Hi all,

my 94 850 turbo has the classic fuel pump symptoms, was good when i drove to work this am and will not start (but cranks well). Scrader valve has no fuel to it.

I want to test the fuel relay, anyone know how to do this with a multimeter and what values I should be getting?
Anyone know how to repair it, (solder) if broken?

If i jump it at pin 15 and 87 and it starts does that mean for sure its the relay?

 

If you bypass the relay and all of your problems go away than that would be very strong evidence that the realy is bad. When I thought mine was going out I cracked the top off of it and soldered on a couple of wires that ended at LEDs, one LED I connected to the input/control signal and the other on the output. No LEDs=ECU problem, Control LED and no output LED=Bad relay. Both LEDs and still no start=bad pump.

 

Bypass the relay, and see if it starts. If it does, next step is to make sure that the relay is getting a signal from the ECM. Check the control terminals for voltage while cranking. If there's voltage, you have a bad relay. If there isn't, then there's an open circuit between the relay and ECM. If the pump doesn't come on when you bypass the relay, check for voltage at the pump. Voltage? You need a pump. No voltage? Make sure there's voltage at the relay, then fix the open circuit between relay and pump

 

thanks for the great input guys. I read a write up that the pump can be changed without taking the tank off, that is to pull off the mats in the trunk and work from the back? true? or does the tank have to come down?

 

You dont need to drop your tank at all. Here is the write-up from luketrash:
http://www.matthewsvolvosite.com/for...?p=56515#56515
If you decide to replace w/ a walbro pump this one will help:
http://volvospeed.com/vs_forum/index...rofit-how-too/
BTW, I got mine from http://www.europartsdirect.com ($57 shipped).