0xenocron

I have a 99 Accord that just all of a sudden lost about 5-8 mpg out of the blue when the cold weather hit in the NE. I am pretty sure it its the O2 sensor as i had a brief issue with this last winter and a few days later this went away. However, it hasnt gone away this year after a number of weeks.

I am showing no codes but I want to hook up an AutoTap or some kind of ODB2 scan tool that can show me live readings so that I can make sure its that before I buy the $115 primary O2 sensor from honda.

I'd appreciate any help anyone could give me...thanks!

Chris

0xenocron

Any hookups for a fellow honda-techer?

Mike813

bring it to any close by autozone. they have the tool, and will scan your car for you free of charge...

5-8mpg could be because of the cold weather, like heat useage, your car takes longer to warm up on freezing weathers, just in general you stress your car a little more in the cold, that could be the reason for the loss also...

honda o2's usually last you a long period of time, my car is a 94 and i just changed it after like 5 years... and just last year i started noticing the loss..
gluck.

0xenocron

They will scan the car for codes but wont ride around with me and tell me what all my sensors are saying...thanks tho.

The O2 crapped out for 3 days on me last year when it was -30 where i was...ran WAY rich on 6 hour drive (all highway and i got like 22 MPG when i normally get 33) and then threw a code the next day. Actaully took it to autozone and they told me it was the primary O2 code. A day later it went off and all my gas mileage was good until about 4 weeks ago. Dropped immediately, and hasnt come back...i just want to make sure because all the signs point to it but you cant ever tell without the right diagnostic tools.

Mike813

have you tried taking out your o2 and examine it?? someone posted a pictorial of damaged o2's and the causes...

0xenocron

I've never seen that and believe me I have searched...if you could point me in the direction I appreciate that.

BTW, my car does have 115k, so Im not upset or anything about the honda O2 quality

Mike813

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by xenocron &raquo;</TD></TR><TR><TD CLASS="quote">I've never seen that and believe me I have searched...if you could point me in the direction I appreciate that.

BTW, my car does have 115k, so Im not upset or anything about the honda O2 quality </TD></TR></TABLE>



http://www.automedicsupply.com/diagnose.jpg

0xenocron

Free lunch and I'll drive to you???

Come on, **** has dropped to 19 MPGs...ugh.

jc836

The AutoTap scantool will read in realtime. The unit I have available has the needed cables, etc. All you need is the laptop.

0xenocron

Too bad you are like 7 hours away!

Well the check engine light went on this morning (Im kinda happy) so i will be taking to AutoZone after work and probably buying a new o2 sensor tomorrow!

Dave Slater

Sounds like it may be an intermittant connection. Why not try exercising the connectors associated with all your o2 sensors before you buy one. Unplug them, inspect them, replug them and see if your problem disappears.
In my experience 95% of all problems are electrical connections.
later, slater

0xenocron

I tried playing with the connectors, but even if it was a bad connection, the CEL would come on as soon as there was a bad connection and go back off as soon as the circuit was connected again.

I took it to AUTOZONE, useless *****.

CODE P1457, auxilary emissions control device...whatever that is...anyone know of a code list site to check this out?

I gotta go search now

jlv55

http://board.hondasociety.com/...79620

evaporative emission (EVAP) control system leakage (EVAP canister system)

JimBlake

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by xenocron &raquo;</TD></TR><TR><TD CLASS="quote">I took it to AUTOZONE, useless *****.

CODE P1457, auxilary emissions control device...whatever that is...anyone know of a code list site to check this out?

I gotta go search now </TD></TR></TABLE>Maybe they're not totally useless, they told you the number, right??

Now what you REALLY need is the Helm shop manual for your car. I got this from mine, which goes for '98&'99 Accord. I posted this for someone else a little while ago, so copy/paste.... here goes.

-----------
P1457 won't make the car run bad at all. It just means the EVAP canister & the related system of hoses & valves isn't airtight.

Check this stuff in this order. As soon as you find something that doesn't behave like it should, fix or replace it. Then hope it was the only thing wrong with the system...

