2003 Honda Accord poor gas mileage


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Old 01-27-13, 08:52 AM
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2003 Honda Accord poor gas mileage

I have a 2003 Honda Accord, L-4, 2.4 lit engine, manual with 95k miles. I am the original owner and have been performing the required maintenance at the intervals suggested in the owner's manual. Normally on a full tank of gas I get 380 -390 miles (filling up when the yellow fuel light appears on the dash). For the last few fill-ups there has been a steady decline in miles between fill-ups. Yesterday's fill-up was required after 344 miles. I also noticed that upon start-up, the Maint Required light flashes and then goes away. I had changed the air filter and the dust/pollen filter a few months ago before this issue materialized. The check engine light is off and no codes are present. Spark plug changes are required at 110k miles, which is another 15k miles away. What should I start checking?
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Old 01-27-13, 09:31 AM
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Well....first, understand that winter blend fuel will normally drop mile somewhat. Also, driving in winter weather (snow, slush, etc) can reduce mileage. How are your tires...worn tires give less mileage. It's winter...are you idling more? Starting the car a few minutes early before driving? Hows the snow been? Do you have a big layer on the car every few days and drive to bow it off? Any extra weight in the car?

You have about a 10% change. I'd go ahead and do the 110k tuneup and see what happens.
 
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Old 01-27-13, 10:13 AM
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I should have mentioned in my original post that this is a 4 door sedan, model LX.

Vic, thanks for your response. After 9 years of ownership I have not noticed any gas mileage changes due to seasons changing. Snowfall has been minimal this season, with no snow on the roads. I don't believe in idling. The tires are fine and there's no extra weight in the car. I'll look into changing the spark plugs.

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Old 01-27-13, 06:29 PM
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the Maint Required light, is just for oil changes has to be manually reset. you should also be getting close to needing a timing belt. it could be slightly stretched making your valve timing ever so slightly off. but start will plugs. also find out if your gas stations have went to this new formula of gas having 15% ethanol, it seems to have dropped gas millage around my area and on my cars. they have been doing this gas around big citys to reduce smog. i make a point to run errands out of town when i need gas just because of this
 
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Old 01-27-13, 08:05 PM
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Hi iceman681, I'll ask a gas station about ethanol spiked gas. I had asked a Honda dealer about the timing belt several years ago. He told me that my particular model of Accord has a timing chain, not timing belt.
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Old 01-28-13, 04:42 AM
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Did a double check on the Gates site for timing belt; correct, no timing belt. May be time to pay for some time on a scanner where a good mechanic can look at operating parameters in real time and see if anything is out of range or marginal.

BTW, second time in the last week reference has been made to lower winter gas mileage. Mine is exactly opposite. I keep a running log on my in-truck laptop and I can point almost to the exact date when the winter fuel shows up. My mileage jumps about 3-4%. Must be a regional thing.
 
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Old 01-28-13, 11:36 AM
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Hi tow_guy,

I called several gas stations in the area. Most of them didn't answer the phone. The ones who did answer, didn't know. They said they accept whatever gas Exxon or Sunoco corporate decide is what gets delivered to them. In any case, I feel that the season is not a factor in my case. I've never had the mileage drop so significantly during the past winter seasons.

You mentioned a scanner. Can you elaborate? What type of scanning should I tell a mechanic to do?

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Old 01-28-13, 12:28 PM
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Yeah, it might be hard to get an answer since most gas stations are also mini-mart/mini-malls nowadays. Not like service stations from years ago. If it is the 15% blend, there should be a sticker right on the pump IIRC.

As to the mechanic...first...do you have a regular trusted mechanic? Just walking in off the street and saying your mileage has dropped and you'd like them to scan it and check it out will bring up dollar signs and a boat payment in the mind of some guys. They'll try to convince you you need everything from new O2 sensors to an engine flush. You may indeed need a new sensor or 2, but thats not the point.

A good shop will have a machine they can connect to the car and actually watch and record engine conditions while it's being driven. It will tell them everything about sensor operation, fuel injectors, air/fuel mixture, etc. Basically actual dynamic engine operation as it occurs. Not a simple scan for engine error codes like you get at Autozone or similar.
 
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Old 01-28-13, 12:37 PM
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Btw...never use E15 in small engines...and try to avoid E10 for them as much as possible. The E10 issue has pretty much been resolved I think, but many say the E15 is too much for smaller engines.
 
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Old 01-28-13, 01:15 PM
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Vic hit it regarding scanner. Much more info and capability than the standard code reader which, as Vic mentioned, merely tells you if the system decided to set a code. Some of them can also do realtime reading of data (my handheld will do it for a limited number of items), but generally all you get from the parts places is a code read. The high end scanners are generally Snap-On or equivelent and can tell someone who knows how to read the data a lot. Hopefully, as Vic asked, you have a regular mechanic you can trust to give it a scanner check without up-selling a lot of unnecessary stuff.
 
