vividcolt wrote:i just wouldn’t expect dirty fuel to cause an issue with starting - poor performance absolutely but starting shouldn’t be an issue should it?

Suzi Q wrote:
Commonest causes are a split hose inside the tank,

92KK 84WW Olaf wrote:I have come to the conclusion best solution is replace everything in the tank and also the external fuel lines. I am about to do in my latest K, I just keep the old ones as spares or to get someone out of trouble. 

External fuel lines marked NBR/CR 8/13mm can be got from Honda dealers, they use the same ones. In tank hoses are marked NBR/NBR for fuel resistant inside and out...by are not UV resistant so don't be tempted to use them outside the tank!.

jbt wrote:

Suzi Q wrote:
Commonest causes are a split hose inside the tank,  

Hose failure is very common and very difficult to see under the gas level. Replace them, but use only  hoses designed to be into gas, they're specific, with an inside and outside layer fuel resistant.

vividcolt wrote:Yup that was something I saw the other day, I went ahead and replaced it with a 3/8" SAE 30R7 hose.

Laitch wrote:

vividcolt wrote:Yup that was something I saw the other day, I went ahead and replaced it with a 3/8" SAE 30R7 hose.

You have chosen an unsuitable hose for that application. It will fail you. Attached is an extract from Continental Rubber about your R7 hose. It is not submersible in gasoline and it is not made for fuel injected engines. What you need is J30R10 hose. A BMW dealer like MaxBMW sells it at a comparatively reasonable price.

Hi guys
just to add a little... Had a similar issue the other week. When you check the fuel pump out of tank make sure the bottom is immersed in fuel and ACTUALLY pumps. I did a DRY check and it made noises in both pos and neg mode. ie wires exchange. BUT when I put it back in the tank it made the NOISE but did not pump...

#2 worked OK BUT had a split in the hose. Couldn't see it until I accidently moved the hose and had a gush noise. An underwater fuel line split is invisible... The PUSH the start button (as above) did keep the engine fired up.

Fuel in-tank hoses... My local (remote) auto shop said ALL fuel hoses are the same... Read the attachment... Gave him a copy and he and the others three days later all went "Sorry. Our mistake"... In Tank HAS to have 

Regards
Mal
Cant seem to add the file so sent as a cut n paste.
Correct Fuel Hose Installation
Fuel hoses are not universal. Outside of the dimensional requirements, fuel hoses have requirements for permeation, pressure and the type of fuel they can carry. This can get even more confusing when you start looking at the lettering on the side of the hose.

By Andrew Markel
Feb 25, 2016

Understanding the Differences Between Fuel Hoses
Fuel hoses are not universal. Outside of the dimensional requirements, fuel hoses have requirements for permeation, pressure and the type of fuel they can carry. This can get even more confusing when you start looking at the lettering on the side of the hose.
Related Articles

• - Lifter Deactivation
  
• - Battery Charging and Diagnostics
  
• - Diagnosing Crankshaft Position Sensors
  

SAE J30R Standards
The Society of Automotive Engineers (SAE) is an industry group that creates standards for the automotive industry. When it develops a standard, it applies to all manufacturers in hopes of reducing engineering and testing costs.
SAE has more than 16 active and inactive J30 standards for fuel and oil hoses. If you look at the side of a fuel, oil or emissions hose you will see the letters “SAE” followed by the number 30 (some will have a J first). Next in the sequence will be the letter “R” followed by a number. The number after the “R” refers to the section of the performance standard it pertains to. The criteria are typically permeation, chemical resistance, construction, temperature range and kink resistance. The higher the standards go, the more criteria that must be met.
“R” numbers in some cases do not determine the pressure rating for the hose. Hose manufacturers typically print on the hose if it is intended for use on fuel injection systems. Also, you should check with the manufacturer of the hose to see if it is compatible with fuels like E85 or biodiesel. NOTE: IF A HOSE DOESN’T HAVE A SAE J30- STANDARD ON THE SIDE, DON’T INSTALL IT IN A FUEL SYSTEM.
SAE 30R6 hoses are designed for low-pressure applications like carburetors. These can also be used as an emissions hose.
SAE 30R7 hoses are designed for fuel. These can go under the hood and are typically used for low-pressure applications.
SAE 30R9 hoses are designed for high-pressure applications like fuel injection and oil. These are designed to stand up to the environment under the hood.
SAE 30R10 includes hoses that are submerged in fuel. This type of hose is used inside the fuel tank and typically on the fuel pump module. This type of hose uses a special layer on the inside and outside to prevent the core layers from being saturated in fuel. But, don’t use it under the hood. R10 hoses can’t stand the heat.
SAE J30R12 includes low-permeation fuel feed and return hoses.
SAE J30R14T1 is the standard for ultra-low permeation properties. This type of hose is typically approved for use with leaded and unleaded gasoline, diesel, biodiesel, E85, methanol, ethanol and gasohol fuels. These are typically used for low-pressure applications.