4wheeln2

I have an '04 outback limited. I recently had the head gaskets done by the dealer. Soon after, the p0031 code showed up (like within 10 miles of the dealership). I replaced the o2 sensor with a generic one, then one from a dealership bought off the web (it had the wrong connector). I carefully soldered and heat-shrinked the connections of the 2nd o2 sensor (came in a subaru box) and it still is throwing the p0031 code. I am beginning to think the 02 sensor is not at fault, but may be wiring or relays. Any ideas would be helpful. I took it back to the dealer, but they had experienced some network probs and could pull and erase the code, but could not use any of the realtime data to delve deeper into a solution (so to speak). The tech was a little puzzled and didn't seem to have any answers. Am trying to sell this car, so I would not like to throw money at it unless I am sure of a solution! Any ideas or FSM troubleshooting tips? I am fairly handy and have a digital VOM and tools. Thanks in advance!

taprack I have to admit, I only skimmed through the artticles you provided. The relevance that they have is questionable, however. The car craft articl3e seemed to remotely support the case for the try and see approach. the corvette c6 article seemed to be an overview of available vac advance units, and an explanation of its function, which you seemed to gloss over. another article was an example of one person's personal preference. as i skimmed through, though it did seem like there was some insight in the operationoof the ignition timing system, particularly vac advance, which is what the discussion is about. not vac advance on drag mustangs, 400 hp corvette c6's, zz502 big block crate motors( which if you read the article required a lot of tuning and an electric vacuum pump to run right) or the like. a more helpful article might have had more to do with street-petrformance or off-roading, where the goal is to have a broad torque curve, and good throttle response. you obviously are a smart fella to find all those articles. All I have beeen trying to get across is that while it might be cool to have a 15 hp spike at some point in your powerband, that it will pay off more to have you motor run its best throughout the rpm range, and have predictable throttle response. that's pretty important if you take your brat offroad- nothing like stalling out at the top of a hill climb, etc. in the final analysis, you are absolutely right- because you are working on your car, not mine and you are the one who has to be satisfied with its performance. I just think if you really understood what you were doing, you'd seee the point in leaving this aspect of the sube stock. its almost like someone trying to reverse the battery terminals for the sake of experimentation. I hope you don't think I'm being a jerk, you can take what I say with the biggest grain of salt, i'll tune my brat my way, you tune yours your way. we can agree to disagree. Patand GD, the deal with the vaccum advance is that it is there to supplement the mechanical timing during part throttle conditions. if you have 24 degrees in the disty, and 12 deg in the vac advance, and 12 deg. initial timing, you dont have 48 deg total. you havbe 36 total, because the vac advance only comes in to the picture at part throttle conditions- or sitting still in your driveway while you work the throttle, maybe. butr in the real world, you don't really "add" the timing from the vac advance, it is just there when the engine requires it.

the last couple of threads were a little confusing to me. I'm not sure if I was misunderstood when I suggested reading old-school hot rod magazines. I do read those mags, have been doing so for 20-25 years. knowledge is power. My intention was to promote this general knowledge as it applies to all cars, including subys. I didn't mean to hurt anyones feelings or insult anyone in any way. I was simply trying to add my .02. that said, I will suggest again to anyone interested in modifying the timing curve on any vehicle to do so after a little research on what exactly spark timing affects, and especially, what role the vac advance unit plays in the overall timing picture. As I tried to explain before, the vac advance unit is there to add extra spark advance (cause the spark to arrive inthe combustion chamber sooner relative to the piston arriving at top dead center) when the engine is in a light load/or cruising mode. ie low demand, part throttle, downhill, etc. the additional spark advance at this point allows more complete combustion, at a low demand time when there is little danger of detonation(also known as pinging or preignition) detonation is the uncontrolled burning of the intake charge (not initiated by the spark plug firing) due to increased cylinder temperature. usually, some sharp edge of the spark plug or combustion chamber glows red hot and ignites the intake charge prematurely- while the piston is still on its way up the cylinder bore. the result is like hitting the top of the piston with a hammer as it arrives at the top of the bore. the first to go is the crank and con rod bearings, piston ring lands, etc. detonation is a condition that will ruin an engine in short order. look for grey specks on you spark plug insulator- that's part of your piston that got melted. like I said before, if your car runs better with the vac advance hooked up differently, it's probably because there is some other problem that you need to address. about the advance all being in at 1700 rpm, I would be more inclined to trust a timing light, and tachometer to plot the timing curve of the stock disty. perhaps the FSM is incorrect. I don't think you will find any stock disty that has all the advance in by 1700 rpm. again, just my .02 the reason you have spark advance at all, incidentally, is because as engine speed increases, there is less time for the intake charge to arrive in the chamber, and for the spark to ignite it, and the flame front to propagate (burn the mixture) and create the energy to push the piston down the bore. lastly, if you have read tons of magazine articles,websites etc, taprack then perhaps you misinterpreted them as you misinterpreted my reference to hot rod magazines. I would like to see ANY reference to running full vacuum as a performance enhancing modification. I apologize for sounding so harsh, but it is important to have some understanding of ignition timing in order to know what effect your experiment is actually having. I agree that it is important to think outside the box, and challenge conventional thinking, but I think if you understood what role the vac advance plays in the overall timing scheme you would hook it up as the factory had it, and enjoy all of the benifits that it provides for part throttle driveability. We might also simply take a survey of some folks on the board. I think the results would support the stock vac advance case. Pat

