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Car Forum / Honda Cars / December 20051990 civic wagon fuel economy
I have a 1990 Honda Civic Wagon, 2WD, 5-speed manual transmission. Currently I am getting around 26mpg (9l/100km) city, and 29mpg (8.1k/100km) highway on a good day. This seems somewhat poor to me, so I am wondering a) if these figures are in the normal range for a car of this model year and age b) what I can do to improve fuel economy? I've checked the air filter and it seems clean, the gas cap and tank have been replaced, and I keep the tires at 32psi (221kpa). What else could I do to help out, and how much would it cost? I know this question gets asked from time to time, but was wondering if I might be able to get some more specific information. Thanks! Also the timing belt is new, the warm idle is around 1100rpm, and I usually shift somewhat early around 2750rpm. Average highway cruising speed is about 118km/h or 73mph. theo.chan wrote: > I have a 1990 Honda Civic Wagon, 2WD, 5-speed manual transmission. > Currently I am getting around 26mpg (9l/100km) city, and 29mpg [quoted text clipped - 12 lines] > > Thanks! EPA estimates for your car were 31 city/34 highway. Here's a partial checklist: I read your second post, and you might want to try reducing your speed a bit. Try 110km/h (68mph). Also, go easy when taking off from a stop if you tend to floor it. Assuming 32psi is the Honda-specified pressure for your tires, are they the correct size? How are the spark plugs, wires, distributor cap and rotor? Are they OEM? Is the weather becoming colder in your area? Cold temperatures will greatly decrease your mileage. >>I have a 1990 Honda Civic Wagon, 2WD, 5-speed manual transmission. >>Currently I am getting around 26mpg (9l/100km) city, and 29mpg >>(8.1k/100km) highway on a good day. This seems somewhat poor to me, so >>I am wondering > EPA estimates for your car were 31 city/34 highway. Here's a partial > checklist: Now being a smart a.s as I often am, the op has a European spec car and is therefore probably using miles per gal (UK) and the EPA is using mpg (US). (I did not convert back from his 9l/100km to check this assumption) A UK gal is about 1.2 US gals, so 31/1.2 = 25.9 and 34 / 1.2 = 28.3 so 25.9 to 26 and 28.3 to 29 seems pretty close to me. > Now being a smart a.s as I often am, the op has a European spec car and > is therefore probably using miles per gal (UK) and the EPA is using > mpg (US). Actually, the OP is in Canada and converted his litres/100km to miles per U.S. gallons. For his city mileage: 100km / 9.1 l = (100 x 0.621) miles / (9.1 x 0.264) US gallons = 62.1 miles / 2.40 US gallons = 25.88 miles per US gallon And the OP said 26mpg. I'll leave the highway mileage conversion up to you. How many miles are on this car? I'm pretty sure your 90 Civic Wagon has the same engine (code #D15B2) as my 91 Civic LX sedan. Your mileage definitely seems low. Try some of the tips at http://home.earthlink.net/~honda.lioness/id11.html . If the PCV valve has never been changed before, I'd pay particular attention to it, per the site above. An update on what you find would be welcome. Next, I echo what High Tech Misfit said about the plugs, wires, distributor cap, and rotor. Then I'd start replacing/checking the other things I list at the site above. Do not coast on hills. Keep the car in gear. The engine control system is actually less efficient, gas-wise, when coasting. See your owner's manual for the optimal shift points, though what you're doing with shifting doesn't sound too far off. I am in Ottawa, Canada, and it is a Japanese manufactured Civic (based on the VIN). What makes you say it is a european spec car? My conversions were also to US mpg. Although the weather is becoming colder here, those figures are about normal through the summer and the fall; as it gets further into winter here, I usually see my mileage drop by an additional 1-2mpg. I keep the car in gear all the time and never coast. The car, I'm pretty sure, has a 1.5L D15B2 engine in it. The mileage on the engine is about 265,000km or 164,663miles. The spark plugs, wires, fuel filter, air pilter, pcv valve, distributor cap, and distributor rotor were all changed at 205,000km; the spark plugs changed again (NGKs) at 250,000km along with the oxygen sensor. Perhaps it's time to start looking at some of those in more detail (if so, which?). The coolant system just had a flush as well. Thanks again for all of your advice. > I am in Ottawa, Canada, and it is a Japanese manufactured Civic (based > on the VIN). What makes you say it is a european spec car? My [quoted text clipped - 7 lines] > The