Steve455 Posted April 13, 2007 Share Posted April 13, 2007 The car has a heavy miss to it at idle and driving,i also get codes po203 and 204 injector circuit open.Could the injectors be making it stumble real bad? also do these codes mean the injectors are bad?i unpluged the injectors and plugged them back in but didnt change anything. Link to comment Share on other sites More sharing options...
nipper Posted April 13, 2007 Share Posted April 13, 2007 Take an ohm meter to the injectors and see what it reads. nipper Link to comment Share on other sites More sharing options...
Steve455 Posted April 13, 2007 Author Share Posted April 13, 2007 i tested the injectors and they are all 11.5 ohms. Link to comment Share on other sites More sharing options...
nipper Posted April 13, 2007 Share Posted April 13, 2007 The injectors are hot on one side, and ground out through the ECU. i don't like to condem ECU's, and i will admit we are getting into an area where i am weak. Someone else will chime in here, but this could be malfunctioing injectors, or the ecu. Odds are of two injectors failing at the same time are long, so i would lean towards the ECU. nipper Link to comment Share on other sites More sharing options...
Steve455 Posted April 13, 2007 Author Share Posted April 13, 2007 i was backprobing the ecu a few weeks ago when the car wasnt running so maybe something grounded out.i can here the injectors clicking.the miss is like every 4 seconds.i will try and use anouther ecu i pulled from anouther outback. Link to comment Share on other sites More sharing options...
OB99W Posted April 13, 2007 Share Posted April 13, 2007 i was backprobing the ecu a few weeks ago when the car wasnt running so maybe something grounded out.i can here the injectors clicking.the miss is like every 4 seconds.i will try and use anouther ecu i pulled from anouther outback.Let's try a little math, and see what it tells us... Assume the engine is idling at 600 rpm. Since there are 60 seconds per minute, 600 rpm translates to 10 revs/sec. Each cylinder has one power stroke per two crankshaft revolutions, so at 600 rpm that would require 5 (10/2) injector pulses per second (at each cylinder). If the misfires are about four seconds apart, at 600 rpm there would be around 20 injector pulses per cylinder between misfires. Since there are injector codes for two cylinders, there could be around 40 pulses on average for the two coding cylinders between misfires. That suggests the problem is marginal, and that most of the time the ECU is properly pulsing the injectors. So, what could cause the ECU to mispulse an injector or two on occasion? The pulses are triggered by info from the cam angle and crank angle sensors, and a faulty signal might be to blame. Those sensors are dependent on the reluctors that are on the back of the sprockets (that is, their condition and position relative to the sensor). Perhaps something unkind happened to one of them: http://www.ultimatesubaru.org/forum/showpost.php?p=594070 ...Just a thought. Link to comment Share on other sites More sharing options...
nipper Posted April 13, 2007 Share Posted April 13, 2007 Let's try a little math, and see what it tells us... Assume the engine is idling at 600 rpm. Since there are 60 seconds per minute, 600 rpm translates to 10 revs/sec. Each cylinder has one power stroke per two crankshaft revolutions, so at 600 rpm that would require 5 (10/2) injector pulses per second (at each cylinder). If the misfires are about four seconds apart, at 600 rpm there would be around 20 injector pulses per cylinder between misfires. Since there are injector codes for two cylinders, there could be around 40 pulses on average for the two coding cylinders between misfires. That suggests the problem is marginal, and that most of the time the ECU is properly pulsing the injectors. So, what could cause the ECU to mispulse an injector or two on occasion? The pulses are triggered by info from the cam angle and crank angle sensors, and a faulty signal might be to blame. Those sensors are dependent on the reluctors that are on the back of the sprockets (that is, their condition and position relative to the sensor). Perhaps something unkind happened to one of them: http://www.ultimatesubaru.org/forum/showpost.php?p=594070 ...Just a thought. hrmm one of those sensors are indexed (i forget which right now). IF we follow that logic, i would start at the indexed sensor. Now if it was truly random, then i could fully support this nipper Link to comment Share on other sites More sharing options...
Steve455 Posted April 13, 2007 Author Share Posted April 13, 2007 the crank sensor did get a little dent in it,i will try using a diferent one.i also tried anouther ecu from a 95 outback with a 2.2 but it wouldnt even let the car start. Link to comment Share on other sites More sharing options...
OB99W Posted April 14, 2007 Share Posted April 14, 2007 the crank sensor did get a little dent in it,i will try using a diferent one.i also tried anouther ecu from a 95 outback with a 2.2 but it wouldnt even let the car start.You might need to verify that the reluctors (those ridges/teeth at the back of the sprocket) are okay as well. A small deformation or piece missing could result in a weakened pulse that might not trigger the ECU consistently. Link to comment Share on other sites More sharing options...
Steve455 Posted April 14, 2007 Author Share Posted April 14, 2007 i just went and looked at the crank sensor,after unpluging it i could see that 1 of the wires going to the sensor was barley atached by a couple of the small strands not sure if this would make it stumble but ill be back out at the wrecking yard tommorow to get anouther plug for the crank sensor.somebody had stripped away both wires for probing and thats what caused the strands to break. Link to comment Share on other sites More sharing options...
OB99W Posted April 14, 2007 Share Posted April 14, 2007 The electrical connection is important, but so is the condition of the reluctors, sensor (especially the tip), and the gap between the tip and the reluctors. If the gap is excessive, for whatever reason, the generated signal will be weakened. Link to comment Share on other sites More sharing options...
