Log of intermittent crank but no start | 08 S60 2.5T

[vtl]

If you could check your fuel pressure before cycling and then after cycling then we should be able to confirm it. AFAIK it should be around 400kpa-480kpa from what i recall.

I can, I have this: https://github.com/vtl/volvo-ddd

The odd behaviour is that the car can catch for one rev, stumble, then go back to infinite cranking and dancing tachometer. If i can get it started then i havent had a repeat issue after the first start.

If it didn't start the first time, the cylinders have gas in them, next few cranks will be hard, until it all vents out and a proper AFR is achieved.

My theory for a bad starter revolves around it drawing more current due to wear of the armature and bearing. It might be causing dips and spikes which are messing with the other sensors. Sometimes the car will crank, go dim, then stop cranking. It will then crank again but at a normal sound.

That stinks like a bad relay. I had to replace (desolder) one big CEM relay responsible for BCM power. They do go bad.

[vtl]

Actually, try to wiggle a little starter wire, which controls solenoid. In my 02 V70 it had a terrible oxidation, which even a new starter didn't fix (of course). Was fixed with a small screwdriver: just scraped the oxidation off and made the spring tighter.

[yanga001]

-5C this morning. Battery voltage 12.65, not a second of hesitation. Guess i will need to plan further diagnostics for the bitter cold (below -10C)

[imaV70Rdriver]

As I mentioned earlier in this thread, the antenna ring was what was wrong with mine. Nothing made sense. Sometimes it would start right up, and other times it could crank a hundred times but not start.
Like other’s, I thought it was an iffy starter, so I put in a new one to no avail.

[yanga001]

As I mentioned earlier in this thread, the antenna ring was what was wrong with mine. Nothing made sense. Sometimes it would start right up, and other times it could crank a hundred times but not start.
Like other’s, I thought it was an iffy starter, so I put in a new one to no avail.

I scanned the car with my near vida code scanner and have not pulled any immo codes or issues with the ring. I don’t get start prevented errors unless I’ve tried to unsuccessfully start the car like 10 times. This is normal behaviour for these cars afaik and is reset by locking and unlocking the door.
Only consistent code I get is bad rpm sensor after a few bad starts.

Waiting for my grounding cables to arrive at this point.

Will check voltage today as yesterday it was at 12.22 for some reason. I thought I may have left the trunk open.

[imaV70Rdriver]

There were no “faulty antenna ring” or immobilizer type codes that showed up for me using VIDA. Only the occasional “start prevented, try again” dash message.
Hopefully the ground straps do the trick. I just looked at mine, going from the block to the chassis, on the passenger side. I think I ought to replace it as it’s looking a bit green.

[yanga001]

There were no “faulty antenna ring” or immobilizer type codes that showed up for me using VIDA. Only the occasional “start prevented, try again” dash message.
Hopefully the ground straps do the trick. I just looked at mine, going from the block to the chassis, on the passenger side. I think I ought to replace it as it’s looking a bit green.

So i have not seen "start prevented, try again" on the little dash whenever this issue occurred. I just assumed immobilizer tripped as it would prevent cranking when i turned the key. Resetting on the door lock would allow the car to crank again.

[yanga001]

Added the aux ground and now the weather is to warm to see if it will make a difference.

Did find that i could consistently start the car after it presented the issue if i immediately affixed a jump pack to it. The jump pack i used is only 500A, but i use this in conjunction with the fully charged car battery.

Added the aux ground from the normal ground point to the bolt beside the upper cam sensor on the driverside of the engine bay. 4 gauge copper wire.

[vtl]

Added the aux ground and now the weather is to warm to see if it will make a difference.

Did find that i could consistently start the car after it presented the issue if i immediately affixed a jump pack to it. The jump pack i used is only 500A, but i use this in conjunction with the fully charged car battery.

Added the aux ground from the normal ground point to the bolt beside the upper cam sensor on the driverside of the engine bay. 4 gauge copper wire.

Remove the positive (red) wire from the junction box and clean the contacts well?