Mechanical vs. Electric fuel pumps

[fredguaz]

Hello,
Does anybody have a definitive answer on which cars were equipped with which? I read somewhere where 1974 and all FI had electric fuel pumps. All other years had mechanical. I also read on a vendor site that 1974 - 1977 and FI all had electric. The reason I ask is that I have a 77 (mfg 8/76) with aftermarket electric but my car has rubber mounted studs, fed by Grn/Blk harness wire and a blocking plate on engine, leading me to believe my car originally came with electric fuel pump. I am leaning toward wanting to install a mechanical pump based on some research I have done on this forum. As a side note, my fuel lines do not run through the cabin. There are hard lines (2 or 3) that run underneath car adjacent to the center arch.
Thank you,

[Dawgme85]

My '77 is equipped with a mechanical fuel pump. However, I'm considering replacing it with an electric, due to the length of cranking time required to start it when it's cold (10-15 seconds). Once it's been started the first time, it'll crank right over (instantly, like just a quick bump of the starter). It's just that first start of the day. I'm of the opinion that there's a check valve either missing or stuck open, but have thus far been unable to confirm or find reference to it, if it truly does exist...

[fredguaz]

Thanks Dawg.
Seems like some time in 1977 cars went from electric to mechanical until the FI cars came along. My car was mfg on 8/76. When was yours manufactured? And do you have rubber mounted studs in trunk and a harness wire (Grn/Blk) to power pump in trunk? Oh, and have you considered trying to install a check valve? I'm sure you're aware of safety issues with constant power to electric pumps.
Thanks

[bonsaiwino]

Dawg me, My '79 was having the exact symptom you described. After asking my mechanic, here's what he said. START UP PROCEDURE: 1) turn key to 'ON' position, 2) pump accelerator pedal 3 times, 3) start car. My car has started immediately every time since using these steps.

[JEEPER]

Dawg me, My '79 was having the exact symptom you described. After asking my mechanic, here's what he said. START UP PROCEDURE: 1) turn key to 'ON' position, 2) pump accelerator pedal 3 times, 3) start car. My car has started immediately every time since using these steps.

My 79 (I bought new) has always done the exact same thing since I took delivery. I complained to the dealer and they got authorization from the factory and put an electric on under warranty.

[blazingspider]

My 77 has a manufacturer's date of 1/77 and originally came with a mechanical fuel pump. No green black wires from the harness in the trunk and no mounting studs for an electric fuel pump. I did convert to an electric fuel pump many years ago. Just my personal preference.

[majicwrench]

The factory mechanical pump has a check vavle in it. If it fails, you can take pump apart and clean it. My 72 can sit for days and fire on the first couple revs. The first few months, before I cleaned the check valve, what a pain. crank crank crank crank crank etc
Keith

[Redline]

The factory mechanical pump has a check vavle in it. If it fails, you can take pump apart and clean it. My 72 can sit for days and fire on the first couple revs. The first few months, before I cleaned the check valve, what a pain. crank crank crank crank crank etc
Keith

Good to know. Mine fires on the first few turns if it sits overnight. If I go a week between running it, then I need to crank for probably 10 - 15 turns, so I assume the float bowls are draining?

[majicwrench]

Float bowl should never really "drain" but yes, level goes down w time, evaporation more than anything I suspect. Then if fuel drains out of line you end up crank cranck crank crank.
Keith

[fredguaz]

Any chance somebody can post a pic of their STOCK (74-76) electric fuel pump setup in trunK? I've got an aftermarket pump that was never mounted by PO but would like to see how the original (Carter?) fuel pump was attached/wired.
Thanks

[aj81spider]

Here's a picture of my 74:

[fredguaz]

AJ thank you much for that pic. I actually did come across that pic in another thread but couldn't zoom in enough on the pump setup to see detail. I would be interested in the following:

1) Is that a Carter pump and are they still available? (I canNOT find them online, ebay, etc.)
2) If so, can these pumps be rebuilt?
3) A close up pic of how these pumps are mounted and wired.
4) Is there an ID number (model number) on pump?

Thanks again,

[aj81spider]

Hi Fred,

I'll try to take some closer pictures tonight and answer your questions when I get home from work. Inconveniently I'm in the middle of replacing all the hoses, but I think only one is missing right now and I'll point it out in the picture.

[fredguaz]

Thanks, AJ
I tend to be a stickler for originality. Right now my OCD is on fuel pumps!
I hope to one day have a trunk as clean as yours. I first need to replace some rusted metal around lip that supports fuel tank at rear of car. Oh, I'm originally from Revere, MA. Spent some time in your neck of the woods.

[aj81spider]

Took some pictures that I hope are of some help. I'll answer your questions to the best of my ability - but I suspect that will be much less help!

1) Is that a Carter pump and are they still available? (I canNOT find them online, ebay, etc.)
> I don't know. There are some patent numbers on the side, but I can't see that well with the pump mounted in the car. I didn't see any "carter" written on it.

2) If so, can these pumps be rebuilt?
> Again - I don't know. I repainted mine, but that's all I did. It ran when I took the car apart. I'm hoping it runs when I get it put back together!

3) A close up pic of how these pumps are mounted and wired.
> Hope this helps. I can take more if you need a different angle. Tank connection is on top, hose to the engine bay on bottom. There is a flow arrow on the side of the pump that points down. There are two wires (red and black) coming out of the pump. The red is wired into the harness, the black ties to a mounting screw on the pump.



4) Is there an ID number (model number) on pump?
> I'm not sure. There are a series of numbers (I took to be patent numbers) on the left side, but I can't read them with the gas tank in.

Other pictures of hose hookups.




In this picture the center hose on the valve was a clear plastic hose that I replaced. It is the one that goes out the trunk to the hard line that runs to the engine bay and the vapor cannister (if you have one). I'm also missing one hose to from the tank to the valve, but it should be apparent where it goes. The valve is off it's mounting as I'm in the middle of replacing hoses.




This is not such a great one of the hoses leaving the trunk. The fuel supply is on the left, the return in the center and the vapor cannister line on the right.



Hope this helps. Let me know if you need any other views.