Adding Fuel Pressure Sensor

Roadrunner · Postby **Roadrunner** » Sat Sep 18, 2021 8:40 am

Looking to add a fuel pressure sensor to my SE and figured the best/easiest place to put it is on the output side of the dampener on the chassis (see blue arrow).
Just wanted to check that this Aeroflow part would be the best thing to use? Straight female to male quick connect. 1/8npt port for my sensor. The “and -6ORB” part in the description confuses me though. Where’s the -6ORB fitting?

Has anyone installed one of these parts or have a different suggestion? Seems it’s a new Aeroflow part and there’s no reviews out there.

Lokiel · Postby **Lokiel** » Sat Sep 18, 2021 9:50 am

The 6-ORB port is for the gauge/port so order the correct gauge/sensor or a different connector - prefer NOT to use a 6ORB-NPT adapter, it's more expensive, adds additional failure points and looks grap.

ORB fittings are nicer than NPT/BSP fittings IMO when they've got something heavy on them, such as a gauge, because the ORB threads go all the way into the fitting vs the NPT/BSP fittings which are tapered and only go in between 25% and 60%.

Your suggestion is similar, but better, than this one (great guide and pictures): http://racetrackdriving.com/tech/miata/fuel-pressure-gauge-racepak-usm/

Your suggestion is better because his solution is on the wrong side of the damper.

Make sire you have the quick-fittings disconnector otherwise you'll risk damaging the quick connect fittings which is something you DON'T want with fuel lines.

Hint on usage:
1. Push the disconnector all the way in
2. Put a finger and thumb under it and hold onto the hard line, squeezing the disconnector into the hard line
3. With your other hand, pull the hose end out - it should come out very easily

DON'T pull the disconnector too - found that out the hard way (I'd used the disconnector years ago and remembered it working easily but the last time forgot about how to use them and blindly tried pulling hard to no avail - then re-read instructions on usage).

Lokiel · Postby **Lokiel** » Sat Sep 18, 2021 10:04 am

Just had a more detailed look at that part - it looks OK:

In the photo:
* Left side housing is the male 5/16" fuel line-in
* middle housing is for 1/8" NPT gauge/sensor
* Right side housing is ORB-6 female port and it looks like it has an ORB-6 Female 5/16" quick disconnect fitting screwed into it.

The fitting is expensive because:
1. It's a quality fitting
2. You're getting the fitting AND the ORB-6 to 5/16" female quick disconnect fitting

greenMachine · Postby **greenMachine** » Sat Sep 18, 2021 12:36 pm

I am confused about the function of the ORB fitting - presumably that is the other end of the return line to the tank, to complete the circuit? Is it another barb like the one on the left of the 'T', but the female?

I wonder about mounting the sensor to that pipe, the engine vibration is going to result in the sensor plus all the fittings stressing the pipe. I think I would mount it remotely, even though that increases the number of joints and the risk of leaks. I would certainly be using aluminium fittings exclusively, to reduce the mass hanging off the end of the pipe.

All things considered, I think I would prefer to cut the flexible line and insert a simple barbed 'T' with the sensor remotely mounted on the engine or bulkhead.

Thanks for the reminder about the correct technique for the disconnection of those fittings - the first time I did it, I did it the right way without realising there was a wrong way, and couldn't understand why next time it just wouldn't work .. eventually I figured it out :roll:

.

Roadrunner · Postby **Roadrunner** » Sat Sep 18, 2021 2:01 pm

greenMachine wrote:I am confused about the function of the ORB fitting - presumably that is the other end of the return line to the tank, to complete the circuit? Is it another barb like the one on the left of the 'T', but the female?

I wonder about mounting the sensor to that pipe, the engine vibration is going to result in the sensor plus all the fittings stressing the pipe.

Yeah that’s what I’m confused about. I’m under the presumption that the quick connect fitting is on both ends, male one end, female the other. And then the sensor port in the middle is either or both? an NPT and/or an -6ORB.
Maybe the side shown in the pic is the ORB and the opposite side is an NPT port too?
Annoyingly neither Aeroflow or a reputable big reseller have responded to my email asking for clarification.

