Hard start after 1 hour cool down

1amdadmt · Post by **1amdadmt** » 09 Nov 2024, 16:20

Car is 2013 s60 r-design.
After Volvo did a software update, if I drive the car to get to running temp, then park it for an hour, it has trouble starting. If I were to wait till the next day to start, there is no problem. Otherwise the car runs great .
Have replace spark plugs, fuel pressure sensor and fuel pump (ouch).
What else could be the problem.

Post by **matthew1** » 10 Nov 2024, 10:10

The easiest, but in a way the most sinister problem, is electrical... in terms of bad battery or bad terminal connection or bad ground.

The heat cool cycle of metal by definition is one of expand/shrink. Think of how a pop or beer can in a freezer acts, but in reverse. Now do that a thousand times, and that's what can happen to a car's electrical connections.

When it's cold, things act one way. When it's hot, they act another. That "tink tink tink" sound of a cooling car is literally the sound of metal in the engine bay contracting.

Now that you've read past my very wordy preamble, I'd check the grounds in the engine bay and the battery cables. How old is the battery? (low chance, but worth it as a shot in the dark)

Post by **scot850** » 24 Nov 2024, 06:26

If this issue started immediately after the update, take it back to Volvo. They should identify the issue under warranty of the repair. It may not be the update itself that caused the issue, but a related action like perhaps a battery disconnect or similar. Like Matthew suggests it is likely electrical. The modern software for diagnostics should be able to test for fuel pressure and the likes when you get the issue.

When you have difficulty starting, is it the engine does not turn over or it turns over but just does not start?

The engine temperature sensor could be an issue if it thinks the engine is cold and over fuels on start up.

Neil.