tock172

Hello all!

I recently acquired a hand me down 2003 automatic Civic EX Sedan. My mother bought the car new in 2003 and then my sister drove the car from 2007 until now. I recently took possession of the car to use as an inexpensive daily driver while my BMW M3 sits in the garage.

So, let's get down to business. Here are some details about the car:

D17A2 with 182k
Timing Belt done at 92k (I'm planning to do it again at 200k).
Bridgestone Ecopia 185/55R15 with decent life left @ 34 PSI.
Plugs were replaced at some point. They look a bit old, but no carbon or oil buildup.
Air filter isn't new, but it's far from the worst I've seen.
I've got all the other receipts, but it was a Honda owned by 2 females, so take it all with a grain of salt.

Here's the problem: I'm only getting 25 MPG. I was anticipating better mileage, but coming from daily driving my M3, I'm definitely missing a bit of the power and I need to rev the little 4 banger to get up to speed.

Should I be expecting better mileage? Could this be attributable to my driving style? I've considered replacing the plugs and air filter, but neither are in bad shape.

The car also likes to burn quite a bit of oil. My sister and mother always had the oil changed frequently, but I believe my sister may have run the car very low once or twice. The oil burning doesn't bother me, but could this be a reason why I'm not getting better fuel economy?

Reverb2005

If you drive the car like you drive your M3, 25 MPG is probably what you would expect. This car is definitely not a race car, though other would disagree... Don't rev the crap out of it, accelerate reasonably fast for the size of engine you have and don't speed excessively.

If you are burning lots of oil, you likely need new piston rings. There are other reasons for burning oil, but this is the most prevalent. Have you got any CEL codes? Have you ever checked? Maybe there are some stored from long ago that could still be giving you a problem?

Do you know how to do a compression test? Do it.... If your rings are worn out, you may be getting a lot of blow-by, thus reducing power and mileage. If you had a look at the air filter, why not just replace it? It's literally only $25 at Honda (here in Canada anyway). I replace mine every 75,000 km or so and my throttle body is literally shiny as new inside!

How are the brakes? Ever had them changed? Do they ever seem excessively hot after driving? Stuck brakes will definitely cause you lower mileage, but you wold probably notice that since your pads would wear like crazy. Ever had the fluid changed?

Some people get as good as 39 MPG here on the forum, but that is excessively good... 30-35 isn't bad.... do you drive a lot in the city or highway?

If you are burning a lot of oil, I bet your EGR valve is plugged with carbon. Also, you had better check your PCV valve... probably also plugged due to blow-by.

CIV1C

I have a 2001 manual ex. I bought the car around 175k miles and it now has 205k. It was very well maintained and had a huge folder of service history. I bought another car a year ago and haven't really driven this one since then. Basically I did 30k miles in a year and beat the hell out of this car pretty much every time I drove it so I don't think it's your driving style.

I haven't driven an auto but the manual is peppy around town and a lot of fun. I had a hard time getting under 30mpg (don't think I ever did) and would floor it all the time to redline. I also had my headgasket go bad, which is a common issue, but prior to that didn't notice a drop in fuel economy and was still getting above 30mpg.

I did notice that my oil would magically disappear. Not gradually, just all of a sudden it would seem to go from full to empty. Keep in mind I didn't check daily or weekly.

I figured that if I drive close to the redline all the time it will eventually use the oil. I think if you're in the vtec range it will burn the oil, but have no idea if that's true. I've heard early s2000s do. If I drove normally the oil level would stay the same. Again, you could beat the hell out of the car all week and the oil level would be fine. I always checked the level when the car was cold. I could also notice when it didn't have oil (it drove slightly different) and would fill it up.

ezone

Absolutely, the gas mileage is 99% your fault.
EDIT: Ok, maybe 75%. LOL


It's not the reason for poor economy until it fouls plugs enough to cause misfire codes.

High RPM will increase oil consumption rate.

