My '98 MPG is bad

[Hondaman4ever]

Hi.

As mentioned in my other posts this is a car that I've only had for a few weeks. The first thing I did when I bought this car was to see what MPG I was getting and I was very disappointed and even shocked. I was getting 23/city -31/hwy. Only once did it I get 33 hwy, which is really bad for a Civic. First I thought maybe because the engine was running too cool (temp was always on C while driving on hwy). So I replaced the thermostat and temp is at normal now. But that didn't change the mileage. Suspected an O2 sensor but the mechanic told me the CEL would've come on if it were. Well, the very next day it came on. So I replaced the O2 with an NTK. Then changed the spark plugs and oil. Air filter is clean. Used Lucas fuel additive. Topped the car off, drove almost all highway and refueled. Big disappointment. I got less than 33 MPG ! WTF ? That's not normal. My '95 with 380,000 kms used to give me 40 miles plus. From what I read the '98 should give me just under that on hwy.

So, could someone please tell me what else could be the cause? I probably need to change the fuel filter but I doubt it's going to make the difference. PCV?

It is a 5 speed. with 143,000 miles. Not sure engine type but everything is stock. Car doesn't seem to have any other issues (engine/fuel system) and the engine runs smooth. Previous owner was a woman who had had the car for 10 years and she did things on time. Living here (BC Canada) where we pay close to $5 ($4.6 US) a gallon and being on a very small income makes things much worse.

So, any suggestions? Thanks.

 

[RonJ]

First off, your hwy gas mileage isn't that bad.

Do a full ignition system tune up, that is also replace the plug wires, cap, and rotor and set the ignition timing.

What CEL code was thrown when you decided to replace the O2 sensor?

Have you fixed the noise in the engine bay?

 

[HeX]

Read through the link on my signature.

 

[Hondaman4ever]

Thanks for the reply, Ron. Well, from reading what some '98 owners are getting (around 40 mpg /hwy and some higher) I consider what I'm getting as bad. My '95 used to give me 40+, so I thought this one would give me close (thought maybe 38). I really doubt changing the spark plug wires and cap and rotor will do much to improve the gas mileage. If the thermostat, O2 sensor and spark plugs didn't make a difference, I don't think those will. I might get my timing checked though but again I doubt that would make that much of a difference either.

I can't remember the code we got but the mechanic told me it was the O2 sensor and since I changed the sensor the CEL hasn't come back.

As for the grinding noise, I still haven't done anything about it.


I'm already thinking about selling this car and getting a '95 again. To me, every dollar matters.

 

[Osiris19]

All of those will affect mileage to some degree, especially timing.

Sent from my Nexus 7

 

[RonJ]

Thanks for the reply, Ron. Well, from reading what some '98 owners are getting (around 40 mpg /hwy and some higher) I consider what I'm getting as bad.

I think you have a 98 Civic LX (D16Y7) 5-speed. I have a 97 Civic DX (D16Y7) 5-speed. Your hwy mileage is about par for mine. Once in a while, I can get 35-38 mpg on the hwy, but typically I get 33-34mpg on the hwy, so your hwy mileage is okay. Your city gas mileage seems low, though, but you also need to consider other factors, like driving style, tire inflation, etc.

My '95 used to give me 40+, so I thought this one would give me close (thought maybe 38).

92-95 Civics generally get better mpg than 96-00 Civics.

I really doubt changing the spark plug wires and cap and rotor will do much to improve the gas mileage. If the thermostat, O2 sensor and spark plugs didn't make a difference, I don't think those will. I might get my timing checked though but again I doubt that would make that much of a difference either.

This^ shows that you know very little about your car. Purge these^ thoughts from your mind immediately. Ignition systems in need of a tune up are the most common source of low gas mileage.

As for the grinding noise, I still haven't done anything about it.

This^ could also lower the mpg.

 

[Trekk]

Buy a 250cc motor cycle or scooter, they get 70+mpg.

I've seen people on the Eco mod forums that have civic HX's which is the most fuel efficient of the civics of that gen and they are only in the mid 40's hypermiling.

I never take my civic(98 lx) on the highway. Just traffic crawling and I get around 26mpg.

