OB99W

Just curious -- how did you come to the conclusion that you need an engine?

In terms of keeping a PCV valve from sticking or if it's clogged, it can be cleaned. It's possible for the spring in the valve to eventually fatigue, causing the operation to become out of spec, but that isn't likely to happen for a long time. You can probably continue to use the original one as long as you don't notice any change in engine operation.

My factory diagram obviously has an error, since B135 #6 is shown in one place as a black/blue ground and elsewhere as a violet/green going to the rear defogger circuit. The green/red wire on B135 #7 is indicated as a hot lead (via F/B fuse #11) -- you might have been measuring the relatively low resistance of a relay coil on that line. The white/blue wire on B135 #28 is shown going to a contact on the starter interrupt relay -- in that case, with the key off, I don't know why you would measure a low resistance to ground there. Given the checking you've done of the ECU wiring, it's probably okay. The erratic temperature gauge reading that we've discussed, however, indicates a definite problem. The portion of the CTS for that function doesn't even go through the ECU, so it should be relatively easy to track down that problem. I'd suggest looking at the sensor for a bad connection, and if that doesn't resolve the gauge fluctuation, consider replacing the CTS. Since the unit has sensors not just for the gauge but also for the ECU, it's important to use an OEM unit if you do replace it. EDIT: Because you're questioning the B135 info on the diagrams you're using, and in case what I have is accurate for the cam sensor connection, I show B135 #2(red) and #9(green) being the two pins for it. If you pull that connector from the ECU and check resistance between those two pins, you should of course measure the same as at the cam sensor itself, about 2 kohms. Other than that, I think we've run out of things to check relevant to the ECU wiring.

It seems this falls into the ''your mileage may vary'' category.

I'm actually outside the city of Ithaca, NY. Ground wires are usually black, and may have a color stripe. Yes, B135 #6(black/blue) is a ground. Other ECU grounds are B134 #7(black/pink), #8(black/white) & #27(black), and B136 #21 & #22 (both black/blue). Those grounds are all routed through the E3/B22 connection I mentioned before. That ground joint connector is 12-pin, blue, single row of contacts, and is indeed the one I referred to before -- it's effectively just a jumper. I have no info indicating anything beyond 12 pins, nor a white/green wire being a ground. I believe the common ground connection is made through the ECU itself. If all of the above checks okay, do consider the CTS. Perhaps connections at that sensor are corroded. The ECU can definitely default to a rich running condition if it's getting incorrect engine temperature data. Again, I don't see a direct relation to P0340, but sometimes the effect of a part failure isn't the expected. The uneven running might be throwing things off enough for the ECU to be seeing timing problems at the cam sensor.

I believe we're talking afterfire (cat/muffler), not backfire (intake). There was a previous thread that should be referenced: http://www.ultimatesubaru.org/forum/showthread.php?t=98943 With respect to that thread, depending on exact conditions, the EVAP system can produce a slight vacuum in the fuel tank when the engine is running. However, if the engine is shut down (as for refueling) there shouldn't be a noticable vacuum when the gas cap is removed. Cougar gave some hints to diagnosing that condition in the other thread, and it makes sense to follow up on it. It's certainly possible for an EVAP/vent problem to develop that hasn't (as yet?) triggered a code.

There's one more connector to consider, a junction for sensor grounds. It's B83(blue), a 12-pin inline. It should be near the ECU (branches off the harness where the three ECU connectors do). Are you saying that with the engine cold, the gauge indicated in a range it should only be at with a warm engine? If so, it's possible that the engine coolant temperature sensor is failing. That sensor is a 3-wire type, and has outputs for both the gauge and the ECU. It might be giving bad data to the ECU as well as the gauge. The ECU can't tell if temp data is wrong, so it might be setting parameters that aren't correct for actual operating conditions. I can't see a direct relation between the CTS and code P0340, so look at the ground junction connector before considering the CTS.

Since the problems are somewhat intermittent, it's possible that there are poor connections that you haven't found yet. The cam and temp sensors don't directly connect (respectively) to the ECU and gauge. Both of them are wired through intermediate connectors that join the engine harness with the body harness. E2/B21(gray) are a 20-pin connector pair where pins #18 & #20 are used for the cam sensor and pin #10 is for the temp sensor/gauge. E3/B22(brown) are a 16-pin connector pair where the temp gauge gets ground via pin #16. Those connectors should be near the rear of the engine, mating its harness with a body one coming through the firewall. Check them for solid contact and lack of corrosion.

If the engine were truly running on only two cylinders, I'd normally expect more than just the cam sensor code to be set. If the ECU isn't getting cam sensor data, it will go to a fail-safe (limping) mode that uses engine speed and throttle position to determine injector operation. Did you reset the ECU? Could you be more explicit about the temp gauge variations? (Conditions, amount of change, gradual or rapid movement, etc.) It could be a problem with the ECU, but I'd suggest that you verify the cam sensor signal (pulses) are making it to the ECU input. If you can, a scope is probably the best tool for that purpose.

First let's determine if the refrigerant charge is in the ballpark. With the engine not running, measure the temperature and what both gauges are reading (allow the system to equalize), and let us know what you get.

