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Car Forum / Honda Cars / January 200693 Honda Civic Mileage gone bad
I recently started getting very low milage in my 1993 Civic EX (1.6 L SOHC VTEC). Previously I've seen between 32 and 38 (34 AVG.) Now I'm getting about 25 MPG (it has steadily declined the last three tanks). Things I have checked/replaced: * Replaced Plugs and gapped them properly (The old ones looked fine) * Checked throttle body (no build-up) * Checked PCV valve: When I squeezed the tube going to the PCV, the idle went up, I guess that means it's open * Checked EAVC valve: I removed it and examined it, cleaned it and tested it. It checks out, the intake port was a little clogged and it was a little oily inside, but it tests fine (opens with a voltage). * Timing: It's pretty rock solid, though it's hard to get an actual reading cause the "pointer" or "indicator" is so far away from the pulley with the marks. * Haven't done a Compression Test yet * Fuel injectors: I was grabbing them with the engine running and could feel the clicking of the valve in only three of them. I removed the odd one and tested it and it seemed to work fine and fast when supplied with a few volts. *The air filter is super clean *Oil + Filter was replaced recently (1500 miles) *Performance seems top-notch, as fast as ever. *Valves: I just adjusted them and they weren't hardly off at all, only the valves on one cylinder were .001" too tight. Note: About a thousand miles before the low milage, I jump-started the car and had noticeable engine shake after that. Recently, I replaced one of the motor mounts cause it was busted all the way through. Wierd, but this didn't really help much. It could be just that the new mount isn't as stiff as the old one was, or there are more busted mounts. So, any ideas about the milage? Thanks in Advance > I recently started getting very low milage in my 1993 Civic EX (1.6 L > SOHC VTEC). [quoted text clipped - 36 lines] > > Thanks in Advance How's your catalytic converter/exhaust system? Maybe you're getting some restriction.Also,cold weather will cause a decrease in mileage. Check your tire pressures,too.  SignatureJim Yanik jyanik at kua.net I have not checked the catalytic converter, I'm not sure how to go about checking it except looking for holes. The sound of the car hasn't really changed. It's not cause of winter, I've driven in the cold before and haven't got milage like this. Tire pressures are correct. 30 PSI. >I have not checked the catalytic converter, I'm not sure how to go > about checking it except looking for holes. The sound of the car [quoted text clipped - 4 lines] > > Tire pressures are correct. 30 PSI. Restricted cats show up mostly as the last bit of throttle not doing anything, or even making the engine stumble and surge at full throttle. The Haynes manual for the '90 to '93 Accord has a slick diagnostic for restricted exhaust systems using a manifold vacuum guage. It has you connect the guage and note the idle manifold reading. Then open the throttle so the engine is revving about 2000 rpm for a few seconds, and watch the guage as you release the throttle. If the reading returns to the original idle pressure within 2 seconds, the exhaust system is unrestricted. If the reading hovers near the 2000 rpm reading before dropping or if it slowly returns to normal the exhaust is restricted... could be the muffler or cat. Mike > I recently started getting very low milage in my 1993 Civic EX (1.6 L > SOHC VTEC). [quoted text clipped - 36 lines] > > Thanks in Advance I could have sworn I answered this for somebody else today. :-) Anyway, on to the questions. Is this 25mpg city, highway, or mixed? Are the new plugs OEM? What about the cap, rotor, wires? How are they? What are your tire pressures? Are they the right size? Are you a lead foot driver? If you are in a part of the world where winter is settling in, that will decrease your mileage. Mixed I didn't get the OEM plugs, but I just replaced the plugs today, Old: NGK's New: Bosch Cap, rotor, wires, and coil were all replaced 30 or 40K miles ago. Tires: 30 psi. Yes, they are the right size No, I'm not a lead foot, The milage changed, my driving habits haven't. Winter, yes but it doesn't get that cold here (Central California) and I've driven in colder weather and still had great milage. > I recently started getting very low milage in my 1993 Civic EX (1.6 L > SOHC VTEC). [quoted text clipped - 15 lines] > reading cause the "pointer" or "indicator" is so far away from the > pulley with the marks. ok, please clarify