[sp53]

Fuel regulator, Well I think I might have found the problem on my 93 9000. When I unhooked the banjo fitting at the rail end nothing happen when I hot wired the pump, but when I unhooked the fuel at the regulator (with the little vacuum line) before the rail the pump pumped very strong. So I am thinking the regulator is bad and blocking the fuel delivery. Could one of the members let me know if they think I might have it figured out? In other words, if you loosen the nut at the end of the rail after the regulator some fuel should pump out when the pump is running, right? I cannot see why it would not. This has been a real battle, so if you might know something PLEASE comment. Thanks in advance.

Steve

 

[tatt001]

Sometimes the diaphragm can go. You can test by smelling or tasting for petrol on the vacuum hose where it connects to the intake manifold.

 

[Jim Mesthene]

The fuel pressure regulator cannot block fuel flow.
If it's plugged, your fuel pressure is too high. If it's open, too much fuel flows through the fuel rail at too low a pressure.

 

[sp53]

Thanks Jim and tatt001 for your comments, they are much appreciated. So then it looks like my fuel regulator has plugged the line because fuel does not go past it. From what I have gathered form you guys, the fuel goes in a loop where the unburned fuel goes back to the tank. The regulator should never really close completely, but it allows more fuel in under more vacuum, right?

Steve

 

[Norman Lovie]

now I thought it was diffrent

fuel comes in the hp line ( one with the banjo union) the pump builds pressure. When it over pressures under constant running the regulator opens at a pre set pressure and vents fuel back to the tank.
More vacuum opens the regulator early
Less vacuum = positive boost pressure helps keep it closed

But why are you getting fuel pumping out the return line ( if i,ve got this right???)
If i,m wrong - sorry for the confusion, if i,m right you,ve got the supply & return from the pump mixed up

 

[sp53]

Hi Norman and thanks for your note. Yes having the lines flipped around is something that I wondered about too. I might be looking at this wrong. I see the regulator at the end of the line with the 17 mm banjo bolt at the other end and there is another check valve or something right after the banjo. The regulator I unhooked is under the large black air intake. I did have some concerns with the pump hookups because this vehicle had no pump or no lines when I first got it. I did notice a check valve with a small needle like thing sticking out on the white fitting and a ball type fitting on the yellow line. What I did was remove the fuel filter and blew air through lines to determine what side to hook the pressure to then I hooked the line without the needle looking check valve to the pressure side. I believe it was the yellow fitting to the pressure side going through the filter. Does that sound right? In addition, I checked the fuel output right before the valve under the large black air intake. I might have it backwards.



Steve

 

[Norman Lovie]

If you have the fuel pump ( fuel pump bucket) removed from the car

There are variuos types - bosch & Walbro but I think they follow the same principle
The supply comes from the side that has a back pressure valve in it, the return is open ( so if you blow down both lines you,ll find out what is what)
and as previously said I think the supply goes to the banjo union hose on the fuel rail and the return comes from the spigot connection under the fuel pressure regulator, again on the fuel rail but on the other side

Sounds like your fuel rail has been empty because if the supply was the other way it might not have got passed the pressure regulator

 

[sp53]

Hi Norman and thanks for you not. The lines on the pump are black and white. I hooked the white coupling to fuel fitter and (pressure side) of the pump and the black one to the return side. I will post some picture when I get my son over with his camera. On this vehicle, there is no junction at the banjo bolt just a bolt at the end of the fuel rail like it would be for inspection or something. The gas feeds in at the regulator end of the rail travels down the rail and loops back to the tank without passing any Y’s. I think I have it right, but I still do not see why the pressure builds up at the regulator, and will not go past so maybe I hooked it up wrong at the pump. The regulator is good I checked out on another vehicle and that vehicle ran. It is making my crazy. I did talk to one of mechanics at the Saab dealer in Seattle and his suggestion was to concentrate on getting spark first, but how could getting spark fix this problem?

Steve