fuel related problem

[cetme1]

Hello everyone.

I need some help. I have noticed that the fuel pressure gauge on my 87 GN has been showing a lower and lower pressure for the last few weeks. When I first start up it has went from 38 to 27 now. This has been over a several weeks period.
How do I diagnose what the problem is?
I am running an electric gauge (old cyberdyne) that was always very accurate. I also have a mechanical one that I am going to hook up. This should tell me if its just a gauge problem.
So if the gauge is correct, then I know it can be the pressure regulator(an adjustable kirban ) or the fuel pump (a walbro 307).

I know I saw a procedure to check which one it was but I can't find it now.Any help would be appreciated!

 

[Dynalow00]

What fuel pressure reg have u got? It may have failed..Perhaps the pump has failed or is failing....dropping pressure...First check should be the filter. Cheap insurance. See if you gain anything by changing it...

 

[cetme1]

I changed the filter a few months ago, So I don't think thats it.

The regulator is the aluminum adjustable one that kirbans sells.

I just need some way of deciding which one to replace the reg or the intank pump?

I know I saw a diagnostic procedure on the net somewhere, I just can't find it.

 

[QUIP'6']

I changed the filter a few months ago, So I don't think thats it.

The regulator is the aluminum adjustable one that kirbans sells.

I just need some way of deciding which one to replace the reg or the intank pump?

I know I saw a diagnostic procedure on the net somewhere, I just can't find it.

Fuel System Check Up

 

[cetme1]

Thanks, thats exactly what I needed!