that point: are the timing marks correctly aligned or not? the pointer & the pulley marks need to line up under the timing light. if the timing belt's skipped, the "so far away" will be your problem - and indication of belt skippage. you don't state mileage. presumably the belt /has/ been replaced at some point. my experience is that some shops are not practiced at getting belt tension just right. > * Haven't done a Compression Test yet > * Fuel injectors: I was grabbing them with the engine running and [quoted text clipped - 17 lines] > > Thanks in Advance I don't know why it is this way... but. The little plastic indicator on the timing belt cover is 3 or 4 inches away from the edge pulley having the marks. Because of this, it makes it hard to see if the marks on the pulley are lined up with the indicator correctly. What I should do is scratch a line from the indicator toward the center of the pulley. I haven't yet because it's super tight in there. That's quite a drop. How many miles are on your car? IMO, you need a complete shotgun approach. You're halfway there. In order, this is what I'd do: Check the coolant levels. Purge the cooling system of air. I'd replace the PCV valve, assuming it's the original one. Is the fuel filter due for replacement? If so, replace it. I would be tempted to pull off the ignition wire of the suspect cylinder (with the suspect fuel injector) and see if engine power sounds like it goes down, as it should. OTOH, if you say performance is otherwise fine, then all four cylinders must be firing. Consider a new oxygen sensor. https://www.automedicsupply.com/ has great prices for OEM oxygen sensors. Stick with NGK plugs in the future. OEM plugs seem to be the consensus here. Are cap, rotor, and wires OEM? My site reinforces a few of these points: http://home.earthlink.net/~honda.lioness/id11.html Elle Original owner, 1991 Civic (1.5 liter, manual transmission), 172k miles, 40+ mpg most of the year; about 39 mpg this time of year. > I recently started getting very low milage in my 1993 Civic EX (1.6 L > SOHC VTEC). [quoted text clipped - 36 lines] > > Thanks in Advance I'd add an OEM thermostat to the list.... Mike > That's quite a drop. How many miles are on your car? > [quoted text clipped - 88 lines] >> >> Thanks in Advance 200K miles. Coolant is fine, new thermostat, the engine runs at the appropriate temp. I'll replace the PCV because they are cheap, but it seems to work correctly. I'm sure the fuel filter could use replacement, but I highly doubt this is the problem. I've done the test on the suspect cylinder and it has the same affect the rest of the cylinders have when I remove the spark wire or fuel injector wire. Oxy sensor sounds possible.. I'll see if there are any testing procedures in the factory manual. The PO replaced the ignition stuff, I'll have to check the reciepts. > 200K miles. > [quoted text clipped - 3 lines] > I'll replace the PCV because they are cheap, but it seems to work > correctly. Do you mean you pinched shut its hose, and within about 30 seconds, you heard it click? If so, I agree this test is an indication it /seems/ to work correctly, but it's not conclusive. Its spring wears, for one, allowing the click to occur, but not allowing proper throttling. I estimate my mileage improved 10% to 15% when I replaced the PCV valve on my 91 Civic at 12 years and about 140k miles. It was /very/ noticeable, since back then I reset the trip odometer at fillups and would drive until the fuel tank was near empty. Seems like all the cheap fixes (including the O2 sensor) have been covered. If these don't repair the problem, then I'd be searching elsewhere. Of note: Someone in the thread did mention that some parts of the country switch to a much lower heating value of gasoline sometime in the Fall, right? IIRC, that right there will drop mileage on the order of 10%. Also, I don't know where you are, but where I am, we're having unusually cold temperatures. My mileage is taking a beating of about 5-10% lower than it did last year at this time. I bought a new PCV, took the old one out and it turns out that the old one works better than the new one(the new one doens't close all the way and the flow is more restricted), it's just a one-way valve, that's it, no wonder they are cheap. So I left the old one in. > I bought a new PCV, took the old one out and it turns out that the old > one works better than the new one(the new one doens't close all the way > and the flow is more restricted), How do you know this isn't the way it's supposed to work? > it's just a one-way