Fuel pressure gauge location

[Jaymanbikes]

Chasing some fuel gremlins in my stock 72.  Would like to put a fuel pressure gauge on the car.  Looking for ideas from folks with cars that have one installed and are running mechanical fuel pump only.  Thanks!

Jay

[Zed Head]

Are you using copper tube from the pump to the carbs?  That's interesting.  The tube looks of small diameter.  Is it a new thing or has it been running fine like that?

There's not much to gauge placement.  The fitting needs to be between the pump and the carbs.

Describe a gremlin and you'll get more ideas.

[SteveJ]

As @Zed Headsaid, you need to place it in the short run between the fuel pump and fuel rail.

The challenge is that the gauge should be vertical for best response. You'll need a tee adapter like this: https://www.amazon.com/GlowShift-Pressure-T-Fitting-Adapter-2002-2014/dp/B072M33C5F. It is for 5/16 fuel line with a 1/8 NPT fitting for the gauge.

Make sure the gauge and tee adapter have the same size fittings.  Some gauges are 1/4 NPT. You'll want no more than 15 PSI on the gauge, otherwise you lose too much resolution.

If you think your fuel pressure is too low, look for the simple things: clogged fuel filter, old & brittle fuel hose, and a fuel pump with a worn/torn diaphragm.

[Jaymanbikes]

1 hour ago, SteveJ said:

As @Zed Headsaid, you need to place it in the short run between the fuel pump and fuel rail.

The challenge is that the gauge should be vertical for best response. You'll need a tee adapter like this: https://www.amazon.com/GlowShift-Pressure-T-Fitting-Adapter-2002-2014/dp/B072M33C5F. It is for 5/16 fuel line with a 1/8 NPT fitting for the gauge.

Make sure the gauge and tee adapter have the same size fittings.  Some gauges are 1/4 NPT. You'll want no more than 15 PSI on the gauge, otherwise you lose too much resolution.

If you think your fuel pressure is too low, look for the simple things: clogged fuel filter, old & brittle fuel hose, and a fuel pump with a worn/torn diaphragm.

I just replaced my cheap knock off OEM fuel pump with another cheap knock off...LOL.  I might just put an electric pump in place.  Any concerns with leaving the mechanical in place along with the electric?  

[SteveJ]

You can run both an electrical and mechanical fuel pump. The electrical pump should have a way to shut off if the engine is not running, such as an oil pressure signal or signal from the alternator.

Many 73 240Zs received a retro-fit from Nissan via the dealer network to add an electric fuel pump. The 260Z came from the factory with both mechanical and electric fuel pumps.

[w3wilkes]

You can also use an inertia switch for electric fuel pump cutoff.

 

[Jaymanbikes]

21 hours ago, Zed Head said:

Are you using copper tube from the pump to the carbs?  That's interesting.  The tube looks of small diameter.  Is it a new thing or has it been running fine like that?

There's not much to gauge placement.  The fitting needs to be between the pump and the carbs.

Describe a gremlin and you'll get more ideas.

No, it’s a OEM fuel rail, a very short piece of fuel tubing between the mechanical pump and the rail.

[Jaymanbikes]

9 hours ago, SteveJ said:

You can run both an electrical and mechanical fuel pump. The electrical pump should have a way to shut off if the engine is not running, such as an oil pressure signal or signal from the alternator.

Many 73 240Zs received a retro-fit from Nissan via the dealer network to add an electric fuel pump. The 260Z came from the factory with both mechanical and electric fuel pumps.

Good to know, yea would definitely need a shut off for safety purposes