I'm losing my mind over this...

[GSCReno]

Hey Guys... First the specifics; "73 with flattops, known good mechanical fuel pump, new fuel filter, 3 and a half gallons of fresh gas with a can of B-12 Chemtool added to the tank... I'm not getting fuel to the filter or the float bowls. When I turn the key I hear an electric fuel pump in the right rear of the car... I see in the Black Dragon catalog that they offer a fuel pump filter for the '73/'74... Did my '73 come stock with an electric and a mechanical fuel pumps??? The old girl will start and run for a few seconds on starting fluid, but it's not drawing any fuel up to the top... HELP!!! Please somebody help me figure this mess out... Cheers, Scott

[SteveJ]

There are a lot of information gaps in here. First, though, to answer your question, it is likely the electric fuel pump was added to alleviate vapor lock problems that many reported in that era.

So, fill us in here.

1. What is the history on this car to your knowledge? Has it been sitting? Are you working on a recent problem?

2. Is fuel getting to the fuel filter?

3. What is the condition of the gas tank? Have you inspected it for rust?

4. Are the hard and soft lines in the fuel system in good condition? How old are they?

My first swag is junk in the tank or the fuel line clogging things up.

[GSCReno]

Hey Steve... Yup, she sat for 3-4 years before I got her...Just got off the phone with Mr. D. Honeycutt and he advises that I drain the tank and start from there. I can't wait to see what kinda crud comes outta that fuel tank... Looks like I'll be sending my roundtops to Z Therapy for the complete treatment... Nothing that money won't fix... Cheers, Scott

[motorman7]

I have a '73 with flat tops and yes mine came stock with both electrical and mechanical pumps. When I first purchased the car niether fuel pump worked, but the electrical did make noise. It also sat for 3-4 years. I tried running just the electrical, because it was making noise, but found that it was not pumping at all...just making noise. I went out and bought a new mechanical pump and by-passed the electrical pump and the car started right up. The car runs great without the electrical pump. I have been operating that way for several months now. I do have plans to install the electrical eventually but right now am running fine without it. I also blew out the lines with compressed air during the whole pump replacement process to make sure all the lines were clear.

Hope that helps.

Rich

Edited May 16, 2011 by motorman7

[d240zx2]

You've got either plugged fuel lines/filters or a bad set of pumps. Probably both. Tank contamination is also quite likely. Drop the tank, inspect and clean. Blow the lines w/compressed air. Replace the electric pump. If that doesn't work, punt.

[GSCReno]

Hey Guys... Thank you, thank you, thank you... Punting may be an option, but I think I'll drain the tank first and filter the contents. Next I'll replace the filter in the electric pump, curse the flattops, just because they're flattops, and give it another try... I may be back here, cursing like mad, at some point in the near future. But at least I've got a starting point... Cheers, Scott

[Bonzi Lon]

I suggest putting carb cleaner or other solvent in the fuel lines in front, then blow them out. It will make a smelly mess if you don't catch it. A new and a spare fuel filter should be purchased.

Bonzi Lon

[240ZX]

When refurbishing my 1970 I discovered that the fuel tank pick-up line has no screen or filter as it leaves the tank. I had a similar problem, like what you've described, and the cause of my fueling problem was a small bit of debris that would find its way to the pick-up line entrance and block it off. I actually used a fiberoptic scope, placed it in the fuel tank and watched this little piece of debris swirl around and plug the pick-up line! Anyway, this is what caused my fuel pick-up problem.

Tom

[240ZGL]

I just did the whole fuel system on my 73, front to back. The tank needed a boil out, no rear pump, bad front pump, clogged lines. I'm running a Facet rear pump 3-4 lb pressure gold 60 series with a filter before the pump, new 5/16 fuel lines in the rear. At the front a new filter to a new mech pump and new 7mm fuel lines. Mine you I have a triple set up but this works fine. I'm not sure what the psi is on the stock pump, but the factory on is a copy of the old Bendix pump which are now Facet/Purolator. I don't think the stock electric pump did more that 4 psi since it was feeding the mech pump.

[GSCReno]

Thanks Guys... I've got the same problem that Rich had. Electric pump makes noise, but she no pump... I've drained the tank and blown out the line, so I think I'm gonna bypass the electric pump and try just running the manual one for awhile... I'll let you know if that helps. Thanks again... Cheers, Scott

[Reverend]

I remember someone had problem with his 73 flattop-Z in zcar.com and he was adviced to use those flattops as a boat anchor..

[GSCReno]

Update: I bypassed the electric pump, drained the tank and blew out all the fuel lines. I have good flow/pressure all the way to the float bowl inlets. She still won't start. I know that the flattops are garbage, but I'm stuck with them for the time being. Are there little screen filters between the fuel inlets and the float bowls on these boat anchors??? Keep the good advice coming, Guys. Thanks in advance... Cheers, Scott