Please help guys. I've a 2001 lude and it's burning about 19 mpg doing 30/70 city/hwy in San Diego. No mods, new NGK iridium plugs and wires, clean k&n air filter, 91 octane, no extra weight, 38,000 miles, meaty tires with proper pressure, and I just did a fuel system tune up at jiffy. 13 gallons for 250 miles sucks. What might be the problem? Fuel filter? O2 sensor? Any info would help, Thanks.

 

Wow, 250 isn't all that great. I get almost 350 with a lot of hard city driving.

How do you drive?

 

why not change both fuel filter and o2 worst it can do is help ya. relatively cheap too. go from there

 

sounds like the problem I had before my o2 needed reaplacing. I was driving very slowing and very conservatively and I would be LUCKY to even hit low 19 mpg. I would usually get 17-18 mpg. I got the o2 sensor CEL, replaced it with a new sensor and I have been getting 24+ mpg city.

Have you tried using different brands of gas? When i used arco i got crummy mileage. 95 miles to half a tank. Went to shell 145 miles to half a tank.
How about changing your oil?

 

forgot to mention, it's an automatic. I used to drag race from red light to red light back when it was like $2 a gallon, but now I drive like a grandma, shifts before 4k rpm(auto), speed limit + 5 mph, haven't seen vtec for like a year, it's a shame.

I consider doing the fuel filter and the o2 sensor, but money is a concern, it'll cost me about $300 to do both. AND I don't know if it'll fix the problem.

Should I take it to the dealer or maybe ammco to have them check it out?

Thanks for your help guys.

 

If you dont mind can you tell me how to check for the o2 CEL? or I can search. =D

Different brand of gas doesn't help either.

Every 3000 miles with mobil1 full syn with k&n fuel filter.

Thanks again.

 

Well inorder to check for a o2 sensor CEL code you need to have the check engine light on; then you can check. When i had my code, i blew it off the first time; i just cleared the code becuase i didnt want to deal with it. 3-4 months later, the same code came back on and i decided the to deal with it. What i am trying to say is that you can have a bad o2 sensor and not throw a code for sometime.

BUT you can visually check your o2 sensor by taking it out. I wish i had a digi cam becuase i still have my old/bad o2 sensor and I could show you what it looks like.

http://www.preludeonline.com/s...76313 << how to check/replace an o2 sensor.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by lvblkjack &raquo;</TD></TR><TR><TD CLASS="quote">I drive like a grandma, shifts before 4k rpm(auto)


</TD></TR></TABLE>

what is before? 3800 rpm? 3600? maybe shift at a lower rpm and feather the gas pedal. I shift a 2800-3100 rpm and it makes a huge difference in mpg.

and dont take it to the dealership, they will rape you of your money.

 

Thanks asdfsad. I guess I'll change the o2 sensor. And that leads to 2 more question, 1) should I change the front one, rear one, or both? 2) it appears denso is the OEM one, which one did you use/ which one is the best one?

It averages about 3400 rpms, and I'm quite easy on the pedal.

Thanks again asdfsad. you're a great help.

 

wow. No vtec for a year?

I know I wouldn't be able to do it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by lvblkjack &raquo;</TD></TR><TR><TD CLASS="quote">
Different brand of gas doesn't help either. </TD></TR></TABLE>

I truly disagree with that statement and probably others as well. Out here in the midwest we have 3 main gas companies (Popular) BP, Mobil, Shell. i started out using mobil on my integra then switched to BP with no MPG change.
Then i heard about top tier gas companies and Shell is the only one in this area. I tried the shell Premium (93) in my 95 Teg GSR, i used to get 220-240 city and 260-280 highway miles to a tank and when i switched to shell Premium (93) i was getting 280-300 city and 320-350 highway miles /tank. i was shocked to find out that different gas does really matter, i told my cousin to try shell out as well and he got the same results and he is driving an 01 Teg GSR.

Since i got my new Lude all I'v been putting in is Shell Premium (93)!!!

Here's a link to top tier gas companies
http://www.toptiergas.com/

 

oh what I meant was different brand of gas doesn't help in my case, i wish it does though. Too bad we only get 91 here is socal, and it's $3.10/g.

 

really thats it.....chicago is $3.29 in the burbs where im at $3.15

 

do a tune up plugs/wires, fuel filter, distributer cap and rotor, oil change, coolant flush, tranny flush, O2 sensor and oh yea when was the last time you did a valve adjustment/tune and change to a top tier gas

 

ya that's kinda low. i get 280-300 miles 1/4 tank remaining. im s/c'd so i tend to stomp my gas frequently. im planning to change my fuel filter, spark plug/wires soon.

 

Done:
plugs/wires
oil change
fuel system tune up at jiffy lube (they change the pcv valve also)

Pending:
fuel filter (jiffy lube checked it and said it's ok)
cap/rotor
coolant flush
tranny flush
o2 sensor
valves adjustment

Quite a pending list, but are they all necessary? it only has 38,000 miles.