Steve455 Posted April 14, 2007 Author Share Posted April 14, 2007 im sure the tips on the crankshaft sprocket are good,but sensor might be bad since it is dented on the top. Link to comment Share on other sites More sharing options...
nipper Posted April 14, 2007 Share Posted April 14, 2007 How did it get dented? There isnt alot to these sensors physically. you dent it you broke it. nipper Link to comment Share on other sites More sharing options...
Steve455 Posted April 14, 2007 Author Share Posted April 14, 2007 the alternator bumped it and dented it. Link to comment Share on other sites More sharing options...
Steve455 Posted April 15, 2007 Author Share Posted April 15, 2007 i replaced the crank sensor and plug and the car still is stumbling every few revolutions,the only good thing now is atleast the car runs and there is no more oil leaks. Link to comment Share on other sites More sharing options...
Cougar Posted April 15, 2007 Share Posted April 15, 2007 If there is a seperate connector for injectors 3 and 4 make sure the connection is in good shape. Also check the wiring between the ECU and to those injectors. There may also be some external resistors that need to be checked though they be internal to the ECU. Link to comment Share on other sites More sharing options...
Steve455 Posted April 15, 2007 Author Share Posted April 15, 2007 would the injector codes make the car miss? Link to comment Share on other sites More sharing options...
nipper Posted April 16, 2007 Share Posted April 16, 2007 would the injector codes make the car miss? The codes dont make the car misfire, the faulty injectors or wiring or ECU will make the car misfire. If the fuel injectors dont operate, no fuel or the improper amount of fuel will get in the cylnder, and the cylinder will miss. Air fuel spark are required for ignition. nipper Link to comment Share on other sites More sharing options...
OB99W Posted April 16, 2007 Share Posted April 16, 2007 i replaced the crank sensor and plug and the car still is stumbling every few revolutions,the only good thing now is atleast the car runs and there is no more oil leaks.If the misfire is consistently happening "every few revolutions", it probably doesn't have an electrical cause. A rhythmic miss like that reminds me of "hot" cam behavior; valve overlap causes a pulsation in the intake manifold that makes sensor readings erratic and can cause the ECU to get really "confused". Steve455 previously reported that the belt had jumped, and was replaced. How about a simple explanation, like the timing is off on one cam? That could have an effect similar to hot-cam valve overlap and explain things if the miss is truly rhythmic. Okay, I've got my Nomex/asbestos suit on, so flame away. Link to comment Share on other sites More sharing options...
Steve455 Posted April 16, 2007 Author Share Posted April 16, 2007 If the misfire is consistently happening "every few revolutions", it probably doesn't have an electrical cause. A rhythmic miss like that reminds me of "hot" cam behavior; valve overlap causes a pulsation in the intake manifold that makes sensor readings erratic and can cause the ECU to get really "confused". Steve455 previously reported that the belt had jumped, and was replaced. How about a simple explanation, like the timing is off on one cam? That could have an effect similar to hot-cam valve overlap and explain things if the miss is truly rhythmic. Okay, I've got my Nomex/asbestos suit on, so flame away. The timing could be off because it was running good before i changed the crankshaft sprocket.I will tear it down and redo the timingbelt and see if that works.I thought the timing was good because the car starts rite up. Link to comment Share on other sites More sharing options...
nipper Posted April 16, 2007 Share Posted April 16, 2007 The timing could be off because it was running good before i changed the crankshaft sprocket.I will tear it down and redo the timingbelt and see if that works.I thought the timing was good because the car starts rite up. They always leave out those little details ... nipper Link to comment Share on other sites More sharing options...
OB99W Posted April 16, 2007 Share Posted April 16, 2007 The timing could be off because it was running good before i changed the crankshaft sprocket.I will tear it down and redo the timingbelt and see if that works.I thought the timing was good because the car starts rite up.An engine that starts could still run poorly due to just a one-tooth misalignment; more than that, and with an interference engine, you can wind up with bent valves, etc. The two links below have some very good information. The first has general info about Subaru t-belts, while the second gives very detailed instructions on getting the marks lined up correctly on a DOHC 2.5L; I suggest both be read fully (ignore the SOHC info in the first link if working on a DOHC) and followed carefully. http://endwrench.com/images/pdfs/TBeltEWWin05.pdf http://endwrench.com/images/pdfs/2.5Timing.pdf Link to comment Share on other sites More sharing options...
Steve455 Posted April 16, 2007 Author Share Posted April 16, 2007 The car does run better at higher speed so the timing being off seems to be right.I also replaced the 2.5 crankshaft sprocket with one from a 2.2. Link to comment Share on other sites More sharing options...
Steve455 Posted April 16, 2007 Author Share Posted April 16, 2007 does anyonoe know if the 2.2 and 2.5 crankshaft sprocket are the same? Link to comment Share on other sites More sharing options...
johnceggleston Posted April 16, 2007 Share Posted April 16, 2007 does anyonoe know if the 2.2 and 2.5 crankshaft sprocket are the same? i have read here that they are interchangeable, but to a casual observer, they appear slightly different. the bolt head on the 97 2.5 is not visible, it's recessed or more hidden. on the 95 2.2 you can see the bolt head, this may not be significant... or maybe my 97 doesen't have a bolt holding the crank pulley on. Link to comment Share on other sites More sharing options...
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