Check valve vs. Fuel Accumulator

[mod]

How does one tell for sure the problem is coming from one and not the other from symptoms only, without taking either one off? Thanks (Any good advice in taking off the fuel accumulator from the cramped space? I figure I'll probably end up taking everything off.) '87 930

[sammyg2]

It is very difficult to diagnose one vs. the other.
I suppose if you have a pressure gauge and take readings every minute for 30 minutes we might be able to make an educated guess, but it is still just that, a guess.

My suggestion is to change the check valve first. They are cheap (around $12) and relatively easy to change. Hardest part is stopping the fuel from running out and jacking the car up. I drained the fuel completely out of mine, but that is not manditory.

If the problem persists, then you can change the $65 accumulator.

Hey wait a minute, I just thought of something. Your car is an 87, so it should have three ports on the accumulator. One in, one out, and one is to vent the air (dry) side (Older models only had two ports). The vent would have fuel in it if the diaphram was leaking. You could pull that line off and pipe it somewhere safe with tubing, them fire up the fuel pump. If it is leaking, you would see fuel on the dry side of the diaphram. I haven't ever done that, but it seems like it would work. It might take a while to eventually see the leak, but it would be there.

As far as access, mine wasn't too bad, but mine isn't a turbo.
I pulled off a couple hoses, I can't remember if I pulled the fuel filter or not.
Make sure you use good wrenches, preferable tubing wrenches and use a back up. The fittings are really tight and easy to round off with the wrong tool.
Good luck.