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Just joined the forum after a few weeks of lurking, and have fixed many problems searching the forum.
I picked up a 2001 XJR a few weeks ago for a good price, however with cheap cars comes problems. So far I have replaced the alternator fixed the ABS module changed the front suspension mounts replaced both rear suspension struts and new spark plugs. I have also replaced all the rotors and pads and replaced a wheel bearing and put 4 new tires on it.
I have finally got to the end of the repairs, or so I thought I am now having a problem at full throttle, the car drives fine when driving normally or upto 3/4 throttle but it then starts to buck around and eventually goes into fail safe mode.
Any ideas would be grateful the car is also not throwing any CEL codes.
Welcome to the club. I highly recommend you get a blue tooth OBS2 reader and the torque app for your phone. It will allow you to monitor a huge amount of real time data and log and save data so you can see exactly what is happening at 3/4 throttle
I would start by looking for air leaks. I would start here because if it were a misfire issue the ECM would set codes. Also, if you can rule out air leaks then you can focus on other systems.
Monitor your short term fuel trims at idle - they should ideally be close to 0 +/- a few percent. Then spray MAF sensor cleaner round the intake, hoses, throttle body, etc. If there are any leaks you will see the fuel trims go crazy right away.
Also check the 1/4" hose from the top of the supercharger to the fuel pressure regulator.
Next I would check your fuel pressure and also confirm that your secondary fuel pump is working. If the engine cranks a long time before starting when cold that is a sign that it is dead
I can't really tell from the pic, but if it is in the boot/trunk near the battery the connector is probably the "shipping" connector. It is connected to something while the car is "on the boat" to prevent problems. It is removed by the dealer and is one of the most frequently asked questions of new owners on this forum.
I would say you have one pump inoperative and one on the way out. The primary pump operates up to 3000 RPM and then the secondary kicks in. Yes, it should be able to idle on one, but usually the wiring gets fried when the pumps go bad so you probably are not getting full power to your remaining pump.
Since it is such a tough job to remove the fuel tank to get at the pumps, most recommend that you replace both pumps and the wiring harness while you are in there.
Welcome to the forum and enjoy your XJR, they are a real sleeper and capable of extreme performance once sorted out.
Vector
The same thing happened to me shortly after buying my '01 XJR last July. I tried to save some money by using cheap fuel while driving from PA to FL. After 3 tanks of premium gas it cleared up and I have'nt had the problem since. I always use 93+ now!
Just to update you guys, I picked up another 99 XJR for a ridiculous price so now I have 2 lol.
I picked up 2 new fuel pumps with the intent on changing them on the 2001 but the 99 XJR does not run the previous owner did not know what was wrong with it. So I did the checks with the relays and low and behold the pumps on the 99 dont work. I put one new pump into the 99 just to try it and it now runs.
Not sure whats going to happen with the 99 XJR yet the previous owner said it over heated but so far I have not seen any water in the oil or oil in the water. The pulley next to the alternator was plastic and broke apart slicing the belt in two and tearing the fan wiring harness out and destroyed it so I need another one. He has also butchered the radio wiring so I need an new plug and wiring.
New guy 2001 XJR
