lolol Posted March 7, 2012 Share Posted March 7, 2012 I just got a 91 Legacy with an NA EJ22. It's been getting poor mileage and something I just discovered is that if I fast idle at 2000-2500rpm for a few seconds it will suddenly drop in RPM along with increased vibration. When I let off the gas at this point, it shudders and CEL comes on. I've been able to narrow it down to cylinder one by invoking a misfire by fast idling, then disconnecting injectors one by one. During the misfire, removing anything but cyl 1 causes further vibration but removing cyl 1(psgr side front) doesn't make any difference, so I've determined that this is the misfiring cylinder. When I listen by the tail pipe at normal idle, something sounds a miss and I can smell that smell you get after using outdoor power equipment in my hair. If I have the auto tranny in gear, I can't get it to misfire/misfire enough to be noticeable. There's no drivability issues so far, but perhaps this is why I'm gettin 15city/18 hwy So far: new air filter oil change (as if this makes any difference) new spark plugs Seafoamed through throttle body induction using Seafoam spray Cleaned PCV valve, throttle body and MAF I believe fuel filter is fine as there's no hesitation under heavy acceleration when fuel flow is the greatest. I wanted to swap out injectors to see if problem follows it, but I couldn't figure out how to get them out:lol: What do I check now? Link to comment Share on other sites More sharing options...
GEE-OTTO Posted March 7, 2012 Share Posted March 7, 2012 What is the CEL? Second you should check your injectors if you look on intake manifold where the injectors plug in there is a metal shroud running the length of the head you have to unbolt that first then you will be able to pull the injectors. Take caution so you don't damage the rubber O-rings. Once you get them out simply swap the no.1 with the other cylinders and see it it causes the issue. Or if you have time you can take them to be flow tested to see if they meet spec. Have you ever changed the coil or IACV ? Link to comment Share on other sites More sharing options...
lolol Posted March 7, 2012 Author Share Posted March 7, 2012 What is the CEL? Not sure. It only comes on for a few seconds and goes away as soon as misfiring stops. It's not OBD II (this is 1991), so I don't know if I can get the codes. Second you should check your injectors if you look on intake manifold where the injectors plug in there is a metal shroud running the length of the head you have to unbolt that first then you will be able to pull the injectors. Take caution so you don't damage the rubber O-rings. On individual injectors, there is an oval metal plate about two inches wide, but undoing those screws seems to remove the cover off the injector, but not actually remove it. You sure you're talking about EJ22 N/A 2.2 liter? Have you ever changed the coil or IACV ? Coil seems fine. When I pull the wire, it produces healthy spark during misfire conditions and connecting it back doesn't restore proper running. The plugs are brand new, but just to test it, I put in the old plug into cyl 1 to test. No improvement. I don't want to throw parts at it, especially costly ones like coil pack. Link to comment Share on other sites More sharing options...
halwith Posted March 7, 2012 Share Posted March 7, 2012 http://forums.sidc.co.uk/topic/137690-reading-ecu-fault-codes/ and http://www.justanswer.com/subaru/2tnnh-1991-subaru-loyale-check-engine-light-on.html this may help pull the cel code. see if there is a code stored. spray a bit of carb cleaner near the #1 intake runner injector. maybe its a vacuum leak at the intake gasket or bad oring on injector. maybe swap the #1 injector with another cylinder and see if the miss follows it. i know you just replaced the plugs but check #1 again carefully for a cracked porclain, ive seen that more than once on brand new plugs. Link to comment Share on other sites More sharing options...
GEE-OTTO Posted March 8, 2012 Share Posted March 8, 2012 And once you remove that metal cover you pull the injectors. Link to comment Share on other sites More sharing options...
lolol Posted March 8, 2012 Author Share Posted March 8, 2012 I'll read the codes when I get a chance. I'll see if I can pull the injectors to swap around without breaking anything. Link to comment Share on other sites More sharing options...
GEE-OTTO Posted March 10, 2012 Share Posted March 10, 2012 As suggested earlier a compression test would be helpful never know if you have a cracked ring land Link to comment Share on other sites More sharing options...
lolol Posted March 10, 2012 Author Share Posted March 10, 2012 Misfire is fixed. Mileage is still being tested. Symptom: The activation of "power mode" was sporadic. It didn't always go into "power mode" even if the pedal was quickly floored on the freeway. Cause: Throttle position sensor was incorrectly installed. I suspect whoever worked on the car in the past took it off at one point and slapped it back on with no regard for calibration. It was skewed towards less opening (caused one of the readings to actually read ~0.55kohms) reporting "no throttle applied, idle" to ECU even when the pedal was slightly depressed. So, I suspect that opening wasn't quite enough for MAF to react. It was however enough that without the ECU compensating fuel injection to account for additional air brought in by giving a bit of gas, it caused a lean out leading to misfire in cylinder #1. The offset also caused the TPS to under-report throttle opening across the entire range which explains sporadic "power mode" activation and may explain the poor mileage. Between terminals 2 and 3, I read 8.5 kohms, which represents the entire potentiometer element. Using the min/max hold function on a Fluke 87V meter, the resistance between 2 and 4 maxed out at 12.5kohm which indicates contact chatter. This is what causes old radios to make static noise as you turn the volume. This is a sign of worn potentiometer, so to cure it, the TPS needs to be replaced. Link to comment Share on other sites More sharing options...
lolol Posted March 10, 2012 Author Share Posted March 10, 2012 What is the CEL? In this order. Do they show up from most recent down? 42, 24, 31, 11, 14 The only one I can't explain is 11. I think the rest are from when I was monkeying around with the throttle position sensor with the engine running and disconnecting #1 injector to identify misfire. Link to comment Share on other sites More sharing options...
lolol Posted March 22, 2012 Author Share Posted March 22, 2012 Got around to checking compression. They all read 140-160 psi. I'm still getting 15-18mpg Link to comment Share on other sites More sharing options...
1991_4wd Posted July 11, 2015 Share Posted July 11, 2015 0 - check CPS (camshaft) sensor (mine had mouse chewed hole through cps causing random misfire.) 1 plug the iacv with 1" al foil ball 2. drive with the idle cracked open wth idle screw. ...if runs good it is the iacv / pcm. sea-foam, synthetic, = plugs wires etc...runs good!!! get the new iacv when you have 300. did this with mine and it runs like a champ with the plugged iacv, no CEL...i am amazed at this hack / fix. Link to comment Share on other sites More sharing options...
1991_4wd Posted July 11, 2015 Share Posted July 11, 2015 0 - check CPS (camshaft) sensor (mine had mouse chewed hole through cps causing random misfire.) 1 plug the iacv with 1" al foil ball 2. drive with the idle cracked open wth idle screw. ...if runs good it is the iacv / pcm. sea-foam, synthetic, = plugs wires etc...runs good!!! get the new iacv when you have 300. did this with mine and it runs like a champ with the plugged iacv, no CEL...i am amaze balls by the way... i am able to idle at < 1000 rpm, no cel with the iacv plug hack fans and ac can kick on without killing idle with the manual button down it gets good gas mileage...let it up and it shifts at 6000 "3" is a little intense...the newbs saying iacv bypass effects max power much are newbs... Link to comment Share on other sites More sharing options...
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