OB99W
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The reason there are so many "opinions" is that there are many causes of surging. That's especially true with modern engine management systems. The ECU monitors and controls several things, and attempts to correct "out-of-limits" operation. Unfortunately, sometimes sensor data lags too much and the compensation is excessive -- eventually the ECU senses the overcorrection, and then pushes too far in the opposite direction. Also, some faults are beyond the ECU's ability to compensate for. The basic requirements for an engine to run are all potential sources of surging and/or hesitation as well. (I'll leave out the things you've recently replaced, although there's no guaranty one of them isn't the culprit.) Air -- vacuum leaks are a common cause Fuel -- fuel pump, fuel pressure regulator, injectors Spark -- coil, plugs, wires, but they don't tend to improve under "heavy acceleration" Compression -- valve issues, possibly related to... ...Timing (belt) -- a one or two tooth mistiming can play havoc with things. Is this the engine that last year had such a problem? If so, I seem to remember that at the time, all that was done was retiming with a new belt, but no replacement of tensioner, pulleys, etc. Perhaps it jumped (again?). Sensors -- yes, you replaced some, but there are others.
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http://en.wikipedia.org/wiki/Ad_hominem_attack You didn't say that. No, what you said was "Just run with the rad cap lose so it doesn't build pressure, you won't lose any water and it really won't care one way or the other." I'll let my previous posts on USMB represent what type of person I am. We'll see how yours reflect who you are. As to the actual topic: I'll admit to sometimes giving advice that tends toward the cautionary side, and when I see the kind that runs the other way, I speak up. Apparently so far rverdoold has had an uneventful trip, and I hope the concern I expressed turns out to be unwarranted. However, even if the car makes the entire trip without incident, I'll stick with my position that running with an unpressurized cooling system is risky.
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Of course; stupid engineers, what do they know? There's obviously no need to raise the coolant boiling point by pressurizing the system. Just think of all the money wasted on cars built that way, when they could just have had radiators with "overflow" tanks. By all means, a 2000 km (over 1200 miles) trip with an unpressurized cooling system is a good idea. Oh, yeah, for anyone who is sarcasm-challenged: :rolleyes: ! Years ago cars were built without pressurized systems. They also didn't have modern sophisticated engines that require them. I'm not saying the trip can't be done, just that it's risky, and there are measures that could be taken to minimize the risk.
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The pressure cap is designed to elevate the boiling point of the coolant. For example, if pure water boils at 212F/100C degrees, pressurizing 13 psi raises it to about 246F/120C degrees.http://www.broadleyjames.com/FAQ-text/102-faq.html Keep in mind that the coolant isn't at a uniform temperature, since the engine has hot spots -- even if the average temperature is below 212F/100C, there can be localized boiling, typically at the heads. If that happens, it's obviously not good. If the leak doesn't get completely fixed, or it breaks again, don't top off with plain water. Ethylene glycol based coolant raises water's boiling point. A 50/50 mix brings it up to about 265F/129C, while 70% concentration raises it further, to about 276F/135C. Therefore, if you absolutely must reduce the pressure, adding more antifreeze/coolant might help offset the lowered boiling point. (However, ethylene glycol doesn't transfer heat as well as water, so I'd limit the concentration to 60-65%.) One more thing you might do is wire both radiator fans to run all the time. If they don't cycle off and on, the average temperature of the coolant should be held lower, making it less likely that boiling will occur. Best of luck -- let's hope you don't overheat!
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Note that I didn't say the system hadn't been evacuated; I said that there was no mention of it having been done, and I also said that if it hadn't been done, sufficient moisture could result in internal icing (which can damage the compressor if there's blockage). Here's some info that might be useful: http://www.aa1car.com/library/ac98.htm http://www.aircondition.com/tech/questions/82/ http://www.autoacrepairs.com/gauge_reading_and_diagnosis.htm http://endwrench.com/images/pdfs/ACTheory.pdf http://endwrench.com/images/pdfs/ACMechanism.pdf http://endwrench.com/images/pdfs/Service07MayEW.pdf
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this doesn't typically cause immediate failure or issues though. but it is a good point and i'd follow up with the question how/why did the old compressor fail? if it spilled guys into the existing system, which was never cleaned, then those parts may be causing fun things to happen in the new compressor. I was primarily mentioning the possible lack of evacuation as an additional indicator that proper procedure wasn't being followed. However, if there was sufficient moisture in the system, and especially if the desiccant in the receiver-drier was already at or near saturation, there can be internal freezing. Even if that doesn't happen, moisture reacts with the refrigerant, resulting in acid formation and eventual damage.
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See section "Legacy and Impreza Engines with No Injection Pulse #1 Cylinder" in: http://endwrench.com/images/pdfs/Emissions.pdf I wonder if the ECU thinks there's an IAC problem, and would be shutting off the #1 injector (as described in the article), except for the idle switch not closing due to the misadjustment. Perhaps checking whether #1 is pulsing correctly, especially if you allow the idle switch to close, might provide a clue. (Yeah, it's just a guess, I haven't run into the specific problem you've described.)
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Listen for piston slap when the engine is cold. (Yes, I realize you might never experience it in Florida, especially this time of year.) Check for torque bind during tight, low speed turns. If an auto trans, see if there's slow engagement when shifting from reverse to drive. Try to determine when the timing belt was last replaced. It may not have been as yet, but is very nearly due. The 2.5 is an interference engine, so that's a critical issue.
