gbb1277 Posted July 18, 2008 Share Posted July 18, 2008 Hi everyone. My 2003 legacy is misfiring like mad and I dont know why. I have changed the plugs and the plug wires. I had a camshaft sensor code and replaced that as well. I took the plugs back out and saw black soot on a couple of them so I was told that means that I am running rich. The car seems to run ok when its a cold start after it sits for a couple hrs but after a few miles it warms up and bang back to running like ************. I was thinking that maybe the engine coolant sensor is bad not telling the computer switch to hot mode if you will and its delivering to much fuel constantly. Is this possible or more likely something else. Af far as I can tell I havnt gotten a code for that sensor. Link to comment Share on other sites More sharing options...
screwbaru2 Posted July 18, 2008 Share Posted July 18, 2008 Were the plugs and wires OEM? I put autolites in my wifes impreza when we first got it, ran like CRAP, it was so bad it was dangerous. I'd try OEM componets before a coolant sensor, which if you do replace use OEM. Link to comment Share on other sites More sharing options...
gbb1277 Posted July 18, 2008 Author Share Posted July 18, 2008 I just read another thread that said useing aftermarket plug wires is bad. Could this all be because I got a set of wires at Advanced Auto? Link to comment Share on other sites More sharing options...
screwbaru2 Posted July 18, 2008 Share Posted July 18, 2008 I just read another thread that said useing aftermarket plug wires is bad. Could this all be because I got a set of wires at Advanced Auto? OH YEAH Link to comment Share on other sites More sharing options...
gbb1277 Posted July 18, 2008 Author Share Posted July 18, 2008 wow everyone I know says a wire is a wire it shouldnt make that big of a difference so go to a dealer and get true OEM wires? and is there anyway at all to tell if that truely is the problem before I thow down more money? Link to comment Share on other sites More sharing options...
94Loyale Posted July 18, 2008 Share Posted July 18, 2008 If it were me, since you said it runs well until it warms up. I would unplug the O2 sensor and see how it runs then. I've had many cars do that. And if you unplug the o2, the car will just run in open loop. If it runs well the whole time with it disconnected, then you know what the problem is. It's worth a try. Link to comment Share on other sites More sharing options...
OB99W Posted July 18, 2008 Share Posted July 18, 2008 Hi everyone. My 2003 legacy is misfiring like mad and I dont know why. I have changed the plugs and the plug wires. I had a camshaft sensor code and replaced that as well.Did you have the misfire before changing these parts? After changing them, did the problem go away for a while, then recur? I took the plugs back out and saw black soot on a couple of them so I was told that means that I am running rich.Carbon is often a sign of a too-rich mixture. If there's enough carbon to foul the plug, that alone can cause misfire. What brand and part number plugs are you using? (I'm asking because plugs with too low a temperature range will more readily carbon-foul.) A rich mixture can also be due to a problem with the oxygen sensor. The car seems to run ok when its a cold start after it sits for a couple hrs but after a few miles it warms up and bang back to running like ************. I was thinking that maybe the engine coolant sensor is bad not telling the computer switch to hot mode if you will and its delivering to much fuel constantly. Is this possible or more likely something else. Af far as I can tell I havnt gotten a code for that sensor.The CTS can cause such problems, and often doesn't generate a trouble code. Link to comment Share on other sites More sharing options...
screwbaru2 Posted July 18, 2008 Share Posted July 18, 2008 Carbon is often a sign of a too-rich mixture. If there's enough carbon to foul the plug, that alone can cause misfire. What brand and part number plugs are you using? (I'm asking because plugs with too low a temperature range will more readily carbon-foul.) A rich mixture can also be due to a problem with the oxygen sensor. The CTS can cause such problems, and often doesn't generate a trouble code. Of course if the plugs are not firing hot enough that will mimick a rich mixture. The idea of unplugging the O2 sensor is good. The engine will run in CLOSED loop. If that improves things than I'd change the O2. I still think it sounds like the wires and/or plugs. Link to comment Share on other sites More sharing options...
94Loyale Posted July 18, 2008 Share Posted July 18, 2008 Screwbaru, I would lean towards the parts he just replaced also. I just threw the o2 idea out there just because of the symptoms. However if he does unplug it, it will keep the car running in open loop. It won't make it to closed loop due to no input from the o2 sensor. Link to comment Share on other sites More sharing options...
McDave Posted July 18, 2008 Share Posted July 18, 2008 Even cheap aftermarket parts should work for a little while. Since you're getting a couple sooty plugs I would suspect the coil. Link to comment Share on other sites More sharing options...
screwbaru2 Posted July 18, 2008 Share Posted July 18, 2008 Screwbaru, I would lean towards the parts he just replaced also. I just threw the o2 idea out there just because of the symptoms. However if he does unplug it, it will keep the car running in open loop. It won't make it to closed loop due to no input from the o2 sensor. Sorry I get automotive dislexya somtimes with open and closed loop. It seems like his problem started after the plugs and wires where installed. I know it drove me crazy the 1st time it happened to me. Seems like the new gen engines are fussy. The older soobs I had used aftermarket without problems. Link to comment Share on other sites More sharing options...
