I have learned a lot from reading through all the posts here and elsewhere about the fuel pump/fuel cell problems on these engines - because my 2003 Regal has a 5.7 Gi engine, and I have had many fuel system problems, which at first I did not recognize.
I have found the black paint inside my "fuel cell". My LP fuel pump and my HP fuel pumps have failed. The Pressure Regulator failed from being clogged with the black paint.
I am a qualified Electrical and Mechanical Engineer. And I was unwilling to simply pay Volvo the money and wait for the next time the fuel system would let me down.
I found that with all the components of my fuel system replaced and running properly, the temperature of my HP pump was too high at light engine loads. The pressure regulator was doing it's job, as was the water cooling. But having both pumps at full power (which is inherent to this Volvo design) simply generated too much heat in the HP system, recirculating gas as it does, in large volumes, at idle and light load.
I found that the HP pump was tending to make the loud noise that it does when it is cavitating on the suction end. The cavitation was caused by the gas getting so hot that it was vaporizing on the suction side of the pump. This cavitation will pretty quickly cause the HP pump to fail.
Basically the "fuel cell" water cooling is inadequate for the amount of heat generated at idle and light load. I decided to change my setup to solve this basic problem. I bought a voltage regulator and installed it on the HP pump. This DC 15 volt device allows me to turn a potentiometer and adjust the speed of the HP pump.
I expected that I would create a set point for idle and light load, set the speed control at that point, and then my intent was to install a micro switch that would be operated by throttle position, and which would apply full power to the HP pump at high loads.
Then I tested the voltage controller on the system, and chose a good set point to reduce the amount of gas recirculation taking place at idle and light load. Doing this stopped the temperature gain in the HP gas system very effectively. The HP pump was running cool for the first time.
I then took the boat out and tested the fuel system at various loads and speed settings on the HP pump. What I found was very surprising; The HP pump speed setting that worked well at idle also worked well at full power.
This says to me that the set point I am using is a good balance between the LP pump and the HP pump. That they work better as a pair with the setting I am using. I am monitoring HP fuel pressure at all times, and I may decide over time to install the microswitch. But at sea level, on my boat, with ambient air temperature of 65 deg F, and humidity of about 40%, my fuel system is working better than ever, the pumps are not overheating, and the HP gas is staying nice and cool.
Obviously I will monitor the situation and the setting carefully. It may well be the case that I will find some operating conditions where I will want to use the pressure switch to set the HP pump to full power.
Your mileage may vary. But I am happy with my system, and I am making this post so that others who are struggling with this poorly designed fuel system are able to use what I have learned and experienced to reduce their downtime and wasted money.
I hope this helps
Rod
I have found the black paint inside my "fuel cell". My LP fuel pump and my HP fuel pumps have failed. The Pressure Regulator failed from being clogged with the black paint.
I am a qualified Electrical and Mechanical Engineer. And I was unwilling to simply pay Volvo the money and wait for the next time the fuel system would let me down.
I found that with all the components of my fuel system replaced and running properly, the temperature of my HP pump was too high at light engine loads. The pressure regulator was doing it's job, as was the water cooling. But having both pumps at full power (which is inherent to this Volvo design) simply generated too much heat in the HP system, recirculating gas as it does, in large volumes, at idle and light load.
I found that the HP pump was tending to make the loud noise that it does when it is cavitating on the suction end. The cavitation was caused by the gas getting so hot that it was vaporizing on the suction side of the pump. This cavitation will pretty quickly cause the HP pump to fail.
Basically the "fuel cell" water cooling is inadequate for the amount of heat generated at idle and light load. I decided to change my setup to solve this basic problem. I bought a voltage regulator and installed it on the HP pump. This DC 15 volt device allows me to turn a potentiometer and adjust the speed of the HP pump.
I expected that I would create a set point for idle and light load, set the speed control at that point, and then my intent was to install a micro switch that would be operated by throttle position, and which would apply full power to the HP pump at high loads.
Then I tested the voltage controller on the system, and chose a good set point to reduce the amount of gas recirculation taking place at idle and light load. Doing this stopped the temperature gain in the HP gas system very effectively. The HP pump was running cool for the first time.
I then took the boat out and tested the fuel system at various loads and speed settings on the HP pump. What I found was very surprising; The HP pump speed setting that worked well at idle also worked well at full power.
This says to me that the set point I am using is a good balance between the LP pump and the HP pump. That they work better as a pair with the setting I am using. I am monitoring HP fuel pressure at all times, and I may decide over time to install the microswitch. But at sea level, on my boat, with ambient air temperature of 65 deg F, and humidity of about 40%, my fuel system is working better than ever, the pumps are not overheating, and the HP gas is staying nice and cool.
Obviously I will monitor the situation and the setting carefully. It may well be the case that I will find some operating conditions where I will want to use the pressure switch to set the HP pump to full power.
Your mileage may vary. But I am happy with my system, and I am making this post so that others who are struggling with this poorly designed fuel system are able to use what I have learned and experienced to reduce their downtime and wasted money.
I hope this helps
Rod
