[xj-s] Fuel injector hose sizes, and overhaul tips

XJ-S
1

Well, I built myself a new injector harness, but on examining the
engine realised that it would be much easier to combine installing
this with overhauling the injector rail.

So now I have the rail and 12 injectors sitting on my desk! I’ve
decided to send them away to be cleaned and checked.

Now here I have found some 8.5mm hose - is this the correct size
for the 8 injector hoses?

http://www.motorcarsltd.com/item.wws?
sku=IN101620&mfr=BRITISH&cookieID=29I14E88F29O1FFVW0&drillid=12&clie
ntid=motorcarsltd&clientid=motorcarsltd

What about the various other bits between the rail and the two fuel
pressure regulators, are they 8.5mm too?

Finally how about the lengths from bulkhead to regulators?

Sorry to revisit this as I seem to remember this was discussed a
few months ago.–
1990 XJ-S V12 Convertible, Glacier White, 59K miles
San Jose, CA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

// please trim quoted text to context only

2

In reply to a message from Mark H sent Sat 5 Jan 2008:

I used generic 50PSI 5/16 hose from Pep Boys on
she-who-must-be-obeyed’s 90 XJ-S when I replaced all the
fuel rubber in the front. Originally I did not use clamps
as per ‘‘the book’’ and other discussions on this forum. I
have had to add fuel injection clamps at every joint as the
generic hose gets blown off the joints very easily and did
so several times in several places. I suspect the original
Jag hose was a different specification as it was overwrapped
with something that prevented it ‘‘spreading’’.

I found markings on one of the hoses I removed that indicate
it was 8.5mm.

There is a small section of larger dia from the bulkhead on
the RHS about a foot or so to a reducing adapter, other than
that all mine is 5/16.–
The original message included these comments:

So now I have the rail and 12 injectors sitting on my desk! I’ve
decided to send them away to be cleaned and checked.
Now here I have found some 8.5mm hose - is this the correct size
for the 8 injector hoses?

–
1990 XJS V12
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

// please trim quoted text to context only

3

Mark H wrote:
Now here I have found some 8.5mm hose - is this the correct size for

the 8 injector hoses?

No. You need 5/16" hose, which is 7.9mm.

What about the various other bits between the rail and the two fuel
pressure regulators, are they 8.5mm too?

They are all 5/16". There is an adapter to 3/8" near where the fuel
line enters the engine compartment and where it leaves again on the
other side.

Finally how about the lengths from bulkhead to regulators?

That’s where those adapters are.

– Kirbert

// please trim quoted text to context only

4

tollive wrote:

Originally I did not use clamps
as per ‘‘the book’’ and other discussions on this forum. I
have had to add fuel injection clamps at every joint as the
generic hose gets blown off the joints very easily and did
so several times in several places. I suspect the original
Jag hose was a different specification as it was overwrapped
with something that prevented it ‘‘spreading’’.

Hogwash. Either you used non-EFI hose or you lubed it with
something. The 5/16" EFI hose will not blow off, even at 1000 psi.

– Kirbert

// please trim quoted text to context only

5

In reply to a message from tollive sent Sat 5 Jan 2008:

Are you sure that was EFI hose? Not normal rubber hose? EFI hose, I
understand, is laminated with re-inforcing layers internally, and
should not blow off.–
The original message included these comments:

In reply to a message from Mark H sent Sat 5 Jan 2008:
I used generic 50PSI 5/16 hose from Pep Boys on
she-who-must-be-obeyed’s 90 XJ-S when I replaced all the
fuel rubber in the front. Originally I did not use clamps
as per ‘‘the book’’ and other discussions on this forum. I
have had to add fuel injection clamps at every joint as the
generic hose gets blown off the joints very easily and did
so several times in several places. I suspect the original
Jag hose was a different specification as it was overwrapped
with something that prevented it ‘‘spreading’’.

–
1990 XJ-S V12 Convertible, Glacier White, 59K miles
San Jose, CA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

// please trim quoted text to context only

6

I was concerned when I read his post whether he had used “Fuel
Injection Hose” which is usually stamped as such or has the SAE code
“30R9” stamped on it. One can easily tell that if it is NOT the
correct hose if only paying $1 per foot or less, as FI hose is ~ $5 per
foot.

If you are NOT sure of what you are getting, don’t try to buy FI hose
at Advance Auto or some place where the parts counter guy doesn’t know
what he’s doing, as you are likely to get vacuum hose or 30R7 standard
fuel hose instead of FI hose (30R9), and of course neither is rated for
the pressures developed by the pump in the fuel injection system.

Anyone know or look up the pressure rating of 30R9 Fuel Injection hose?
I’m sure its more than 50 PSIG, as that is near the operating pressure
of the fuel injection system, and I would expect a safety factor of at
least 2X that pressure. I’m thinking a pressure rating in the 200-300
PSIG range?

George Balthrop, Clifton, VA USA
85 & 89 XJ-S Coupes; 89 XJ40 VDP-----Original Message-----
From: Mark H mark944s2@yahoo.co.uk

Are you sure that was EFI hose? Not normal rubber hose? EFI hose, I
understand, is laminated with re-inforcing layers internally, and
should not blow off.

