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Germain's Avatar
 
Join Date: Sep 1999
Location: Michigan
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Fuel Pump

Hello all,

I've read the artical on the fuel pump, and excuse my ignorance but this is what happens. I turn the key to the run position, and a loud buzzing noise comes from the fuel pump. This noise lasts for about 1 second, then no noise. I get no fuel to the injectors, even though I have repeated this process several times. Is my pump dead???

Second, can I test the pump by putting 12V directly to it? I.E. wire from the car battery terminals both positive and negtive lines.

Thanks all, any input would be great.
Old 10-14-1999, 05:35 PM
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The behavior you describe (1 second BUZZ) is normal. That's how the FI starts to build up fuel pressure. The BUZZ is the pump running.

How do you know you are not getting any fuel to the injectors? Mount a fuel pressure gauge (capable of reading at least 35 PSI, up to 50-60 is preferable) to one of the fuel rails (or Tee it into the line from the pump to the right-side fuel rail) and see if you get any pressure at all.

You can pull the fuel pump relay off of the relay board (second from the rear) and jumper between the "forward" connection and the "left-rear" connection. That should force the pump to run ALL THE TIME. Ignition on or not. Don't let it run for more than about 30 seconds, though. I hear it's not great for it to run for a long time without the engine running.

Good luck!

--DD
Old 10-14-1999, 06:10 PM
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Well, I can tell no fuel is getting to the injectors because there is not fuel in the fuel lines to them. I disconnected the hose that goes to the metal peice that runs to the injectors, and it was dry. I see no fuel. Should I? Should the fuel run up this hose with it disconnected?

One other thing I just thought of, I prob would have looked at it had I thought of it, but can you plug the pressure regulator in backwards, where it wont let fuel pass? Anyway thanks Dave, and thanks to everyone else too.
Old 10-14-1999, 06:51 PM
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Well, how long has the car sat? Is the fuel fresh? Is the fuel filter new? If the tank is old it may be filled with junk blocking the pump. If it is a 70-74 pump it may be hooked up wrong, there are three hose conections, look at DD's hose diagram. I know the regulator should be hooked up a certain way, it makes sense that if it hooked up backwards it would not allow fuel through.

Try putting the pressure side hose in a 1 gallon gas tank, then wire up the pump to see if any fuel comes out.

Another thing, is the pump in a stock location? I think it NEEDS to be at a point BELOW the level of the bottom of the gas tank or it will not prime.

Also, if the pump was jamed and enough power was shorted to the motor, the motor spins and shears of some internal "fingers" that spin the roller part of the pump. SO the pump will sound fine, but won't pump.

Pumps cost big bucks new, so make sure it is the pump before buying a new one.

http://www.pelicanparts.com/914/technical_specs/914_20FI_diag.htm
Old 10-14-1999, 09:24 PM
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I've learned the hard way --- always check the simplest things first.

Since the filter is on the intake (suction) side of the pump, a plain old clogged filter could be restricting fuel to the pump. No fuel in = no fuel out.

Also, (even though this may seem plainly obvious) check anything that has changed on the car since the last time the engine was running well.

These suggestions may not be overly insightful, but it is surprising how often the simple things get overlooked.

Good luck.
Howard
Old 10-16-1999, 07:22 AM
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Well, heres an update. The fuel was being restricted because of the regulator being pulgged in the wrong way. Now what you ask?

Well, I can confirm that I am getting spark, and I can confirm that I am getting fuel out of the injectors (I undid one and watched it shoot out fuel). I drained all the gas from the filter, emptying the tank, and refilled 2 gallons with 94 octane fuel. All the engine does now is crank. If I pour a TBLS of gas into the throat, it was run for .5 second, and start cranking again... Also, I have the air unhooked from the system, all the air is traveling freely to the openings next to the pistons. Any ideas???
Old 10-16-1999, 03:28 PM
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