2006 S60 fuel pressure reading on code reader

Mrk3cobra · Post by **Mrk3cobra** » 13 Dec 2014, 09:54

I have a 2006 volvo s60 T5 I am getting a fuel pressure reading of 44psi on my code reader. Today I will connect a fuel pressure gauge to the fuel rail and see what it reads. I think at idle I should see 54psi. My question is what is the correct psi reading on the code reader.

The problem with the car is sometimes it does not want to start without turning over for about 3 seconds.

draser · Post by **draser** » 13 Dec 2014, 15:06

I read 43.9 psi with Torque at idle.

Post by **jimmy57** » 13 Dec 2014, 16:36

The fuel pressure is not fixed. When the engine is switched off hot and restarted the pressure is raised to around 60 psi to condense any vapor for a vapor lock remedy. Once running it is 44psi and then under higher load on T5 and R models it goes up to 53-55 psi.
Occasionally there is a pressure rise to 70+ psi to open a relief valve and flush it. This happens infrequently but you might see it and think it is a fault.

Mrk3cobra · Post by **Mrk3cobra** » 13 Dec 2014, 16:49

I connected a fuel pressure gauge to the fuel rail today and here is what I saw.
With the car warm and at idle the code reader is reading 44 psi.
The fuel gauge at the fuel rail is 53 psi. Does this sound correct.

Post by **jimmy57** » 14 Dec 2014, 00:43

I have torque pro and it shows the same as gauge.
There is a chance the fuel pressure sensor is faulty or the scan tool is not interpreting the data correctly.
If the car is running fine and fuel economy is normal for that car then I would think it is a scan tool issue. You haven't mentioned any problem you a re trying to repair.

Mrk3cobra · Post by **Mrk3cobra** » 14 Dec 2014, 13:52

The problem I am having is intermittent hard start. The car turns over fine but takes about 3 seconds to start.

Today I got a new fuel gauge and connected to the fuel rail and it reads the same as the code reader. They both show 58 psi at start up and then they both show 44 psi at idle.

Does any one know if 44psi is correct at idle, my service manual says 3.8 bar which is like 55psi but the book is a cheap chilton service manual that I do not trust.

I changed the fuel filter today just because I have know records of it being changed.

Post by **jimmy57** » 14 Dec 2014, 14:10

The fuel pressure at cold start is less than the hot start as explained in earlier post. You need to look at retained fuel pressure after engine is switched off. Intermittent hard start when? After you drive and park 10-30 minutes, overnight, 2 hours off or ???

The most common cause of long crank is rest pressure loss. The most common cause of that is the fuel pump check valve that is there to prevent fuel from returning to tank through the pump.

Mrk3cobra · Post by **Mrk3cobra** » 14 Dec 2014, 18:04

The hard start is after the car sits for at least 8 hours. The fuel pressure readings look good, I get 58 psi at start up when the car is cold or hot. At idle and normal driving I get 44 psi, and under a load I get 55-60 psi.

I will check the fuel pressure in the morning when the key is turned on before I try to start the car.

Post by **jimmy57** » 14 Dec 2014, 19:29

The pressure is software controlled. I can't remember which ones have the fuel pressure increase on start all the time and which have it only when engine has been above a coolant temp threshold and then is restarted with it still above that threshold.

Try this to see if it is in fact draining down and causing the problem: turn ignition on for 2 sec and then off and then go depress the schrader valve in the fuel rail test port, repeat 4X or until liquid fuel comes out. Then crank it over and see if it starts after only a couple of crank rotations as normal. If so then it is not holding. The hard part is that there is no ready way to know if it is fuel pump or the pressure ventilation valve (Volvo speak for a pressure relief valve that limits fuel pressure to 5.5 to 6 Bar. The system uses this pressure as default if the fuel pressure control system has an issue). It doesn't matter if you are replacing the fuel module (cup-pump-sender-etc.) but if you were of mind to replace the pump only then if it is PVV then a pump wouldn't fix it.

rmroseman · Post by **rmroseman** » 22 Jun 2022, 22:00

My code reader "says", fuel pressure control valve. What is a "fuel pressure control valve"? (Not finding a reference to it anywhere. I have had the fuel rail sensor, fuel pump, etc. replaced but the check engine light goes out only long enough for the inspection. I am left to fix the car again the next year.)