snake05 Posted May 15, 2012 Share Posted May 15, 2012 Hello all, I have a 1998 Subaru Legacy Outback with the DOHC 2.5, I rebuilt the engine myself about 14,000 miles ago. The check engine light came on about 2,000 miles ago, the code was misfire cylinder 1. Reset the code continued to drive it, CEL came back on and starting blinking at me, code was misfire cylinder 1 and 2. Changed the ignition coil, light back on, new ignition coil, light back on. Put new plugs and wires on it, drove it, the light came back on. This past weekend after I changed the ignition coil again (new brand), I had driven a few hundred miles and the CEL came on and started blinking, it was still running fine, no jerking or wanting to die on me. The code this time was misfire cylinder 1 and 2, plus exhaust code. Any ideas as to what the problem could be? Link to comment Share on other sites More sharing options...
idosubaru Posted May 15, 2012 Share Posted May 15, 2012 what brand plugs/wires? wires are notoriously problematic on EJ engines - i've seen brand new aftermarket wire cause cylinder misfires. if they're not Subaru then some folks would suggest to start there. that being said it sounds like you've done enough trouble shooting to almost rule that out.... if that's the case then swapping the intake manifold may fix the issue. i say that from experience and my only guess is that maybe fuel injectors can also cause a misfire? so maybe you could also swap out the fuel injectors rather than an entire intake manifold like i did. not sure if it's related but the motor i was working on was driven by someone who just kept driving and driving on low coolant and cooked the motor - so the overheat may have compromised something in the manifold too, i really don't know. Link to comment Share on other sites More sharing options...
davebugs Posted May 15, 2012 Share Posted May 15, 2012 Move plug wires front to back/back to front. See if problem stays on same cylinder or moves. It's free and may give some insight. Link to comment Share on other sites More sharing options...
Fairtax4me Posted May 15, 2012 Share Posted May 15, 2012 What condition were the plugs in when you removed them? Dusty White? Dusty Black? Oily? Wet? 1+2 are on the same coil, so any ignition problem that effects both is likely the coil or igniter, and since you replaced the coil already... Bad fuel injectors possible, spark plug condition can indicate. Compression related issues, timing not likely, but valve lash could be too tight. Burned valves are common enough on that engine. Lash is easy to check with an angle feeler gauge. Link to comment Share on other sites More sharing options...
snake05 Posted May 15, 2012 Author Share Posted May 15, 2012 I did get the car with a blown head gasket. And I have heard that problem tends to cook the ECU. The plugs only had a 12k on them and they were not very sooty. Compression was #1-165psi #2-175. Did a valve job when I rebuilt the engine so I do not think its a hangup. I have moved the plug wires and changed them, they are now standard, and were bosch. The plugs are NGK. I have replaced the fuel injectors in #2 & #4 already, and 4 has have never thrown a code. And #2 the code only comes after prolonged driving with the CEL on. Ignitor, I will try that next if its not $$$$$$$. If it is I will see what I can do about the injectors as well. I was reading similiar posts for cylinders #3/4 and they just put seafoam in the vacum line. They think it was a carbon buildup problem. The car runs fine my mpg is 22.7-27.9, the light on just drives me nuts. Do not want to drop hundreds of dollars for a light fix. I appreciate all the advice, will keep posted. Link to comment Share on other sites More sharing options...
davebugs Posted May 15, 2012 Share Posted May 15, 2012 I don't understand. You had the time/money to do a valve job and left the old plugs in it ? NEVER seen a bad ECU in a Subaru. I don't even bother saving them when I scrap a car. I have known good injectors and ignitors, coils, etc even heads as probably a lot of us do here if you need something PM one of us. I'm tearing down engines right now. Link to comment Share on other sites More sharing options...
idosubaru Posted May 15, 2012 Share Posted May 15, 2012 I did get the car with a blown head gasket. And I have heard that problem tends to cook the ECU. Subaru ECU's basically never fail unless you hook up battery cables wrong. Link to comment Share on other sites More sharing options...
unibrook Posted May 15, 2012 Share Posted May 15, 2012 When you redid your engine, did you replace your front 02 sensor? If not, had it been replaced within the last 40k miles? If not, that might be it. Link to comment Share on other sites More sharing options...
bstone Posted May 15, 2012 Share Posted May 15, 2012 NGK Laser Platinum plugs are the same as the OE Subaru plugs (same model number, same manufacturer). Start there. Link to comment Share on other sites More sharing options...
GeneralDisorder Posted May 15, 2012 Share Posted May 15, 2012 Encountered my first bad EJ ECU recently. Heater core leaked coolant on it and shorted the injector driver amp - causing the #3 injector to be fully open at all times with the ignition on. The ECU uses the crank sensor signal to determine misfires - instantaneous acceleration can be derived from the hall effect wave pattern. If nothing else is confirming the misfire you should probably inspect the crank sensor/wiring and the crank sprocket for damage. GD Link to comment Share on other sites More sharing options...
snake05 Posted May 15, 2012 Author Share Posted May 15, 2012 I don't understand. You had the time/money to do a valve job and left the old plugs in it ? No I did not leave the old plugs in it. I changed the plugs whenever I did the rebuild, which was when I did the valve job. I had the heads resurfaced as well. I changed the plugs last week along with the wires, and tried two different ignition coils to try and get rid of the CEL, none of which worked. If it was an O2 sensor would that not throw its own specific code? Is there a way to test the ignitor? The dealership wants $300+ for a new one. Link to comment Share on other sites More sharing options...
Fairtax4me Posted May 15, 2012 Share Posted May 15, 2012 Get an igniter from a junkyard. $20-25 and there is almost 0 chance of getting a bad one. O2 sensors don't always trip codes right away. But they also don't generally cause misfires unless the engine is warm. Does your misfire happen while the engine is cold? Link to comment Share on other sites More sharing options...
snake05 Posted May 15, 2012 Author Share Posted May 15, 2012 . Does your misfire happen while the engine is cold? The CEL comes on randomly. Sometimes cold sometimes warm, the CEL flashes at me however only when I have driven 60+ miles of highway speeds. And last weekend it only did it going uphill. Link to comment Share on other sites More sharing options...
GeneralDisorder Posted May 15, 2012 Share Posted May 15, 2012 Did you even bother to read my post? GD Link to comment Share on other sites More sharing options...
snake05 Posted May 16, 2012 Author Share Posted May 16, 2012 Did you even bother to read my post? GD I did, and that is what my mechanic buddy suggested. I am trying to cover all bases. I will not be able to hook it to a lab scope until next week or so. I might be able to test the ignitor before then. I heard of a test with a 12v light grounded out to the harness on the ignition coil harness to tell if it is the ignitor or not. I can do that with parts in my garage. Link to comment Share on other sites More sharing options...
Recian Posted May 16, 2012 Share Posted May 16, 2012 Im curious now because you have a misfire code and no actual misfire based on your previous posts. It would seem that if you had any faults intermittent or not that you would experience a misfire conscern coupled with the code. Only time ive seen a misfire code with no miss was a coil problem on a ford. HOWEVER if im not mistaken misfires are judged by the ecu looking at the knock sensor to find knock and label the adjascent cylinder as missing. An overheated ej will melt a knock sensor quick. Mine did on my ej22. Link to comment Share on other sites More sharing options...
Recommended Posts
Please sign in to comment
You will be able to leave a comment after signing in
Sign In Now