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Hi Everyone,
I have a 2001 S Type 4.0 and it has the typical issue of running out of fuel when down to a 1/4 tank. after searching and reading all the threads regarding this I understand that this will typically be a problem with the Fuel pump on the primary side (passenger) of the gas tank. I am also understandfing that the Fuel pump is located on the passenger side and the secondary unit is located on the drivers side. What I am not understanding is why everyone keeps refrerring to the secondary unit as a pump or a "jet pump" I have taken the drivers side unit out and the only mechanical part that i can see it contains is a 2 wire sender. Where is this "jet pump" that everyone keeps refrerring to that transfers fuel back to the primary side?
Hi there, I recently replaced my pump and sending units on my 2001 3.0.
I’m no expert but I read this somewhere.
The jet pump is the name of the device that creates and maintains a vacuum in the fuel lines which causes the transfer of fuel across the saddle due to fuel pump pressure.
When the tank is full the sender on the left does the level detecting, from half tank and below the right sender does the level detecting.
It sounds like you have fuel on the left side that will not be 'picked-up' by the electric pump so you run out of available fuel.
I saw this when I worked at the dealer a few times. A customer would 'run out of gas' and the level indicator says there is fuel in the tank.
A wrecker would load the car on a flat bed and when the car came into the shop, it would start normally. (the car being tilted to load on the truck would 'slosh' fuel onto the electric pump side)
We would replace the 'jet-pump' and send the car 'down-the-road'.
The jet pump just continually transfers fuel from the left side to the right side to keep the electric pump submerged. The senders are tied together to send an 'average' to the gauge. Technically the left side could be completely empty and the right side would have all the fuel left in the tank available to the electric pump.
Last edited by motorcarman; Jan 23, 2023 at 07:45 AM.
So i am still not seeing the jet pump, where is it and what does it look like?
It is the bundle of pipes that lives on the other side of the car to the electric pump. It incorporates a venturi type nozzle that uses the speed of the flow from the main pump to return some extra fuel to the "main" side of the tank.
Finally! Thank you so much. There is so much useless content on the Internet its nice to have something thats clear and concise. I genuinely appreciate your time and answer. I noticed that there a lot of new Fuel Pumps on Ebay (for less than $100) but I havent seen a new one of these yet. Would you have a part or model number that I could use to search more easily?
Find the right category by VIN and engine. The side with the electric pump is called the "sender and pump assembly". The side with the jet pump is called the "sender and outlet tube assembly". I think that's what you need. Once you get an OEM number, you can search that way. The jet pump itself probably never wears out, as it has no moving parts. The check valves or pressure relief valve may fail, but I don't believe they are available separately. You may have to get the complete "sender and outlet tube assembly".
Even if Jaguar shows it as discontinued, you will probably find other sources still have it. eBay, for example, has a lot of stuff like that. Dealers clean out their old stock and guys buy it surplus and make it available.
In case you have any trouble with those miserable couplings (and release collars) at the fuel tank, be sure to see this thread for an easy workaround before causing any damage:
Thankyou again. Yes having the right terminology helps when ordering parts. I think the previous owner had issues with those fittings because they are wrapped with electrical tape. One of the reasons i bought the pump and sender assembly.
Thanks again for everyones help. There was a cracked hose on the pump side as well as the inlet/outlet fittings not having all their components, so I just replaced the pump with a new one. The driver side unit had a broken OEM plastic hose so I just replaced that with a nice fuel line and clamps. Pretty certain between the two units the return line just wasnt holding pressure. everything works now and its the first time I was able to drive the car with less than an 1/8 of a tank and not run out of fuel.
S Type Fuel Pump and Sender Question
