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Comments
One thing I do periodically (ok, almost every time I'm driving) is to accelerate mildly to about 4k or so, sometimes 5k. Not only does it make for an exhilirating drive, but I believe it can help rid of carbon deposits - which can cause ping-ing. (I may be way off base here)
Even our Saturn SL adjusts for ping (sometimes referred to engine knock). If you're accelerating up that hill in 4th doing about 30-ish, it'll ping a couple of times and then the ECU adjusts the timing and the pings go away. I believe this is similar to what our Sube's have. So, if it's just a couple of pings, then it's 'built that way'.
-Brian
Frank - My driving is about 50/50. Usual urban driving and West coast highways at 70+. Champion and NKG plugs have had no effect on pinging.
There's also been no change with 89 octane, but I'm willing to try going up to 92. Close by our only name brands are Amoco and Phillips; Shell and Sunoco are further away.
We primarily drive lots of small trips in a small city, so I've been concerned with carbon build up. But I do accelerate it to or above 4K rpms on a relatively regular basis, have used Techron quite regularly, and we make frequent 4+ hour highway trips. We've also experienced pinging on highway ramps, so it's not just happening in town. My opinion: If it does have carbon build up at 20K in 16 months, something isn't right with the powertrain's design.
Much of what I've read suggests that detonation is caused by a lean condition which can lead to excessive heat. I'd hate to move to cooler plugs (which are usually recommended with performance mods) when it's an ECU keeping the mixture too lean.
Thanks for all your comments, and to Patti for her concern.
-Colin
-Eric
Can you feel the difference between premium and other grades of gasoline right away? I'm curious since Patti mentioned that it takes a few tanks for it to kick in.
I've personally found that I get a tad better milage and maybe some performance by going from 87 to 89. No knocking or pinging.
Ken
My long post was just for some "other" considerations based on some of the cases I have seen. The "few tankfulls" process has helped some.
Hopefully we can straighten this out soon.
Thanks for your patience.
Patti
Can't knocking also be caused by premature detonation from the ignition firing too far before the piston is at top dead center? The knocking is actually the noise produced by the early detonation forcing the piston down while its still moving in an upward position (before top dead center). If pinging and knocking was being caused only by excessive heat, maybe from carbon buildup or too lean of a mixture, retarding the timing would not correct the problem.
Making the mixture more gas intensive can help on the heat side by helping to cool the chamber but it also reduces gas mileage and could also lead to carbon buildup because of the richer mixture. This also has air pollution considerations.
Vince
Can't knocking also be caused by premature detonation, or the spark firing too far before the piston is at top dead center? The knocking is actually the noise produced by the early detonation pushing back against the piston before the crankshaft positions it "at or over top dead center". If pinging and knocking was being caused only by excessive heat, maybe from carbon buildup, retarding the timing would not correct the problem.
Making the mixture more gas intensive can help on the heat side by helping to cool the chamber but it also reduces gas mileage and could also lead to carbon buildup because of the richer mixture. This also has air pollution considerations.
Vince
-Frank P.
Frank P. - I lived in Georgia 1981-85 and 86-88 for college, grad school and work. I still miss it sometimes though Atlanta has changed so much since '88 it's become like Los Angeles East to me.
Ed
Brian, too many coincindences... 00 Outback, I own a Saturn SL and live in northeastern Ill too.
Now that I'm enlighted (candle power) - you'd described earlier for Kate (marbles in can), would the reaction on MT sound like "grrrrrr" and some rattling(like letting off the clutch and not giving enough gas)and for the 4EAT would be like accelerate grudgingly or like all revs but no increase in motion?
The UK Impreza club has good info on switching octane. Although they recommend resetting the ECU when going to a higher octane (advised against by Patti as it could wipe out ECU error codes).
http://www.sidc.co.uk/faq.htm#2.4
Dennis
Mark
It also ran like a dog when I tried Texaco. A few years ago on another forum, people in the West swore by Texaco.
Dennis
There's no such thing as premature detonation. Detonation is when the fuel explodes, which is a very violent burn. Proper ignition is a controlled burn. It all happens fast, no doubt, but the air/fuel mix is definitely burning and not exploding.