More new features than ever. Check out the new AOL Mail ! -
http://webmail.aol.com

// please trim quoted text to context only

7

Since I was too lazy to Google “30R9” before I posted the question
below, I will now answer my own question by suggesting anyone
interested in changing fuel hoses read the following from Gates (hose &
belt manufacturer):
http://www.gates.com/common/downloads/files/Gates/brochure/TechTipsForm.pdf

If that link doesn’t work, just Google “30R9” and the Gates link should
be the first hit.

George Balthrop, Clifton, VA USA
85 & 89 XJ-S Coupes; 89 XJ40 VDP-----Original Message-----
From: @GBalthropXJS

Anyone know or look up the pressure rating of 30R9 Fuel Injection hose?
I’m sure its more than 50 PSIG, as that is near the operating pressure
of the fuel injection system, and I would expect a safety factor of at
least 2X that pressure. I’m thinking a pressure rating in the 200-300
PSIG range?

More new features than ever. Check out the new AOL Mail ! -
http://webmail.aol.com

// please trim quoted text to context only

8

In reply to a message from gbalthropxjs@aol.com sent Sat 5 Jan 2008:

George, et al,

SAE30R9 FI hose has a working pressure of 125psi, and a burst
pressure of 900psi.

The ONLY definitive way to be sure you get the correct hose…is to
READ the mfgs’ stamped ink impregnated on the HOSE.

You can’t rely on the part guy, or how the part cost gets rung up
on the register.

Also…even it the hose is SAE30R9, that does not mean there may
not be a fuel leak at the hose/injector connection, or hose/rail
connection, or hose/metal fuel line connection. The pressure
rating of the hose, has nothing to do with whether the hose makes a
correct (leakproof) seal to the part to which it is fitted. That’s
in reply to another poster…not yours.

SD Faircloth
www.jaguarfuelinjectorservice.com–
www.jaguarfuelinjectorservice.com
Jacksonville, Florida, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

// please trim quoted text to context only

9

— gbalthropxjs@aol.com wrote:

I was concerned when I read his post whether he had
used “Fuel
Injection Hose” which is usually stamped as such or
has the SAE code
“30R9” stamped on it.

Anyone know or look up the pressure rating of 30R9
Fuel Injection hose?

You can learn so much on this forum. There is a 30R00
which I think is no longer made and 30R07, 30R09,
30R10, 30R11. With 30R09 being best for our FI hoses.
A little from Gates and Goodyear with links for
further reading:

http://www.gates.com/common/downloads/files/Gates/brochure/TechTipsForm.pdf

Standard fuel and oil (SAE 30R7) hose is rated for
low-pressure applications at 50 psi working pressure
up to 3/8" size, and 35 psi for sizes over 3/8". This
general-purpose hose contains a light reinforcement,
and the rubber materials can be any compound that is
suitable for fuel, oil and vapors.

However, Gates Corporation engineers warn installers
that fuel formulations at many US refineries are
constantly changing as proprietary blends are
introduced according to government mandates and
seasonal influences. At times, more aggressive fuels
can extract the oils that give SAE 30R7 hose its
flexibility. The result is a brittle, stiff tube that
will greatly reduce the performance and service life
of the hose.

Fuel injection (SAE 30R9) hose or MPI (multi-port
injection) hose is reinforced to handle higher
pressures up to 180 psi. It can be used on all
injection systems that use hose clamps. It is not
designed to replace coupled assemblies on fuel
injection systems.

Fuel injection hose is designed for low permeation
contact with a wide variety of alcohols, alcohol fuel
blends, and diesel fuel. It allows 15g/m2/day
permeation whereas standard SAE 30R7 hose allows
550g/m2/day. (Gates fuel injection hose routinely
performs at 1 to 2g/m2/day

Finally, for submersible applications such as on the
in-tank fuel pump, only SAE30R10 hose should be used,
because when the hose fails, the pump will fail. Hose
construction consists of low swell fluoroelastomer
compounds in the tube and cover that resist gasoline
and diesel fuel permeation and aging. Standard hoses
have these fuel-resistant characteristics in the tube
portion only.

Goodyear SAE 30R9 and 30R11 are compatible with a
variety of fuels, including gasoline, diesel and
ethanol. In addition, the SAE 30R9 can be used for
sour gas and environmentally-friendly biodiesel fuel
applications.

The hoses also meet new U.S. EPA and California Air
Resources Board (CARB) emission requirements that
began going into effect January 2007.

// please trim quoted text to context only

10

In reply to a message from Kirbert sent Sat 5 Jan 2008:

Kirby,

You said…‘‘The 5/16’’ EFI hose will not blow off, even at 1000 psi’'.

I’d think that may be a bit subjective. The working pressure
rating, or burst pressure rating, of the hose has little, if
anything, to do with whether the hose will leak at the joint where
the hose fits to the injector, or the rail. Hence, the need for a
clamp, or a hose ferrule.

