softroader

Yes, I think it is the one that cars101 is talking about when they mention PZEV in 2004. Three cats and 5 O2 sensors for a 4-cyl! Insane. I will be avoiding it, probably a quick way to spot one would be the throttle body. I've seen pics of the different airboxes between the EJ251 and EJ259 but I'm still a bit unclear which is which. The throttle body would be a sure sign.

Related question: does anyone know if a non-California emissions 2000-2004 OB can be registered in California without difficulty or penalty, or be rejected for emissions testing because it's not a California emissions car? DMV is impossible to reach right now or I would ask them.

Question about Gen 2 emissions equipment. The attached dataplate image is from a 2001 H4 4EAT OBW I looked at last week. The other image is from the 2004 FSM. I have read that PZEV hurts engine performance and economy, and is more expensive to repair. According to cars101 PZEV appeared on the OBW in 2004. Should I try to avoid the 2004 California OB's? Presumably this would be "C" in Engine Type. I am in the People's Republic of Kalifornia if that makes a difference. I will need to register the car and pass emissions testing. Interested in how undesirable it is to have PZEV on the car, not interested in discussing climate change or any of that stuff.

You're looking for a very recent OB, right? I hope that works out well for you. Several late model OBs in my neighborhood that the owners seem happy with. I think I'll end up with a Gen 2 H4 4EAT after considering all the good advice I have received here, and I like the Gen 2 OBs more and more as I get more familiar with them.

Thanks for the replies everyone. 4EAT it is. Seems like Subaru engineering and reliability is progessing backwards after 2004.

Bulletproof is what I am looking for. It would be nice not to have to replace the clutch every 100-150,000 miles. Also curious if the 5EAT (and its TCU) is a direct swap into a Gen 2 OB H4 with 4EAT?

Yeah, "hybrid" was a joke Stole that from my dentist, who also runs an ancient 22RE in his pickup truck. And I agree brake pads are cheap, though I rarely use the brakes, I last replaced the pads in 2009, almost exactly 100,000 miles ago, and there's still quite a bit left. They do fade quite quickly though on the DD, so prolonged use isn't a good option.

Good point. I guess you would have to install EGT thermocouples in the header downpipes and do some software magic to get that. Not sure about individual cylinder AFR, that sounds tricky.

I just follow the FSM. If it says don't replace undamaged ones, they're not TTY. Baffling to me why some people still want to argue about it when this is so clear in the FSM, and the FSM is so readily available for download.

The irony is that parameters like this are readily available by sniffing CANbus frames. But CANbus cars no bueno.

Cool, another software hacker! Agree with all of this, with one exception... My DD has a 22RE which didn't leave the factory as a hybrid but is one now. It runs on gasoline and oil. Lots of oil. Like 1qt every 200 miles lots of oil. The valve stem seals are shot (37 years old, I got my money's worth out of them), and the oil rings have seen better days, so she burns oil. Can't fix that without removing the head bolts, and the head gasket is at 400,000+ miles, if I remove the head it will be a one way trip with the inevitable pitting. So I leave it alone and just wave a chicken foot over it from time to time, hoping for the best. I keep up with adding oil, but sometimes, especially when descending from the mountains when engine braking is high and there's low pressure below the stem seals, she uses a lot of oil. So much so that, in hard turns, especially to the right, the oil pickup will unport and there's a brief loss of oil pressure. This triggers the EICAS led driven by the arduino until the turn is over and the oil in the pan returns to level. Time to add oil! This has been very useful.

Cool, I just downloaded and installed Piston v2.1.3. Agree it does look better than Torque Lite, useful basic functions instead of silly eye candy. Also half the size. Should have my ELM327 OBD-2 Bluetooth dongle from Amazon tomorrow, then I'll be all set to find me a car.

Are you using Torque Lite on your phone for this? (Their web page says it might not work with some Subaru ECU's, but doesn't say which ones).

I agree, what presslabs did was kick a$$ impressive. A very elegant hack that used unused memory in the stock TCU. Good stuff.

Thanks. That makes sense. The 2005+ CANbus cars presumably report everything and frames containing interesting parameters are flowing on the bus continuously. But I don't want CANbus. I added an oil pressure sensor to my DD. I'll just do that to the OB too. It drives an arduino which converts it to a signal that drives my oil pressure gauge and gets upset if the pressure is too low for the engine rpm. And a few things like that. Simple, and way more useful and responsive than the stock snail-slow gauge. And way, way more useful than just an idiot light (it's really just a "too late" light).

I'll look into the GM units, which seem a bit expensive for what they are. Or maybe just build something from scratch for the paddle shifters. It doesn't have to do much, inputs are the paddle shifters and engine RPM, outputs are the 4EAT solenoids and maybe some lights. The logic is simple, shift the tranny according to paddle commands, refuse to shift or upshift if engine RPM is too high. And some smarts to make it play well with the TCU so it doesn't fight for control of the AT or cause the TCU to generate unneeded fault codes.

On a topic related to my looking for a good used 2000-2004 OB, I have a question about OBD-II Code Readers. I have never used one, my DD predates OBD-2. I need to buy one for my used car search to check for fault codes etc. I'm looking at an OBD-2 reader that supports live data. Live data would be very useful after I buy the car. Does the 2000-2004 OB support live data on the OBD-2 port (oil pressure, AT fluid temperature, etc)? I can't find this in the FSM.