-Colin
-mike
Greg
-Greg
Ross
bit
I buy the Getty in Bayonne near the train I take. Its the only gas between the light rail and SI, and it's 20-25 cents a gallon less than SI. When I travel I try to use Sunoco or Shell, but like I say its a lot cheaper than home. So far, so good as goes having no problems.
Mark
-Brian
-mike
anybody try that?
Robert
-Frnak P.
Right now the light rail goes from Bayonne to Jersey City. Eventually, it will go to Hoboken and up to a Park & Ride on the Turnpike.
Earlier when we where talking about SoA focus groups, the focus group I mentioned was a light rail focus group. They were trying to find out if people would take the light rail from Liberty State Park Park & Ride to J.C. I said no and left with my $75 cash. :-)
Dennis
-mike
I'm new and not sure whether this topic is trivial or not, but here goes. I bought a new 2001 Outback (auto) in early April '01. My brother-in-law (a car technician in Japan who sees lots of Legacys and Imprezas in his work) told me today if I want to keep my car in good shape, I really ought to have the front and rear differential fluid replaced after the first month, along with the engine oil and filter.
I use the car everyday mostly for those short spins to the grocery etc. that wear an engine down, and can understand the logic of giving everything clean oil early on (my engine oil looks pretty dirty now, and the car only has a 1000 miles on it). But I can't see how one can change the front differential oil without one of those vacuum-tube devices that many of the lube shops use. Heck, I can't even get my hand down to that little yellow differential oil gauge.
Is this a procedure for qualified Subaru shops only? Anyone have a rough idea how much they'd charge for this?
Wally
To change the rear differential you'll need a bit of strength. Its located on the back of the differental crank case. You will need something to suck the old fluid out. Doesn't have to be a fancy vaccum hose, get one of those little hand suction pumps.
On my 96 they sealed that differential plug in with some type of glue/sealent. Its hard and brittle after you break it, you would do well to clean the threads off, you'll need a small dental pick like instrument (I know the dealer doesn't take the time to clean them out). Otherwise you run the risk of pushing grit back into your differental case when you close it back up.
One thing I do is drive around town in 3rd. The 4EAT likes to shift into 4th even at 30 MPH and less than 1500 RPM. With the OB's weight, I like to keep the RPMs above 2000, otherwise the engine feels like it's bogged down.
-Brett
Anyway, I've learned more about "Ping" today, than I think I ever wanted to. Some things to consider:
Pinging is not the cause of carbon build up in the engine. The ping can be the result of carbon which is a result of poor fuel quality.
Since our vehicles are CA Spec., they are designed to meet CA emissions standards which are very stringent. CA puts a lot of limits on additives where other states do not have these limits (sulfur for example).
Severe and constant pinging can cause damage. However, pinging under load or in warmer more humid weather can be considered normal and not harmful. Attempts to retard engine ping can decrease fuel economy and increase hesitation. If it is retarded significantly, you can get a misfire, stumble and hesitation.
I'll post more as I learn more. Keep in mind. You should always have a dealer check the car out and let them differentiate severe ping from characteristic ping.
Also, try the 4 tanks of a known good grade fuel.
Patti
On the pinging front, use 87 octane with no notable brand loyalty and have no ping problems.
Even if the fuse looks good replace it anyway.
If that fails attack it with a multimeter. How about corrosion inside?
With Patties help, I finally got the district ops manager and technical trainer to go for a ride with me on Monday of this week. They downloaded a data stream which is being looked at. The pinging occurred during the drive but was not dramatic since there is mostly very flat ground near the dealership (I live about 40 miles away in a very hilly area). I know they heard the pinging but the district ops manager definately played it down and was not willing to say one way or another whether pinging was considered bad or not. He deferred to the data stream analysis. The tech trainer sat in the back with the computer but did not offer any comments at all regarding ping. But Im sure he heard it as well.