i have a 96 legacy wagon 2.2 n/a, and my wife has a 04 outback 2.5 has anyone out there added a cold air kit or exhaust to either of these cars? the 96 hass 111k on it and is ready for struts. any suggestions there? would like a little more performance from the 2.5 as it seems reallyt sluggish for a brand new car. any help appreciated. thanks, Pat

the vacuum advance is for part-throttle driveability. it allows more advance during light throttle/ light load cruising operation. the advice to disconnect and plug the vacuum advance diring setting the initial timing is so the vac advance will not affect the overall timing. ie- the vac advance is adding or subtracting timing advance while you are really only interested in setting the (mechanical advance) timing. the disty's mechanical advance has a fixed amount of advance like maybe 24 degrees (just a guess) and if you set the initial timing at 12 deg btdc (before top dead center) the result is that you have 36 deg total timing. aand you would get full advance (36 deg) at the rpm that the spring pressure is overcome by the centrifugal action of the advance weights. likely close to 4k, but every disty is different, and by checking advance at 500 or 1000 rpm intervals, it should be easy to plot an advance curve. ideally, for a street driven, or off roaded vehicle, part throttle driveability (ie throttle response) should be the main focus. you want the advance in as soon as possible, ther curve miught start adding advance at 1200 rpm and have all 24 deg in by 2500-3000 . the stock curve is probably struggling to get a full 24 or whatever the disty is designed to provide by 3500-4000rpm. the vacuum advance should be left as is (factory stock) and the disty should be used to alter the timing curve. any use of the vac advance to provide more advance would only improve a vehicle's performance in a narrow band of operation, if at all, and then only because the vehicle was not properly tuned to begin with. true there are a lot of smog related items that can provide a performance boost if removed- but most of the benifit is from lost weight. biggest cork to performance is clearly the exhaust system. then the intake, then the cam and heads. you're going to have to work really hard to get another 25 horses out of an ea81 ea82. they are only 80hp or so to begin with. the better plan is to marginally improve performance by 15 or 20 horses across the rpm range, rather than trying to get 50 horses at the top end. the other guy will be outrunning you for 4000 rpm of a 5000 rpm powerband. final word- fix the vaccum advance, it promotes mileage, throttle response and driveability. you guys could also consult some of the old-school hot rod toype magazines, as they all still regularly run articles that explain in much better detail the function of complicated engine systems, and most of the knowledge is very general in nature and does apply to our subes. Pat

if your compression is 11:1 then I would suspect crank and rod bearing damage from detonation. even with aluminum heads, 11:1 compression is a lot to run with pump gas. usually, when compression is raised, like in a performance application, the cam is swapped out for one with more lift and duration. the additional duration can help bleed off cylinder pressure at low revs (effectively reducing compression) and this will allow the motor to survive. i don't recall if you still have the stock cam or not, but the low speed torque building properties of a stock cam will further complicate the issue by causing the motor to build a great deal more cylinder pressure than the motor can survive. one solution can be to use a die grinder to remove ANY sharp edges from items in the combustion chamber - spark plug bosses, piston crowns, etc. the additional pressure can cause sharp edges to act as a glow plug, which causes preignition or detonation, which causes the cylinder to fire before the spark plug initiates combustion, which is like hitting the piston with a sledge hammer on its way to TDC. look for greyish specs of metal on the spark plugs- that is metal coming off the pistons. also examine the ring lands at the top of the piston, and make sure the rings still seat square in tyheir grooves. hope this helps. good luck!

hey if you get in a jam, call me up, i'm in lex ky. at the intersection of i75 and 64. cell #859 621 5838 pat

hey skip, for what it is worth, I would suggest running as cool a thermostat as you can find, using the stock radiator setup, and obtain a compressor tio get the AC back into operation. you already seem to have a handle on watching the oil and coolant temps closely, the coolant extracts a lot of heat from the oil in the block. all this would seem to help to lower te underhood temps, which I believe is where the real performance gains are to be found. the old formula I believe that Smokey Yunick used was as follows: for every 10 degrees F that you decrease the temp of the intake air, you get a 1% horsepower increase. I think the motor in question for theis formula is a "typical" 300 horse chevy v8, but the logic still applies- cold air is denser, has more oxygen per volume. Plus, I would hate to have oil and coolant that close, in case you had a hidden leak allowing coolant and oil to mix. I am not actually clear if the condenser is seperate or a part of the existing radiator- so if it is seperate, then disregard last comment. In my n/a brat, I was amazed at the difference in having a mechanical secondary carb, advanced timing, and a free flowing exhaust. I never believed the ea81 had that much throttle response. But, still, at 90 mph or so, it really shows that it has 70-80 horsepower! I would rather have some intercooling setup that would allow more timing- subaru's seem to be timed very conservatively, and insulate everything to keep heat in the exhaust and out of the intake air. hope this helps. Pat