The damper is mounted to the chassis and the line to the fuel rail is flexible so technically this will remote mount it away from engine vibrations.

I personally hate NPT but the sensor I have is NPT.

Lokiel · Postby **Lokiel** » Sat Sep 18, 2021 3:10 pm

On the fuel rail of return-less systems (like the MSM, NBs and all modern cars), there is a damper at one end.
On the cold-side shelf there is a bunch of fuel-line "spaghetti" with another damper on it (in the original photo, see the cylindrical thing that the 2x hard lines go into.
These dampers are supposed to minimise pulses generated by the fuel injectors.

Q: "I am confused about the function of the ORB fitting - presumably that is the other end of the return line to the tank, to complete the circuit? Is it another barb like the one on the left of the 'T', but the female?
A: No, this adapter is just to insert a sensor inline with the fuel hose going from the pump to the fuel rail. There is NO return line to the tank.
The ORB-6 end's female quick-connect connects to the OEM male barb and the adapter's male 5'16" barb connects to the OEM female quick-disconnect fitting (blue arrow).

Q: "Yeah that’s what I’m confused about. I’m under the presumption that the quick connect fitting is on both ends, male one end, female the other. And then the sensor port in the middle is either or both? an NPT and/or an -6ORB.
Maybe the side shown in the pic is the ORB and the opposite side is an NPT port too?"
A: This fitting is clearly 2 fittings. Left side is the male 5/6" quick-connect barb, centre female thread is for the NPT gauge/sensor, and right side the female ORB-6 port with a female 5/16" quick connect fitting screwed into it.

The Aeroflow fitting has a female ORB-6 fitting on the right (it's very long to allow a 5/16" female quick connect fitting inside of it).

As I alluded to earlier, ORB fittings are great because they screw in 100%, making them very strong.
This gives the fitting maximum flexibility, you can use a male ORB-6 adapter to whatever you want (eg. male ORB-6 to male 5/16" barb, male ORB-6 to female 5/16" quick-connect, male ORB-6 to 90* AN-6 barb,etc).

With aftermarket fittings, it's not uncommon to require 2 because it's not economical to cover every combination with a specific fitting.

Ideally you just want an adapter with an input 5/16" female quick-connect barb, centre housing with the NPT female thread for the sensor, output 5/16" male quick-connect barb.

Roadrunner · Postby **Roadrunner** » Sat Sep 18, 2021 4:26 pm

Ahh ok. A female quick connect screwed into an -6ORB port. That would be why the 3/8in version has a -8ORB as it’s physically larger.

So next question then, I understand how the mazda quick connect works, (your explanation was perfect. thank you), so how does the Aeroflow female quick connect work? I’m guessing the lip on the male barb sits inside the open sided groove, but how do you get it in there? Is this similar to another manufacturers quick connect? I assume a tool is needed for this as well. Googling brought up a few different types but none that look like that.

The American · Postby **The American** » Sat Sep 18, 2021 6:21 pm

Roadrunner wrote:Ahh ok. A female quick connect screwed into an -6ORB port. That would be why the 3/8in version has a -8ORB as it’s physically larger.

So next question then, I understand how the mazda quick connect works, (your explanation was perfect. thank you), so how does the Aeroflow female quick connect work? I’m guessing the lip on the male barb sits inside the open sided groove, but how do you get it in there? Is this similar to another manufacturers quick connect? I assume a tool is needed for this as well. Googling brought up a few different types but none that look like that.

The male part that is screwed into block in the image, comes out, you then insert the male hardline into the block. The male part is then slid on to the tube behind the ‘bump’ in the hardline and screwed into the block. You can see the ‘male part’ is cut to allow it to slide sideways onto the tube. Only tool needed is a spanner.

Clear as mud?

My black car uses same style to attach AN lines to the fuel tank, fuel filter and flex sensor (no quick disconnects left in the car)

greenMachine · Postby **greenMachine** » Sat Sep 18, 2021 9:21 pm

Lokiel wrote:On the cold-side shelf there is ... another damper

Thanks Lokiel, I misidentified the location of that damper. That is a less demanding location than the one on the rail, and stress from the fittings should be minimal.