valve, that's it, If you google on the internet and examine a cut-away, it's far more than a check valve. > no wonder they are cheap. > > So I left the old one in. Suit yourself. :-) I saw your other post and see you're now dealing with a bigger problem. I'd be checking the coil. >I bought a new PCV, took the old one out and it turns out that the old > one works better than the new one(the new one doens't close all the way > and the flow is more restricted), it's just a one-way valve, that's it, > no wonder they are cheap. > > So I left the old one in. I've never found a reliable way of testing them. I clean the bejeebers out of them with carb cleaner (some don't survive parts dip) if I don't have any place to buy a replacement at the time. They normally shouldn't close all the way, although they can close at wide open throttle or when you are holding it in your hand. At idle, they should allow some bypass to scavenge the small amount of blow-by. At cruise throttle, they should open to scavenge the increased amount of blow-by. Your old one may be defective - it sounds like the spring has become weak. Normally you should feel quite a bit of resistance (the proper direction, blowing from the engine end) at pressures we puny humans can produce. Mike > Of note: Someone in the thread did mention that some parts > of the country switch to a much lower heating value of > gasoline sometime in the Fall, right? IIRC, that right there oxygenated gas. used in many parts of california from (IIRC) nov thru march. > will drop mileage on the order of 10%. Also, I don't know > where you are, but where I am, we're having unusually cold > temperatures. My mileage is taking a beating of about 5-10% > lower than it did last year at this time. | Consider a new oxygen sensor. Without checking its output 1st ? This is stupid, user can chk sensor's output easily. http://home.flash.net/~lorint/lorin/fuel/lambda.htm If voltage is unstable, injectors are likely clogged. | > any ideas about the milage? chk car's minimum toe force needed ; tyres' toe-in may have increased with usage, present tyres may have higher rolling resistance >| Consider a new oxygen sensor. > Without checking its output 1st ? This is stupid, user can chk sensor's > output easily. http://home.flash.net/~lorint/lorin/fuel/lambda.htm That is a classic pass/fail test for O2 sensors, but most sensors fail by becoming more and more sluggish - degrading over time. When new, they should produce over 7 transitions per second as the output drives the mixture back and forth past the ideal point. As the sensor ages, the response rate drops until the ECU will no longer tolerate it and you get the "check engine" light. As another recently reported here, replacing an old O2 sensor can improve throttle response even if the reaction time of the old one was not causing the ECU to complain. The ECU must also adjust the mixture at a rate that is independent of the condition of the O2 sensor (because it has no direct knowledge of the sensor's condition), so the mixture will fluctuate more in proportion to the sluggishness of the sensor. IMHO the "sweet spot" in the car's life for replacing the O2 sensor is around the half-way mark, or between 100K and 150K miles. I doubt many O2 sensors last the life of good modern cars, so we can all expect to replace the sensor once (whether the little light comes on or not). If we are going to remove the sensor for testing because we suspect it, I suggest the best thing to do is put in a new one and be done with it. Mike > IMHO the "sweet spot" in the car's life for replacing the O2 sensor is > around the half-way mark, or between 100K and 150K miles. I doubt many [quoted text clipped - 4 lines] > > Mike Question;use a OEM Honda/Acura O2 sensor,or will a 3rd party sensor suffice? (at a lower price) SignatureJim Yanik jyanik at kua.net >> IMHO the "sweet spot" in the car's life for replacing the O2 sensor is >> around the half-way mark, or between 100K and 150K miles. I doubt many [quoted text clipped - 7 lines] > Question;use a OEM Honda/Acura O2 sensor,or will a 3rd party sensor > suffice? (at a lower price) Elle found a place to get OEM on-line at a nice price for early models. I thought I saved the link but maybe she'll see our plight and repost it. Mike > "Jim Yanik" <jyanik@abuse.gov> wrote > >> IMHO the "sweet spot" in the car's life for replacing the O2 sensor is [quoted text clipped - 3 lines] > >> we are going to remove the sensor for testing because we suspect it, I > >> suggest the best thing to do is put in a new one and be done