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

[yanga001]

So my mechanic did the fix and the car seems to start a lot snappier now then it did before. I notice cranks seem to be shorter and the tachometer does not fluctuate at all now. Will do a cold morning start to confirm, however this may have solved my issue.

For reference, he said he has seen many failures due to issues with the cam position sensor and has fixed most by rewiring the connector and replacing the sensor. He has been in the business since the 850's so i put a lot of faith in this judgement.

[dikidera]

The wiring on these cars is so prone to failure...I know they are 20 years old, but some cars are 30 and don't have this problem.

[yanga001]

Car started perfectly in -8C weather today. No hesitation and no jumping tach. Hoping this $80 fix ends my starting saga.

[yanga001]

So it was -18C lastnight and -11C today. The no start came back with a vengeance. Bought a battery maintainer (a noco 10 amp one) and will charge up the battery to keep it good. I have a undersized jump pack (noco 500A) which i will try later today after the battery is charged. A buddy can come by and we can jump it until it starts. Im about 100km from home base so it would be ideal to drive back.

Spoke to my mechanic and he says the starter could be causing the issue due to too much emi. I suspect the same. My hope originally was that rewiring and replacing the sensor would overcome the EMI to an extent that the car could start. Seems like the starter is working too hard and spiking all the lines. I had a steering angle sensor code come up during this round of starting which is suspect is due to noise.

[vtl]

Try to add a few more thick ground straps all around the engine.

[yanga001]

Charged it with a battery maintainer and got it to fire up on the second crank. Had a booster hooked up for a combined 1200CCA of power for the starter. She fired up more or less normally after the first start.

Got the battery tested, 13.25V and 930 CA for a 900 CA rated battery. Guy said it was in perfect condition. Bought some 4 gauge, 24 inch starter cables for 4 cad each. Will put two of them on the car (one at the alternator, one by the starter) and see if it provides an adequate grounding path for the noise.

20$ cad is better than paying for a new starter so i will take the gamble.

[vtl]

Try to start (move to pos III) only after you cycled I->II a few times, with couple of seconds in II before switching back to II. This makes sure fuel rail pressure is where it has to be.

[vtl]

My fuel pump is on its way out, I read a low fuel pressure in pos II in the morning. Cycling a few times - it starts right away, no problem. Looks like pressure relief valve is stuck partially open inside the pump. Or the filter mesh is clogged badly. Duty cycle is about 48-50% though, which is not bad for a 20 y.o. pump.

[yanga001]

Try to start (move to pos III) only after you cycled I->II a few times, with couple of seconds in II before switching back to II. This makes sure fuel rail pressure is where it has to be.

Have done this multiple times previously, and measured good fuel pressure according to the OBD2 live data output (my scanner is close to what VIDA does). Swapped PEMS too during this process. I know my check valve is not the greatest but i always cycle a few times if its giving me the no start. No difference in operation.

[yanga001]

My fuel pump is on its way out, I read a low fuel pressure in pos II in the morning. Cycling a few times - it starts right away, no problem. Looks like pressure relief valve is stuck partially open inside the pump. Or the filter mesh is clogged badly. Duty cycle is about 48-50% though, which is not bad for a 20 y.o. pump.

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.

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.

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 is, it does not sound like it killed the battery, but it is drawing an overtly significant amount of current that it wears down the battery.

If i have another car jumping my car then it seems to eventually start up. Our volvo batteries are already massive for the kinds of cars we have. For reference, a full sized Honda 2012 Pilot V6 uses a 600CCA 24F battery which is similar in dimension and identical in capacity to the H6 the S60 calls for. That car is a 4500pound vehicle where the s60 is 3500. I already use a 730CCA battery so i doubt there is more I can do on the capacity end.