How to measure fuel pressure

[nwguy]

Is there an established way to measure fuel pressure on an XB (9SX)? If so, what is it specifically?

 

[d_adams]

Fuel pressure gauge?


https://st-paul-harley-davidson-bue...-1125-models-l19d?_pos=1&_sid=32614b728&_ss=r

 

[34nineteen]

Is there an established way to measure fuel pressure on an XB (9SX)? If so, what is it specifically?

Specifically...


To prevent spray of fuel, purge system of high-pressure
fuel before supply line is disconnected. Gasoline is
extremely flammable and highly explosive, which could
result in death or serious injury. (00275a)

1. Remove air cleaner assembly. See 4.44 AIR CLEANER
ASSEMBLY.
2. Purge the fuel supply line of high pressure gasoline.
a. See Figure 4-24. Disconnect the 4-place fuel pump
connector [86]. The connector is located inside the
left rear portion of the fuel tank/frame.
b. With the motorcycle in neutral, start the engine and
allow vehicle to run.
c. When the engine stalls, press the starter button for 3
seconds to remove any remaining fuel from fuel line.

WARNING
With fuel tank drained, gasoline can spill from bore when
supply valve is loosened or removed. Gasoline is
extremely flammable and highly explosive, which could
result in death or serious injury. Wipe up spilled fuel
immediately and dispose of rags in a suitable manner.
(00277a)

3. See Figure 4-25. Depress button (2) of fuel line connector
and disconnect the fuel line (3) from throttle body inlet
(1).
4. See Figure 4-26. Attach FUEL PRESSURE GAUGE
ADAPTER (Part No. B-45522) (2) to throttle body inlet
(1).
5. Connect the fuel line (3) to fuel pressure gauge adapter.
NOTE
See Figure 4-27. Verify that fuel valve (2) and air bleed petcock
(5) on the gauge are closed.
6. Attach FUEL PRESSURE GAUGE (Part No. HD-41182)
(4) to fuel pressure gauge adapter (1).

7. See Figure 4-24. Attach fuel pump connector [86] to
main wiring harness.
8. See Figure 4-27. Pressurize the fuel system.
a. Start and idle engine to pressurize the fuel system.
b. Open fuel valve (2) on fuel pressure gauge to allow
fuel to flow down the gauge hose.
c. Position the air bleed tube (3) into proper container.
d. Open and close the air bleed petcock (5) to purge
the fuel pressure gauge and hose of air. Repeat this
step several times until only solid fuel (without bubbles)
flows from the air bleed tube.
e. Close the air bleed petcock.
9. Open throttle and increase engine speed to 2500-3000
RPM. Note the reading on the pressure gauge.
a. If pressure is 49-51 PSI (338-352 kPa) then system
is operating within limits.
b. If pressure is not within limits, see Test 4.13 (Part 1
of 2) flow chart after disconnecting pressure gauge.
1
WARNING
With fuel tank drained, gasoline can spill from bore when
supply valve is loosened or removed. Gasoline is
extremely flammable and highly explosive, which could
result in death or serious injury. Wipe up spilled fuel
immediately and dispose of rags in a suitable manner.
(00277a)

10. See Figure 4-27. Turn engine off. Detach pressure gauge
(4) from adapter (1).
a. Open the air bleed petcock (5) to relieve fuel system
pressure and purge the pressure gauge of gasoline.
b. Remove pressure gauge from adapter.
11. Detach adapter from vehicle.
12. Connect fuel line to throttle body inlet.

 

[Cooter]

Hey man, is that copy/pasted right from the service manual you can get from Buellmods.com? The FREE one?
Here?
http://buellmods.com

Thats so cool! I bet it has LOTS of good Buell specific info, if you read it.

:angel:

 

[kz6fittycent]

Hey man, is that copy/pasted right from the service manual you can get from Buellmods.com? The FREE one?
Here?
http://buellmods.com

Thats so cool! I bet it has LOTS of good Buell specific info, if you read it.

:angel:

I also wrote a script to grab all of them and put them on my own server in case that site ever goes down...

I'll share a link so anyone can grab them if requested. Maybe we could make it a sticky as a backup thing.

P.S. Grabbed all the EEPROM's, too.

 

[34nineteen]

I’m pretty sure that buell mods is jetlees site. If I’m wrong he’ll pop in soon to correct me.

 

[Cooter]

You wanna-be Mr. Helpy-McHelpsterpants?!?


You're a jerk because your fridge is out of beer:crushed:

 

[34nineteen]

You wanna-be Mr. Helpy-McHelpsterpants?!?


You're a jerk because your fridge is out of beer:crushed:

No, thats not why I'm a jerk.

 

[Cooter]

That darn padlock is really tough!

 

[34nineteen]

That darn padlock is really tough!

 

[Cooter]

OP, sorry for the fun
FYI. I have the proper fuel pressure tester, gauge and fitting. If you want to borrow it, PM your address.

34:19 is a j3rk because he won't stock his fridge.

 

[kz6fittycent]

Is there an established way to measure fuel pressure on an XB (9SX)? If so, what is it specifically?

Rev-Mo has this now: https://www.rev-mo.com/product-page/xb-fuel-pressure-tester

 

[Cooter]

Good find! Avoid the normal Bueller move.
It's worth $25 to have on in the toolbox. Because guessing (and spending $700 to swap in a new fuel pump...) sucks.

