I know this question has been addressed many times now, but the answers are always conflicting.
So please correct me if I am wrong here...from what I understand the jags do not use a fuel return line..is that true?
On my chevy ls1 it does have a return line so that is where the fpr is located
If the 2000 s type does use a fpr then where is it located?.
I do know that the new mustangs do not use a fpr but the fuel pump in the take has a variable voltage sensor to the pump..more load higher voltage more pressure . So it can be fooled into raising the pump pressure, using what is called a boost pump..this offers more voltage to the pump for more output

so question, does the 2000 s type v8 not use a return system?
Does it use a fpr and if it does where is it located?

If no fpr used then I would assume it works off variable volts to the fuel pump?

The reason why I'm looking for this is i need to raise the fuel pressure to the injectors a few pounds to make up for a few mods that have been done

any help here guess would be appreciated............and yes I did search the forums first and some some other manuals that just didnt really address this issue............thanks in advance

 

I take it "fpr" stands for: "fuel pressure regulator"... just curious what "mods" you completed that would require more fuel pressure.

As far as I know there is no way to increase fuel pressure to the injectors.. and there is no fuel return line... also, I don't believe there are any mods that can be done with success on the 4.0 V8 engine. Finally, I wouldn't try and mod anything on this engine - they are very sensitive and once you "mess up the apple cart" be prepared....

 

Not withstanding abonano's comments, there is a fuel pressure regulator in the system and it is controlled by the Power Train Control Module.If you have the equipment and knowledge it should be possible to reprogram the PCM to adjust fuel pressure.

 

well as for the mods, It has a real cold air intake. It comes from the bottom of the bumper. More or less ram air. The heads have been ported and the compression has been raised just a little. And the only other main thing is that the throttle body has been enlarged and polished..and then some other few things.

The engine actually responds very well to these mods, so dont be afraid to mess with it. This is not a new thing I'm trying. it has been running this way for some time now,,no problems except the reason I would like to raise line pressure a bit. I just bought a wide band a/f mixture gauge and it shows running rather lean on top...So I figured the cheapest and fast way would to just raise the line pressure as mentioned. I always did this on my vettes with great success. I'm really sure there has to be a way to raise line pressure to the injectors, Its just one of the things you just have to find out how.

oh, almost forgot yes fpr does stand for fuel pressure regulator,,,thanks guys for the input ..any other takers out there???
oh six rotors I will try and see if that can be done...thanks for the info

 

just some info for you guys.......it uses no regulator it has no return and as I asked it does indeed use a variable sensor to up or lower the voltage to the fuel pump this will raise or lower the output of the put........gotta says guys a little let down by this forum, I would of thought somebody here would of know that...oh well

 

Any car can have a a real adjustable fuel pressure regulator if you want it enough to spend the money.

I have seen a number of cars that do not use a return converted over.

Run new bigger such as -8 an hose or hard line up front. Install aeromotive regulator with gauge, and convert stock fuel feed line into a return line for new setup. Place serious real fuel pump or pumps in tank or in line depending on hp goals.

The thing is, tuning via raising or lowering fuel pressure is a crude type of setup for a street car. IE the car just won't be richer when on the throttle, but all other times as well. I have seen it work ok on simpler efi setups where there was a chip installed into the ecu which took account for this raised fuel pressure. But I doubt this would work with the jaguar ecu.

There are piggy back air/fuel controllers that give you access to high,mid, and low throttle adjustments. These work by tricking the factory computer by altering the signal from the mas air flow sensor. I also doubt the ecu in the jag will be happy with this. Some computers are smart enough that they learn around this device.

I think the only real option would be finding a place that can tune the factory ecu on a dyno for you. I am not sure of who has the capability of doing this to the 4.0 ecu.

 

S-Types did not use a FPR.

 

Sorry for your "let down" possibly call Jaguar directly when you have a question and maybe they'll give you the guidance you are looking for to modify their product...

 

+1, as as previously stated, owners really don't look at the 4.0 engine as a good starting point for shade tree mods.