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I have an X305 and I am in the process of replacing both the fuel pumps, one is acting old and tired but while I’m in there I’m doing both.
The tank had a lot of scale and sediment in it so I decided to clean it out as well.
There is a removable fitting in the bottom of the tank called a jet pump. All the return fuel from the fuel rail passes through the jet pump and this action scavenges fuel from the very bottom of the tank and feeds it into the surge tank where the fuel pumps are located ensuring that there is always sufficient fuel for the pumps even at a very low tank quantity.
All this sounds good in theory, however when I removed the jet pump fitting the two nozzles were completely blocked with scale and sediment which as far as I can see this would completely prevent any excess fuel from being returned to the tank from the fuel rail. Apart from a tired fuel pump the car ran normally. There is another thread by me re this subject on the X305 forum.
I soaked the jet pump fitting in injector cleaner and cleaned out the blocked nozzles so it will be interesting to see if there is any difference in operation when I get it all back together.
Has as anyone else had this experience or could anyone suggest any adverse effects of a blocked return fuel line? I’d be interested in your thoughts on this.
Well the job is done and the difference in response and performance is astounding. The fuel line I had trouble releasing was twisted badly, it is a wonder any fuel was getting to the engine at all, and the metal fitting on one end was almost straight instead of having a 90 deg bend in it. The OEM hose is NLA so I replaced the flexible bit with high pressure fuel line and re-bent the metal fitting and it fitted just like a bought one.
As mentioned in another post the jet pump in the base of the tank was completely blocked with sediment and scale and once cleaned out and re-installed you could hear the fuel returning to the tank where previously you couldn't.
Fuel Tank Jet Pump