High mileage combined with lower quality oils ---- engine probably has stuck oil control rings.
I'd switch to 0w20 oil and see if it slowly reduces the oil consumption over several oil change intervals.

tock172

Reverb, thanks for the detailed response. I appreciate your time and input greatly.

I think you have a point about my driving habits. Coming from my M3 (and previously a 4.2L V8 Audi S4) I am used to torque in any gear. The Honda is going to take some getting used to. The fact that fuel cut is at 7,200 for the little VTEC is definitely encouraging to me, and that isn't helping things.

I have not pulled any codes yet. I only have diagnostic equipment for VAG and BMW vehicles. I'll definitely look into picking something up or having them pulled in the mean time.

I know how to do a compression test and I have the gauge as well. I have done some other reading and piston rings came up. But to be perfectly honest, piston rings, and an engine rebuild are not in my plans for this car. I would consider a manual swap if the trans goes, but beyond that, I plan to drive the car until the wheels fall off.

The brakes have definitely been changed. There is plenty of life left on the rotors and the pads. I see no evidence of them being stuck or seized.

When I looked at the air filter, my throttle body did have minimal blowby buildup on it, which I cleaned. And to answer your question about the filter, I'm planning to give the car the attention it deserves; oil service, air filter, plugs, etc. Thank you for the input on the EGR and PCV valves.

Thanks for the input!

The plugs are definitely not fouled enough to cause any misfiring or rough running, but they are old. Should I still consider replacing them? I haven't found the receipt in my file to verify their age yet.

I think you may have a point about lower quality oils. I've always spoiled my BMW with whatever I discerned to be the best on the market, but the Honda always got the express treatment.

So, just to make things clear, here's what I've got planned for the car.

Oil service (I'll look into 0w20)
Air Filter
New Plugs? (I'd be happy to post a photo of one of mine)

So besides taking my foot off the gas a bit more, are there any other thoughts/suggestions?

ezone

Will either handle reading generic OBD2 data?



Precious metal plugs are supposed to be changed at 100,000 miles, but in reality they may outlast the car as long as they don't get fouled.


The oils that keep European cars alive can kill another car in short order.
Likewise, the oil that keeps our cars alive could kill a Euro car in the same short order.

The engines have very different lubrication needs. Specs are very important.

-------

Copied from another post of mine:

Nothing other than a ring job would give perfect, immediate results.

Another thing to do is to switch to a better quality oil and hope it can slowly clean carbon out of the ring lands of the pistons (carbon buildup is usually what causes the oil rings to stick in their grooves).




"Heavier" oil can help or hurt. You can't tell which. Some engines respond as you would expect, some don't.
Example: 10w30 is some of the lowest quality, and the cheapest to make. Therefore it generates the highest profit and is pushed the hardest on the consumers.

5w20 and 0w20 use better base stocks to start with.
I personally favor "thinner" oil of higher quality, for multiple reasons.

IMHO
Look for and use 5w20 oil with specs of:
ILSAC GF-5
ACEA A1/B1
API SN (or higher)

Much of the Mobil-1 5w20 meets these specs.
So do many/most of the oils bearing the DEXOS-1 logo. Read the labels though.

May take a looooong time to have any effect though.


I have been doing this with my GF's Saturn, it has taken 30k+ to slow down the oil use. It was using a quart in 500 miles, now it has gone as far as 1500 -2000 miles per quart. But it varies a lot, and I still have to check it very regularly.




I picked up an 05 CRV with 105,000 miles on it for the ol' ladys son and his family a few months ago (early Feb.).
It used about 2 quarts in 3000 miles with the oil it came with (I have no idea what was used).
I changed it over to 0w20, and it's used one quart in 5000 miles as of last weekend. I'm gonna keep it on 0w20.




If you want to run a 5w20, look for those specs above.
If you decide to run 0w20, look for Mobil 1 or Pennzoil Platinum Plus that states it meets Hondas specs.

