urdrwho Posted October 9, 2013 Share Posted October 9, 2013 I use my 97 to go to the store, Starbucks for coffee, etc. and it entails all short trips. Stop and starting the engine and probably a MPH average of 18 MPH (or less). Is 17.60 MPG ok for such driving? The car still has a lumpy idle and throws a P304 (always at idle never on highway). I went two days with my daily driving without a P304. So with an imperfect running car I think that the MPG isn't bad. The Feds say -- 18 City 21 Combined 25 Highway I've been running premium to see if there was any difference in driving but I didn't notice anything so I'll stop wasting the money. 97 Legacy Outback Link to comment Share on other sites More sharing options...
sunny5280 Posted October 9, 2013 Share Posted October 9, 2013 Doesn't seem unreasonable given the type of driving and possible loss of efficiency which may be setting the code. Link to comment Share on other sites More sharing options...
pleaidestar Posted October 9, 2013 Share Posted October 9, 2013 17.6 is pretty bad imo, I also don't think premium fuel is a waste its cleaner and you will see your gas mileage drop a bit with Reggie. If you could have seen the sparkplugs I replaced after getting this third gen 3 weeks after I replaced them and started using the premium fuel, that motor was filthy and the plugs reflected that..already replaced them. Link to comment Share on other sites More sharing options...
Kennyfvholla Posted October 9, 2013 Share Posted October 9, 2013 I somewhat disagree about the fuel type. Running premium in the 2.5 motors is fine. They have 10:1 compression which is good enough for premium. The 96 LGT with the "premium fuel" ECU with a 4EAT running the second design 2.5 averages an easy 20 MPG with regular gas and and easy 23/24 MPG with premium. It actually came as a shock.... 17/18 ish isn't too terrible for a 2.5 with a 4EAT running around town on short trips. My 98 LGT 5MT averaged about 20/21 with ease around town. So I'd only expect 19/20 out of the 4EAT. Especially since the 96 with a 4EAT and the first design 2.5 motor would only average 16/17 MPG on premium and much worse on regular. Fix that misfire issue and I'm sure you'll be up to the 19/20 mark. It can be caused by a bad plug, wire, injector, or even a leak in the intake manifold. Link to comment Share on other sites More sharing options...
pleaidestar Posted October 9, 2013 Share Posted October 9, 2013 I think just about all 233 of his posts are tracking down that misfire..hasn't it been prevalent throughout the ownership of that car urdrwho? I can't believe you still haven't found it..you have some bad valves or seats sir. Link to comment Share on other sites More sharing options...
urdrwho Posted October 9, 2013 Author Share Posted October 9, 2013 Ha ha....233 posts? You could correct but some will be for the 95 Leggie. No I haven't found the misfire but I am fairly sure it is a deeper mechanic problem than wires, plugs, etc. all of which I replaced. On the cold engine compression check that #4 cyl was 79 pounds. The engine suffers from subbie piston slap when cold so I think that testing compression on a cold engine with piston slap is not good protocol. I just don't feel like getting my skin burned doing it on a hot engine. I would be much more motivated to search out the misfire if it ran badly when giving it throttle. On throttle you don't notice anything, getting on the highway it can easily merge with speed. Sitting at the stop light....yep it is one lumpy little car. From Jaguar motor problems to tractor motors I have a lot on my plate. The poor Subbie runs well enough that I'm not hot to trot to pull apart the motor. Maybe this winter. The interior and exterior is darn near perfect, new tires and I paid $1,100 for the car. I guess the low purchase is allowing me to get away with being mean to the car. It is an odd little beast. Just for kicks I've wanted to see if the computer is healthy and I removed the lines to the EGR and ran for a few days expecting to see an EGR code but nope. I did the same thing for the gas cap and it never blew a code. Sometimes when sitting in my driveway it will blow the P304, I attach my code reader and the code reader shows no codes. Oh I just remembered, I never took the covers off to check the timing marks. That is easy....gotta do that one!! I think just about all 233 of his posts are tracking down that misfire..hasn't it been prevalent throughout the ownership of that car urdrwho? I can't believe you still haven't found it..you have some bad valves or seats sir. Link to comment Share on other sites More sharing options...
Kennyfvholla Posted October 9, 2013 Share Posted October 9, 2013 On the cold engine compression check that #4 cyl was 79 pounds. The engine suffers from subbie piston slap when cold so I think that testing compression on a cold engine with piston slap is not good protocol. I just don't feel like getting my skin burned doing it on a hot engine. I would be much more motivated to search out the misfire if it ran badly when giving it throttle. On throttle you don't notice anything, getting on the highway it can easily merge with speed. Sitting at the stop light....yep it is one lumpy little car. It is an odd little beast. Just for kicks I've wanted to see if the computer is healthy and I removed the lines to the EGR and ran for a few days expecting to see an EGR code but nope. I did the same thing for the gas cap and it never blew a code. Sometimes when sitting in my driveway it will blow the P304, I attach my code reader and the code reader shows no codes. Oh I just remembered, I never took the covers off to check the timing marks. That is easy....gotta do that one!! Hmmm 79 lbs is VERY low on a cold engine. You should be getting twice that. Piston slap only comes from the motor being older and not having floating wrist pins. It's not going to cause and compression issues. The only compression issues that could come from anything piston related is ring issues, or even a bent rod. But, I doubt either of those are your issues. I don't think it's a timing issue either, as if one cylinder was off so would the other. Either way, I'd check it. Now, I'd say it could all be in the ECU, but it's obviously not. It could be part of it though. It could also be valve or valve seat related. My Honda had a damaged valve seat and bent exhaust valves. It had a slightly rough idle, posted misfire codes (for ever single cylinder along with the random misfire code, but this was from the bent valves mostly. I don't know what it'd of been with just a chipped valve seat) BUT as soon as I gave it some gas and the revs got up to about 1,000 it would post no codes and run butter smooth. So yeah, I agree with pleaides on the possibility of a valve or valve seat issue. Have you checked the injector? Link to comment Share on other sites More sharing options...
