2011 SV6 Series 2 VE - Slow crank after being driven for a while ( wont start)

[wetherow]

The terminals and inside the battery clamps need to be cleaned with either a battery cleaning tool or at the least, emery cloth and or a file.
They should be shiny like a new pin before fitting.
As should be any connections that are removed and refitted.
Doing them up tight is only a small part of the battle.

I agree, I have done this across the car making sure they're all shiny and done up tight.

 

[mechanic]

as well as checked the earth points and the wiring loom for resistance and voltage with a multimeter which have all been well within parameters

can you tell me how you did this and what the parameters were?
How did you test for resistance?
What was the result?
under what conditions did you check the voltage?

Starting circuits are very current-heavy and need to be tested using the right method.

 

[wetherow]

can you tell me how you did this and what the parameters were?
How did you test for resistance?
What was the result?
under what conditions did you check the voltage?

Starting circuits are very current-heavy and need to be tested using the right method.

As per my previous post - with a multimeter and all results were within normal parameter range.

 

[mechanic]

As per my previous post - with a multimeter and all results were within normal parameter

You ask for help then give answers like this?

I don't believe you tested properly.

If you did, what parameter did you use? What unit of measurement? What setting in the meter? What condition did your test under?

 

[wetherow]

You ask for help then give answers like this?

I don't believe you tested properly.

If you did, what parameter did you use? What unit of measurement? What setting in the meter? What condition did your test under?

Howdy, sry about the late reply,

So I tested with a multimeter on voltage setting starting with the battery (which is brand new) when the car is off to get a base line and got 12.9v from +ve to -ve posts. then checked the +ve to chassis (ground) and got the same.
moved to the front of the car and checked the positive jumper post to ground post and got 12.9v . I then tested +ve jumper post to engine which I think got 0v .
I tested +ve fusebox post to chassis and got 12.8v
I then put multimeter on ohms 20k setting and went from chassis to engine and got 0.01 ohms (Passenger side post) then repeated on drivers side and got 0.01 ohms. I also tested +ve jumper post to engine and the ohms steadily climed from 0.01 up to over 1.0 ( I presume is normal since going from +ve to -ve?) I repeated the ohms test on the fuse box +ve to chassis and engine and same thing happened. I've ohms tested the ground strap and starter motor +ve cable from end to end (while off the car) and it had 0.01 ohms.

when the car was running the voltage test showed 14.8v at the jumper post and right back to the battery. I repeated the ohms test while the car was running and it was the same.

hopefully that was correct?

since my last post I have replaced the crank shaft position sensor with a brand new one and replaced the ground strap with a new 4awg ground strap ( designed for battery negative) but it's still doing the same thing.

one thing to note was I tried to voltage and ohms test the other connector going to the starter motor which is the only other wiring going to the start and didn't get any readings. I've looked everywhere as to that that connector is for but couldn't find anything. I presume it's the signal connector from the ignition?

if there's anything I've missed please let me know.

 

[blaydesfromoz]

Hi guys, I have the same issue with my 2012 sv6 z series. Starts perfect first thing in the morning or after work but if I stop along the way it doesn't want to start as if the battery is flat. I had noticed that the radio has constant power with the keys removed so I removed the fuse yesterday for the radio and it has started first time every time since so ill give it a couple more days of testing but looks like it could be an issue there not sure what yet but at least it might narrow it down.