Coil pack melting

StephenG · Post by **StephenG** » 21 Jan 2021, 16:15

Zero (hard down) on all the coils. Today found the crank sensor base totally destroyed and the sensor floating in a sea of silicone and held in place by nothing but luck and gravity. Managed to get it out without dropping anything into the flywheel and ordered new parts. I don’t know if it will solve the problem, as I said, would it just one coil to overheat, though I believe it affects the timing. Now I’ve got to wait a week for new parts so if you think of anything else I will check it out. Thanks for input,

StephenG · Post by **StephenG** » 28 Jan 2021, 07:10

Back to it, changed the crank sensor, which needed changing, but it made no difference to the coil pack, still overheating within 2 minutes, so I can’t find anything else to test except the ecu. Unless someone knows another answer?

StephenG · Post by **StephenG** » 28 Jan 2021, 07:22

Sorry Abscate, missed this question, no3 to ground is hard down which I believe it should be.

StephenG · Post by **StephenG** » 18 Feb 2021, 04:26

Ok, back with latest update, my car is just back from the local Volvo dealer after 3 days of technical scrutiny and they haven’t found the answer. So to change tack slightly if you had a single coil pack wired up on a bench, what would you do to make melt in a short period of time?, allowing for the voltage etc being correct

Post by **jonesg** » 18 Feb 2021, 04:35

I'd put a coil on the bench and find out.

Post by **RickHaleParker** » 18 Feb 2021, 08:10

StephenG wrote: 28 Jan 2021, 07:22 Sorry Abscate, missed this question, no3 to ground is hard down which I believe it should be.

Measure the electrical resistance with an Ohm meter. A coating of oxide can cause high resistance. Current through a high resistance produces HEAT!

If the resistance in the pathway to ground on #3 is high. It will slow down the energy transfer rate. The energy in the collapsing magnetic field has got to be transferred or converted in a finite amount of time. Any energy that cannot be transferred in that amount of time is convert into HEAT!.

Post by **erikv11** » 18 Feb 2021, 09:44

RickHaleParker wrote: 18 Feb 2021, 08:10
StephenG wrote: 28 Jan 2021, 07:22 Sorry Abscate, missed this question, no3 to ground is hard down which I believe it should be.
Measure the electrical resistance with an Ohm meter. A coating of oxide can cause high resistance. Current through a high resistance produces HEAT!

If the resistance in the pathway to ground on #3 is high. It will slow down the energy transfer rate. The energy in the collapsing magnetic field has got to be transferred or converted in a finite amount of time. Any energy that cannot be transferred in that amount of time is convert into HEAT!.

This!

The earlier comments about looking for a short are logical but in practice it is usually the opposite when you find a hot spot - a poor connection like an internally corroded cable etc.

kaupz · Post by **kaupz** » 06 Mar 2023, 09:58

How did it end?