SD Faircloth
www.jaguarfuelinjectorservice.com–
The original message included these comments:

Hogwash. Either you used non-EFI hose or you lubed it with
something. The 5/16’’ EFI hose will not blow off, even at 1000 psi.

–

Jacksonville, Florida, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

// please trim quoted text to context only

11

In reply to a message from SD Faircloth sent Sat 5 Jan 2008:

At best though, it doesn’t look like the existing ferrules do much -
just prevent the end of the pipe from spreading.

Most of the info I’ve read suggests that clamps are a no-no - so
I’m not sure what to think.

To me it seems likely that clamps would be ok if not overtightened -
overtightening could cause the barbs to cut through the hose. If
not too tight though they would just have the effect of stopping
spreading of the hose.–
The original message included these comments:

the hose fits to the injector, or the rail. Hence, the need for a
clamp, or a hose ferrule.

–
1990 XJ-S V12 Convertible, Glacier White, 59K miles
San Jose, CA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

// please trim quoted text to context only

12

In reply to a message from Mark H sent Sat 5 Jan 2008:

So the answer is 30R9 spec hose or better?–
1990 XJS V12
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

// please trim quoted text to context only

13

In reply to a message from Mark H sent Sat 5 Jan
2008:

So the answer is 30R9 spec hose or better?

The answer is 30R9 spec. The other numbers are a
different spec and may or may not work.

// please trim quoted text to context only— tollive tonyollive@cox.net wrote:

14

In reply to a message from Geoffrey Green sent Sun 6 Jan 2008:

To clamp or not to clamp?

That is the (remaining) question!–
1990 XJ-S V12 Convertible, Glacier White, 59K miles
San Jose, CA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

// please trim quoted text to context only

15

SD Faircloth wrote:

Kirby,

You said…‘‘The 5/16’’ EFI hose will not blow off, even at 1000
psi’'.

I’d think that may be a bit subjective. The working pressure
rating, or burst pressure rating, of the hose has little, if
anything, to do with whether the hose will leak at the joint where the
hose fits to the injector, or the rail.

The fact remains, it won’t blow off. The guys at the local hydraulic
shop tried it, just because they wanted to see for themselves how the
clampless fittings worked.

Hence, the need for a clamp,
or a hose ferrule.

If you need a clamp or a hose ferrule on the HE fuel injectors, you
installed the hose wrong or used the wrong hose – and in either
case, a clamp or a hose ferrule won’t help for long, you’re driving a
fire hazard.

– Kirbert

// please trim quoted text to context only

16

Mark H wrote:

To me it seems likely that clamps would be ok if not overtightened -
overtightening could cause the barbs to cut through the hose. If not
too tight though they would just have the effect of stopping spreading
of the hose.

DO NOT USE CLAMPS ON THE H.E. FUEL INJECTORS! If the hose is
spreading, you bought the wrong hose, and clamps won’t help for long.

– Kirbert

// please trim quoted text to context only

17

In reply to a message from Mark H sent Sun 6 Jan 2008:

Just don’t do it!!!

But do get the correct hose :)–
The original message included these comments:

To clamp or not to clamp?
That is the (remaining) question!

–
Mike Blair 2x94 XJS(6.0 Coupe&4.0 Convert)+85 HE&96XJ12
powhatan/Va, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

// please trim quoted text to context only

18

I vote not to clamp

Ed Sowell
1976 XJ-S
http://www.efsowell.us/ed/myJag.html

To clamp or not to clamp?

That is the (remaining) question!

1990 XJ-S V12 Convertible, Glacier White, 59K miles
San Jose, CA, United States

// please trim quoted text to context only

19

In reply to a message from Ed Sowell sent Sun 6 Jan 2008:

i have recently refurbished my fuel rail from 1989 V12 , with double
barb type connection that DO NOT use clamps

this is evidence in that even on a perished system , the hose can not be
simply pulled off, it needs to be cut off and the barbs do a fantastic job
of even making that hard,

i got some 5/16 FI ( unleaded rated ) fuel hose from the UK Jag spares day
some time back , 2 mtrs ( 6’ ) which is enough to do it twice if needed,

i bought new ferrules from Jaguar at �0.30 each , 24 are needed, but they
were only cosmetic really , as the originals would have been ok, these are
the items that stop the pipe from wanting to spread once over the barbs

pictures and words can be seen here
http://www.kelsey-forums.co.uk/cgi-bin/jwm/YaBB.pl?num=1198664852

i hope this can help some of you out

BB–
The original message included these comments:

I vote not to clamp

To clamp or not to clamp?
That is the (remaining) question!

–
1989 XJS 5.3 HE V12 having major body lift in my garage
Gloucester, United Kingdom
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

// please trim quoted text to context only

20

In reply to a message from Brake-buster sent Sun 6 Jan 2008:

No clamps, understood!

Thanks everyone for the advice, now I have a clear idea of what
hose I need and looking forward to getting it back together.–
1990 XJ-S V12 Convertible, Glacier White, 59K miles
San Jose, CA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

// please trim quoted text to context only