Cluelesswoman

I have an 06 Civic EX. Auto trans, 1.8L. 236XXX miles on it. Car drives fine, but the problem happens when I stop at a stop sign or red light. Idle seems to be normal, but after being stopped for more than 5 seconds or so, I can almost gaurantee that the car is going to hesitate and stall when I attempt to accelerate from a stop. It will still do it if I idle in nuetral before I put it in drive to accelerate from the stop. I have replaced the mass airflow sensor (less than a week old), the air filter, and the fuel pump/fuel filter. The CEL is currently on and the codes are reading

MAS low voltage
Bank 1 running lean

The car sat for about 6 months because it eventually bogged down and wouldn't drive. I'm a woman with no help so it, unfortunately, took me trial and error to figure out the problem and fix it, hence the fuel pump and filter were replaced when it apparently didn't need to be. (Not that I am complaining) I just started driving the car again and ran a bottle of Chemtool through the fuel system to help clean it up since it sat for so long. The person that diagnosed the CEL code said that the bank 1 lean code could be because of the Chemtool, but I have a feeling it is because of the MAS. I'm getting ready to spray the throttle system with Seafoam to help loosen any grudge and clean the throttle in hopes that this may clear up the hesitation, but after I do that, I am clueless as to what to do if that doesn't fix the issue. I do not have a multimeter to check the voltage of the MAS wiring system, and the one person that I know has one happens to be a man that assumes I'm a dumb woman because he's insistent that the MAS is bad and there's no way it says low voltage because he's never seen that code on any of his other vehicles. (For the record, this person is my dad, who has never owned or done any mechanical work on an import as he's only ever owned Fords or Chevys.) I've managed to get the car running again, but my safety is at risk every time the car stalls at a red light and that concerns me. If anyone has any ideas, please let me know. I can't afford to take the car to the shop right now and I have no idea where to look next to try to resolve this issue.

mac25

You'll need to get us the exact code.

(Bank 1 is usually accompanied by sensor 1 or sensor 2, plus some other useful info)

Cluelesswoman

The CEL codes read as follows:

P0171 Fuel system too lean (Bank 1)
P0113 intake Air Temperature Sensor Circuit High input
P0102 MAF SENSOR VOLTAGE LOW
P0171 Fuel System Too Lean (Bank 1)


Those are the only 4 codes I received. The MAS is less than a week ild and bought brand new from Autozone. My car would not even start before it was replaced, and it starts just fine and drives just fine now. The only issue I'm having is the stalling and the hesitation when accelerating from a stop. I would assume this would mean the sensor itself is good but the issue lies somewhere associated with the sensor, but I'm not too sure where to look.

mac25

With the new sensor did you reset the ECU and do an Idle relearn?

It probably will not fix the issue but it's easy and worth trying.

-Disconnect the battery for 20min.
-reconnect the battery
-start the car (e-brake on)
-do not touch anything until the rpm gauge is stable and holding around 750-1000 rpm (usually takes a few minutes).

ezone

Are all of these brand new codes?
Were all previous codes erased when the sensor was replaced?

Meaning, are any of these codes leftover from the previous fail events, 2 of them can be caused by simply disconnecting the sensor. (or wiring faults)


Idle relearn:
Engine already at operating temperature.
Make sure all electrical consumers are turned off during the process.
No fan, no heater or AC, no lights, no defroster, no radio, no heated mirrors, etc.
Give it at about 10 minutes to learn, idling in park/neutral

Cluelesswoman

As far as I am aware the codes came after the initial replacement of the MAS. I didn't get a CEL when the car became inoperable about 6 months ago. I went to autozone once the part was replaced and had them reset the CEL. When I started the car up, the check engine light came back on about 5 seconda later, so maybe it didn't reset at all??? I will have it done again, just to be safe. I have not tried a new idle relearn so I will try that next. With that, I simply need to dosconnect the battery for a little while to give everything time to reset, and then reconnect it and start the car (while ebrake is on) with zero power to any accessories and just let it idle for a while. Am I understanding that correctly? What should happen when I do that so I know whether or not that worked?

ezone

If it's resetting fault codes that needs resolved first.

After that problem is solved then the idle relearn can be completed.