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Old 01-28-13, 08:09 PM
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Vic and tow_guy,
I don't have a trusted mechanic. I quite understand what you mean by a mechanic trying to upsell me stuff. My first move will be to examine the spark plugs, clean and regap them, and see it that makes a difference, before I do anything else. I just have to wait for a somewhat warmer day. With 20 degrees outside, even my garage is very cold.
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Old 01-29-13, 05:03 AM
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I was going to suggest plug wires, but I checked and yours is "wireless" with coil-on-plug.

As for a mechanic, I would ask around with family and friends; chances are someone will have a mechanic they swear by (as opposed to swear at). Independent towing companies know the good ones, too; when my daughter graduated college and got a job cross state, I emailed one of the local towing services and got names of some trusted garages.
 
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Old 01-29-13, 07:34 AM
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Tow Guy beat me to it.
Areas to check around the age and millage on a vehicle are (not all may apply to you);
- Plugs and wires.
- Tranny fluid (gear oil in manual tranny is not required to replace, but I always do)
- PCV valve
- Inspect and replace questionable vacume lines
- Water pump and timing belt
- Clean and grease all braking components (I do this yearly)
- Injector Clean (use air intake arosol can and fuel additive kit)

I have a few other items I do, but those are the most common fuel consumption related items and easily done in your driveway.
If it's been really cold there, this will affect your milage as the grease and fluids in your car will be thick and not want to move very easily. Last week, I lost about 5MPG average with the temp outside in the -35'C to -45'C. Bearing grease doesn't move well at that temp.
 
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Old 02-02-13, 06:16 PM
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Hi guys. I finally got a a chance to remove the spark plugs and take a look at them. They show normal wear. The gaps are slightly less than specs, but not by much. One is not supposed to regap these types of spark plugs. The one thing I noticed was that 2 of the ignition coils have bolts missing. I would rather that the bolts be in place, but looking at how they are put together, they can't really move even without a bolt. I put them on my shopping list but it is not an emergency. My next move is to check out the PVC operation and also buy a fuel injection cleaner. Incidentally, I am noticing prolonged cranking to start the engine. However, I wouldn't connect this with low mileage necessarily. The usual suspect is the battery, which is 4 years old.

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Old 02-03-13, 08:56 AM
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JUst because you did not, I did mpg calculation for you. You originally did around 27-28 mpg, which was real good mpg for Accords, as they are historically lousy in that respect.
So, it dropped a little. Vic is right - 1st thing is winter gas. Gas prices go higher, bet you, they do NOT improve gas quality either. But the drop is not that significant, actually.
But anyhow. What kind of plugs exactly do you have, that you can not re-gap them? As original NGKs for Hondas are gappable just fine.
Folks know me - unless it's Seafoam, I shall not recommend any cleaner.
HOW IS AIR FILTER? Your engine may be choking with dirty filter, low oxygen resulting will cause engine run reach.
Definitely reinstall ignition packs bolts. Sounds like someone messed with them already, as they do not come out by themselves.
Replace spark plugs. Buy factory spec NGKs, they are not that expensive. Ask clerk at parts store to check and re-gap them for you. After done, locate and remove ECM fuse for several minutes. What it will do, is it will remove all pre-set programming in it, based on old plugs and whatever else you replace (AIR FILTER) and ECM will learn how to run power train again.

Oh, and last, but DEFINITELY not least. CHECK YOUR TIRE PRESSURE. Tires have tendency to run low on pressure winter time, and THAT will surely cost you mileage.
 
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Old 02-03-13, 02:26 PM
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Hi Igor,

Thank you for your response. I did the mpg calculation, I just did not post it. I keep a running tab. I was previously getting around 29 mpg, now I'm getting 26, which is a 10% drop. As I already mentioned on this thread, I had not observed this drop during previous winter seasons.

These are iridium tipped spark plugs. The Honda published shop manual says do not adjust the gaps of these plugs. I agree that the ignition coil bolts did not come out by themselves. I certainly didn't remove them previously, nor did I have any kind of service performed that would compel a mechanic to remove them. This is still a mystery. Another possible explanation is that the factory did not install them.

From what I've read on the web, Seafoam can be used in the gas tank, mixed with crankcase oil and also sucked up through the PCV vacuum hose. I picked up a can from Autozone today. I will first try it in the gas tank on the next fill-up.

I change my AIR FILTER at the suggested intervals. I changed it last less than a year ago. I'll take a look on its current condition.

I happened to check and adjust my TIRE PRESSURE very recently. I quite agree that the pressure can drop during winter. The pressure and temperature have a direct relationship. I think it is Boyle's law or Charle's law or a combination.

I also performed the PCV test today. The shop manual says at idle, pinch the hose between the PCV value and intake manifold, you should hear a clicking sound. If there's no clicking sound, check the PCV washer for cracks or damage. If the washer is ok, replace the PCV valve and recheck. When I performed this test, I did not hear a clicking sound. I will investigate this further by removing the valve.

