The wife's Mazda 3

[jay929]

Is hard to start sometimes it's a 2010 with 50,000 miles on it. Only maintenance I've done is new battery, oil changes and air filter It cranks fine but just seems to crank more that should sometimes like its struggling
Any ideas where to start?

 

[Falken]

Check the condition of the battery first with a DMM set to DC Volts.

If it is around 12.6V in the morning before you start the car let us know.

If it is less than that, like 12.3V, you have a charging system / battery issue.

 

[KGMtech]

Crank position sensor? Fuel pump?

 

[nwjones18]

Whenever I hear 'hard starting, but runs fine' Crankshaft position sensor is always my first guess.

 

[Eddie]

Check the grounds first and especially the ones to chassey. Then do a voltage check at the battery with engine not running and running at ~ 1500 rpm. Running voltage should be ~ 14.2-14.6 volts. ed

 

[Greasymechtech]

Toss in a couple bottles of Techron Concentrate to rule out bad fuel spray pattern clogged injectors...

Struggling to crank? New battery is junk. Have it tested.

 

[Vuflanovsky]

If it's not battery / charging related then I would pay attention to any sounds coming from the front timing chain cover. I believe this is a pre-SkyActiv model and VVT actuator failure is a known issue. I know this because I lost a 2009 Mazda3 at 78K miles and there was apparently a class action lawsuit trying to be brought a couple of years ago due to related pins not being forged properly. With mine, there was initial hard starting and eventually a slight rod knock sound where apparently damage had occurred. No issue with metal particulate in the filter, chain and tensioner were fine, but it was difficult to diagnose.

 

[maximus]

I had a 2008 Mazda3, purchased new. It always took a bit longer than normal(compared to other cars) to light off.

 

[jay929]

Lots of good replies here. Interesting about the Vvt actuator failure she's not good with describing noises but she did say her engine was making a loud noise one morning then finally went away. Should I just change the crankshaft position sensor to rule it out ?
I will check out the battery voltages soon and I'll try a bottle of techron concentrate can I buy that at any auto parts store ?

 

[nwjones18]

Scanned for codes?

 

[deepsquat]

Originally Posted By: jay929
Lots of good replies here. Interesting about the Vvt actuator failure she's not good with describing noises but she did say her engine was making a loud noise one morning then finally went away. Should I just change the crankshaft position sensor to rule it out ?
I will check out the battery voltages soon and I'll try a bottle of techron concentrate can I buy that at any auto parts store ?

You could do something really weird with the Crank sensor...wait for it .......test it??
Not that tough ..check you tube ..all you need is a multimeter