I've installed an Airtex pump on the car as recommended by many.
The car does run but terribly....
I hope I've installed correctly and put the "T" adapter in the right place.
Click to view attachment

The fuel line from the tank goes to the filter then to the pump.
The pump output line is then T-eed to the other 2 lines....
Click to view attachment


Have I got this wrong?
Is the filter restricting flow?
The car has been sitting awhile and I've put fresh gas in.
Otherwise nothing has changed.
Any help is appreciated.

There should NOT be a T fitting when using the airtex pump. The brass fitting on the fuel pump should connect to the filter. The other side of the filter should connect to the big line on the tank. The return line from the engine should connect directly to the smaller line on the tank.

If you put in the T fitting, you are dumping fuel pressure. That will make it run terrible.

Thanks for the response but I'm still confused...
I've got a pump with an input and and output, understood.
There's a third gas line (return) that I need to account for...

The input on the pump comes from the tank. The outlet on the pump goes to the pressure line going back to the engine. The return line coming from the motor hooks directly to the tank.

Ignore the blue line. Your car won't have it.


This diagram should help.

Ok.
I've disconnected the T and plumbed directly to the pump.
Car runs good.
I still have an orphaned line that's just hanging there.
Original pump had 3 spiggots.
Appreciate your patience.


Click to view attachment
Click to view attachment Click to view attachment

Where does the other end of the orphaned line go?

i also suggest to add fuel pressure gauge or borrow from store for a fuel gauge test pressure.

Click to view attachment

Click to view attachment

I’m sure the T line came is from F.I. line from engine bay (fuel regulator) going back to tank that split: 1 from your original 3 port fuel pump and 1 back to tank return.
You can just remove the T line and let the fuel line coming from tunnel return line and directly connect to fuel tank return.


Here is a pic how the 3 port fuel pump.

Click to view attachment

It's the fuel return line from the engine that originally attached to the third spigot on the original pump.

I can't remember what the 3rd line does, but I think it's an overpressure relief or balance. Not required on a two port pump, remove the plastic y fitting, you don't need a t fitting. Plug or remove the extra hose.

The Fuel pressure regulator in the engine compartment dumps fuel to the fuel return line back to the tank. The 3 port fuel pump also has a pressure relief valve that can dump fuel to the return line to the tank. The return line from the fuel pressure regulator and the pressure relief valve on the pump are "T"d together near the pump.

If you replace the 3 port pump with a 2 port pump you eliminate the "T" fitting and the old line from the pump to the "T". The return line from the pressure regulator goes straight to the fuel tank.

You should also be sure you are using fuel line rated for Fuel Inject pressure and the ethanol our gas has these days, J30R9 rating I believe. I have not seen any cloth braided fuel line that is rated for I pressure.

Jim

Yes they do make braided FI line, BUT I wouldn't use it because of methanol fuels. In fact I won't use it any more because it's poor quality and begins to crack in as little as one year.

Only use SAE 30R9 rated fuel hose and FI hose clamps
Gates Barricade hose is a good brand. Do not use standard worm gear hose clamps.

Even with good hose I'd recommend replacing it about every 5 years.

Thanks to all for the advice.
I thought about it last night ...
I've re routed the fuel return line (from engine) back to the pump input ahead of the filter.
Seems to run good and no leaks!
Took it out for some fresh gas and air in the tires
and all seems good.
Click to view attachment

I look at this pic and say get rid of the braided hose, worm gear and spring hose clamps.
To me those things are a recipe for disaster on a 914 FI system.

Proper FI clamps only, SAE 30R9 FI hose.

I'd also use a vibration dampener on the pump mount, and a boot for the positive power lug.

I second dumping the braided hose. Bad news. Not ethanol rated. Pic makes no sense. The return line should go back to the tank, not the pump. What is the other end of that hose attached to, and what line do you have to the return hard line at the tank?

No!

Do you still have fuel injection or do you have carbs?

If you still have FI and you switched to a 2-port pump, the return line will go from your pressure regulator (the last part in the fuel system on your engine) straight back to the second nipple on the tank.
That way the system can bleed off excess pressure and pump the not needed fuel back into the tank.

Again, if this is still FI, you are also using the wrong hose and hose clamps, the whole system after the pump is under a lot of pressure and using the wrong components is a good way to burn your car to the ground.

Outlet of tank, inlet of filter, outlet of filter, inlet of pump, outlet of pump, back to engine's FI loop, in/out pressure regulator and back to inlet of tank. High pressure FI pump
That's it.

Carbs only need one line. Outlet of tank, inlet of filter, outlet of filter, inlet of pump, outlet of pump, to engine, here there can be a T fitting to feed the two carbs. Low pressure fuel pump and some use a low pressure regulator used before the carbs.
Plug the FI return line.

Exception, the PMO regulator for carbs does do a return to tank from the regulator.
High (Stock) or low pressure pump can be used, PMO regulator only and a return must be used if using the high pressure pump.

I switched to the two-port pump several months ago. Plumbing is easy, a single circuit. Fuel tank➡️filter➡️pump➡️engine(fuel rail farthest from pressure regulator)➡️pressure regulator➡️fuel tank. There should be no tee or y in this setup.

Let's summarize things a little bit here.

- The original pump had three ports. One was intended to dump extra fuel from the pump back into the fuel tank. They later figured out this wasn't really needed, which is why pretty much all fuel pumps are now two-port pumps.

- The 914's fuel system works by the pump pressurizing the fuel, and the pressure regulator acting as a flow restriction or blockage, like putting your thumb over the end of a garden hose. Any excess fuel that gets through or past the restriction is dumped back to the tank. That's what the return line is for.

- If you split the outlet of the pump and run one leg of that back to the tank, the majority of your fuel will take the easy way and wind up being dumped back into the tank. You will have very very low fuel pressure.

- If you take the outlet of the fuel pressure regulator and hook it back into the outlet of the pump, excess fuel will go straight back into the high-pressure loop of the fuel system and the pressure will build until the pump cannot push any more. You will have very very high pressure.

In this situation, you should get rid of all of the "T" and "Y" fittings in the fuel line except for those at the fuel rails. (The fuel rails, more or less, are complicated T fittings.) Run your lines from the tank, to the filter, to the pump, to the fuel rails, to the pressure regulator, and back to the tank.

--DD

Thanks
That's a most consice explanation.

I'll have to find that T in the return line and eliminate it.
Any idea where it might be?
For the sake of discussion, would the return line not
be under very low pressure?
I.E
The pressure regulator maintains @ 35 +/-
and the excess is returned at 5 +/- to the tank and
this extra line I've cobbled together.
Also, I appreciate everyone's concern over the lines.
Braided lines are original and new pieces are
SAE 30R7 50 PSI
I do have a fire extinguisher in the car as well.

After the FP reg the fuel SHOULD flow unrestricted back to the return, as opposed to the supply spigot on the fuel tank. You should not be overthinking the 'Y' thing.

Where are you pulling the pump power from?

I think the T or Y split is under the fuel tank unless if the previous owner installed 3 fuel lines inside the tunnel lines from engine compartment all the way to fuel tank area.

I think also the FI fuel pressure should only be between 28 to 32. 35 psi can be too high. Fuel pressure regulator can be adjusted to lower it.

Why do you need to "find the T" when you just posted a pic of it? Are you here just to waste our time?

Surprised it ran @ all with that contra flow ,I agree it needs to be checked for pressure,I've experienced 2 types of carbs pumps that made more than there rated pressure.