Replacing the Fuel Injector Hoses

My original fuel injector hoses were 23 years old. They were showing signs of cracking. They needed to be replaced yesterday. First, I removed the fuel rail with injectors attached. Using a sharp razor or utility knife, carefully slit the hoses at the fuel rail and remove them. Jaguar recommends burning off the FI hoses from the injector with a soldering iron. This is not necessary. Use the following method with care. First, place the hose (with injector attached) in a vise (as pictured below). Carefully slit the hose at a slight angle with a sharp razor.

Do not go all the way through to the injector, even a minor nick on the injector aluminum barb connection can cause the injector to leak.

Next, using a small screwdriver as leverage, remove the hoses from the fuel injector.

Jaguar's original fuel injector hose size was 9/32" (part number CAC-8901/22). Note: The more conventional 5/16" fuel injector hose should not be used on a Pre-HE V-12 engine. (the fuel rail connection diameter is smaller than the rail connections on the HE cars) I used the original 9/32" hose. On the later Pre-HE engines that do not use clamps on the injectors, the fuel injector barb connector is slightly larger than the fuel rail connection. This means that this hose is a bear to get onto the later Pre-HE's fuel injector barbs. I found that heating the hose with a hair dryer prior to installing worked marvelously using a simple support system pictured below.

I devised a support system for the fuel injector by clamping an old alternator pulley in my vise. This allowed me to use two hands to leverage the heated hose on to the fuel injector barb connection. Once the hose is on it cannot be removed.

There is some question whether the metal cup between the injector body and the hose is necessary. I believe the cups protect the cut end of the injector hoses. In addition, they look good. I recommend reinstalling the cups.

Do not cut the hose until after you have installed it on the fuel injector. The hose is then cut at 1 1/2 inches. This applies only to my fabricated fuel fail. The purpose of this short hose is to lower my customized fuel rail sufficiently to clear the throttle kick down switch. Cut hose to the required length with a sharp razor blade.

Attach all injectors to fuel rail and install as one unit. Even though Jaguar gets an absurd $2.50 US for each injector seal, make sure you replace all injectors with new seals (part number EAC-2415)

Fuel rail with new injector hoses installed. Tighten all clamps and check for leaks.

Finally, clearing the engine "V" of fuel vapors with compressed air is critical prior to starting the engine. Fuel vapors have been known to seep into the distributor cap and destroy the cap when the engine is started. Roger Bywater, former Jaguar engineer and currently with AJ6 Engineering, offers this advice. "To this day, my advice to anyone doing anything that involves fuel leakage on the V12 is to always blow over the centre of the engine with an air line before switching on the ignition."


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