Dear all,
I came across a random issue on my XJR6... when giving strong acceleration push, the car start juddering, etc...(above 2-2500RPM). I can keep accelerating but cannot really force it (or kick-down). This things happen randomly but start to be more often lately. Half the time the car works perfectly fine though (constant acceleration, kick-down etc...)

I suspected the second fuel pump so I did a quick diagnostic:
- Start the car with fuel pump 1 relay IN & fuel pump 2 relay out ==> car starting
- Start the car with fuel pump 1 relay OUT & fuel pump 2 relay IN ==> not starting (I understand that the fuel pump 2 is supposed to kick-in if the one is out)
- Start the car with fuel pump 1 relay OUT & fuel pump 2 relay BRIDGED ==> car is starting normally (I can hear the pump noise)

I switched all the blue relay, same problem appear. So it's not a relay issue...

I think there is something that randomly don't kick the Fuel Pump 2 when it's needed...

I will take it for a ride with the Fuel Pump 2 BRIDGED to see if it work properly.

Do you have any advice? Thanks in advance!

 

Talking to myself, but after writing the post and looking at the service manual, it appears that the Fuel Pump + Relay2 are controlled by a Fuel Pump Control Module....which is beside it... (Part DBC12504)

However, looking at my car, I have a substitute (Bosch 0332019150 - 5PIN relay) and I would say it looks old and was reused from somewhere...

Will try to replace it and see how it works.

For now, the car is running smoothly on the fuel pump 1.

 

The 2nd fuel pump doesn't kick in until 4000 RPM and drops out as you go under 3200

You may have a open spot on the throttle position sensor but do not remove or adjust until you get more information on the criticalness of the adjustment

Codes ?

Main fuel filter change ? requires o - rings

 

HI Parker,

The problem still appeared very randomly... car would work perfectly and one time have this juddering I did't have code....up to today!

But now, the car has completely stopped. Idle is rough, car is stalling, it cannot move at all...

I get the following code:
- P0340 (generic) - Camshaft position sensor A circuit Bank 1 or single sensor
- P1193 (jaguar) - Both front HO2S Heater Circuits (High Resistance MAF Sensor Faulty)
- P1178 -(jaguar) - adaptive fuel metering trim too lean

Note that I have replace the coils, plugs (original specs), O2 sensor (bosch/NTK), crankshaft sensor.

Do you think it can be linked to the TPS? or MAF issue? (or others?)

 

Could you have water getting into your fuel tank? Check the drain at the filler is clear.

 

You can override the # 1 fuel pump control by directly powering the pump by placing a heavy jumper in the forward and aftmost position in the # 1 fuel pump relay socket , use a blade type wire connection to not damage the sockets

This control can be a problem with the Crankshaft position sensor and not the Camshaft as it is not involved in the fuel pump control

This control fault will not give a code

This will keep the pump running at all times with the keys in your pocket so it will drain the battery

You have the option to directly power the # 2 fuel pump but the instructions are different

There have been problems with the harmonic balancer delaminating causing the signal to not be steady with the crankshaft position sensor and can be checked by marking the pullies and checking they stay together after a engine run . Your supercharged engine will have a different part # then a non - supercharged version

 

Regarding water in the tank, I don't think it is the case, let me explain! When I bought the car, the drain seems clogged. The vendor "solved" it apparently. Until I realized when checking it this week-end that the drain pipe was disconnected from the cap!! :-(( Nice work! Water was flowing all this time in the trunk...
Well, after removing drain pipe, it appears to be "burnt" at the end of it therefore the water was stuck. I cut the burnt end part of it and fix back the pipe, now it's back to normal....

I have check the two fuel pumps with direct bridging, it works the same... I don't think the fuel pump are the cause of it...

I will definitely check the harmonic balancer! Interesting point! But if it appears to be the issue, what is the solution then?!

 

Check the HB with the marks and all pully belts installed

Run the engine with a heavy electrical load like the main cabin blowers

Watch your engine coolant temperature for overheating as your water pump may not be turning properly

Run the A / C compressor to have a load on that right side belt

After the engine run the marks should still be together

The fix is to remove the HB and have it rebuilt at a specialist , there are a couple in the United States

To find a used one to swap out for the supercharged engine will be difficult as yours has 3 pully belts

https://parts.jaguarlandroverclassic.../brand/jaguar/

See page 8 ( crankshaft bolt ) of the PDF file below , 183 - 223 Nm torque , there has been debate on the correct socket size of 33 or 34 mm

See a recent discussion on the HB replacement in the following link :

https://www.jaguarforums.com/forum/x...d-help-211483/