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Old 02-03-13, 03:44 PM
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1. PCV is easy. Disconnect, pull it out, and spray brake cleaner inside until it starts clicking. As in - shake it. Though they are cheap to replace. Before reinstalling, put a bead of red sealant on it, to seal it well.

2. Have my word, Ir tipped plugs do gap. Done countless times.

3. yes, of course. Good old man Boyle. It's colder outside, air reduces in volume. That easy. Plus, if you have alloy rims, they are known to be slow leakers.

As of that little mpg drop. I think, you over reacting, though bolts have to be replaced. Ain't no mystery or blaming on Honda, human hand did it. I tanked at Arco, my Camry Hybrid, refill before last one, and it cost me 60 miles drop per tank. That's more than what you experience, and I do not freak out over it. Went back to Sam's, as usual - and she's back to her normal winter mpg right away.

Btw, check intake hose for loose clamps. Any air leak into throttle will cause engine running rich. And poor start ups, btw.

Speaking of poor start ups. Battery terminals clean and lubricated, right? I seriously doubt, 4 yo battery will be failing on you.

Oh, the beauty of Seafoam. Magic fluid. Works very well actually. What you need is narrow funnel, as they keep making Seafoam in containers not suitable for pouring directly into fuel tank. Also, you will need to go though: ready to refill>gas station>insert funnel>using pinky or car key, pop cap open, without spilling Seafoam all over>pour Seafoam in>flush with gasoline. If I were you, I'd have it added to crankcase 500 miles before oil change, as it also softens and removes tar on piston rings, restoring compression.

Air filter - if you can see sun through it, you good. I am big fan of K&N filters.
 
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Old 02-03-13, 04:25 PM
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This last post jogged a memory. When I worked at a dealership we had a customer that reported low mileage on a new car. I checked the normal things then did a mileage test and it was all OK. This didnt stop the complaints,and I rechecked all again,same results. One day he came in smiling and said he cured the problem,,, he switched places where he bought fuel.
 
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Old 02-03-13, 05:57 PM
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Yep. Stay away from old stations, do not refuel in the morning. Shop around to find gas that fits your car best, and stick to it. I went to Arco as light was on, and Sam's computers crashed. Normally, I am smarter than that. Arco, AM/PM, Circle K do not count to me.
 
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Old 02-14-13, 06:26 PM
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Here's an update. I did put a can of Seafoam into the gas tank. Have to wait till the next fill-up to determine whether it made a difference. I'll get another can and try sucking it up through the pcv hose and also put some in the crankcase.

The pcv value was screwed on so tight that it did not budge when I used a combination wrench and WD40. The wrench handle is short so the torque I can apply is limited. I tried a socket wrench with a large bar. The socket wasn't deep enough, so I splurged on a deep socket set. With the deep socket I was able to unscrew the pcv valve. When I shake it, it clicks but when I try to pinch the hose at idle with the valve installed, I don't hear a clicking sound. The vacuum produced when I remove the pcv hose is pretty good. Igor, you indicated that I should apply a sealant. What brand name do you suggest? Is this an anti seize compound?

I still have to check out the intake hoses. Is Seafoam also good enough to use with the throttle body? I also have to check out the battery connections. I'll clean the terminals and see what happens. It is the 100 months warranty battery. They don't make it with the eye any more that turns green or red to indicate the condition.

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Old 02-15-13, 10:19 AM
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Anupm12,

I didn't go back to read all the other postings. I really don't have to. I only read what you posted originally. If it's possible I'd like to see the results of the the test's below.

Cylinder Compression
Cylinder Leak Down
Engine Vacuum Pressure
Exhaust System Back-Pressure

Also has the fuel filter been replaced recently, and are you using NGK spark plugs and ignition leads and have the plugs and ignition leads been replaced recently?


Thank You
Amy
 
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Old 02-17-13, 02:37 PM
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Hi Amy,

I don't have the equipment to check Cylinder Compression etc. The fuel filter, spark plugs etc have never been replaced, they are all original factory equipment.

I did make progress on some other items that folks have suggested. I cleaned the throttle body and PCV valve. I do hear a rattle for mthe valve when it is off the car, but when I try to pinch the PCV hose, I don't hear a clicking sound. According to the shop manual I should change the valve if I don't hear the clicking sound. I also sucked Seafoam up the PCV hose. The engine started to stall in the process so I moderated the flow. I turned off the engine and let it sit for 15 mins. When I restarted the engine, I saw the check engine come on and stay on. I drove around the neighborhood and came back home. I'll have to wait a few days to determine what affect all this will have.

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Old 02-17-13, 09:48 PM
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why would you not perform regular maintenance before asking about fuel mileage, that would be like not changing your oil and wondering why the engine failed.
 
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Old 02-18-13, 03:54 PM
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Iceman,

I am performing all the regular maintenance that are listed in the owner's manual. I am now performing services that are beyond what's listed in the owner's manual.

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