Mechanics

FUEL PUMP, OR FUEL PRESSURE REGULATOR

1994 Ford Ranger • 200,000 miles

So this is the second time I have posted on this topic. I have run through all the previously suggested tests and I'm still having the same problem. I have replaced the fuel pump, only to find that I wasted $75.00. I did come acrossed an issue that I could see would cause a fuel pressure issue. The hose that connects the pump to the sending unit was split down the side and basically shooting gasoline back down into the tank. Attached is a pic of what I removed and replaced. I'm pretty sure the pump is still good but I replaced it anyways because with the hose like that I simply dont know how long that pump has been over working itself. With the new fuel pump, I still only get 26psi running pressure, but the static pressure is holding at about 36 pis(key on engine off)
The diaphragm on the fuel pressure regulator seams to be holding a vacuum well, and isnt leaking any fuel. The injectors dont seam to be leaking off per the test I ran. I have a timing light that I'm going to hook up to it and replace the fuel filter again. Any other suggestions would be helpful.
Thanks.


Avatar
Craig jaster
August 26, 2012.



Pinch off the return line to the tank at the pressure regulator and see what the pressure measures.

Roy

ASEMaster6371
Aug 26, 2012.
Symptoms indicates the fuel pressure regulator is faulty.

KHLow2008
Aug 26, 2012.
OK, the pressure went up to about 50psi. Does that explain it?

Tiny
Craig jaster
Aug 26, 2012.
Yup, that means a bad pressure regulator.

KHLow2008
Aug 26, 2012.
Ok, I unhooked the vacuum line off the fpr and the pressure went up to normal operating pressure 35-36 psi

Tiny
Craig jaster
Aug 26, 2012.
35-36 psi is at lower edge of specs but vacuum line should be attached.

KHLow2008
Aug 26, 2012.
That is normal. With no vacuum, the pressure should rise.

ASEMaster6371
Aug 26, 2012.
Put a brand new regulator on it with no change in results it seams the regulator works properly without a vacuum line hooked to it?

Tiny
Craig jaster
Aug 26, 2012.
With vacuum, it will lower the pressure. Thats normal as I said before.

What kind of pump did you use?

Roy

ASEMaster6371
Aug 26, 2012.
The name brand on the pump is airtek.
Now the truck is getting 26psi @ idle but if I give it a little more throttle, the pressure goes up to 36psi. Naturally a higher rpm is going to require more volume @the same pressure correct? So, does that mean the regulator is operating correctly? Maybe the old regulator was bad and I just need to take it for a spin and see what happens in stead of looking at the pressure gauge.

Tiny
Craig jaster
Aug 26, 2012.
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