with it. > > Question;use a OEM Honda/Acura O2 sensor,or will a 3rd party sensor > > suffice? (at a lower price) > Elle found a place to get OEM on-line at a nice price for early models. I > thought I saved the link but maybe she'll see our plight and repost it. https://www.automedicsupply.com/ I bought one for my 91 Civic from these folks about a year-and-a-half ago. Good service. No problems. I think their prices are competitive for more recent models, too. From my reading on the net last year, people say to only buy OEM. Aftermarket are not as reliable. For the original poster: Check that timing! I monkeyed with mine a bit a month ago, and I think it's why my mileage dropped a bit below 40 mpg on the last three tanks. So darn hard to see the timing marks lined up, especially with middle aged eyes. Or I didn't let the car warm up enough. >> "Jim Yanik" <jyanik@abuse.gov> wrote >> >> IMHO the "sweet spot" in the car's life for replacing [quoted text clipped - 27 lines] > From my reading on the net last year, people say to only buy > OEM. Aftermarket are not as reliable. Thanks much for the URL. I looked,and they did not list the 94 Integra GSR motor,just the RS,LS,SE models. I suspect the O2 sensor would be the same,though. Also,quite a big price difference between the OEM sensors and the universal.I guess you would have to "adapt" the wiring on the uni sensor.(no connector match) SignatureJim Yanik jyanik at kua.net > Thanks much for the URL. > I looked,and they did not list the 94 Integra GSR motor,just the RS,LS,SE > models. I suspect the O2 sensor would be the same,though. > Also,quite a big price difference between the OEM sensors and the > universal.I guess you would have to "adapt" the wiring on the uni > sensor.(no connector match) In my experience, universals come with crimp splices to re-use the connector of the OEM. Mike | > the best thing to do is put in a new one and be done with it. Then why not buy new car & sell off old car ? I heard [i] japs export all their cars >5yr old, in whole or as components, to less developed countries with lower labour cost [ii] in Japan, new cars are cheap & repair costs high. Doesn't USA have the same situation ? | will a 3rd party sensor suffice? only if it has the same capacitance value ( usually in µH i.e. micro Henry ) as the OEM part, so your ECU will not detect any difference >| > the best thing to do is put in a new one and be done with it. > Then why not buy new car & sell off old car ? I heard [i] japs export [quoted text clipped - 5 lines] > only if it has the same capacitance value ( usually in µH i.e. micro > Henry ) as the OEM part, so your ECU will not detect any difference UH,microhenry is an INDUCTANCE measurement,capacitance is in microfarads,or picofarads. the O2 sensor might be rated in millivolt output (per oxygen unit). SignatureJim Yanik jyanik at kua.net >>| > the best thing to do is put in a new one and be done with it. >> Then why not buy new car & sell off old car ? I heard [i] japs export [quoted text clipped - 11 lines] > > the O2 sensor might be rated in millivolt output (per oxygen unit). Right about the units, and the output is rather a moot point. The capacitance is immaterial, since it is used as a DC device. All use the same chemistry and are as very nearly identical, with the exception of the heater characteristics. Even at that the heaters are all 12V DC. The essential characteristics (as I understand them): *open circuit when cold, they are biased to 0.45 VDC to signal an inoperative condition *once they reach something like 450 degrees, they become conductive. If the exhaust has enough CO compared to the outside air, the device becomes a fuel cell and the output rises to approx 0.9 VDC. If the exhaust is lean, the output drops near zero (about 0.1 V is the figure usually given). If the mixture is close to correct initially, the ECU drives the mixture back and forth across the transition point as rapidly as the feedback allows - thus the need for rapid response. Seven transitions per second is considered good, but I don't have a good handle on how slow is really considered bad. Maybe four... three? Mike > I recently started getting very low milage in my 1993 Civic EX (1.6 L > SOHC VTEC). Low mileage => more gas or more work by engine for a given baseline hmm ... I presume you have ruled out obvious driving changes such as altitude/distance/less hwy/more city/lead footing/avg speed etc... is that automatic tranny ? - have you noticed an increase in RPM per given cruising speed ? that is at 60 mph you used to be at say 2500 