Good idea, I'll look into that.

That type of hardware usually lives a long time. My guess is the failures are due to memory cell changes from high energy particles. Same thing that occasionally causes computers and phones to need an unexplained reboot. Reflashing the TCU should fix that. If the memory cell is damaged not just flipped, the memory chip could be replaced and reflashed. Or it could be a failed solder joint from vibration - my cruise control computer in the DD suddenly started to drop out at random times after working for years. I resoldered every joint on the board (easier than finding the bad one), reflowed the conformal coating with some alcohol, let it dry and reinstalled. It's been fine for years.

I get to drive a very high performance vehicle at work, so have no need to go fast in my car. Especially since a suicidal deer decided to run in front of my DD in the mountains a couple of years ago, now I drive mountain roads at the speed limit or less, much to the annoyance of the drivers behind me who seem to think a twisting two lane blacktop with blind curves and sheer drop offs is an extension of the freeway. Reasonable power should work fine for me. I'm used to my DD which has over 400,000 miles on the original 22RE engine, which wasn't exactly a speed demon when it was newer... now, when I drive up that long grade on 395 from Bishop to Mammoth Lakes, I'm in the far right lane, 3rd gear, giving the engine as much gas as it can use, one eye on the temperature gauge and another on the rear view mirror watching the rapidly growing sight of a vehicle with more torque than mine as it gets ready to swerve past me mere feet from my bumper, horn blaring, middle finger extended, as though I chose to crawl up the grade as slowly as crankcase sludge on a cold winter morning. I love my car, she gets me there, but that is no fun at all.

Numbchux, did you ever try hacking the TCU to add paddle shifters to the 4EAT? I came across a thread from 2008 (yeah, I know) in which you were planning to try this on your XT6. Did anything ever come of this? I'm toying with the idea of doing this to my OBW when I finally find the one I want, it isn't necessary at all but it would be a really fun project. I'm a EE/CS and have years of experience writing assembly language for embedded processors and operating system kernel code so taking on a TCU modification project like presslab's in that 2008 thread doesn't faze me in the least. Though as I recall he had to make some hardware modifications to the AT, and I would not want to do that.

Great info, thank you. No longer sure it makes sense to get the EZ30 OBW with its DOHC headaches, expensive parts, cheaper to swap in a JDM EZ30 ($1200) vs replace the HG's (ouch!), all for an extra ~45HP and ~45ft-lbf torque (and a heavier vehicle) ... and most 2001-2004 H6's for sale around here seem to be right in the "175k to 225k and lose HG's" range so it would be a ticking time bomb. No longer sure it makes sense to get the 5MT either with those common center diff failures, and no way to know the car's real history... maybe it was run on mismatched tires for years and damage already done that wouldn't show up on a short test drive without fully warming up the viscous coupler... and I do plan to do a lot of offroading (softroading, nothing gnarly) in this Outback. Looks like the sweet spot is the 2001-2004 EJ251 4EAT MPT, and just deal with the timing belt (easy) and head gaskets (not difficult) when the time comes. My assumption coming into this, after having driven 4-cylinder cars with AT's years ago, is that if I bought an H4 4EAT OB I would be buying a snail that couldn't get out of its own way, but the 2001 H4 4EAT I test drove a couple of days ago didn't seem like that at all, and there are a lot of H4 AT OB's out there whose owners seem satisfied with their performance, even in mountain states. Guess I need to drive another one to make sure, then grab the first good one that comes along.

Was part of that change the twin cup holder vs single? I'm looking at a 2002 OBW today that (from the pics) has a twin cup holder, so will that mean it also has the front brake size upgrade?

Does "modern EJ manuals" include the 2001-2004 Gen 2 OBW? I'm asking because I'm going to see one that's for sale today. A 2002 5MT. Why did those cars get torque bind? What failed and what caused it? Is it certain years/models I should be avoiding?

I've come to the right place then. Yes, willing to ask, and very willing to learn. I am an engineer, anecdotes are sometimes useful but what I really want to hear is knowledge from those with actual experience, real data. A good example is the recurring question of whether the EJ25 head bolts are torque to yield or can be reused. The FSM says they can be reused. So that's the correct answer. But the tribal skirmishes keep happening over it regardless of the fact. Anyway, I actually was asking about the VDC system, not the MPT. Sorry, I wasn't clear in my question, I should have written "which the clutch discs will try to compensate for" instead of "which the MPT will try to compensate for". The scenario would be temporarily installing a spare tire, which for whatever reasons might not match in diameter or tread type etc, to extract from an offroad situation and drive, perhaps a few hundred miles, back home or to where a matching tire could be obtained. What I'm curious about is whether, with the VDC system temporarily disabled, the AWD system would tolerate the mismatched tire on one axle because the center differential, being a differential, inherently wouldn't mind the difference in front vs rear axle rotation rates. I'm curious because (a) I want to understand how this system works and (b) the vulnerable and always connected viscous coupling in the MT Outbacks makes me uneasy in this scenario. Loved your Little Boy comment! Totally agree about Subaru marketing dogma, and those who regurgitate it. I'd much rather understand te system and be able to make fact/knowledge based decisions.