 

[Endopotential]

$700 ?!? Is that the special friend's rate that Aaron charges you?

I think Barrett's replacements are around $200. I'm glad my monkey thumbs work well enough for me to do the rest of the swap myself.

Though that fuel pressure gauge would be a cool addition. Can it be hooked to anything else? Is the Buell's connection a unique one?

 

[34nineteen]

$700 ?!? Is that the special friend's rate that Aaron charges you?

I think Barrett's replacements are around $200. I'm glad my monkey thumbs work well enough for me to do the rest of the swap myself.

Though that fuel pressure gauge would be a cool addition. Can it be hooked to anything else? Is the Buell's connection a unique one?

I dont think the "regular" fuel pressure testing kits available out there will attach to the Buell fuel hose without a special adapter. $25 is cheap for this. Maybe Rev Mo will sell me one.

(FYI... the $700 is a special Cooter price because.... yep, he is a jerk).

 

[Cooter]

Thats a reasonable charge for a OE assembly and labor from a V-twin shop (I bet HD is even more, IF they will even touch it:mad-new::upset. Especially if they don't know the shortcut. Kinda makes you realize what a great service John does for us. If your pump tests bad, he's the only guy to goto IMO.

IMO, Don't bother. Staring at a gauge that stays at 49psi all the time is boring. I would recommend putting in a tap though. For future diagnosis. So here's some options:

1) Easy and un-doable... You can use a 3/8" quick connect tee and plumb a gauge into the fuel line. Its a short line and not a lot of room in there.
https://www.glowshiftdirect.com/3-8-quick-connect-efi-fuel-line-adapter/

But then you have more fuel lines to route to the gauge around a hot engine.

2) You can also tap into fuel pressure at the injector casting on the TB. Remove the casting, tap for 1/8"FPT, and screw in one of these.
https://www.homedepot.com/p/Everbilt-1-8-in-MIP-Brass-Valve-Fitting-804519/303518383

from there you can screw in the gauge to that valve.

3) You can use a small digital pressure gauge

and screw a 1/8"MPT sensor directly into either tapping method. That way there isn't a lot of extra high pressure fuel snaking around in those tight confines.

I would personally go the #3 route and go to a gauge that will do more than just FP. A small display that includes all the things Erik left out would be nice. You could cycle through volts, temp, ambient temp, fuel pressure, oil temp. Ahhh in a perfect world

 

[Endopotential]

Those are some great ideas!

Merry Christmas to our SoCal Buellers :eagerness: And to the rest of you in AZ, PA and around the world too!

 

[TheWood]

Merry Christmas to all! This gauge seems crazy inexpensive for the gauge,line,and fitting for the quick connect. But it doesn't allow you to run the engine and check it @ 2500-3000 rpm's as instructed. Is this not necessary to check for possible fluctuations, and not just a static "key on" pressure check? I was wanting to buy one of those "KENT MOORE?"made test gauges but don't see where to buy. Also, is a lot to spend for maybe only a one time use. If you guys think this $25. test is adequate, I'll just get one of those. Although I like the "option #3" from Cooters #16 post, but am a bit chicken to tap into my new to me Uly. EDIT: Just found the fuel test rig @ St.Paul($75.sans the actual gauge),but I think I have one floating around here somewhere.

Rev-Mo has this now: https://www.rev-mo.com/product-page/xb-fuel-pressure-tester

 

[Cooter]

Option #1 is a $19 one piece, removable, fuel line "tee" that you can use with your gauge. Literally the exact function of the ugly home-built looking thing that SPHD sells for $75.

You can even buy those fittings at your local auto parts store and make it yourself, but for $19 I'd buy the simple one-piece one.

I agree the check needs to be done at 2500-3K RPM's and under load. IMO if your pressure doesn't drop when in 5th gear-WOT, your fuel pumps volume is adequate and that is actually what you're checking for fuel pump health. Pressure is only a part of the equation.

If you're not confident of tapping the fuel rail yourself, sent it (or another one) to me and I'll tap it and send it back. It's a little PITA to remove on the engine, but a 1/4" drive ratchet with a phillips bit will get it done.

 

[TheWood]

So with that "tee", I could install a schrader valve on it, screw a pressure line on and tape the gauge down temporarily in front of me where I could glance at it at 5th gear WOT for the ultimate test. Oh, and thank you for the generous offer to tap; will consider this as an option for me. This bike has become my newest obsession:upset: Will report back what my WOT pressure is in a month or so.

Option #1 is a $19 one piece, removable, fuel line "tee" that you can use with your gauge. Literally the exact function of the ugly home-built looking thing that SPHD sells for $75.

You can even buy those fittings at your local auto parts store and make it yourself, but for $19 I'd buy the simple one-piece one.

I agree the check needs to be done at 2500-3K RPM's and under load. IMO if your pressure doesn't drop when in 5th gear-WOT, your fuel pumps volume is adequate and that is actually what you're checking for fuel pump health. Pressure is only a part of the equation.

If you're not confident of tapping the fuel rail yourself, sent it (or another one) to me and I'll tap it and send it back. It's a little PITA to remove on the engine, but a 1/4" drive ratchet with a phillips bit will get it done.