rpm now you are at 3000 rpm ? - any chance your transmission is the problem maybe you lost 4th/5th gear ?? - if manual are you forgetting to shift into 5th ;) - since a vtec any chance your engine stuck in vtec high rpm performance mode ? or something wrong with vtec system ? - has the CHECK engine light come on or blinked recently ? considering VTEC function is controled electronically (ECM function) could be VTEC malfunction > you could try running self diagnostic and look for system error codes ? > maybe try reseting the ECM > Previously I've seen between 32 and 38 (34 AVG.) i have '93 Civic Si same engine and have never really seen (> 31mpg) maybe the VTEC was broken before and now it works ? > Now I'm getting about 25 MPG (it has steadily declined the last three > tanks). I usually get about 28-30 , maybe your foot is heavier now :) > Things I have checked/replaced: > * Replaced Plugs and gapped them properly (The old ones looked fine) [quoted text clipped - 14 lines] > *The air filter is super clean > *Oil + Filter was replaced recently (1500 miles) using different grade oil (factory recommended) or any new additives ? > *Performance seems top-notch, as fast as ever. ah ha ! thought i had an idea > *Valves: I just adjusted them and they weren't hardly off at all, only > the valves on one cylinder were .001" too tight. [quoted text clipped - 9 lines] > > Thanks in Advance HTH most of this was out of Factory Service Manual, a very good book if you like to work on the honda i do not know how chilton/hayes etc compare but the Honda Service manual seems very good Manual tranny. VTEC is *not* electronic, it is controlled PER cylinder by oil pressure. RPMs go up = more pressure. at a certain point, the pins slide in and the intake valves use a different cam lobe. I checked when I adjusted the valves, they weren't stuck. But I doubt one VTEC being stuck on one cylinder would change the mileage this much. Driving habits have not changed. Nope, Oil is 10w30, hasn't changed. I have the Factory Service Manual, it's pretty useful. > Manual tranny. VTEC is *not* electronic, it is controlled PER cylinder > by oil pressure. RPMs go up = more pressure. at a certain point, the > pins slide in and the intake valves use a different cam lobe. the vtec /is/ applied by oil pressure, but the oil is "switched" on and off from the oil channel by an electrical solenoid. that is in turn controlled by the ecu. simple oil pressure control is subject to too many variables to be reliable. > I > checked when I adjusted the valves, they weren't stuck. But I doubt one [quoted text clipped - 5 lines] > > I have the Factory Service Manual, it's pretty useful. non-activating vtec is /most/ unlikely to be the cause of declining gas mileage. > > Manual tranny. VTEC is *not* electronic, it is controlled PER cylinder > > by oil pressure. RPMs go up = more pressure. at a certain point, the [quoted text clipped - 4 lines] > controlled by the ecu. simple oil pressure control is subject to too > many variables to be reliable. that is what i am talking about, i wish i had read this before posting my rebutal > > I > > checked when I adjusted the valves, they weren't stuck. But I doubt one [quoted text clipped - 8 lines] > non-activating vtec is /most/ unlikely to be the cause of declining gas > mileage. non-activating may give better gas mileage ? i was thinking constant-activation, either VTEC solenoid stuck in high rpm mode, which i supppose effectively becomes manual oil pressure control (is that a trick to get lower mid-range performance out of VTECs ?) or the ECM signals causing VTEC engaging are maybe engaging high rpm mode a bit lower than factory design specs. say engage VTEC at 2500-3000 rpm instead of 4500 >>>Manual tranny. VTEC is *not* electronic, it is controlled PER cylinder >>>by oil pressure. RPMs go up = more pressure. at a certain point, the [quoted text clipped - 30 lines] > bit lower than factory design specs. say engage VTEC at 2500-3000 rpm > instead of 4500 ecu's/ecm's do not get it wrong. they either work, or they don't. and these honda ecu's/ecm's are spectacularly reliable. of there /is/ a vtec problem, it's more likely solenoid or wiring. Thanks guys for the VTEC info... I'd always wondered how oil pressure was stable enough to engage something at a specific RPM. I guess I better read the factory manual a bit closer. I'll find some way to check the solenoid. > Manual tranny. VTEC is *not* electronic, it is controlled PER cylinder > by oil pressure. RPMs go up = more pressure. at a certain point, the > pins slide in and