Been out of the Volvo scene for 5 years now but recently got another 850T. I forgot how much i love these cars! Now onto the problem.

I am experiencing a long crank and rough idle. More so when the car is already hot. I have hooked up a fuel pressure gauge to it and i get 43psi when the key is turned on. 15 minutes later its down to 12 psi. Would this be a problem with the FPR? Or is there a check valve somewhere?

I am on my phone and for some reason the search function isnt working, so sorry if this question has been asked 100 times already

 

If key is turned on and you get 43psi immediately, issue is not with FPR or fuel pump.

Start with the basics, do a tune up.

 

New oem plugs, wires, cap and rotor,fuel filter......

 

You have OBDII, right? You could potentially pull some data.


There are a lot of people having this same sort of problem with OBDI cars, and you can't say in that case what the airflow is. If the idle air valve is not opening enough, you'd see that looking at live data. have not ever had an idle air failure on mine, so I don't know what sort of symptoms you would get into with that.


What I have experienced is for the car to have an air leak that is throwing off the MAF. Turbos are bad for that. You could have a vacuum leak, but you could also have a non-vacuum leak between the turbo and the throttle (it's a long way).