Subaru Outback Forums banner
  • Hey everyone! Enter your ride HERE to be a part of this month's Outback of the Month Challenge!

1 - 8 of 8 Posts

·
Registered
Joined
·
34 Posts
Discussion Starter · #1 ·
Hi i have this intermittent hesitation at the starting moment on my legacy 3.0 at 2007
Run the Freessm and this is the results.
Fuel injection pulse #1 0.51 at lowest.
Fuel injection pulse #2 2.05 at lowest.
Battery drops to 8.1 volts when cold start.
No misfires at all. But still feels like a misfire at the starting moment.
510257
510258
 

·
Premium Member
01 VDC, 05 R Sedan, 06 BAJA EJ257
Joined
·
15,565 Posts
Given the low voltage at start you should check your battery condition, the ampere output, and the grounding as a starting point.
 

·
Premium Member
2008 JDM Outback 3.0R, 5EAT
Joined
·
480 Posts
I wonder if the low voltage recorded is related to data logging. This morning, out of curiosity I connected both FreeSSM and a multi meter across the battery. Whilst cold cranking FreeSSM showed a low of 8.5V whilst the multi meter showed a low approx 10v. The battery here is a year old and my car, a 2008 3.0R starts quickly cold. Of course FreeSSM will read data way quicker than a consumer grade multi meter could be interpreted so the drop could've been just a microsecond or perhaps the OBD-II adapter lost power very briefly during cranking.

The fuel injector pulse width is computed by the ECM for the desired air fuel ratio and other compensations such as short and long term fuel trims by bank (#1=right, #2=left, sides are described as viewed from inside the car). If you can share the trims from FreeSSM (Air Fuel Correction, Air Fuel Learning banks #1 & #2) that may help figure out what is happening. There are several other reasons why you could feel a misfire at star up but as cardoc says check your battery, cables and grounds first. Also is there any overheating or leaks of oil/coolant/other fluids ?

510569
 

·
Registered
Joined
·
34 Posts
Discussion Starter · #4 ·
I checked with a multimeter cold start it was somewhere at 9 volts.
The first three pictures is from when im driving.
Last two idle.
510607
510608
510610



510612
510613
 

·
Premium Member
2008 JDM Outback 3.0R, 5EAT
Joined
·
480 Posts
The long term fuel trims look good, both within +-5% which is better than the factory service manual recommendation of +-10%. I think we should defer to @cardoc's electrical advise on the cold start cranking voltage.
 

·
Premium Member
01 VDC, 05 R Sedan, 06 BAJA EJ257
Joined
·
15,565 Posts
IF the voltage values are correct and the system is dropping to 8V then there is a bad cable or two on the car. It could also be the battery is not supplying sufficient ampere flow. 12.6V does not mean good ampere flow.

Electricity runs from negative to positive. First and foremost is a good supply, the battery. Next is the ground cable to the engine. Third is the positive cable to the starter. The starter has to have a good ground supply and a path back to the battery. A bad ground limits current to the starter. A bad positive cable prevents current from flowing back. Either or both being bad will create a large load when the starter is activated and this is seen with the voltage dropping below 10V while the starter is running.

It could also be the starter is going to shite.

The engine looks to be running normally.
 

·
Registered
Joined
·
34 Posts
Discussion Starter · #7 ·
I see i will look at the cables soon.
But still when I drive for a while and stop the car sometimes i can feel small vibrations in the seat when idling.
Feels like the engine is misfire. But still the readings say normal.
 

·
Registered
Joined
·
34 Posts
Discussion Starter · #8 ·
I don't have a video on the misfire but this is similar.
Not as severe like this one but similar.
And my legacy start right up after 2-3 sec.

 
1 - 8 of 8 Posts
Top