the intake valves use a different cam lobe. maybe i misunderstand ... you completely by passed the *EC* (electronic control) part of VTEC variable valve timing and valve lift electronic control system The mechanics of the VTEC engaging is hydraulic (oil pressure) via the VTEC oil solenoid which performs as you describe *BUT* the control of the VTEC engaging through VTEC solenoid is the ECM which is electronic and uses several measures to control VTEC solenoid operation {rpm, load, temp, speed } > I > checked when I adjusted the valves, they weren't stuck. But I doubt one > VTEC being stuck on one cylinder would change the mileage this much. and engine would probably vibrate, seem unbalanced i was thinking about VTEC solenoid or ECM control signal which would affect all the cylinders > Driving habits have not changed. > > Nope, Oil is 10w30, hasn't changed. > > I have the Factory Service Manual, it's pretty useful. well my VTEC electronic info comes from page 5-9 "switchover from one VTEC profile to other is controlled electronically" so i am just suggesting that one cause for using more gas (your %25 drop in fuel economy) could be fault in the VTEC control, for instance if the VTEC solenoid is stuck in high rpm mode all the time then you would be using more gas, of course i suspect there would be some other symptoms like low rpm and low end rough starting and rough idling, but once you get into 2500 rpms or so it would just seem like great performance I like the HO2S idea too but there should be some performance problems there as well like rough idling or stumbling or some noticeable performance problem associated with richened air mixture Thanks for the VTEC info... I'd always wondered how oil pressure alone was stable enough to engage something at a specific RPM. I guess I better read the factory manual a bit closer. I'll find some way to check the solenoid. > I recently started getting very low milage in my 1993 Civic EX (1.6 L > SOHC VTEC). [quoted text clipped - 36 lines] > > Thanks in Advance Doesn't matter how you drive it. You should still be getting better mpg's. I second elle's opinion about the oxy sensor(s). The engine computer no longer gets realistic data from the oxy sensor and is running in default mode. dan > Doesn't matter how you drive it. You should still be getting better mpg's. > > I second elle's opinion about the oxy sensor(s). The engine computer no > longer gets realistic data from the oxy sensor and is running in default > mode. id third that. its pre OBD2, so it isnt going to throw a code. if you have 2 sensors, id replace the one *before* the catalytic converter. on my 98, it went and threw a code. it also ran like crap/stalled at idle. Sounds resonable, but then the Check engine light would be lit if the sensor were failing... Well, "should" be it. > Sounds resonable, but then the Check engine light would be lit if the > sensor were failing... Well, "should" be it. i dont think itll light up the check engine lamp on a pre-96/OBD2 car. might not even throw a code. but the O2 sensor definately has an effect on the mileage, and by 200k miles with the original sensor, its time to replace. > * Haven't done a Compression Test yet > So, any ideas id do a compression test and replace the O2 sensor if its the original one. its due, and directly effects emissions. if its bad, the engine could be running rich. is the tailpipe sooty? were the plugs black? grey? tan? a small factor could be tire pressure. another factor could be brakes dragging. jack up each wheel and see if they spin freely. The old plugs were perfect and all the same. Tires are properly inflated, brakes are not dragging. I also just replaced the front rotors and pads. > The old plugs were perfect and all the same. > > Tires are properly inflated, brakes are not dragging. I also just > replaced the front rotors and pads. Did you readjust the parking brake? In one of the Prius groups a member was complaining the mileage dropped about 10-20% after the most recent service, and another suggested the parking brake had been adjusted too tight. Bingo! (I am also assuming the slide pins were lubed during the brake work. Once I overlooked that bit and received one of life's little lessons.) If you have verified the brakes are not dragging, the parking brake isn't it... but the lubrication state still could be. Mike >>The old plugs were perfect and all the same. >> [quoted text clipped - 10 lines] > > Mike parking brake is self adjusting. should not be affected by servicing the front! but it's a good thought - check the brakes - especially as decreased gas mileage seems to coincide with recent brake service!!! Update: Could be completely unrelated. The PO told me about this very intermittent problem and this is only the second time I've run into it. The car doens't start after it's been warmed up. It turns over great... but just doesn't run. The previous time, It started after several attempts (30 sec or so). This time, I had warmed it up and then did a compression test. Then, when going to start it again, it just won't run. I've checked the usual stuff (sparks plugged in, injectors plugged in). I even tried cranking for 20 seconds to see if the ECU would register something faulty. Nothing. My guess is it will start after cooling down.... why though? Could I have messed something up ignition wise by cranking with the plug wires removed? > Update: Could be completely unrelated. The PO told me about this very > intermittent problem and this is only the second time I've run into it. [quoted text clipped - 12 lines] > Could I have messed something up ignition wise by cranking with the > plug wires removed? Sadly, it's very possible. Honda spark coils are not very tolerant of being fired up without a load. My son zapped his coil just using the starter to "bump" the distributor to the proper position. The result can be seen at http://tegger.com/hondafaq/badsecondary/internal-arcing.html D'oh! The initial problem sounds like a bad "main relay" - see http://tegger.com/hondafaq/faq.html#startrun for the straight scoop on that. Mike You are right. The secondary coil shorted someplace and is now only half the resistance it should be. I'll post the best price when I find it. I purchased an Ignition Coil online at http://www.thepartsbin.com/ $46.50 + Distributor O-Ring ($3) + some random $1 thing to push me over the $50 free shipping mark. >I purchased an Ignition Coil online at > [quoted text clipped - 3 lines] > + Distributor O-Ring ($3) > + some random $1 thing to push me over the $50 free shipping mark. Thanks for the link! Mike > I purchased an Ignition Coil online at > [quoted text clipped - 3 lines] > + Distributor O-Ring ($3) > + some random $1 thing to push me over the $50 free shipping mark. After market, hmm. Let the group know how it goes. I'm afraid the aftermarket coils I've had did not last nearly as long as the original, OEM one. Way to troubleshoot! Top Notch Shipping. Ordered itSunday night, recieved it Tuesday morning. Anyway, it looks exactly like the coil that was in there already, it measures in spec (resistances of the coil), and has worked fine now that I've put it all back together. Well.. I seem to have found the problem. It was, as many have suspected, an old Oxygen Sensor. I was getting about 25ish MPG, and then I replaced the O2 sensor and now I have gone about 150 miles with the needle still above the 3/4 tank mark. I'll let you know the actual mileage when I finish the tank. Thanks to everyone. > Well.. I seem to have found the problem. > [quoted text clipped - 4 lines] > > Thanks to everyone. Especially thanks to Elle, who has been championing the O2 sensor issue for a while now. I'm coming to believe there are a lot of cars that are suffering degraded O2 sensor performance that haven't degraded enough to set the "check engine" light. My daughter's '93 Accord with 220K miles is a prime example. It doesn't make sense to assume a sensor that old is still working well. I hope to replace that one this spring - it's just too chilly now. Mike >> Well.. I seem to have found the problem. >> [quoted text clipped - 12 lines] > working well. I hope to replace that one this spring - it's just too chilly > now. cars older than 1996 when OBD2 went into effect might *never* trigger the check engine light. i know my moms 1993 eagle summit never did. im sure someone here with more knowledge would know whether itll even blink a code if/when checked. > "Danny Beardsley" <dbeardsl@gmail.com> wrote > > Well.. I seem to have found the problem. [quoted text clipped - 8 lines] > Especially thanks to Elle, who has been championing the O2 sensor issue for > a while now. Yeah but I may have messed him over by casually mentioning my temptation "to pull off the ignition wire of the suspect cylinder (with the suspect fuel injector) and see if engine power sounds like it goes down." Shoulda been more complete; told him to follow a manual or Tegger's site on this point (which I believe mentions your experience on this, Mike); warned him about cranking the engine with any wire disconnected. It may very well have cost him the coil as well as