Even though the oil cap says otherwise, 0w20 is approved for use in that engine by Honda. You may even gain a little bit of gas mileage with it.


HTH

tock172

The cable I have for my old Audi might work, but the BMW system is highly proprietary.

Well I definitely agree with the bolded statements. I've done tons of exhaustive research and Blackstone Labs analysis over the years for my various German cars, but I'm essentially clueless about the nuances of Japanese engines. I have run Castrol, Liqui Moly and Genuine BMW oil in my various BMWs, but so far Shell Rotella T6 was my favorite. Totally irrelevant of course.

I like your suggestion of 0w20 for my Civic. I'm going to use Mobil 1 0w20 Advanced Fuel Economy for my next few oil changes and continue to monitor things. Hopefully I'll have an actual consumption rate established soon.

tock172

Got an update.

This evening I changed the oil with M1 0w20 Adv. Fuel Economy, replaced the air and oil filters and also replaced the spark plugs with NGK Iridium units.

Here's a shot of my plugs. I'm not exactly sure what to think, but I suspect the are fouled by the oil consumption and perhaps past their prime? Old on the left, new on the right (duh).


And here's the worst part. I used my borescope camera to inspect the combustion chambers and the tops of the pistons. Check out the ridiculous carbon build up. What can this be attributed to? Cheap oil? Infrequent OCIs? Also notice around 0:47 that there appears to be vertical scoring on the cylinder walls? Does anyone else suspect this? Are these engines known to score?

ezone

Ashy coating on the plugs, not heavy, probably would attribute to slow oil burning.

Carbon on top of the piston, also expected. It's supposed to become "self cleaning" once it builds up to a certain level, meaning once it builds up so much it doesn't accumulate a bunch more.

Around the edges of the pistons: Is it carbon free? Is it standing oil? I can't tell what it is.

At any rate, all this kinda points to rings, as expected.

If the oil consumption rate becomes so great it is fouling plugs and causing misfires, I'd switch to (much cheaper) copper NGKs ZFR6F-11 and change them out whenever needed.

Vertical lines are common (maybe run very low on oil at some point?) but if you can hang a fingernail in them then they are considered deep enough to warrant concern and possibly closer attention if the engine ever gets torn down.


HTH

tock172

Thank you for the continued input. The edges of the pistons appear to be carbon free, but covered in rust. I didn't see any standing oil, just bright orange rust. Any insight relating to that? I haven't looked inside too many engines, but I've never seen it.
So do you think I should run some kind of top end cleaner or seafoam? Or should I just let it be? Keep in mind, the engine has always run great, I was just hoping to get a few more MPGs out of it.

I will definitely keep that in mind. The OE plugs were $12, the Iridium units I installed last night were $7.

ezone

Well, it might be a reddish brownish color but IMO it can't be rust.

It may just be an indication of how the engine was last run, such as a cold start to pull it in the garage then shut off.

It was running fine, I'd leave it alone.
You can if you want, but I personally wouldn't mess with it at all.
It will just return again anyway. It was running fine, I'd leave it alone.
Keep your foot out of the radiator.


Check out the hypermiler forums, and check out the ecomodder forums for some gas mileage ideas.

tock172

Well I'm happy to report an improvement. I changed the oil about 600 miles ago with Mobil 1 Advanced Fuel Economy 0w20. I can't say much about the fuel economy, as it has remained steady at around 24.7 MPG, but it did shoot up 26.6 when I ran a tank of Shell V-Power 91 octane. My driving style is certainly the culprit.

The oil consumption, however, seems to have dropped dramatically. I have been checking the oil religiously and from what I can determine, the level is not dropping on the dipstick. Prior to switching to the 0w20, the consumption was noticeable between fuel stops. I haven't bothered to pull a spark plug or use my camera again, but so far, so good!

ezone

This sounds quite encouraging!