McDave Posted July 18, 2008 Share Posted July 18, 2008 It seems like his problem started after the plugs and wires where installed. The way I read his original post, the problem started before he changed any parts. "I have changed the plugs and the plug wires. I had a camshaft sensor code and replaced that as well. I took the plugs back out and saw black soot on a couple of them so I was told that means that I am running rich." Link to comment Share on other sites More sharing options...
howards11 Posted July 19, 2008 Share Posted July 19, 2008 Even cheap aftermarket parts should work for a little while. Since you're getting a couple sooty plugs I would suspect the coil. I had the SAME problem on my 2000 Forester. The CEL code was P0303 (Misfire #1). I needed new wires and a new ignition coil. All were replaced with Subaru parts. The Forester is better now and runs like new. My mechanic is a bit richer too...........$500.00. ~Howard Link to comment Share on other sites More sharing options...
94Loyale Posted July 19, 2008 Share Posted July 19, 2008 Screwbaru, I didn't mean to sound like an rump roast. If I did, I apologize. Regardless of whether the problem was before or after the parts. (I may have read the post wrong). Yank the o2 sensor wire connection and give it a run. Let us know what happens, I'm curious now Link to comment Share on other sites More sharing options...
screwbaru2 Posted July 19, 2008 Share Posted July 19, 2008 Screwbaru, I didn't mean to sound like an rump roast. If I did, I apologize. Regardless of whether the problem was before or after the parts. (I may have read the post wrong). Yank the o2 sensor wire connection and give it a run. Let us know what happens, I'm curious now You didn't sound that way to me. I think the post could be read either way. At 1st reading I thought the plugs and wires were done as part of the cars maintance. After reading it again I can see where one could take it that they were done in response to a problem. I'm curious how it turned out too. Link to comment Share on other sites More sharing options...
gbb1277 Posted July 19, 2008 Author Share Posted July 19, 2008 The way I read his original post, the problem started before he changed any parts. "I have changed the plugs and the plug wires. I had a camshaft sensor code and replaced that as well. I took the plugs back out and saw black soot on a couple of them so I was told that means that I am running rich." Thanks guys I am going to find and unplug the o2 sensor and see what happens. Can I unplug the coolant temp sensor will that possibly make it better for a bit? If nothing works I am going to get new wirer from subaru. My buddy checked the coil and said there was spark for all cylinders. Is it a all or nothing deal or can it just be too weak of a spark? I had a check engine light come on a while ago. It was usualy at highway speed going up a long hill but no bucking or sign of missfire. It came and went and I didnt have a chance to do anything. Then the car just started running realy bad half way to work one day after I drove somewhat aggressively. A buddy looked at it and he noticed my crankpulley was bad but thats not what caused the check engine light. It still bucked after new pulley and I checked the codes and it was a cam sensor with no missfire. I replaced that and then it ran bad again. I checked codes no camsensor code but now alot of missfires. Link to comment Share on other sites More sharing options...
Gloyale Posted July 19, 2008 Share Posted July 19, 2008 Replace the Plugs with NGK or Denso. If the wires are "belden" change them out too. Check all the insulation for the wires to the fuel injectors, I had a car with similar symptoms that turned out to be a combination of cheap "belden" plug wires, and a knicked insulation on the injector wires. Link to comment Share on other sites More sharing options...
gbb1277 Posted July 19, 2008 Author Share Posted July 19, 2008 Well I changes the wires to oem subaru wires. It seems to run better but still misses quite a bit. I havnt had a chance to try the o2 sensor yet waiting on a jack. Link to comment Share on other sites More sharing options...
gbb1277 Posted July 21, 2008 Author Share Posted July 21, 2008 Well I finnaly was able to get a multimeter and check coil resistance. Assumeing I did it correctly I found primary coil resistance to be in the megaohms. I am going to check it again in the morning to see if it gets lower when its cold which it should. So all this agrivation ans parts replaceing may finaly come to an end. Oh and I found out the previous own aparently didnt want to buy a new pcv valve and replaced it with a open pipe fitting. Link to comment Share on other sites More sharing options...
OB99W Posted July 21, 2008 Share Posted July 21, 2008 Well I finnaly was able to get a multimeter and check coil resistance. Assumeing I did it correctly I found primary coil resistance to be in the megaohms.[...]The Subaru coil packs have two coils. The two primaries (of coils without an integral igniter) each typically measure about 0.7 ohms. (The secondaries of your coil pack should be about 13 k-ohms.) If you're seeing resistance in the Megohm range, something certainly isn't right -- did each primary measure that? Is it possible you measured about 700-something milli-ohms, which is the same as 0.7 ohms? Link to comment Share on other sites More sharing options...
gbb1277 Posted July 23, 2008 Author Share Posted July 23, 2008 Ok I wanted to give everyone a followup. The car finaly runs good again. The main cause was a bad coil. If cold the coil resistance was inspec but higher than a new coil and when hot it went way high out of spec which must have been why it ran good for a while when it was cold. Also there was a flaw in the wiring to my IAT sensor which may have contributed to the problem. I have all OEM parts now except plugs are Bosh OEM equivalents but I am changesing them out with NGKs from the dealer as soon as I can. I thank eveyone for there input you were all a great help. Link to comment Share on other sites More sharing options...
McDave Posted July 23, 2008 Share Posted July 23, 2008 Glad you got it figured out! Sometimes it the wires, sometimes it's the coil, and sometimes it's the bad wires that kill the coil. You didn't waste any money. Link to comment Share on other sites More sharing options...
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