time lost. Gotta come clean, so maybe, with enough repetition in the archives someone else won't have this happen. Sorry Danny. > > Well.. I seem to have found the problem. > > [quoted text clipped - 14 lines] > > Mike you have convinced me to change mine as well (probably i'll check it first then change) as i am sporting a '93 civic si @ 195k with original sensor btw is the accord having any oil trouble ? i am loosing about 1/2 qt between oil changes ? was ther a final consensus on where to get good quality O2 sensors ? robb "Rob B" <RobB@where.on.net> wrote Re oxygen sensors-- > you have convinced me to change mine as well (probably i'll check it first > then change) > as i am sporting a '93 civic si @ 195k with original sensor > > btw is the accord having any oil trouble ? i am loosing about 1/2 qt > between oil changes ? How much times is that in miles and months? Doesn't sound too serious, but I'd still be checking for leakage around the valve cover; under the distributor; and into the spark plug tubes. How old's the valve cover gasket and the several other seals in the valve cover (spark plug tubes, oil filler cap, rubbery washers for the hold-down bolts)? Ever had the distributor O-ring seal (IIRC) replaced? I did all of these not long ago, and my 173k mile, 1991 Civic's oil consumption seems way down, from about 1/2 quart between oil changes. Plus the exterior of the engine and the spark plug tubes are cleaner. :-) > was ther a final consensus on where to get good quality O2 sensors ? In 2004 for my 1991 Civic, I used https://www.automedicsupply.com/ for an OEM oxygen sensor at a significantly better price than the usual online OEM parts sites. Good service. The sensor seems fine--still getting 40 mpg most of the year on my 1.5L engine, manual tranny. So I have been recommending this company here when the subject comes up. > "Rob B" <RobB@where.on.net> wrote > Re oxygen sensors-- [quoted text clipped - 9 lines] > > How much times is that in miles and months? around 4500 mile oil changes, usually quite charcoal'd by then takes about 10 months, it doesn't get the miles like it used to, recently went from 15k yr to about 5k yr > Doesn't sound too serious, but I'd still be checking for > leakage around the valve cover; under the distributor; and [quoted text clipped - 3 lines] > bolts)? Ever had the distributor O-ring seal (IIRC) > replaced? well i already had answered his in my head as (no leak) but i checked anyway and there was a freek'n leak coming somewhere from vicinty of valve cover and distributor base .... I can not believe i missed this on last oil change, it has a fine film oil all over that side if engine, wililnvestigate further the distributor was replaced about 3 yrs ago so something has gone wrong > I did all of these not long ago, and my 173k mile, 1991 > Civic's oil consumption seems way down, from about 1/2 quart > between oil changes. Plus the exterior of the engine and the > spark plug tubes are cleaner. :-) I'll check those as well > > was ther a final consensus on where to get good quality O2 > sensors ? [quoted text clipped - 6 lines] > have been recommending this company here when the subject > comes up. just looked there, i will compare with local foreign auto parts shop for sake of curiousity thanks for info robb > "Elle" <honda.lioness@earthlink.net> wrote > > > btw is the accord having any oil trouble ? i am loosing > > about 1/2 qt [quoted text clipped - 6 lines] > takes about 10 months, it doesn't get the miles like it used to, recently > went from 15k yr to about 5k yr For 10 months, that sounds like a leaky gasket somewhere, as I listed earlier. My manual says to change the (non-synth) oil every 7500 miles or 6 months. Sometimes I hit the 6-month limit first. I'd say half a quart was what I was going through over that time--before I replaced certain gaskets. I assume you're comfortable with the 10 months. If not, consider 6 months, which I think is what your manual also says. > > Doesn't sound too serious, but I'd still be checking for > > leakage around the valve cover; under the distributor; and [quoted text clipped - 11 lines] > > the distributor was replaced about 3 yrs ago so something has gone wrong My distributor housing was replaced about 2.75 years ago, and I think I'm seeing a little oil leakage down beneath the distributor. I cleaned up there (for the first time) a month ago, then checked again recently. I will probably replace the distributor O-ring within the next six months. That's not a hard job. |
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