Pre-Delivery Inspection EDIT: Of course, the dealer only needs to do that after they determine that you have sufficient ''Personal Disposable Income''. Later on, if the payments turn out to be too much, your credit card issuer will inform you of the ''Past Due Interest''.

Improved disposition?

Possibly because the Gates ones seem to have a reasonable reputation.

It's easy to damage a MAF. Although there are some carb cleaners that claim to be ''MAF safe'', you're better off with a cleaner that's specifically for MAFs. Even so, be gentle when you work.

I don't have any personal experience with the Gatorback parts, but a Google search on ''gatorback timing belt'' turns up some comments about their belts which aren't too encouraging. Perhaps the idlers and tensioner are decent, but...

Mike, I'm not sure I can rise to your challenge to ''account'' for the apparently weak spark to #4, so how about some conjecture? If you reread the last paragraph of my post #29 in this thread, I was wondering whether the ECU was providing a compromised ignition pulse for #4. The ECU determines EREV (engine speed) from pulses developed by the crank sensor and reluctors on the sprocket, and uses that data to influence ignition timing and dwell. If the ECU detects a drop in EREV a sufficient number of times after a particular cylinder is supposed to have fired, it ''assumes'' that the cylinder is misfiring and sets a code. Now for the conjecture -- perhaps the detected drop in EREV causes the ECU to markedly change the ignition dwell for the affected cylinder, thereby affecting the spark intensity.

Yes, it's ''time'' to take off more than the side (cam) covers. See the links in http://www.ultimatesubaru.org/forum/showthread.php?t=100505

Knock sensor mounting bolt tightening is somewhat critical. Have you verified the torque as per the EndWrench article that I linked to?

Since cam sensor data is used along with that from the crank sensor to determine fuel injector pulse timing and duration, if the data is ''wrong'' (or the ECU ''thinks'' so and relies on default values) the result could certainly be a rich mixture. What Cougar suggested is proper ''by the book'' diagnosis for the P0340 and P0341 codes. However, since the cam sensor was replaced and the wiring apparently okay, there might be another possibility. I've seen reports that the timing belt tensioner can fail, causing looseness of the belt that can result in mistiming of pulses from the cam sensor and generation of the codes.

The P1133 code is for a problem in the heater circuit of the O2 sensor. If the ECU/PCM ''thinks'' it can't control the heater properly, it will set the code. The high voltage you measured for the sensing element is apparently not a concern, as others have reported proper operation as long as the O2 sensor/heater and wiring are good. Although not specific to your model/year, see the following threads for further insight: http://www.ultimatesubaru.org/forum/showthread.php?t=66744 http://www.ultimatesubaru.org/forum/showthread.php?t=98800

Naturally, and the one that was missing in the replacement probably had just about fallen out. Murphy's Law? You're welcome.

Perhaps the following link will help solve the mystery: http://www.ultimatesubaru.org/forum/showthread.php?t=58418

Can we assume that the car is a '92 Legacy with a 2.2 engine? (You didn't say, although your screen name suggests that.) At 120 PSI, the compression is too low if the right procedure was followed. With a well-charged battery, all spark plugs out, the throttle held open, and a good oil film on the cylinder walls, a healthy engine with proper valve timing should be closer to 170-175 PSI. You mentioned that you're using the correct mark at the crank, but make sure that's true at the cams as well. See http://www.ultimatesubaru.org/forum/showthread.php?t=100505 for links to articles that will help you verify proper timing belt installation.

The CO2 and O2 numbers at idle are further indication that there's too much fuel for the amount of air available. The CO2 is a bit low, but more importantly, the O2 being 0.0% shows that the engine ran out of available oxygen to burn the fuel (and the catalyst had little or none to work with), resulting in high HCs and CO. Do you have a means of measuring the O2 sensor voltage? By the way, was the replacement sensor an OEM unit? Awww, well come by even if you don't have a problem. The PCV valve is normally open very little at idle, so if the valve or tubing were obstructed the idle mixture would typically only enrichen slightly. Still, it wouldn't hurt to check the PCV system operation. There are several possible causes of a rich mixture -- the CTS can be one if it tells the ECU that the engine is cold when it isn't. It would be good to determine if the ECU is remaining in open-loop operation, which is one of the reasons I'm asking if the O2 sensor voltage can be measured.

The problem is not likely caused by catalytic converter failure. When both HCs and CO are high, it indicates a very rich mixture (either excessive fuel, or not enough air). Since the emissions drop at higher engine speeds, it means the mixture is not overly rich under that condition. Usually an oxygen sensor thats bad enough will cause elevated HCs and CO even at the higher RPMs, and especially since it was replaced not that long ago, probably isn't the culprit. One possibility is that the fuel pressure is too high, which could be caused by a problem related to the fuel pressure regulator. You could check that the vacuum hose connection to it is good, and also pull the vacuum hose off to make sure that there's no fuel in it (which would indicate a ruptured diaphragm). If you have access to a fuel pressure gauge, an actual measurement would be best. Do you have more than just the HC and CO readings? CO2 and O2 numbers could be helpful in determining what's going on. EDIT: The symptoms could also be caused by a MAF problem, although if only dirty that usually leads to a lean (not rich) running condition.