Fuel Pump Woes, I think

Flormat · Flormat's Garage

My new 914 was in storage for 10 years so upon arriving at it's new home she recieved new oil & filter, thorough cleaning of the gas tank and new lines up to the filter- no more leaks. The engine turns over just fine but will not fire. I don't hear the fuel pump turning on for a second or so when I turn the key. Does D-Jet do this? I figure I am either not getting power to the pump due to bad relay, wires or connection, or the pump is simply bad. It was getting to dark and chilly last night to investigate. Any other suggestions from all you experienced owners? Where is the pump located? Is is just downstream fromt the filter? And is the filter and little dinky plastic box? The manuals only show location for the carbed 6. Thanks for any help you can provide?

Dave at Pelican Parts · Dave at Pelican Parts's Garage

D-jet does about a 1.5 second "buzz" of the fuel pump to start building pressure when the key goes from "off" to "on".

After 10 years, the pump is a definite suspect for this. When gasoline goes "off" and turns into varnish, it can definitely gum up the pump...

Check the power connection to the pump. Actually, check the power to the AAR--it's the same circuit. If you get +12V for a moment when the key gets cycled to "run", then check again at the pump itself. If you don't get any power at the AAR connector, then the problem is likely in the pump control system.

http://www.914fan.net/fuelpump.html describes troubleshooting the pump power circuit.

--DD

Bruce Allert · 03-26-2003, 07:50 AM

Hey, good goin' & nice rescue. My 73 was in storage for 10 years too.
The fuel pump is next to the filter which is the little plastic box located on the passenger side just in back of the heat control flapper (nice place for it, huh? [flamables & heat???])
bruce

Flormat · Flormat's Garage

What is AAR, auxilary air regulator? Thanks guys

Bruce Allert · 03-26-2003, 08:34 AM

yup

Potter · 03-26-2003, 08:40 AM

Bruce, I'm embarrassed to ask this........but in your description of the location of the pump and filter are you under the car or from above?

Bruce Allert · 03-26-2003, 11:27 AM

yup, under it. It would be so easy it it were put above in the engine compartment, especially to change the filter. I love gas running down my arm to my pits! No matter where I pinch it off there's always enough gas left in the line to run down the path of least resistance!

bruce

Jared at Pelican Parts · 03-26-2003, 12:01 PM

One other thing I might add, if the AAR is bad, it will prevent the engine from starting. What happens is that the contacts inside short out, and since it is on the same circuit as the fuel pump, it prevents voltage from going to the pump.

If it's bad, just unplug the AAR and bypass it. You don't really need it there anyway.

Flormat · Flormat's Garage

I did some testing today, I pulled the pump relay and connected a jumper wire between terminals 30 & 87. There is no power at the pump. There IS power at the AAR. I then connected the power wire for the aar to the pump- showed voltage but the pump would not run. I then ran power from the battery to the pump and still nothing. I read through the articles mentioned above but am still stumped. It appears to me the pump is bad, but if I get power to the AAR why not at the pump? Also , does the pump have a 2 prong harness that connects to the pump? I see a cylindrical 2 prong connector near the pump but it is disconnected. In place there is a red wire going from the pump terminal to the terminals mounted on the ign. coil and a black ground secured to the top side of the engine.

Flormat · Flormat's Garage

I seem to have discovered the problem. For some reason the previous owner disconnected the wire connector to the fuel pump and replaced it with his own ground and a positive lead connecting to the terminals on the coil. The connector that was disconnected had corroded terminals but the ground was still good as was the power wire. After cutting the wires back and replacing the connector I determined the pump was bad. Can these be rebuilt?

Peter_Hinkle · 03-30-2003, 05:20 PM

Quote:

Originally posted by Bruce Allert
. I love gas running down my arm to my pits! No matter where I pinch it off there's always enough gas left in the line to run down the path of least resistance!
bruce

Just a side note. I happened to be @ a swap meet the other day and found a cool little thing called a fuel filter replacement kit. It is the perfect little device for our cars in stock trim. It has this little deal that looks like a "cigarette" roller (if you get my meaning) and it pinches off the fuel line so well that nothing comes out. The mechanism appears to be in the realm of a vice grip mechanism except that it doesn't have teeth and wont hurt the line. It also comes with a couple of different fittings to put in the end of a line that work alot faster and better than a bolt or a golf tee. I am trying to get ahold of the manufacturer so i can figure out if they are still being made and if so, where to get more. The name of the company is Closnech (yep, I spelled it right) and I have never heard of them. Anyone?

Dave at Pelican Parts · Dave at Pelican Parts's Garage

Quote:

Originally posted by Flormat After cutting the wires back and replacing the connector I determined the pump was bad. Can these be rebuilt?

Yes, with a varying level of difficulty depending on what is messed up.

The rollers may be gummed up. You can remove the screws that hold the end cover on (mark the pump body, the end cover, and the piece sandwiched between them because they need to go back on the same way) and pull the cover and chamber piece off. There are three rollers on the pump impeller. Take them off as well, and clean up everything you can with carb cleaner/brake cleaner and a brass-bristle brush. Try to get the impeller to turn by hand.

If you can do that, put the pump back together again (don't forget the rollers) and see if it will turn when you apply power and ground.

If not, you will have to open up the cannister by prying back the peened-in (pressed-in?) parts. You'll have to clean it all up and make sure the electrical bits (brushes, etc.) are OK and put it back together again yourself. I haven't seen the inside of that part...

If all else fails, there's always the option of a new or rebuilt pump. Or used--but you already have a used pump...

--DD

Bruce Allert · 03-31-2003, 05:20 AM

Quote:

Originally posted by Peter_Hinkle
It has this little deal that looks like a "cigarette" roller (if you get my meaning) and it pinches off the fuel line so well that nothing comes out.

Good job Peter

I'd deffinetly buy one of those...
as for getting your meaning, well, ah.... I inhaled

(once)!
bruce