Hi everyone, got another mechanical question
My 2009 Mazda 3 2.0 has this odd low idle issue which I can't pinpoint. Once the car is fully warm, in P, R and N, it will idle normally around 750rpm, but when in D, it will idle at 600 (sometimes down to 500) only IF my foot is on the brake. I pulled the e-brake while the car was in D and let my foot off the brake, and the idle went back to 750rpm... as soon as put my foot on the brake, back down to 600 it goes... however, if I turn on the fan to max, the idle stays at 750 while in D and foot on the brake. Same thing if I turn the AC on.
On top of this, I was having a hard starting issue after filling up the car, and what seems to me as poor fuel consumption, but can't say if the idle and these issues are related or not
The hard starting i've read is common, and can be the purge valve solenoid or gas cap. I tested the purge valve solenoid by removing it and giving it power, and nothing happened, so I concluded that it's likely bad and replaced it. I also threw in a new gas cap since it was cheap, went to fill up, and didn't have any starting issues, so I believe that issue is now fixed. As for the fuel consumption, it's around 10 L/100km (23 MPG), which is hard to say if it's normal or not given the weather is now colder, and the car does sit a lot in heavy city traffic before getting onto the highway.
I also cleaned the throttle body since it was all gunked up, and cleaned the MAF, and the spark plugs are new NGK iridiums. Needless to say, none of these things solved the odd low idle... so the only thing I'm left with at this point is to do an idle relearn since i've heard this can be caused by disconnecting the battery (although I never have since owning the car).I won't get a chance to do that until the weekend probably, and if that doesn't solve it, i'm not sure what it can be, other then possibly the evap canister that sits under the fuel tank, which is a pain to get to.
Also, for what it's worth, the rad fan kicks on constantly even now with temps around 0 degrees Celsius, which is odd... I checked the coolant temp and it's right on 87-88 degrees Celsius, and no coolant leaking anywhere... again, no idea if this could be related to the low idle.
My 2009 Mazda 3 2.0 has this odd low idle issue which I can't pinpoint. Once the car is fully warm, in P, R and N, it will idle normally around 750rpm, but when in D, it will idle at 600 (sometimes down to 500) only IF my foot is on the brake. I pulled the e-brake while the car was in D and let my foot off the brake, and the idle went back to 750rpm... as soon as put my foot on the brake, back down to 600 it goes... however, if I turn on the fan to max, the idle stays at 750 while in D and foot on the brake. Same thing if I turn the AC on.
On top of this, I was having a hard starting issue after filling up the car, and what seems to me as poor fuel consumption, but can't say if the idle and these issues are related or not
The hard starting i've read is common, and can be the purge valve solenoid or gas cap. I tested the purge valve solenoid by removing it and giving it power, and nothing happened, so I concluded that it's likely bad and replaced it. I also threw in a new gas cap since it was cheap, went to fill up, and didn't have any starting issues, so I believe that issue is now fixed. As for the fuel consumption, it's around 10 L/100km (23 MPG), which is hard to say if it's normal or not given the weather is now colder, and the car does sit a lot in heavy city traffic before getting onto the highway.
I also cleaned the throttle body since it was all gunked up, and cleaned the MAF, and the spark plugs are new NGK iridiums. Needless to say, none of these things solved the odd low idle... so the only thing I'm left with at this point is to do an idle relearn since i've heard this can be caused by disconnecting the battery (although I never have since owning the car).I won't get a chance to do that until the weekend probably, and if that doesn't solve it, i'm not sure what it can be, other then possibly the evap canister that sits under the fuel tank, which is a pain to get to.
Also, for what it's worth, the rad fan kicks on constantly even now with temps around 0 degrees Celsius, which is odd... I checked the coolant temp and it's right on 87-88 degrees Celsius, and no coolant leaking anywhere... again, no idea if this could be related to the low idle.