Electric fuel pressure gauge sending unit mounting

[Low Budget]

Does it matter where I "T" into the system? My return line is slightly kinked about 6" from the injector fuel rail. I'd like to cut out the kink and "T" in there. Will the pressure readings from this position be accurate, or is there too great a pressure drop from all the injectors having been fired? I really don't want to remove the Schrader fitting near the regulator and use that spot. If my idea is NFG, where would anybody else suggest please?

Thanks, Jeff

 

[Tim Riecks 6]

I never removed the Schraeder fitting when I installed my gauge. I've just got a line with the proper connector running from the fitting to the sender. All I did was screw the connector on the end of the rail.

 

[S10xGN]

I tee'd my electrical sender about 3" in front of the filter. It reads within 1# of the rail-mount gauge...

 

[Low Budget]

Thanks guys.

Travis,
What do you ask for to get the fitting that threads on at the schrader fitting? Where did you get it, and what does it consist of? Just the fitting, or a hose/line of some kind too? I might remote mount the sending unit to the inner fender and would need something flexible like braided line.

Anybody out there able to answer the other part of my original question? Can I "T" in on the return line and get accurate reliable readings? This is my first choice.

 

[soonergn]

The return line only carries the fuel back to the tank that the regulator has bled off and would not show your fuel pressure. It will have to be in the feed line somewhere and I would think the closer to the fuel rail the better, with actually at the fuel rail being optimum since the reading at the injectors is what counts. However, you should be tuning with a scan tool and the fuel pressure reading should only be a reference number anyway.

 

[Low Budget]

I think it just became clear.

Anything beyond the last injector is really not going to have appropriate readable pressure. It can't be read just from as near to the fuel rail as possible, but prior to the last injector or pressure is just at return levels. So.. the last injector in line is the final bottleneck that holds whatever pressure to which the regulator has been set. When it opens, whoosh, it's gone. I imagine with the injectors opening and closing it would be a very irratic read if anyone were to read from the fuel rail itself beyond the regulator. I'm thinking, now that I've had my epifany, that anyplace between the pump and regulator would have to have close to the same pressure. Constant as is available anywhere in the system. It does seem as though the best place would be at that test/system cleaning port in front of the regulator, huh?

Do I understand now? I thought maybe I did before and was wrong.

I plan on using a Scanmaster to tune, but I am still going to need to know what my pressure is doing. It will be as soonergn said, a reference number.

Thanks everyone!
Jeff

 

[GNSCOTT]

You want fuel pressure readings after the injectors have been fed, that is why it is run off the fuel pressure regulator.

 

[Low Budget]

Then why do so many people put these under hood gauges right on the Schrader fitting in front of the regulator? (Pre-injectors flow wise.) Where exactly are you saying I should hook-up?

I just spent big bucks for a custom steel braided line to remote mount the sending unit. I still need to buy the piece to fasten it to the Schrader fitting though, so I can still change my tie in point.

 

[GNSCOTT]

The fuel flows in the passenger side and flows out the drivers side. If you put the regulator before the injectors you will lose all pressure out the return line .

 

[GNSCOTT]

a fuel pressure regulator isn't like a dam opening flood gates to feed injectors, its like a dam with closed flood gates, with the resevoir being the fuel rail and the injectors at the bottom of the resevoir. Any excess fuel spills over the top of the dam (or fp regulator)

 

[Low Budget]

Oh no sh*t? I thought the return line was the feed and vise versa. So I'm ok then with where I plan to hook up?

 

[GNSCOTT]

Not sure, but i'd say no because you want to know what the fp is AFTER the injectors, but before or at the regulator. I know Cottons carries the fuel line and it shouldn't take more than 15 minutes to install it. I think I just threw or gave away my stock fuel line.

 

[Low Budget]

Where I am proposing "is" after the injectors according to the direction of flow you indicated. I'm talking about putting my connection the same place everybody puts their under hood "test gauges." Right next to the regulator. Wouldn't this qualify as being exactly as you suggested?

 

[soonergn]

The schrader valve fitting on the end of the fuel rail right beside the regulator is where everyone puts it and it's the best place. Your hose must have a fitting that fits the schrader valve and if it doesn't have something to depress the little valve in the fitting then you can remove the valve by screwing it out with a valve tool just the same way as a tire valve. If you don't want to tie up the valve with your guage then there are "t" fittings available that have a schrader valve and a port for your guage line that just screws onto the valve on the fuel rail.

 

[Low Budget]

Schrader

Thanks for everyones help.

Just got a call saying my hoses were done at the hydraulics shop. (Got some other stuff made up too. Oil cooler hoses etc.)

I'll use the Schrader port. Sounds good!

Jeff