Based on others' experiences, I dont have high hopes reagrding the data stream but I am glad the situation is receiving some attention from Subaru. If I felt confident that this was a minor nuisance, it would be no big deal. But there is no debate among most mechanics that knock and ping CAN be very bad for an engine; it is normal to want to protect a 25,000 investment by trying to correct something that may jeaopardize that expendature. If Subaru is truly confident that this condition will not cause harm, maybe they would be willing to extend the basic warranty against the types of engine problems that may be caused by knock and ping to 100,000 miles or so...with no resolution, some (me included) have expressed a sentiment of feeling a need to trade the vehicle before the warranty expires. This is too bad because other than this condition, I truly like my Forester. Its my first Subaru but I will be hard pressed to buy another one if I am unable to get some hard reassurance on this. Hopefully we will all know something more definative soon.......
With the front differential though (my car has the AT), I can't even see a drain plug. That's why I was wondering whether a suction tube thing is needed (to replace/refill through the oil gauge tube).
Oh well, looks like this is a procedure I should be prepared to pay for, so that it gets done properly. I'd like to be able to maintain this car all by myself, though. At least that way, I know what's been done to it.
Dennis
I really do like my Outback and would like to keep it for a long time, but I am concerned about the longevity of the engine with this type of problem. I hope SOA won't take the corporate line that this is normal and not detrimental to the engine. To the local dealer and SOA's credit, they have taken my concerns seriously. I do hope SOA is able to find a resolution to this problem soon.
-Eric
Mike, a lot of people take the train to Exchange Pl and then take the PATH into the Trade Center. Its a lot faster than the express buses. My commute to Exchange Pl is approx 40-50 minutes door-to-door (Great Kills,SI). Hope this helps.
Mark
-mike
As for parking in JC- they get $225 per month in my building!
Mark
Pinging is also called pre-ignition. It occurs when the fuel/air mixture in the combustion chamber ignites before it is supposed to, catching the piston still on its way to the top of its stroke and causing it to whack the side of the cylinder wall, hence the rattling or "pinging" sound.
Pinging is caused by one or more of the following, possibly others too: fuel with too low of an octane rating (the reason high compression hot rod engines need higher octane is to prevent pre-ignition), carbon deposits in the combustion chamber (they hold heat and ignite the mixture before the spark plug does), timing errors or problems, fuel/air mixture problems (lean mixtures tend to pre-ignite more than rich mixtures). Like I said, there could be more.
Octane ratings vary by state and even by regions within a state. The same method of determining octane rating is not universally used. Also, what one area calls "regular" might be 85 octane, and one does not reach 87 octane until they move up to a higher grade of fuel. Also, fuel additives and blends vary by supplier, state and region.
Finally, I do not think that a *little bit* of pinging under high load conditions or on rare occasions should give anyone pause. I had a '71 MGB-GT that pinged if I let the revs dip too low; the combustion chamber on that car was cleaner than any of the other engines I ever tore down, which I attributed to the pre-ignition knocking all the crap loose :-)
My '00 Subie Legacy with the 2.5L Phase II motor always ran fine on 87 octane, until I got to California. Then it pinged, but not severely; I went to 89 octane, which stopped the ping. Once back in PA I switched back to 87 octane, and all has been well.
At any rate, looking at the stuff above, that's a lot of variables to contend with for someone trying to get at the root of a pinging problem! Even so, with modern engine control technologies being what they are, I am very, very surprised to hear of the constant, severe pinging problems being discussed. It seems to me that a technical fix should be possible.
To the guy driving around at 2000 RPMs, all I can say is, rev it up! My Subie absolutely loves to be above 3000 RPMs, and there is a considerable torque and power band that goes from there up through 4500 RPMs. Also, driving at low RPMs *all the time* will increase the likelihood of carbon and other residue buildup in the combustion chamber. Blow those cobwebs out of your Subie every once in a while, and it may very well thank you ;-)
Cheers,
-wdb
Cheers,
-wdb
Knock (or detonation) is exactly that-- an explosion.
-Colin
the drain plug for the front differential ('98 OB w/AT) is located in front of the AT fluid pan (manual pg. 10-24 - if not revised). You would need a long (long) flexible snort [=< size of dime in dia.] funnel to refill.
I generally pleased with the Car (except a frequent idler arm repair) and am seriously considering a newer Subaru. I have read a lot about pinging, but nothing about transmissions.
How is the automatic transmission? How often does it need service? Do they have to be replaced often?
Is the Manual transmission on the newer cars as fun as the one on the car that I have? Does the manual work will with AWD?