over 1000, then it sounds like it's choking and eventually dies. Will start again and die if you increase rpm. Eventually, if will run smooth for undetermined time, then repeat issue. One suggestion was water in fuel, these problems didn't start until topping off tank one day with 4 or 5 gals. With it running well somtimes after poor without cooling down, I'm not thinking vacuum, good thought or bad? No knock sound to engine. It doesn burn a very slight amount of oil, but not noticable to the point of ever needing to add oil between changes. As for rotten egg smell, not really, just not a normal exhaust smell. Thanks. Topping off? Check your charcoal canister under the hood. I bet it is flooded with fuel. nipper Quote Link to comment Share on other sites More sharing options...
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