#$&* '74 fuel pump issues

[74-911]

PART I

Week or so ago went out to fire up the 911 and blast around some back roads. It was very hard to start and ran really rough when it did start (had been running great). As I backed out of the garage I noticed a large wet spot on the garage floor, killed the car and - yep it's gasoline. Turned the key to on and sure enough, the fuel line from the pump to the accumulator was leaking near the swaged rubber hose to metal line. Pushed the car back into the garage.

Yesterday I removed the bad line (this was the only original fuel line left on the car - not a smart move). To remove it I had to unclamp the fuel pump and pull it down from the shelf in order get at the clamp on the banjo's barb. Dremeled off the swaged sleeves and put new high pressure hose on with good fuel injection clamps and reinstalled the fuel line..

When I went to start the car, the fuel pump was very loud and making a kind of rattling/swishing noise and is not pumping any fuel at all.

Question is: did I damage the pump somehow in replacing the line or is this just a very strange coincidence of bad timing that the pump picked this exact moment to go out? This is the original pump with 150K+ miles on it. I double checked everything, there are no pinched hoses.

Anyone else experienced anything like this?

PART II

After extensive searches of this forum, my options for bad pump replacement appear to be:

original OEM '74 pump - $850+ (not gonna happen)
rebuilt '74 pump $300+ (never had much luck with rebuilds)
replacement Bosch pump $250 and requires modifications
Walbro pump $120 and requires modifications

Anyone know of any other or better solutions ?? I try to buy all P-Car parts from our host but that's a big hit between the Bosch and Walbro...

thanks

[lindy 911]

It sounds like your pump may be cavitating. Crack open the fuel line at the other end in the engine bay, have a helper turn on the pump and then wait for it to push all the air out of the line. When fuel shows at the engine bay end, turn off the pump and tighten the fitting.

Worth a try.

[74-911]

Originally Posted by lindy 911

It sounds like your pump may be cavitating. Crack open the fuel line at the other end in the engine bay, have a helper turn on the pump and then wait for it to push all the air out of the line. When fuel shows at the engine bay end, turn off the pump and tighten the fitting.

Worth a try.

I removed the fuel line from the accumulator fitting which should have prevented that (how I knew it wasn't pumping any fuel). The fuel pump on a '74 is right in front of the driver side rear wheel. However, it does sound like it was cavitating. Maybe it was air-locked between the fuel tank and pump ??

[Targalid]

With your description of the fuel pump location being back by the engine, Lindy's advice is even more relevant. Push the fuel through to the pump by pushing at the tank with air pressure and a rag to help seal the opening or pull the fuel through with vacuum to the pump. I recommend a vacuum pump but the old sucky pukey always works. I think Lindy is right. You are trying to pump air instead of fuel. I bet your pump is just fine. All it needs is some fuel to pump.

[gimlet911]

Back when the '74 was only a couple years old, wrench moved the fuel pump from the rear wheel well to the front like the later cars, so it would always have cool fuel coming in. Vapor lock problems stopped, never had an issue with fuel pump again.

All fuel lines need to be changed on a car this age. I've seen the puddles of gas too. Scary.

[74-911]

Originally Posted by Targalid

With your description of the fuel pump location being back by the engine, Lindy's advice is even more relevant. Push the fuel through to the pump by pushing at the tank with air pressure and a rag to help seal the opening or pull the fuel through with vacuum to the pump. I recommend a vacuum pump but the old sucky pukey always works. I think Lindy is right. You are trying to pump air instead of fuel. I bet your pump is just fine. All it needs is some fuel to pump.

Another "Duh" moment. Don't know why I didn't think to siphon gas back through the pump to "prime" it as there is probably no gas in the line from the tank to the pump. The very distinct rattling noise when the pump is running or you shake it made me assume something had broken inside. I have no idea what kind of impellor the pump is using but the rattling may wwell be normal.

Will try again in a couple of days when I get time.

Thanks again for the responses...

[kodioneill]

Chances are your fuel tank is contaminated with rust. Pull the fuel sender unit out and look inside with a flashlight.

[exc911ence]

I just changed the pump on my '75. It shares the same mounting location as yours. It's a vane-style pump so you will hear the vanes rattling in their grooves if the pump is full of air. As mentioned above, I used a rag to seal the fuel filler and stuck an air-gun attached to my compressor to push fuel back down to the fuel pump. Worked beautifully.

Sadly something else failed two weeks later sidelining the car again...

[jess p]

Napa sells one that essentially bolts right up,no mods,$110.00,new. I have one on
mine 3 years old and still running strong.

[Jim75911S]

To prime the fuel pump on my 75 I jacked up the front end and disconnected the fuel line on the WUR. Turned ignition on and held a jar under the line, waited to just fuel came thru. Took longer to jack up car than to bleed the line.HTH Jim