Idaho subaru Posted October 9, 2013 Share Posted October 9, 2013 My '97 legacy wagon with a 5sp and a blown head gasket has averaged 22.1 over the last 4 fills. All city driving. Link to comment Share on other sites More sharing options...
Stevo F Posted October 10, 2013 Share Posted October 10, 2013 My dad says his 2000 Outback gets 18 MPG in town (short trips) and he got 24 MPG on a 200 mile round trip recently. In comparison, my '98 with an EJ22 averages 26- 27 MPG, with the worst tank coming in at 23 MPG. In my case, I believe I do have some piston slap and the idle could be smoother, but not getting any codes (so i believe it's running as it should). Link to comment Share on other sites More sharing options...
Zues Marine Posted October 10, 2013 Share Posted October 10, 2013 everyone should do the grounding mod. it's a ridiculously cheap and effective DIY everyone seems to overlook Link to comment Share on other sites More sharing options...
sunny5280 Posted October 10, 2013 Share Posted October 10, 2013 everyone should do the grounding mod. it's a ridiculously cheap and effective DIY everyone seems to overlook What is the benefit of the grounding mod? Link to comment Share on other sites More sharing options...
urdrwho Posted October 10, 2013 Author Share Posted October 10, 2013 Injectors were swapped out with known good ones and no difference. I do find it odd that I can't get the car to throw an EGR or gas cap code. It is an OBII. My 90 Jag is OBD1 and you pull the EGR out of the mix and it will throw an EGR code. Rings? No smoking burning oil can be seen. Valve shot? Although low, the compression held and held and held. So if I had a valve leaking it wasn't showing up on the leak-down. <<If all the cylinders have low compression but show minimal leakage, the most likely cause is incorrect valve timing. The timing belt / chain may be off a notch or two.>> Working on these horizontal engines is for people with elf like hands, minimal room to do anything. I guess it is why everyone pulls the engine to do work, it is probably more efficient than to do thing with the engine in the car. I was bad the day I did the compression test because I didn't remove all the plugs. I only removed #4 and left all other plugs in the car. I know, I know I was bad and should have removed all plugs and tested all cylinders. I'm getting lazier as each day passes. Give me simple things like removing the ECU and I'm happy. Hmmm 79 lbs is VERY low on a cold engine. You should be getting twice that. Piston slap only comes from the motor being older and not having floating wrist pins. It's not going to cause and compression issues. The only compression issues that could come from anything piston related is ring issues, or even a bent rod. But, I doubt either of those are your issues. I don't think it's a timing issue either, as if one cylinder was off so would the other. Either way, I'd check it. Now, I'd say it could all be in the ECU, but it's obviously not. It could be part of it though. It could also be valve or valve seat related. My Honda had a damaged valve seat and bent exhaust valves. It had a slightly rough idle, posted misfire codes (for ever single cylinder along with the random misfire code, but this was from the bent valves mostly. I don't know what it'd of been with just a chipped valve seat) BUT as soon as I gave it some gas and the revs got up to about 1,000 it would post no codes and run butter smooth. So yeah, I agree with pleaides on the possibility of a valve or valve seat issue. Have you checked the injector? Link to comment Share on other sites More sharing options...
twisty Posted October 14, 2013 Share Posted October 14, 2013 I somewhat disagree about the fuel type. Running premium in the 2.5 motors is fine. They have 10:1 compression which is good enough for premium. The 96 LGT with the "premium fuel" ECU with a 4EAT running the second design 2.5 averages an easy 20 MPG with regular gas and and easy 23/24 MPG with premium. It actually came as a shock.... 17/18 ish isn't too terrible for a 2.5 with a 4EAT running around town on short trips. My 98 LGT 5MT averaged about 20/21 with ease around town. So I'd only expect 19/20 out of the 4EAT. Especially since the 96 with a 4EAT and the first design 2.5 motor would only average 16/17 MPG on premium and much worse on regular. my 96 GT gets about 25MPG in all city driving. i usually use 91 but lately have been alternating 89 and have not seen much change in the mileage. my 95 2.2 wagon gets about 27 mpg in the same use, but goes up to 30ish on long trips and highway usage. well, at least if the speed limit is 65. at 75-80, the mileage drops back down to 27ish. Link to comment Share on other sites More sharing options...
pleaidestar Posted October 14, 2013 Share Posted October 14, 2013 ^i love the ej22..that's awesome mpg's, this 3rd gen gets about 22 mixed driving on 91 not too shabby for a 2.5. Link to comment Share on other sites More sharing options...
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