RMVR53 Posted August 18, 2019 Share Posted August 18, 2019 (edited) Heres one for ya. I have a 2000 Outback 252 w/automatic. I had a miss that went away with new cam cover gaskets and oil seals. While there, I did plugs (NGK platinum) and coil. Now it runs like a scalded ape. Almost When under load, like going up a hill and on throttle, it starts to "buck" or" shudder" like a miss but its not setting a code. Also, this only happens over 3000 rpm. If you can go up that hill and keep it under 3 grand everything is fine. But by 3200 its starting to kick and buck. ideas? thanks Bill Edited September 28, 2019 by RMVR53 Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 18, 2019 Share Posted August 18, 2019 Probably going lean. Fuel delivery issue. Watch the fuel trims and the O2 sensor. If it's a narrow band front sensor (or watch the rear), check the mV on the sensor signal. under WOT load the sensor should be over 800 mV indicating power enrichment mode - somewhere in the 10.8 - 13 AFR. GD Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted August 18, 2019 Share Posted August 18, 2019 maybe check for bad cap/o-ring on fuel pump bad knock sensor can kill power Link to comment Share on other sites More sharing options...
RMVR53 Posted August 18, 2019 Author Share Posted August 18, 2019 GD thanks for the ideas. Not having any high-tech "stuff" to monitor trims and voltage, I may just opt for replacement...maybe one at a time because of $$. Fuel filter is about 40k old but will do it as well. Tex, I would think the KS would set a code and we have none. Bill Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 18, 2019 Share Posted August 18, 2019 A $3 harbor freight DVOM and a T pin for back probing is all you need to measure mV on the O2 sensor signal wire. A scan tool that can read generic OBD-II fuel trim data is about $25 on Amazon. GD 1 Link to comment Share on other sites More sharing options...
RMVR53 Posted August 18, 2019 Author Share Posted August 18, 2019 ok cool. Engine at op temp, cold or? Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 18, 2019 Share Posted August 18, 2019 Full operating temp. Must be in closed loop. GD Link to comment Share on other sites More sharing options...
RMVR53 Posted August 18, 2019 Author Share Posted August 18, 2019 will do - thank you Sir Link to comment Share on other sites More sharing options...
RMVR53 Posted September 5, 2019 Author Share Posted September 5, 2019 (edited) update. I've now replaced 4 Cam Position Sensors in 2 weeks. I finally got it to throw a code - P0341 (along with 0301-0304 - misfire). So replaced the CmPS. It lasted about 2 days and started the same crap again. Next one I installed Sunday and it didn't even start. Third one went in Monday but didn't have time for a test drive. I did that this evening. I made it 5 miles before it got so bad I wondered if I'd make it back home. Yeah it could be a bad batch of sensors, but is there anything else I should check that could be taking out the CmPS? Cold it starts/runs fine so I assume its either a heat or closed loop condition (or both). Oh..and GD - voltage varied from .84 to .99 when hot on the downstream. I don't remember now what the front read, but it was the same as my Son-in-Laws 05 Legacy GT which we used to cross-reference readings. thoughts? thanks all Bill Edited September 5, 2019 by RMVR53 Link to comment Share on other sites More sharing options...
GeneralDisorder Posted September 5, 2019 Share Posted September 5, 2019 Are the sensors from Subaru? Aftermarket are garbage. GD Link to comment Share on other sites More sharing options...
RMVR53 Posted September 5, 2019 Author Share Posted September 5, 2019 No they are not and I was beginning to think the same thing. Import Direct from O'Riliey's Link to comment Share on other sites More sharing options...
GeneralDisorder Posted September 5, 2019 Share Posted September 5, 2019 Better off with a used Subaru one typically. They aren't a high failure item really. GD Link to comment Share on other sites More sharing options...
RMVR53 Posted September 5, 2019 Author Share Posted September 5, 2019 verifying the most recent question - is there anything that could take out the CmPS or make it act like one is failing? I read on another post that the bad/noisy alternator could trigger a failure. Bill Link to comment Share on other sites More sharing options...
GeneralDisorder Posted September 6, 2019 Share Posted September 6, 2019 Not really. It's a Variable Reluctance sensor. The sensor is isolated from the vehicle's electrical system - it is an entirely passive sensor relying on a permanent magnet and a coil of wire that either end of which is connected to the interface circuit inside the ECU. So nothing the alternator or battery or ignition does can have any real effect on the sensor. There would have to be a short to power in one of the leads connected to the sensor, or the ECU would have to be somehow shunting power through the interface circuit...... unlikely. What is much more likely is a cheaply made sensor that is failing due to vibration, heat, and generally poor construction in a third world $hithole. Get a proper Japanese sensor. GD Link to comment Share on other sites More sharing options...
RMVR53 Posted September 6, 2019 Author Share Posted September 6, 2019 ordered the correct sensor from local Subi dealer today. Be in tomorrow. I will say that the lil sucker (non-factory replacement) was hot as a pistol even an hour after the engine was shut off. Link to comment Share on other sites More sharing options...
GeneralDisorder Posted September 6, 2019 Share Posted September 6, 2019 You might want to double-check that there is no significant voltage present on either of the sensor circuit leads. GD Link to comment Share on other sites More sharing options...
RMVR53 Posted September 6, 2019 Author Share Posted September 6, 2019 define significant... Link to comment Share on other sites More sharing options...
RMVR53 Posted September 6, 2019 Author Share Posted September 6, 2019 checked to ground from the two leads in the plug? Link to comment Share on other sites More sharing options...
GeneralDisorder Posted September 6, 2019 Share Posted September 6, 2019 Yes that will work. I don't believe there will be a bias voltage present to the crank sensor - most likely you will see nothing. If you see 5v or like 4.8v that's a normal bias voltage but like I said I don't believe there should be any voltage to the sensor - bias or otherwise. GD Link to comment Share on other sites More sharing options...
RMVR53 Posted September 7, 2019 Author Share Posted September 7, 2019 next?.... just installed a dealer item cam sensor. Same issue although it did take it about 6 miles before it started missing going up a hill under load. Bill Link to comment Share on other sites More sharing options...
GeneralDisorder Posted September 7, 2019 Share Posted September 7, 2019 Are you still getting a cam sensor code? GD Link to comment Share on other sites More sharing options...
RMVR53 Posted September 7, 2019 Author Share Posted September 7, 2019 yes and no....it hasn't thrown a code yet but its doing the same thing. So I assume it will pop the code if I kept driving it Link to comment Share on other sites More sharing options...
RMVR53 Posted September 7, 2019 Author Share Posted September 7, 2019 (edited) went out and plugged in the reader to verify - no code...yet. Also cleaned the gear to make sure there was no debris to mess up the magnet getting a read on the sprocket. Also to verify - its only under load and over 3000 rpm Edited September 7, 2019 by RMVR53 Link to comment Share on other sites More sharing options...
GeneralDisorder Posted September 8, 2019 Share Posted September 8, 2019 If there's no code - pending or otherwise, then I would say the cam sensor issue is likely resolved. Your symptoms are most likely ignition related. I understand that you replaced plugs, wires, and coil. Where did this coil come from? If you have the original put it back in. GD Link to comment Share on other sites More sharing options...
RMVR53 Posted September 8, 2019 Author Share Posted September 8, 2019 still have it and will put it back in tomorrow. really appreciate your help Sir Bill Link to comment Share on other sites More sharing options...
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