I'm having a long term issue with starting the car when warm (hot!). The hotter the weather the worse the symptoms. What happens is after turning the car off once I want to start it (regardless of instant or 5 minutes later), it performs like it's trying to crank 2 engines at once, sluggish. It does start on the first go but it's like forcing an old man to lift a heavy object. When cold it starts fine. Fuel pump is new as well as fuel filter, spark plugs, coil packs, changed the battery, coolant sensor in the past, even got the starter serviced at one point so I presume they cleaned the connectors but the issue still persists long term for more that 10 years now. When my fuel pump died recently it was cranking nice and fast, no struggles.
I'm really puzzled what is causing this behavior and the only thing I can think of is the heat soak of the starter. Or maybe the fuel pressure sensor? Or crank sensor? Or leaky injectors? There are no codes.
Starting wise I also noticed when the car is pointing uphill it also took more effort to start, sometimes even on the second go with hot weather. And even now with the new fuel pump I noticed it took twice as long to start in mild weather. So far I blame it on the 1/5 full tank.
And for diagnostic reasons when the car is warm it runs fine, no issues, smooth. But when starting cold...starts fine but short trims shoot up to +25 and stay around there until the engine warms up. As it's warming up they slowly go down and the car feels nicer to drive. Long trim is okay, about 1-2% but I don't like how it runs when cold and with low rpm/starting to accelerate, it's almost jerky and not as smooth. Once the rpm is up it's okay. Again no codes, MAF sensor seems to be working, vacuum leak and excess air? No idea how to even test that, I have no specialized tools. Or maybe injectors are doing something wrong when cold.
Anyone has some ideas?
It's an old Volvo but I love it. Everything works otherwise, it's super comfy, has decent power and I don't want to sell it!