 

ya fairly new, mines 2001 with 40k miles

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by lvblkjack &raquo;</TD></TR><TR><TD CLASS="quote">forgot to mention, it's an automatic. I used to drag race from red light to red light back when it was like $2 a gallon, but now I drive like a grandma, shifts before 4k rpm(auto), speed limit + 5 mph, haven't seen vtec for like a year, it's a shame.

I consider doing the fuel filter and the o2 sensor, but money is a concern, it'll cost me about $300 to do both. AND I don't know if it'll fix the problem.

Should I take it to the dealer or maybe ammco to have them check it out?

Thanks for your help guys.</TD></TR></TABLE>

Depending on which state you live you may be able to take it to a DMV service center and have the emissions checked the old school way for next to no money. They can use a sniffer and test your a/f mixture among other things. It's like being on a dyno that doesnt tell you your horsepower. If your sensor is on its way out but not yet throwing a code then the standard OBD2 test isnt going to tell you half of what a sniffer in the muffler will.

 

Dude, I wouldn't take Jiffy Lube's word for your fuel filter... I work at one and I think it's very possible that they told you it was ok because they didn't want to deal with it. Prelude fuel filters are a major PITA... although, if you've never changed it in 38,000 miles I'd say it's time for a new one...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by lvblkjack &raquo;</TD></TR><TR><TD CLASS="quote">oh what I meant was different brand of gas doesn't help in my case, i wish it does though. Too bad we only get 91 here is socal, and it's $3.10/g.</TD></TR></TABLE>

It's gone down over the past week here but it was $3.59/gallon for 93 by my house just over a week ago.

I am having a similar problem and assume it's because of the dirty intake around the egr. I replaced the o2 sensor last november (cel was on) and the cel went away. Then it came back with a code for egr-insufficient flow. I've taken it off and cleaned around but didn't use a wire brush to really get in there. That's what I have in store for next weekend (along with other things) and if my mpg doesn't improve, I will be back here for advice on other things to check.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SnoMan &raquo;</TD></TR><TR><TD CLASS="quote">Dude, I wouldn't take Jiffy Lube's word for your fuel filter... I work at one and I think it's very possible that they told you it was ok because they didn't want to deal with it. Prelude fuel filters are a major PITA... although, if you've never changed it in 38,000 miles I'd say it's time for a new one...</TD></TR></TABLE>

I've never changed a fuel filter. Is it something I should attempt on my own being as how there is a lift session coming up through a club I am affiliated with or should I take it to my local indy shop?

 

If you've never changed a fuel filter, I don't think you wanna learn on a Prelude... but if you have some good technical know-how and alot of patience I'm sure you could tackle it. They cost like 10 or 20 bucks from Honda...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by lvblkjack &raquo;</TD></TR><TR><TD CLASS="quote">Thanks asdfsad. I guess I'll change the o2 sensor. And that leads to 2 more question, 1) should I change the front one, rear one, or both? 2) it appears denso is the OEM one, which one did you use/ which one is the best one?

It averages about 3400 rpms, and I'm quite easy on the pedal.

Thanks again asdfsad. you're a great help.</TD></TR></TABLE>


Well its hard to say which you should replace without throwing a cel or looking at the o2 sensor. Personally, I would re-evaluate your driving style. 3400rpm is kinda high to get good mileage. Try litterally feathering the pedal for about a tank or so and see if your mpg increases. Try not to go over 3300rpms.

shhh151 is proof that different brands of gas doesnt indeed make a difference in mpg and I too experienced the same thing. Which gas are you using? are you using arco gas? that crap is cheap and you dont feel bad for buring that stuff up quickly. Try serveral tanks of shell and see if makes a difference. ($2.99 for a gallon of 91 from shell in my area. the shell i go to offeres cash discounts)

Oh yea, a little thing you can go is change your gas cap. I remeber seeing somewhere that it can increase your mpg if your cap is damaged. Can anyone verify this.

If you are going to change your o2 sensor, make sure you know how to wire up the denso sensors. If you dont your going to have to go to honda and buy one from them. I asked a few months ago and it was 250 + tax. RAPE!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by asdfsad &raquo;</TD></TR><TR><TD CLASS="quote">

Oh yea, a little thing you can go is change your gas cap. I remeber seeing somewhere that it can increase your mpg if your cap is damaged. Can anyone verify this.
</TD></TR></TABLE>

Yeah, it'll help if it is not sealing. Gas will vaporize inside the tank from thepump pressurizing, heat expansion, and general sloshing around. If your gas cap leaks you'll be losing that vaporized gasoline pretty consistently.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by godslayer &raquo;</TD></TR><TR><TD CLASS="quote">

Yeah, it'll help if it is not sealing. Gas will vaporize inside the tank from thepump pressurizing, heat expansion, and general sloshing around. If your gas cap leaks you'll be losing that vaporized gasoline pretty consistently.</TD></TR></TABLE>

and there you go. thanks for the explanation.

 

valve adjustment should help. Also, check/reset ignition timing.