98hx only getting 25-28 mpg?!?!?!
 

I'm the 2nd car owner of this 98 honda civic hx. I bought it with 125,000 miles and now it only has 130,000. I just changed the spark plugs, spark plug wires, distributor cap, oil,oil filter, air filter. Nothing is wrong with the car but a ticking noise from the engine but its not my valves. I just checked them. Shouldn't I be getting over 30mpg easy? I'm going to sea foam and clean my egr up next. Any other advice?

"Ticking" noise might be:

bad rod bearings?
piston slap (especially when cold)?
noisy PCV valve?
valve rocker arm(s) needing adjustment?

You should be getting close to 40mpg highway.

I just checked my valve rockers and they're fine. The noise is coming from the engine. I'll check pcv valve and piston slap. I have no idea why I'm not getting good mpg either, I've never driven my car to empty but my gas tank will be half filled when I get close to 150milesof driving.

Only way to find out... fill it to the brim, drive a bit and fill it again (preferably without turning the engine off in the interim) to get your ballpark economy.

Bad:

Thermostat.
Oxygen sensor.
Timing-distributor.
Compression.
Fuel pressure regulator.
Timing belt installed incorrectly.
Brakes dragging.
Plugged converter-exhaust.
Low air pressure in tires.
Dragging brake calipers.
Very short driving distances.
Alignment.
Injectors-ecu fried.

As well multitude of additional potential causes working individually or in conjuction with each other.

Need much more information.

regards
mech

Sorry, I'm in the process of learning how to take care of a car. Just bought a Chilton book about a week ago and have been reading it. Any other advice will be great. How would I know if I have bad rod bearings or if I have psiton slap?

Commute distance?

How easy is the car to push of a flat surface?

Does the temp gauge read in the middle of the range and does it warm up in less than 2 miles in moderate ambient temperatures?

Shift points in rpm?

Engine rpms at 60 mph?

regards
mech

My daily commute is less than 5 miles a day. It takes a while fory car to warm up and it only reaches 1/4 of the way on the thermostat. I shift between 2k-2.5k rpm my rpm @ 60mph is 2.5k or less

You can do way better than the Chilton manual. I can share the 1996-1998 Civic factoy manual (1500 pages) witn you. It is a big file, but if you PM me with a gmail account or something, I'll try to email it to you. Among other things, it has useful trouble shooting flow charts and such.

Xxxxxxxxxx@xxxxxxxx ^ when I reply do you guys get notifications? I'm new to this site so I'm not sure if you guys are getting my responses.

Your commute is your problem. I get 65-70mpg in my insight, but when I used to work 6 miles from home, I would struggle to get 50 WITH a kill switch and pulse and gliding. Go for a 300 mile cruise on the freeway at 70mph. Fill up at a gas station, drive 150 miles, turn around and come back, then fill at same station, same pump. Guarantee you will be at 40 or better. My civic had knockoff tires, old plugs and distributor, and old oil and I still got 38-42 depending on driving habits.

I might just have to make this trip to really find out lol I've made trips 2 hours out of town but had to drive in the city as well. Therefore, I couldn't get an accurate reading. But, I feel like I should still be getting over 30mpg easy with my hx.

You need to replace the thermostat, preferrably with an OEM Honda unit. Make sure the system is properly bled when you refill the coolant. IF you dont when really cold weather arrives, you probably will not have any heat to warm the car. Gauge should read around half way within 1.5 miles.

A BAD THERMOSTAT WILL CAUSE OTHER PROBLEMS OVER TIME AND CONTRIBUTE TO CARBON FOULING, BOTH IN THE ENGINE ITSELF AND IN THE EGR PASSAGEWAYS.

On a 10 miles round trip in my Mirage (5 each way) I can get close to 60 mpg as long as speeds are lower. In your HX, if the commute is at lower speeds, over 40 should be fairly easy, even higher speeds would not be much lower.

The HX transmission should give you right around 2k rpm at 60mph. If not that is part of your mileage issue, especially on the highway.

Calcivic drives a HX, look at his mpg and his techniques and mods are specific to that vehicle. He has written the book on his HX.

regards
mech

As far as rod bearings and piston slap, I doubt you have either of those as a problem unless the oil has been severely neglected or the mileage is much higher that you think.

Some engines have a little piston slap when they are cold but it goes away when they warm up. Nothing to worry about.

A rod knock is a very "heavy sound" like banging a hammer against the engine.

regards
mech

Most important at your mileage is to be absolutely certain the timing belt has been replaced. Documentation from the previous owner with a receipt from a reputable shop is your best insurance. A broken timing belt means bent valves and possibly much worse, up to needing a new engine.

regards
mech

98, have you seen http://ecomodder.com/forum/showthrea...tml#post497746

Standard MPG gauges are problematic on cars with lean burn because they calculate fuel use based on air flow, but air increases, and fuel reduces, so they would erroneously . The MPGuino actually measures fuel usage, but it is a bit complicated. I have had this open for a while, but I am waiting for my life to actually come together a bit more:

MPGuino trip computer - MPGuino and
http://ecomodder.com/forum/showthrea...ures-8355.html

I was suggesting a private message ("PM"), but I got your email address and will send a message to you in a moment to test whether the email is correct.

james

Yeah, I'm new to this site. I clicked on your profile and tried to PM you but I wasn't sure how to do it. But, I just sent you a reply in my email as well and I'll edit my rmail out of the previous post.

