AdventureSubaru Posted October 5, 2015 Share Posted October 5, 2015 95 legacy was purchased with EJ22 and 5 speed. Newish clutch and 178k. It starts smooth but after about 60 seconds the idle starts hesitating a bit. When driving it's normal for those first 60 seconds but quickly becomes undriveable under load. bucks all over the place and has no power. Never stalls out though. I crept it over the hill by throttling up and tapping the clutch into 1st gear just going bump, bump, bump about a foot at a time until I could push the clutch and coast down the hill. 6 check engine codes were pulled. p0500 - speed sensor p0505 - idle air control p0420 - anything! p0130 - o2 sensor bank 1 p0133 - slow o2 p0101 - mass air flow Figuring initially that mass air flow would be the most likely and easiest to replace, I put a known good MAF sensor in and cleared the codes. Driving since then, with no change no CEL. Still bucking and gutless and completely tripping over itself. No bubbles in the radiator, coolant loss or anything to suggest head gasket issue. What next? Since I have some spares I may try plugs, wires, coil and see if that helps but it does not feel like the plug wire style of weakness. Maybe blocked fuel filter, pressure regulator, pump? Swap o2 sensors? IACV? Any suggestions on what next? Lots of possibilities so trying to get an order of priority. Link to comment Share on other sites More sharing options...
mikaleda Posted October 5, 2015 Share Posted October 5, 2015 (edited) Those all run off the same set of connectors in the harness I would check those connections. Edited October 5, 2015 by mikaleda Link to comment Share on other sites More sharing options...
AdventureSubaru Posted October 5, 2015 Author Share Posted October 5, 2015 The main connectors at the back of the motor? Link to comment Share on other sites More sharing options...
Fairtax4me Posted October 6, 2015 Share Posted October 6, 2015 (edited) Spark plugs and Wires? How old are they? Two O2 sensor codes could mean its going lean when it gets into closed loop, which could be within about 60 seconds depending on outside temp. Edited October 6, 2015 by Fairtax4me 1 Link to comment Share on other sites More sharing options...
Bushwick Posted October 6, 2015 Share Posted October 6, 2015 (edited) Sounds like one of or both of your O2 might be bad. Can try disconnecting one/both and seeing if the engine will run OK in closed loop. You'll get more codes, but running is what you are looking for. Suggest pulling the battery cable first, to rest the codes. Then disconnect the O2. Start engine and see if bucking stops. Can also get the codes pulled with O2 disconnected. IF only O2 codes are showing now, that might rule out connector. I had issues with my 99' Saab 9-3 where it was basically doing the same thing. It started OK, but within the first couple minutes it'd start bucking, missing, etc. For awhile, it'd clear itself and run fine for the rest of the trip, then not reappear. Then it got to the point it'd do it routinely. Only code I was getting was for the actual O2 heater element, which it had when the car was bought and didn't affect drivability. Eventually, while coming home from a gas station, it started doing it again. I put it in neutral and revved slightly and backfired something crazy and blew the seams out of the muffler! Thankfully the car was cat-less at the time as it would have screwed up much more. Anyways, what was happening was the O2 sensor's metal casing had split, and was peeling. This allowed moisture in. The bucking was an actual short occurring. Seems the engine was OK on closed loop where it wasn't relying on the input of the sensor, but once it did had a fit. Also, believe it or not this was the REAR downstream O2 causing all this trouble which everyone said couldn't as it's "not important" for the engine to run. It could be the connector like everyone is saying, or could be the O2. If the O2 is shorted and sending erratic signals to the engine, the engine won't run right and it can possibly think other things are wrong. I also got a random misfire code with mine due to the O2, so that "appeared" to be a coil or plug issue. Edited October 6, 2015 by Bushwick Link to comment Share on other sites More sharing options...
mikaleda Posted October 6, 2015 Share Posted October 6, 2015 can you get live data on your 02 sensors with your scanner? if so you may be able to see what the o2 sensor signal is doing and could tell you a lot. if its staying high i would be saying its a bad sensor, if low i would go through and check all of your connections. i believe all but the IACV run off of the same connectors and i do believe those are the ones at the back of the motor. Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted October 6, 2015 Share Posted October 6, 2015 (edited) disconnect the exhaust - might be clogged. Or check for that with a vacuum gauge. Edited October 6, 2015 by 1 Lucky Texan Link to comment Share on other sites More sharing options...
AdventureSubaru Posted October 6, 2015 Author Share Posted October 6, 2015 Good info. I'm going to work with it for a while this afternoon and post back what I find. Link to comment Share on other sites More sharing options...
AdventureSubaru Posted October 7, 2015 Author Share Posted October 7, 2015 Disconnected, cleaned and reconnected the main wiring harnesses. Disconnected the o2 sensors and started it up. Again, seemed fine for about 30 seconds and started hesitating. This time though, I could hear a buzzing/humming sound coming from the back of the car. Pulled the plate above the fuel pump and can hear VRRRR-vrrrr-VRRR!!!! VRRR etc. Buzzing and struggling along. Safe to say that the pump is about shot. Just to be sure it wasn't strained by a blocked filter, I swapped a known good used filter on since the one in there looked original and no change. Wiring looks good. Gonna grab a fuel pump from the junkyard in the next day or two. 1 Link to comment Share on other sites More sharing options...
AdventureSubaru Posted October 9, 2015 Author Share Posted October 9, 2015 Trip to pick n pull and $30 later it's running just fine with a JEGS pump motor in there. Drove it for a half hour and have the pending code p0130. Going to replace the front o2 sensor next I guess. Question is - I have an o2 sensor from the same location on an Impreza but the wiring harness is not a match. Can I splice it in? Two white wires and one black. Does it matter which white wire goes where? Hate to spend $60. on a sensor when I could use this one. Link to comment Share on other sites More sharing options...
Fairtax4me Posted October 9, 2015 Share Posted October 9, 2015 Should work if its just three wires. The two same color wires are just for the heater element, polarity shouldn't matter for that. Link to comment Share on other sites More sharing options...
AdventureSubaru Posted October 9, 2015 Author Share Posted October 9, 2015 That's what I figured with so many universal types. Just didn't want to get sparks or do the job for nothing. Dropping the exhaust tomorrow I guess. Link to comment Share on other sites More sharing options...
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