 

[sixwhip14]

I second Ron. My 97 accord was taking longer to crank over when starting. It had been several years since I did a tune up. I did plugs,wires, cap, and rotor. I noticed an improvement in mpgs.

 

[Hondaman4ever]

Thank you all for the replies. I know my car wasn't going to give me the same mileage my '95 used to but I didn't think the difference was going to be as much as 7.5 miles/gallon. That's a lot, especially that the two cars have almost identical engine sizes (1.5 vs 1.6) and horse power. I drive a lot and that would add up especially where we pay almost $5 CaD/gallon. I've decided I'm going to find me another '95 Civic. Yeah no airbags but I'm ok with that.

I don't think I'm going to do any more tuning up on this car. I've already spent close to $200 (O2 sensor, thermostat, spark plugs) and I barely got 1 mile difference in mileage. If I change the cap, rotor and spark plugs wires, fuel filter, do the timing that will cost me another $200 (this is Canada not the US) and from what you're telling me I probably won't get much more mileage -if any at all- than what I'm getting now.


Trekk, if I didn't live in a place where it rains constantly for more than 10 months of the year I would get a scooter.

 

[RonJ]

If crazy gas mileage is your main goal, shop for a 92-95 Civic VX or a 96-00 Civic HX.

 

[HeX]

I don't think I'm going to do any more tuning up on this car. I've already spent close to $200 (O2 sensor, thermostat, spark plugs) and I barely got 1 mile difference in mileage. If I change the cap, rotor and spark plugs wires, fuel filter, do the timing that will cost me another $200 (this is Canada not the US) and from what you're telling me I probably won't get much more mileage -if any at all- than what I'm getting now. .

You already changed a few less common issues, such as the O2s & thermostat. However, spark plugs, wires, cap & rotor & fuel filter are common maintenance parts. Leave a timing job for last but its good to have it checked at some point. FYI, a fuel filter is extremely cheap & can be replaced in 30 minutes or less. Inspect your plugs for obvious wear before blindly purchasing new parts. If you choose not to perform regular maintenance then most cars you own wont last long before you have issues.

 

[Ice Cream Kid]

Is there snow there? Here in minnesota I've been driving in the snow and noticed a huge drop in mileage. Whereas average mileage was about 30 in the summer, it's dropped to something like 24 for me

 

[Hondaman4ever]

Ron, my goal was to get a car that gives me the same mileage or close to what I used to get from my "95 Civic, which I was pretty happy with at close to 41 a gallon on hwy. 2-3 times a week I make 100-120 KM ( 60-70 miles) trips and that alone amounts to about $10/week in extra fuel cost, plus I still have the other regular driving. So that's at least $50-60/month. It might not sound like it's too much to you all but to me it IS (with my current financial situation). I figure that's at least $600 a year, which is money I can use to pay 6 months of insurance (@ the rip off rate of $95/month here).

Hex, I changed my spark plugs when I changed the O2 sensor. The wires and cap don't seem to be bad and that's why I don't know if it's worth it to change them. The wires alone cost $100 here (this country is a rip off). The fuel filter does look old though but I don't know if a new one would really make a difference in improving the mpg but I know it's part of maintenance. It costs $23 here. Actually I like to take care of things and especially cars and I'm the kind of guy who likes to fix things even when they're not broken -at least when I can- but if I'm going to sell this one I don't see a reason for spending another $200. However I am going to get the timing checked, and will probably take the car to get it aircared (smog check) to see if it passes.


Ice Cream kid, no. There is no snow here so far. It is below zero though but I think gas mileage does go down during the winter and snowy conditions.



One thing, I've noticed this car unlike all the other ones I had, when I first start it up in the morning the RPM doesn't seem to go as high as the others. You know, engines normally are revving at around 2000 RPM (when cold) until they're warm and then the RPM drops by itself. It's like something's choking it (but not really bad).

 

[RonJ]

One thing, I've noticed this car unlike all the other ones I had, when I first start it up in the morning the RPM doesn't seem to go as high as the others. You know, engines normally are revving at around 2000 RPM (when cold) until they're warm and then the RPM drops by itself. It's like something's choking it (but not really bad).