car, I'm pretty sure, has a 1.5L D15B2 engine in it. The mileage on > the engine is about 265,000km or 164,663miles. that's not cause for concern. > The spark plugs, wires, > fuel filter, air pilter, pcv valve, distributor cap, and distributor > rotor were all changed at 205,000km; the spark plugs changed again > (NGKs) at 250,000km along with the oxygen sensor. is the sensor oem? aftermarket ones can be terrible. oem have fast reaction times and produce much better performance. > Perhaps it's time to > start looking at some of those in more detail (if so, which?). The > coolant system just had a flush as well. > > Thanks again for all of your advice. other things to check: 1. check or replace the coolant sensor. if it's not sending accurate information, the ecu will inject excess fuel. you get a similar result if the coolant level is insufficient. to be sure of coolant, remove the radiator cap, do NOT rely on the fluid level in the expansion bottle. 2. be certain the ignition system is ok. apart from ensuring all the usual suspects are in good condition, i can report that performance and therefore mileage can be substantially improved if an ailing ignition condenser is replaced. also make sure the ignition timing is correct. 3. ensure the injection system is ok. run injector cleaner through the system. a leaky injector can dump a lot of gas. 4. ensure the cam timing is correct. if the belt has jumped a tooth, mileage and performance will degrade substantially although the motor will still run. again in my experience, it's not uncommon for the belt to be incorrectly tightened on replacement. it may not show as a problem immediately, but it will after it jumps. with an ignition timing light, observe the timing marks for a few moments [with the service connector shorted as per the manual]. if the timing seems to be fluttering back and forth a few degrees, that's a good indicator of a loose timing belt. fix accordingly. >> I am in Ottawa, Canada, and it is a Japanese manufactured Civic (based >> on the VIN). What makes you say it is a european spec car? My >> conversions were also to US mpg. Dangerous things assumptions - If you VIN starts JH it is a Japan built car. For your interest it would have been made in Suzuka, and you can even see a fuzzy image of the plant on Google earth !!! I think it's at 34 51' 55" N, 136 31' 40" E The Honda plant in Marysville is at 40 16' 47" N, 83 30' 47 W Just cut and paste into the google earth search window. but based on my current track record - who knows? > Although the weather is becoming colder here, those figures are about > normal through the summer and the fall; as it gets further into winter [quoted text clipped - 4 lines] > the engine is about 265,000km or 164,663miles. The spark plugs, wires, > fuel filter, air filter, pcv valve, distributor cap, and distributor > rotor were all changed at 205,000km; The coolant flush you mention below makes me suspicious. Did you do it or a shop? (Just kinda curious on that one.) Check the coolant level per the owner's manual, and do an air purge of the system. This time of year, it's going to take a while to get the radiator fan to come on twice during the purge, like at least 35 minutes, so have a magazine. Post if you want more info on what coolant to add, where to find a procedure for the purge, etc. The cooling system supplies coolant to some engine control components. If they're not properly submerged, they'll malfunction and, ISTM, may affect mileage. I know you said the air filter looks okay, but it is due for replacement about every 50k km, and it's cheap and easy to replace, so I'd replace it. Do you have a maintenance schedule for this car? It's in the owner's manual but I also know some web sites that have it. Were all the new parts you list above OEM? Add a bottle of a fuel injector cleaner to the gas tank, per the bottle's directions. I don't think that's critical; I only started doing it a year or so ago with my 91 Civic, but plenty here think it's a good practice. Does the power (that is, acceleration) seem okay? > the spark plugs changed again > (NGKs) at 250,000km along with the oxygen sensor. Perhaps it's time to > start looking at some of those in more detail (if so, which?). The > coolant system just had a flush as well. > > Thanks again for all of your advice. Well it's not good if it doesn't fix the problem. I appreciate your thoroughness, as others learn from it. Keep the group updated, and keep checking back. The coolant flush was done at a garage; I put a pellet of leak stop in as well because I've had a pesky coolant leak that I haven't been able to diagnose. I changed all