Any way to test Volvo fuel cell?

[Z275]

I have a 7.4GSi/PEFS engine that uses the fuel cell with LP and HP pump plus filter. It started making a loud whine and now I'm having severely reduced power. I had it out today and it would only turn about 3500RPM while under load and then I heard what sounded like a backfire so I took it back down to idle and came in.
My questions are:
1. Is there a way to test the pressure from the 2 pumps? I'd like to be sure it is the cause since a new fuel cell is close to $700. The service manual I have doesn't mention any way to do this. It appears someone may have replaced just the high pressure pump with a Sierra pump at some point. This is the one making the loud whine from what I can tell. When I wrap my hand around it the tone changes.
2. What exactly is the reason Volvo went to this fuel cell and why do they tell you that you can't (or shouldn't) replace just one of the pumps?

Thanks,
Jason

 

[Don S]

Re: Any way to test Volvo fuel cell?

2. What exactly is the reason Volvo went to this fuel cell and why do they tell you that you can't (or shouldn't) replace just one of the pumps?

Because they wanted to I guess, they NEVER tell the VP dealerships WHY they do anything they do. Only that they have done something and that's the way it is.

And now you have an aftermarket pump that won't work. Wonder if there is a reason?
One thing that usually cause the pumps to be noisy, is air in the system. Might want to do this test and pressure check both fuel pumps to see if you can track down the problem.

http://forums.iboats.com/showthread.php?t=167561

 

[Z275]

Re: Any way to test Volvo fuel cell?

Thanks Don. That link has some great info in it. Everything up to the pump looks good so I suspect if air is getting in it's from within the fuel cell. I think I will go ahead and just replace the whole assembly since I know it has been taken apart before. Might as well do it right the first time.

One more question. Where can I find the screw on fitting for the pressure relief valve on the fuel cell? I have a few I've used on car EFI systems before but they are different sizes.

Thanks,
Jason