Hoping for some Baja clarification

[kensei]

I have had my '05 Baja Sport 5MT (165K miles) for about two months now. Got a decent deal on it and with the help of this board have been fixing lots of small things and a few bigger ones, too. We also have a '10 Forester and a '16 Outback, and I am impressed with how well the Baja handles compared to those two. And while the Outback has the CVT, the Forester has the regular auto trans, which I have never liked; the 5MT in the Baja is so much more well suited to the engine!

I finally got to the point where I wanted to address the floppy shifter and based on what I had seen, it looked like there are some bushings on the rod to replace, a couple of oval ones that mount somewhere and then possibly the transmission mount, too.

I inquired with one of the popular Subaru aftermarket vendors as to which application I should be looking for, since it seems like few websites list Baja specific parts. I was under the impression that most parts interchanged with the 2000-04 Legacy/Outback. The vendor responded to me with the suggestion that I look at another vendor's website and that all of the parts from the same year ('05) Forester will "bolt right up." This doesn't seem to align with most of what I've seen, but wanted to see if this was the experience of other scobytruck users...

I have lots of other questions, but don't want to bombard the board with them all at once...

[Guacamole]

Hey there! Yes, the NA (Classic/Sport) Baja drive train is in fact Gen-2 Legacy (2000-2004). Matter fact, the only thing different about the NA Baja drive train is the suspension as it's Baja-exlusive but interchangeable with a Legacy/Outback. The Turbo Bajas however *DO* use the Gen-2 Forester XT (2004-2008) drive train.
I'm not 100% sure that the trans parts for an NA 05 Forester will be fully compatible on an NA 05 Baja, and I wouldn't want to be the person to find out- best to stick with Gen-2 2.5L Legacy parts unless you plan to do a complete transmission swap, then all you have to worry about is drive ratio.

Don't be shy and ask away, we love being helpful here!

[kensei]

Okay Guac, thanks for help me feel not so crazy. In defense to the vendor, I did not specify that I had a N/A, so maybe his assumption was that I had a Turbo since his is a more performance oriented site. I will just look for Legacy parts and go with those.

I did have to do a little patchwork on the exhaust, which will have to do for a while. I was following your exhaust search thread with interest, and then noticed that the previous owner had a shop weld the catalytic converter to the midpipe with a patch pipe when their joint failed, so I will have no choice but to do a complete replacement when that time comes. And, of course, my patch work is at the midpipe and muffler joint, which in the short time that I have been looking seems pretty common...

Previous owner had the head gaskets done along with the timing belt and water pump at 100K, so I have about 35k left on those, and he did the clutch at 150K, so lots of life left there, too.

Gonna work on getting that shifter under control, and then keep going on smaller issues. My other MT car is a Miata, so it is putting it mildly to say there is a difference in the shift action/feel of the two...

[Guacamole]

Don't feel bad! The only one crazy here is... well... ME
Your gaskets *should* be good for the rest of the car's life. Just keep an eye on your temp gauge, check your oil and refill the coolant every so often, and religiously follow the maintenance schedule. Oil change every 3,000mi, timing belt at 105,000mi, etc, etc.

Important on your cats: DO NOT REPLACE THEM!!! Subies are very finicky with the cats and if they're not throwing 02 codes, don't replace them. I almost made this mistake. There's two things Subaru is terrible at designing: cupholders and exhaust. My 97 Corolla's exhaust is in better shape than my Baja, and that little junker has nearly 300k on it, has been through 4 hurricanes, 12 blizzards, and 20 years of fabulous MD road salt. The pipe flanges always go, and worse yet the muffler is proprietary. Luckily though the rest of the exhaust is exactly the same as the Gen-2 2.5 Legacy. The headers for most 2.5 Legacy RS, Impreza RS, and Gen-2 Forester models will fit too. I chose to replace my catback because they were beyond repair at this point and I got tired of sitting in traffic smelling my exhaust. We'll see how long Bosal parts last through an MD winter- so far so good though.

If nothing's majorly leaking from the cat forward, I wouldn't even touch it since getting the header bolts out of the block will be an absolute pain and the likelihood of them just snapping off is unfortunately quite high. As long as the pipes are fine and it's just the flanges leaking, simply welding them all together will do no harm, and the patch pipe on the flex joint is no big deal. Plus the cat is actually held on to the body by screws, unlike the muffler.

Funny thing about Japanese manufacturers- some have agreements between them and share parts. Your Baja's driver side window switch gone bad? Pull one out of a 98-04 Nissan Frontier- literally the same part, plugs and all.

[kensei]

Great heads up on the cats!