Are you planning to do more work on this^ car?

It might not sound like it's too much to you all but to me it IS (with my current financial situation). I figure that's at least $600 a year

If crazy gas mileage is your main goal, shop for a 92-95 Civic VX or a 96-00 Civic HX.

 

[Hondaman4ever]

Are you planning to do more work on this^ car?

Well, if I can get the car to give me around 37 MPG/Hwy somehow, then I'd keep it and do more work.

 

[HeX]

Hex, I changed my spark plugs when I changed the O2 sensor. The wires and cap don't seem to be bad and that's why I don't know if it's worth it to change them. The wires alone cost $100 here (this country is a rip off). The fuel filter does look old though but I don't know if a new one would really make a difference in improving the mpg but I know it's part of maintenance. It costs $23 here. Actually I like to take care of things and especially cars and I'm the kind of guy who likes to fix things even when they're not broken -at least when I can- but if I'm going to sell this one I don't see a reason for spending another $200. However I am going to get the timing checked, and will probably take the car to get it aircared (smog check) to see if it passes.

One thing, I've noticed this car unlike all the other ones I had, when I first start it up in the morning the RPM doesn't seem to go as high as the others. You know, engines normally are revving at around 2000 RPM (when cold) until they're warm and then the RPM drops by itself. It's like something's choking it (but not really bad).

If the wires seem ok then I agree not to change them. A heavily clogged fuel filter may restrict fuel flow and give the bogging choke feel. If you also feel some resistance while pressing the accelerator pedal then that may also be a sign of a potentially clogged fuel filter. You should also clean our the EGR chamber, located under the fuel rail. You can do it yourself in less than 2 hours at most and all you need is carb/choke cleaner. So for around $30 more you may get the issues resolved.FYI, these suggestion are in my signature link I recommended you to read through.

 

[RonJ]

If the wires seem ok then I agree not to change them.

Please explain how visual inspection is a reliable method for determining whether plug wires are good.

You should also clean our the EGR chamber, located under the fuel rail. You can do it yourself in less than 2 hours at most and all you need is carb/choke cleaner.

The OP would search for eternity trying to locate the EGR system that doesn't exist on his D16Y7 engine.

And this thread is now dead in the water as the OP plans to invest zero time or effort into this 98 Civic.

 

[Hondaman4ever]

Thanks HEX. I don't feel any hesitation (choking) when I press the accelerator but the fuel filter does look pretty old. I might sacrifice another $25 just to see if that improves the MPG but I doubt it.


RonJ, I dropped $200 on the car the first week I purchased it because I was really excited and was going to do things (maintenance) it didn't really need until I found out about the sub-par MPG. So, I don't know how you're saying I don't want to invest time or effort into this car. At this point, I don't believe there are any more things I can do to improve the MPG of this car and thus I don't see any point in spending more money on the car if I don't plan on keeping it. I think the only thing I want to get checked out or fixed -if it's not too costly- is that grinding noise I was talking about so it will be easier for me to sell the car. I'm already looking for a '95 Civic but I know it will take forever to find one.

 

[RonJ]

I don't know how you're saying I don't want to invest time or effort into this car.

I don't see any point in spending more money on the car if I don't plan on keeping it.

if it's not too costly

With respect to tech, this thread is dead. Just close it or move it to Off Topic. Leaving it open would just waste member's time.

 

[HeX]

Please explain how visual inspection is a reliable method for determining whether plug wires are good.

He did mention the wires dont seem as if theyre hardening so I assume he visually & manually inspected them.Hes clearly on a budget so rough estimates on quslity will suffice.

The OP would search for eternity trying to locate the EGR system that doesn't exist on his D16Y7 engine.

My mistake. I was under the impression the other D16 engines also have EGRs.

And this thread is now dead in the water as the OP plans to invest zero time or effort into this 98 Civic.

I agree in part. If the car is running well & only experiencing relatively mibor issues then its worth some added attention. otherwise, its likely he'll sell a solid base for something with potebtially worae & costly issues since he doesnt have the money to purchase a less risky vehicle.