Leaderboard

I recently went through an extended period of troubleshooting a charging problem on a 2001 LL Bean (3 wire system). To make a very long story short it was a bad alternator. It started out intermittently with several warning lights flashing, eventually total loss of charging. When measuring voltage at the battery it should read approx 14 to 14.5 volts when initially started, and depending on load and state of charge will then modulate between approx. 12v to 14.5v. When we had the total failure the voltage while running was erratic, but less than 10v. There are people who have de pinned pin C (black/red wire), and the car electrical system works fine. Some say this is hard on the system, but apparently the internal voltage regulator in the alternator works just like the 2 pin systems in the 4 cyl cars where there is no signal at pin C which should produce approx. 14.5v with no problem. There is also some info floating around about a Subaru service bulletin for certain Foresters that changes the signal to the ECU, simulating a load, presumably to influence the signal at pin C. I have also read several reports of people trying to determine what the signal is supposed to be at Pin C, there does not seem to be a consensus on what the signal is supposed to be. There are tons of people that have had trouble fixing charging issues with the H6 I think a lot of it is due to not understanding the system. Also the aftermarket alternators have a bad reputation. Also I don't think the local parts store can do a good test on a 3 wire system, most don't know what it is.

It's more of a rhythmic thumping vibration noise. I used the word knock but not in the sense of predetonation. I've had a spark plug wire go loose on me so I know what a nonfiring cylinder sounds like. And I've had my timing belt improperly installed on an old EJ22 so I know what misfiring like that sounds like. These are neither. Engine performance doesn't seem to be affected except for the vibration. My underbody is pretty impeccable. I've replaced the front CV axles, all the struts and shocks, and every damn bushing I could identify. Many control arms replaced. I've put a lot of time into getting the underbody in good shape to eliminate possible sources of weird annoying noises and to ensure my alignment is good. I wouldn't rule out a differential or even the manual transmission going bad, but all the small stuff has been buttoned down. I see no difference when turning. This seems completely unrelated to turning, road speed, or engine speed, only engine load, which is what makes me suspect an engine mechanical or engine sensor / ignition device issue.

It's often said, but I'll say it again: The toothed idler has a failure rate that's staggeringly higher than the smooth ones, so if you're doing the belt and tensioner and not a whole kit, be sure to do the toothed one too. Also, I stick with Mitsuboshi belts.

Rod knock comes from connecting rods, not pushrods. EJ251 is not a rotary engine, so they absolutely do have rods.

Timing tensioner - heat is soaking the hydraulic mechanism. Get it hot snd making the noise and then rev it in park with the timing covers off you’ll see it slapping around Inner axle cv joints. usually there’s considerable vibration - like the rear view mirror is shaking if it’s as bad as you describe. And it’s more prominent under load - accelerating or just driving up a hill.