alright, Im sick of my bad gas milage. Ive read on the boards, and it seems the culprit of the car is the ecu and air filter communication. the overwhelming idea is to reset the ecu. To do this, I guess all i need to do is unplug the battery for a period of more than 24 hours. Ive called the nissan place with no response. How unhealthy is this? Is there a better, more healthy way to restart the ecu?

 

http://vbxmaxima.8m.com/ecu.html

Reseting instructions are at the bottom.

Good Luck.

------------------

If anyone knows of any other way to reset the ECU please post it here, I'm having trouble with a reccuring code for a O2 sensor that I know is not bad because I've changed it twice. So I'm wondering if there is a way to "fully" reset the ECU?
9-1 Code pops up on the second start after reseting the ECU- ever heard of anything like this?

 

no, unplugging the car for 24hours is not "unhealthy for the car.

And yes, there is an easy way to reset your ecu.








wondering what the easy way is yet?








ok, i will tell you. on the page where all the threads are for the forth gens are look at the one that is the 6th one down from the top. there you will find easy instructions to diagnose your ecu. or you can just go to the link below.

http://forums.maxima.org/showthread....hreadid=104931

and also i took the liberty of doing the legwork for you to post the reset directions below.... but only cuz your a newbie.

RESETTING THE CHECK ENGINE LIGHT

To reset the engine light is a simple procedure.
1. Turn the selector screw clockwise to its stop.
2. Wait 2 seconds.
3. Return back by turning the screw counterclockwise to its stop.
4. IMMEDIATELY REPEAT steps 1 to 3.

The next time you start your engine, the check engine light should go away!


well there you go, use it learn it, and enjoy it!

good luck.

Chris

 

The problem is not your ECU. Resetting it will not fix the problem. Your Bank 1 O2 sensor's heater is not working. Could be a broken/pinched wire somewhere or a bad connection.

Take a volt meter and check for 12 volts at the 2 ouside pins. (pin1 and pin 3 see below....)

x x x
pin 1 2 3

The reason your check engine light always comes on the second time you start the car is becasue this fault must happen TWICE before the check engine light comes on.

Good Luck.

 

Thanks for the help MaxVQ

 

[QUOTE]Originally posted by Blkmax95c
[B]no, unplugging the car for 24hours is not "unhealthy for the car.



alright, well, the thing about the car is the milage. the check engine light is not on. supposedly i can restart the computer so that it relearns everything (including new info for the air filter)and i get normal gas milage. those directions were good for diagnosing, but what about reseting the whole thing. sorry for the annoyance, just not very familiar with computer-related problems

 

Also check the resistance between pin1 and pin3.
Should be between 2.3-4.3 Ohms.
Any more or less, replace the sensor.

 

Flaky O2 sensors can also cook your mileage.

I don't think resetting the ECU is going to do d!ck but it's worth a shot....

What are you getting in mpg for city/highway?

-RMB

 

can an o2 sensor be "flaky" and still not affect the car's performance?

 

[QUOTE]Originally posted by jlsund
[B]come on man, i already told you how to reset your ecu!! just actually READ my post. at the bottom of it it says:

RESETTING THE CHECK ENGINE LIGHT

To reset the engine light is a simple procedure.
1. Turn the selector screw clockwise to its stop.
2. Wait 2 seconds.
3. Return back by turning the screw counterclockwise to its stop.
4. IMMEDIATELY REPEAT steps 1 to 3.

The next time you start your engine, the check engine light should go away!

there you go... AGAIN. g/l.

 

Not that one. The front O2 sensors have a huge impact to fuel economy and performance. The rear O2 is only there to make sure that cat is working.

 

i think i want to buy thses 02 sensors... i am getting HORRIABLE mpg.. less then 200 on a full tank. do you know the model numbers for the sensors, and also what their location is? price too if you know off hand. thanks.

 

Why would you want to "throw parts" at a problem?
You need to find out what the cause is. Many things have a negative effect on fuel economy. (Temperature, dragging brake pads, clogged air filter, plugged exhaust, flooring it often and shifting at redline to name a few.)

As for your O2 sensors, if your ECU is not complaining, and your car is less than 3-5 years old, with low milage, your O2 sensors are probally OK.

An O2 sensor responds slower as they get older. If your car has a lot of miles (~130,000+ Miles) you may want to think about changing the O2 sensors. I changed mine (all three) at 122,000 miles)

They are about $100 each. (in Canada, not sure in the US) The front O2 is very easy to do. The rear O2 requires small hands to properly route the new sensor wire harness.

Good Luck tracking down your problem

 

oh. damn. i thought replacing them would be an easy fix to better gas mileage. my car is an 98 w/63,000 miles, so i guess i shouldn't replace them. o well, i guess i will keep on working on the tune up i am doing. thanks for the help.

Chris