The American wrote:The male part that is screwed into block in the image, comes out, you then insert the male hardline into the block. The male part is then slid on to the tube behind the ‘bump’ in the hardline and screwed into the block. You can see the ‘male part’ is cut to allow it to slide sideways onto the tube. Only tool needed is a spanner.

Neat! I haven't seen that style before.

:mrgreen:

Lokiel · Postby **Lokiel** » Sun Sep 19, 2021 11:24 am

See my build thread, https://mx5cartalk.com/forum/viewtopic.php?f=57&t=76716&p=962335#p962335 Sep 19, 2021 10:11 am, for my solution on installing a fuel pressure sensor (I was installing this yesterday which is why I'm so familiar with the task).

- Note: I pushed the radiator hose down in this photo to give a clear view of the bent fuel hard-line, normally it sits above the bronze bracket

Here's what I meant about the need to use multiple adapters because manufacturers make generic adapters so that you can fit anything to anything using combinations of adapters:

Roadrunner · Postby **Roadrunner** » Mon Sep 27, 2021 5:42 pm

So this is a touch annoying. Appears Aeroflow don't even know their own product. I eventually got a reply from them which said:

"Sorry for this confusing listing. It looks like the web notes are wrong. This fitting features a 1/8” npt port in the middle. With a male 5/16” efi push on barb on one side and a 5/16” efi push on fitting female on the other side."

So I ordered the item and figured I'd just return it if it was wrong as the image on their site is clearly NOT an NPT fitting. Turned up today and it has BOTH 1/8npt (with a plug/cap in it) and -6ORB port on the opposite side (with no plug).
So because my sensor is NPT, now I need to order a 6ORB plug!! If I knew this I would have ordered the ORB plug at the same time to save time and postage! :cry:

NPT port in centre

-6ORB in centre on opposite side to NPT port

Female Quick Connect end is exactly as The American explained. Simply unscrew the end piece, put the removed part around the barb flange and slide the adaptor down onto the CC barb and screw together with 2 spanners.

Lokiel · Postby **Lokiel** » Mon Sep 27, 2021 11:20 pm

Thanks for the photos, clears up the 6-AN fitting (which I assumed was one of the end connectors that a fuel-quick-connect adapter screwed into , inside the large-diameter barb end).

The annoying thing about most of these aftermarket barbs is that when fitted to the hard fuel line, they're too short to get the disconnect tool in.
I ended up cutting a margarine container lid into two long, thin strips that I could slide down the shaft to allow the locking tabs to be released.

I've now ordered these type of fittings to replace all OEM fuel fittings not connected directly to OEM hard lines.:

(PROFLOW Nylon 5/16" Female QR Quick Connect Straight To 5/16" (8mm) Barb)

With these connectors, you just need to squeeze the white part with needle-nose pliers and the hard line comes out with the white piece still attached. It's simple to remove it and put it back in the female connector.

Roadrunner · Postby **Roadrunner** » Fri Oct 01, 2021 3:07 pm

Having never touched a fuel line before....that was amazingly easy!
Unplugged the fuel pump relay, cranked a few times.
Slipped the tool under the line fitting and slid straight off. Maybe a teaspoon of fuel came out.

The hardest part was fitting a 14mm spanner in there to tighten the Aeroflow fitting.
Primed the pump a few times and checked for leaks. All good!
Went to start the car to check again for leaks, but would you believe.....the car battery is flat - 11.1v

Enough to sort of crank, but not start.

Now just have to set up the fuel pressure safety and change the fuel pressure modelling from "Nominal" to "Measured" in the Adaptronic.

NOTE: As Lokiel mentioned, the Aeroflow fitting leaves zero room to get the removal tool in to undo the Quick Connect, but i suppose you would just undo the 14mm bottom fitting if you ever needed to undo the lines again.

Can hardly see it's there. Perfect.