Some background for the electrical troubleshooting:
All the solenoid valves have constant +12v supply from the main relay. When the ECM wants to energize a valve, it closes the ground side of it's circuit. If the +12v supply is broken, then the ECM can't energize the valve. If the wire to the ECM is shorted to ground, then the valve is energized even when the ECM doesn't want it to be.

EVAP Purge Control valve - between intake manifold & valve cover.
Valve should be normally closed, so it will hold vacuum when it's not energized. Ground is supplied by pin A6 of the ECM to open the valve. So jumper pin A6 to ground, turn on the ignition, and check again - this time it should NOT hold vacuum.

EVAP 2-way valve - underneath the car roughly under the left-rear seat.
It's a little can with 3 hose barbs & a solenoid valve attached to it. Leave the connection on top, disconnect both on the side, attach MityVac to lower one. Normally open, when the solenoid valve is energized, it should hold vacuum.

EVAP Vent Shut valve - attached to the charcoal canister underneath the car.
Normaly open - when ECM closes pin A4 to ground, it should hold vacuum.

EVAP Charcoal Canister - the big can under the car, about under the left-rear seat.
Leak test: Connect all the hoses together, plug the Vent Shut valve, connect the MityVac. Pump vacuum while watching the fuel tank pressure (FTP) sensor. You can read FTP sensor voltage with a scan tool, or use a voltmeter between pins A29 & C18 at the ECM. Pump down to 1.5v & it should hold that vacuum for at least 20 seconds.

EVAP 2-way valve vacuum & pressure test.
If you get this far you'll want the manual for a good picture of how to connect the hoses. Keep pumping the vacuum pump & it should stabilize between 6 & 16 mm Hg of vacuum. Then pump pressure, it should stabilize at 8 mm Hg or more of pressure.

Then there's a test of the ORVR Vent Shut valve, which is located on top of the gas tank. You check vacuum & pressure at a couple hoses alongside the fuel filler pipe. If the valve is bad you drop the gas tank to replace it...

0xenocron

I said useless because I called ahead to make sure they had the scan tool...they said yes and when I got there, it wouldnt link up. They have a defective unit that they are just too lazy to replace. So i had to drive to another Autozone to get it read. Just a major inconvience...

The EVAP is something I have no experience with...so Im a bit uneasy to jump in to fix this on my daily driver. As far as i know, it just sucks fumes from the gas tank and puts them into the intake manifold so they dont escape to the atmosphere, correct or incorrect?

Code hasn't come back in two days so that is a good sign...still doesnt explain my bad gas mileage...hmm.

Thanks for the link and the help tho! Much appreciated

COOKIEPUSS

I too live in NNJ and have been getting horrible gas mileage, as well as my girlfriends bone stock Cavalier, and a bunch of other people I know. I do not know if it's the frigid temps we have been having, or bad gas, or that winter gas (not sure if they still use it). Just figure I'd let you know.

Anyways good luck with your car.

0xenocron

Winter gas? Whats that...sounds like a Jersey thing

Mike813

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by xenocron &raquo;</TD></TR><TR><TD CLASS="quote">Winter gas? Whats that...sounds like a Jersey thing </TD></TR></TABLE>

i think hes talking about that mix they have in the gas now, ethanol? i think... it says it on the pump "gas now contains 10%"

MTL_civic

As a fellow engineer I apreciate the detail on the writeup Jim!!!

This is exactly what I was looking for but are there any pics of these items?
Also could someone scan the FSM for troubleshooting code P1457?

I have a 2002 Honda Civic LX-G which the dang dealer can't seem to fix the CEL and I am tired of looking at the stupid light and wasting my time over there by having to drop off my car for the day, then picking it up and they tell me they can't fix the problem, etc.....I just want to be done with it. I used to be a mechanic as well so I get a little fed up with the incompetence I have to deal with when I go down there and I don't mind the challenge as well.

I am definately not a newbie.....you can look me up on http://www.yotatech.com as mtl_4runner over there.