My 2004 S40 1.9T has 108k miles and I just had the 105k maintenance done this past October. They did all the 105K mile work ( timing belt, serpentine belt, fuel fiter, water pump). Starting in early November i noticed that the car was taking longer to start.

It got progressivley worse until now, where in order to start the car i need to:

1. Attempt to start the car (which usually fails)
2. Open the hood and remove the 15A fuse for the fuel pump
3. Start the car
4. Quickly run back out and put the fuel pump fuse back in.

I know the fuel pressure regulator is often the culprit, so I changed it out with an OEM one from IPD. But that didn't help.

I don't think it's the battery, since jump starting doesn't help.

After the engine gets going, I am able to drive just fine it just idles i little higher (1250-1500rpm) and very little surges at idle.

It runs really rich, so I think I'll need to change the thermostat and coolant temperature sensor (again...) I also bought new spark plugs, so i'll try that too.

My car starting procedure makes me think it's a fuel system issue, but I'm not really sure. I don't really know what to do, and would like to avoid sending her back to the mechanic.

Thanks in advance

 

Faulty MAF perhaps?
Try a startup with the maf wiring plug disconnected.
If its okay then the same issue will still be present.

 

First check the small hose that runs from the throttle body area to the intercooler. It's maybe 3/4" diameter and 6" long with a z shape. It tends to get brittle and crack at one end. This can cause starting and idling issues.

If that looks good then clean the Idle Air Control motor. Usually you need a new gasket when you remove the IAC so have one handy, they are cheap. Spray some throttle body cleaner into the orifice to clean out as much carbon as you can.

If you are adventurous you can actually have a friend start the car while you hold your thumb over the IAC air passage and control idle by how much air you let through. With the IAC motor electrically connected to the car and in your other hand you can watch the pintle move back and forth as the car tries to control idle speed. The intake gets a bit warm so do this with a cold engine so as to not toast your thumb. Have the friend cut the ignition if it revs too high.