I have an UltraGauge and had been getting a check engine light on immediate startup with a P0135 code, which usually means an upstream O2 heater. I did notice that the upstream sensor was at 1.000 lambda no matter what, so I suspected a problem there. The downstream sensor was registering, but had values all over the place, there was no long term or short term fuel trim taking place and the system was always running in open loop mode. With the downstream values all over the place, I was concerned about the cat. I, foolishly, replaced the upstream sensor without a thorough diagnostic and had no change on the reading. So I am thinking the best thing might be to replace it all... After some searching and YouTubing, I did some diagnostic on the sensor and the plugs and was able to determine the problem was that the ECM was not sending the heater signal to the sensor. The (new) sensor tested out fine. I did notice that the original mounting brackets had rusted off and many of the plugs and wires on the right side were wire tied together. Close inspection revealed that one of the wire ties was rubbing right on the upstream sensor plug wires on the ECM side. I didn't notice any cut wire, so repositioned the plugs, tried to straighten the wire runs as best as possible, and for the last two days the upstream sensor has been functioning normally! I am getting appropriate values on both sensors, there is measured long and short term fuels cuts and the system is running in closed loop mode. I must have looked like a fool driving around with a huge smile on my face. Now that I know what the issue is, if it occurs again I may just strip some sheath and wire in a new connector with a good run of wire, but for the time being I am gonna roll with it. Plus, no cat replacements!

[walfredo]

For anyone reading this I want to just mention that when diagnosing front sensors, you should be paying attention to the voltage of the upstream air fuel sensor and not lambda. Even though in a typical scenario, you should be seeing lambda swap between rich/lean, you would want to watch the actual voltage (air/fuel ratio) and see what thats reading (and if its fluctuating). Lambda is just saying its rich, which may be true, but by watching the voltage you can see if there is any fluctuation in that richness value (air/fuel ratio) and can see if the front air fuel sensor is actually working, or if its defective.

See if you can do a datalog on the actual voltage. Depending on your diagnostic tool preferably, it should read 0-5 volts, since our cars have wideband upstream sensors (a true air fuel sensor). This front air fuel sensor should fluctuate in a wave form (even if lambda is 1 because it may just be rich). If you are not seeing any fluctuation in the voltage of the front A/F sensor at idle, then I would replace it with a new one (you should also be getting a CEL).

The rear o2 on the other hand is an actual o2 sensor, should read a constant 0.8 volts (or there about) and on a fully warmed up car, should not fluctuate in tandem with the front a/f voltage. If it does, then that indicates a bad cat, if you have a bad cat, you may also have a fueling (running rich) issue, especially if lambda on the front sensor is always at 1.0 but the air fuel voltage fluctuates.

And yes, never forget that a sensor may not be bad, but that the connection/wire may just be broken!

[kamesama980]

P1035 is for the sensor heater circuit. While this could certainly be the sensor itself, it could also easily be the wiring. You'd need to (with the key-on-engine-off) backprobe the O2s plug (O2s side of the plug) and check for 12v on the hot side and ground on the other side. If you see less than battery voltage on the hot side, that indicates a poor connection from the battery to the ECM or ECM to the sensor, seeing voltage on the ground side (or resistance, checked with the key off) means a bad wire going back to the ECM or bad ground from the ECM. (either could also be a bad ECM but that's rare)


wideband O2 sensors are NOT magical AFR sensors. they do not sense anything to do with fuel and they will still read dead-lean on a misfire where you get fuel and air in the exhaust: they are still an O2 sensor! the difference is in how they are read. Any O2 sensor functions as a voltage cell, the simple version is when there's a difference in O2 content on either side of a membrane, electricity flows. Kinda like different metals (alloys, chemicals...) on either pole of a battery in your flashlight, watch, cell phone, etc. When the engine runs rich, it uses up all the O2 so the exhaust has none while the atmosphere being compared to does... so it generates voltage. the problem is it's incredibly sensitive, so much so that for all intents and purposes, it's an on/off switch hence the .2-.8v wave typical to back-probing them.

Somewhere along the line, one of the mfrs got smart and figured out that a voltaic cell doesn't just put out volts, there's also a host of other things to measure as well, such as current and resistance. Wideband O2 sensors are chemically and electrically very similar but tuned differently and read differently. They still output a 0-1v signal (sometimes) but it isn't linear. There are a few different ways to read them but it comes down to combining voltage with resistance or inversely, current. the ECM applies a voltage to the O2S sensing circuit and sees what current flows. Obviously the voltage still being a switch you'd think it wouldn't work but the resistance of the sensor also changes and can be computed by the ECM into an AFR within a certain range (but wider than a narrowband). You'd only see 0-5v as an output after processing, such as the analog out of an aftermarket gauge. That 0-5v isn't a reading from the sensor but a deliberate output controlled by the computer in the controller that tells the gauge what to show. Back-probing a WBO2 sensor actually won't get you very far and may throw off the reading to the ECM, as sensitive as it is.

I know the turbos have a WBO2 as the upstream sensor, not sure about the NAs. There isn't much need for a WB on an NA, maybe with as stringent as emissions are getting now but not 15 years ago. I'll try to remember to check my NA tonight. Unfortunately, since the difference is mainly in the programming and what's inside the magic box (ECM or controller) it's practically impossible to tell them apart externally except that if there are more than 4 wires it's almost certainly a WB and if there are fewer than 4 it's definitely a NB. You can tell from the signal which it is because a NB will show the typical sin-wave-like oscillation while a WB is likely to be pretty steady (my turbo is).