the hoses, but the car still loses about 50ml of coolant per 100km of driving. It's small enough to be annoying in that I'll have to check the coolant every fill up. After the flush and changing the hoses, however, the leak seems to have diminished. The rad is original, though, and missing a big chunk out of it. I do have an owner's manual with recommended maintenance, and the new parts are OEM. Power in the car seems fine with no hesitation and healthy throttle response all the way to 6000rpm. When I get a bit more time later this week I'm going to check the fuel filter, air filter, and spark plug wires; they are about 60,000km old now so that could be part of the problem. I'll also check out the timing. The oxygen sensor and spark plugs are further down the list seeing as the are only 15,000km old. I'll also look into getting a bottle of injector cleaner. I should mention I've owned the car since 250,000km and have always had this kind of mileage. I've always felt the mileage should be much better but haven't really gotten around to addressing it. In talking to the previous owner, he mentioned that his best and worst experience for the first 250,000km of the car was 9l/100km or 26mpg during the winter in the city, and 6l/100km (39mpg) on highway trips in the summer. Seeing as I'm doing 26/29 at the moment I'm pretty confident that there is room for improvement. The problem is finding out how to get it. I'll go through my records and see if I can post my mileage pattern. > > Although the weather is becoming colder here, those > figures are about [quoted text clipped - 52 lines] > appreciate your thoroughness, as others learn from it. Keep > the group updated, and keep checking back. > The coolant flush was done at a garage; I put a pellet of leak stop in > as well because I've had a pesky coolant leak that I haven't been able > to diagnose. I changed all the hoses, but the car still loses about > 50ml of coolant per 100km of driving. That's less than 1/4 cup. I don't think losing this little coolant between fillups is the problem, /unless/ the leakage point also admits air into the system. > It's small enough to be annoying > in that I'll have to check the coolant every fill up. After the flush > and changing the hoses, however, the leak seems to have diminished. The > rad is original, though, and missing a big chunk out of it. As a result of this 'missing chunk' do you feel the radiator may not be dumping enough heat to ambient? What does the temperature gage read? My 91 Civic's is noticeably below the halfway mark. With this damage, can you even do an air purge of the cooling system? Plenty of folks have inquired here about replacing radiators and where to buy new ones. Consider this at some point. > I do have an owner's manual with recommended maintenance, and the new > parts are OEM. Power in the car seems fine with no hesitation and [quoted text clipped - 3 lines] > filter, air filter, and spark plug wires; they are about 60,000km old > now so that could be part of the problem. The wires are supposed to last way longer than the plugs, fuel filter, or air filter. You'll see it in your maintenance manual. People here post about wires being much tougher than in the past, as well. No harm doing a resistance check on them, though. They should be no more than about 15k ohms each. Running the car in the dark with the hood up is supposed to be a quick check as well. If you don't see sparks coming from the wires, and the resistance is sat, then they're likely fine. > I'll also check out the > timing. The oxygen sensor and spark plugs are further down the list > seeing as the are only 15,000km old. As long as they're both OEM, I agree. > I'll also look into getting a > bottle of injector cleaner. [quoted text clipped - 7 lines] > Seeing as I'm doing 26/29 at the moment I'm pretty confident that there > is room for improvement. The problem is finding out how to get it. Lately I am wondering (based on my own experience and posts here) whether an aged distributor coil knocks down mileage a lot. That's not too expensive of a part (around $100 online OEM), but the labor isn't difficult. If you know it's around eight years old, then I would replace it as well. It's not likely to last much longer. Sounds like you realize this is going to take awhile. Hang in there. > I'll go through my records and see if I can post my mileage pattern. > > > Although the weather is becoming colder here, those [quoted text clipped - 53 lines] > > appreciate your thoroughness, as others learn from it. Keep > > the group updated, and keep checking back. |
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