2006 S60, CEL for fuel trim and MAF sensor

[abscate]

Is 300 kPA close to spec fuel pressure? Sounds low to me. Check threads...found it for my 2006 v70...

375 KPA and up

viewtopic.php?f=9&t=75015&p=398621&hili ... on#p398621

[zjevik]

Yeah, that looks low. Thank for pointing it out, I didn't see it. The fuel pressure should be around 400kPa. I will record the fuel pressure and fuel pressure nominal value tomorrow on my way to work and see how it goes.

Maybe I got lucky and changing the fuel filter solved the problem. I usually got the air mass code once every 10 driving cycles.

[mrbrian200]

Fuel pressure is not regulated as a constant pressure.
Key on/engine off or while cranking the starter 58-60psi
Idling in park or coasting in drive 43-45psi
Varies under acceleration: the harder you punch it the higher the fuel pressure is regulated up to 60psi neighborhood.
The range in kpa would be 296-413kpa.

[zjevik]

Everything looked normal today. There is one spike to 680kPa when I floored it but the pressure never dropped below 380kPa.
The car drives good and I feel like I am trying to find something wrong with it. It is 11 years old and has 118k so getting a code here and there is I guess not a big deal

Thanks guys for your help!

Here are the data:

fuel_pressure.png (223.52 KiB) Viewed 1616 times

[mrbrian200]

I don't like the spike. That most likely some sort of electrical disturbance (I doubt the pressure actually spiked to 680kpa). By '06 they had deleted the fuel pressure damper on the rail. It is possible it happened to capture that instant one of the injectors closed and that's a fluid hammer. I have toyed with the idea of drilling/tapping a hole into my rail and adding the pressure damper back where it was on the older ones. They changed the way the fuel line connects I don't think I can simply pull a rail of an older one that has it already.