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If you reread the original post, it seems like the belt may have been on the way out, and finally broke. (Possibly a chunk was missing, causing the reported "clunking" during turns due to increased load on the PS pump?) Or (as you previously suggested, Gary) the crank pulley is loose, and the belt got thrown due to lessened tension and misalignment. Or, a Road Gremlin took it.
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Subarut, I'd also suggest that you return to the forum before you put the car back in service. There are steps to take to "reverse" the storage process. Here are two examples: 1) Thoroughly inspect the car visually for possible critter damage. Look in particular for damage to wiring and hoses, including brake flex lines. Obviously, fix/replace anything that's important before using the car. 2) There will be some corrosion in the engine after nine months. Even if the oil/filter were changed at the start of the storage period, once the engine is running again it's not a bad idea to change them once more after just a short time.
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Several of the steps suggested at that site aren't practical, since the car will apparently be stored outdoors (see the link to the earlier post). Step 5 makes a good point -- a car battery that isn't used for 9 months will self-discharge even if disconnected, and sulfate to some degree. (If it discharged sufficiently, low specific gravity of the electrolyte could allow it to freeze if the temperature got low enough, which obviously shouldn't be allowed to happen.) After the storage period, if the battery is put on a charger at a low rate (2 amps or so) for several hours (it could take a day or more, actually), it might recover. Otherwise, the battery could be removed from the car before storage and put on a trickle charger. It still might not perform as well as it did nine months before, but that's probably as good as could be done for it.
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I suspect that the snow's effect was not due primarily to its weight, but rather to air damming. Any prolonged increase in MPG is probably because you're not driving under winter conditions with winter-formulated gas, as you mentioned. Info I've been able to find points to possibly one MPG improvement by removing rack crossbars, but only at high sustained speeds. However, I think it's appropriate to say "your mileage may vary".
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If anyone wants to see what was said here previously:http://www.ultimatesubaru.org/forum/showthread.php?t=89436 Nobody can answer that question with absolute certainty, but if the engine is prepped correctly I'd be inclined to not run it at all for the nine months. Short runs at idle, especially in the winter, tend to cause accumulation of moisture and gasoline byproducts. If all you're saying is that the car will be tilting slightly from side to side, that won't be a problem. Why would you empty the tank? It's more likely to develop corrosion problems that way than if nearer to full (I'd avoid completely full, as it might expand enough to vent on a hot day). I would add some gas stabilizer to it, however.
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Are you saying that you got an increase of 3 MPG "around town" by removing the roof rack crossbars, or was that improvement just on the highway? What's your average "around town" and highway speed? (I'd love to gain 3 MPG, but I have the feelling that I don't go fast enough for the air resistance to make that much of a difference.) ... ... Okay, I just did some research. These guys say "up to" 5% penalty (about 1.0-1.5 MPG, and that's probably at highway speed): http://www.cartalk.com/content/features/fueleconomy/ Here's some anecdotal "data": http://www.fixexpert.com/phpbb/viewtopic.php?t=6435&sid=35766fd4f7acb3bb3042a698756e0dfa Still, if you're not using the rack, any improvement might make removing the crossbars worthwhile.
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Great, now we can move on. Don't beat yourself up, the dead horse will do. If the fuel pump isn't running (assumed since no fuel pressure) and the igniter isn't pulsing, it's likely to be a cause common to the two, and not separate problems. I know you previously checked the fuses, but I'd suggest doing so again, as well as testing fusible links. I think SBF-2 is common to the main relay and fuel pump relay. Also, does anything under the hood or dash look non-stock? An aftermarket anti-theft shutdown module could make the troubleshooting difficult. You're welcome, let's hope for further progress.
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Pic of #4 is much better now. Pitting noted -- #3 (rear pass) and #4 (rear drvr) are on opposite sides of the same coil in the pack, and receive reversed spark polarity with respect to each other. The electrode that wears most (center versus ground) is dependent on that spark polarity. Also due to polarity, some types of deposits will tend to form on one electrode or the other. I think I see a bit of the deposits in question on the side of the center electrode of plug #3. I suspect you'll notice a difference between #1 and #2 as well, although perhaps not to the same degree. As I mentioned previously, slightly differing cylinder conditions isn't uncommon. Unless the engine is otherwise giving reason to suspect a problem, I wouldn't be too concerned. A reference for reading plugs can be found at: http://www.ngksparkplugs.com/tech_support/spark_plugs/faqs/faqread.asp?mode=nml For green deposits, see "Erosion, Corrosion and Oxidation". Many of the plugs shown give good reason to investigate further. EDIT: By the way, some ideas for posting pics: http://www.ultimatesubaru.org/forum/showthread.php?t=83977
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As to the pictures: The difference in lighting of the two plugs makes it a bit difficult to comparatively "read" them. Electrode wear on both seems reasonable, insulators look good, etc. The temperature range of the plugs seems to be about right for the type of driving being done. If we ignore the "speckles", the #4 plug appears similar to the other one, within the limitations of the pics. Can we see a picture of #4 with lighting like the other one? If not, does #4 have similar-looking deposits (carbon, etc.) on the inner surfaces of the plug shell to the other? Keep in mind that due to the wasted spark arrangement, two of the plugs are fired with "reversed" polarity. Also, minor differences in fuel distribution and combustion chamber temperatures can change the way plugs look even in a well-running engine. Responses to my previous questions (please feel free to ignore the fourth one), might provoke further comments from me.