Okay, thanks A LOT! I'll replace the thermostat with an OEM unit. My belts look great but one of them sounds loose. In the handbook it says that the drive/alternator belt has an automatic tensioner so would it be my power steering belt that is squeaking? Both belts look relatively new and have no signs of wear and tear.

Just, I forgot to add that my power steering does not make noises when I turn. So, would this be my drive/ alternator belt? Or, do I have a bad pulley/bearing?

Maybe, maybe not.

I don't know if it's true on all Civics, but on my '01 the factory gauge is all but useless. It has no numbers, just evenly spaced tick marks with one red one at the top. Based on what my Ultragauge reports, normal operating temperature (180°F) is only about 1/3rd of the way up the gauge, when the fan turns on (206°F) it's still less than halfway. When my headgasket blew and it was overheating (~230°F) it finally got to halfway. I have no idea how hot it would have to get to hit that red mark, but I bet the head would be warped.

So, good advice on the thermostat, just be aware that the gauge may give you poor information.

Also, more details about the car:
Is it an auto or manual?

Is it stock or does it have modifications? In particular:

• Large wheels
• Cold air intake
• Header
• Big wing/spoiler

All of these can negatively impact economy.

I just sent the google-drive file/link to you... you should be able to download it. Did you receive it?

Benz tech bulletins stated their cars could run as high as 256 degrees without issues as long as coolant was 50-50 mix and proper pressure cap (13 psi). Probably lost the head gasket then ran hot.

regards
mech

The old wire wound bimetallic gauges used in the first z cars were the same as those in a F15 fighter jet.

Good advice anyway, the real question is how long does it take to get to operating temp.

180 degrees at the top hose, you can tolerate for a few seconds placing your open hand on the surface of the top hose.

regards
mech

It's all stock and manual transmission.

Thanks James, I'll look at it after work.

On thing that really affects mpgs on Honda lean burn is EGR system condition. Are you getting any check engine lights? Make sure the check engine might comes on for a few seconds at start up to verify the bulb is functional. The main issue with the EGR system is clogged passages and sticky/faulty EGR valve.

No check engine light at all. I figured that I would clean it out since I've read that it helps out with mpg. I just sea foamed the car and I've notice little improvements, especially with the idle. If someone thinks I shouldn't clean the egr passage ways please let me know.

Are you sure it's stock? Post the RPM in fifth gear at a certain speed and we can check that the transmission didn't get swapped with a lower geared one at some point.

Only reason not to clean the EGR is if you don't think you'll be able to put it back together correctly. ;)

Your short trips certainly aren't helping, but you should be able to get at least in the 30s in all but the worst conditions.

I'll post a pic up of my rpm/mph. I'll double check to make sure its the stock transmission. It was previously owned by just one person which was an older gentleman. I'm looking to purchase either Scangauge 2 or Ultragauge. Any recommendations?!?! Pros vs cons

I have the UG. It was much cheaper. It had more data available on each screen. And I think it looks better in our cars (the rounded corners of the black plastic housing fit the OEM dashboard design better than the ScanGauge color and form).

EDIT: btw, if you have the stock wheel/tire sizes your HX will likely show 2300 RPM at 60mph in 5th gear. My old DX trans showed maby 2450rpm, and my 93 CX/VX trans about 2050rpm at 60mph.

Stock tire size is a good thing to check. If you have oversized tires, you'll have under-reported mileage because you'll be traveling farther than the odometer reads.

2300 rpm for 60mph 2700/2800rpm 70mph

Cool. I was spot-on. 2300. Fwiw, I compiled a set of transmission specs including OEM tire sizes here:
http://ecomodder.com/forum/showthrea...tml#post378478

James

Hey everybody! My ultragauge just came into today and I finally got around to using it after work. I'm pretty excited! After driving around for 15-30 min the gauge was telling me that I am getting 42.1 mpg. A quarter of it was in the small roads. I haven't calibrated it yet because I'm not sure how to go about it. So, does anyone have any suggestions?

See what the gauge reads for a whole tank then refill and see what it really takes, then adjust the gauge until they both read the same.

regards
mech

HX has lean burn, he will never get the calibration right sadly

The Ultragauge will never be accurate if you engage lean burn. http://ecomodder.com/forum/showthrea...how-24948.html

With lean burn I should be getting better gas mileage then? I know these cars are made for the lean burn but will consistently getting into this mode be bad for the catalytic converter?