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"Pins 5 & 6 were connected to keyed power and ground." I'm sure have you didn't source your keyed power from the cut wire. Chances are, there's no positive voltage of any nature coming from the cut wire, but it bears examining with voltmeter, or oscilloscope better yet. Just turning key on should initiate the brief pump/rail priming for a response. Maybe it is time to check that right out of the ECM.
Also, switch key to run mode and check continuity from the cut ground wire to ground. That should verify the integrity of the ground wiring, inertia switch continuity as well as ignition switch run circuit.
Rather than bore other readers, I sent you some lengthy ramblings in a Personal Message.
"Pins 5 & 6 were connected to keyed power and ground." I'm sure have you didn't source your keyed power from the cut wire. Chances are, there's no positive voltage of any nature coming from the cut wire, but it bears examining with voltmeter, or oscilloscope better yet. Just turning key on should initiate the brief pump/rail priming for a response. Maybe it is time to check that right out of the ECM.
Also, switch key to run mode and check continuity from the cut ground wire to ground. That should verify the integrity of the ground wiring, inertia switch continuity as well as ignition switch run circuit.
Rather than bore other readers, I sent you some lengthy ramblings in a Personal Message.
Jim1947
Thank you, Jim1947, for this information. I am onto other matters for the next day or so but I will check those reading when I get back to the CAT .
Have you checked the function of the fuel pressure sensor? Does the 2003 NA XK8 have one?
on the SC version it's on the RH side of the rail and sends a signal to the ECU,,, the ECU generates is PWM control signal to the fuel pump controller this way. I would expect a p0193 code if the sensor was a problem but,,, one never knows. There is also a vac tube (on my 2004 SC) that is important.
Have you checked the function of the fuel pressure sensor? Does the 2003 NA XK8 have one?
on the SC version it's on the RH side of the rail and sends a signal to the ECU,,, the ECU generates is PWM control signal to the fuel pump controller this way. I would expect a p0193 code if the sensor was a problem but,,, one never knows. There is also a vac tube (on my 2004 SC) that is important.
The 35lbs reading is low low low...
Now that I have the ability to get the vehicle running, some of the more transient signals will be easier to test, Fuel Rail Pressure Sensor being first on the list.
I can vary the fuel rail pressure by altering the duty cycle of my square-wave generator, which is at my elbow in the car. Driving the car around yesterday and going as fast as 45mph, the 35 lb. constant pressure seemed adequate to the engines needs.
Thank you, JayJagJay, all contributions to getting the CAT back on the road are greatly appreciated. If any other ideas come to mind, please let me know.
My car is a 2002, then the other is a 2004 but with charger. I'm not familiar enough with the 2003 XK8 to know BUT,,, (and maybe someone else can tell) what I want to know is one,,, does this car have a fuel pressure sensor, whats it's role and what is the "normal" fuel rail pressure? Is it the 55.3 there and abouts?
Of the fuel pump is working with your modified set up, providing PWM control, and it doesn't with it set up OEM,,, I think your problem lies in there, somewhere
So, if I understand your steps 1-4 above, you now have a second fuel pump control module feeding the fuel pump, and the original control module is still in place and connected (other than to the fuel pump)?
[QUOTE=JayJagJay;2591142]Hey Paul...
BUT,,, (and maybe someone else can tell) what I want to know is one,,, does this car have a fuel pressure sensor, whats it's role and what is the "normal" fuel rail pressure? Is it the 55.3 there and abouts?
If the fuel pump is working with your modified set up, providing PWM control, and it doesn't with it set up OEM,,, I think your problem lies in there, somewhere[
/QUOTE]
It does have a Fuel Rail Pressure Sensor, on the right front corner of the engine. Since I had been unable to run the engine, it seemed premature to check its output. Now that I can run the engine, its function or lack thereof has moved to the top of the list.
I have no idea what the normal pressure should be, as previously mentioned, the 35 lbs of pressure seemed adequate to the needs of the engine over a range of RPM's.
I agree with your assessment, Jay. My setup seems to confirm that the pump and the Fuel Pump Driver Module are okay. Because of the cost of ECM replacement, I have been reluctant to accept it as the culprit, since there are still a few suspects such as the Fuel Rail Pressure Sensor, the vacuum line to the FRPS, the presence of the "Restricted Performance" message in the speedo display, and, of course, any other system fault that would cause the ECM/TCM to go into limp mode (Restricted Performance) as the ECM may be intentionally turning off the fuel pump in reaction to such a fault. You Senior members, particularly present or former Jag servicemen, may be better able to speak to that last item.
QUESTIONS THAT HAVE ENTERED MY MIND:
1.- What is the Flight Data Recorder? Where is it? Can I access it? What sort of data is stored there? For how long? See DTC P1582 above. Since this DTC seems to be the result of going into limp mode, perhaps it stores an explanation ( naugh, to easy )
2.- What is "Watchdog"? What is Watchdog reset ( see DTC 0x0000 above)?
3.- Not to muddy up my current problems, It seems odd the the BPM (Body Processor Module) and the SLM (Security Locking Module) are throwing the same code.
4.- AC not blowing cold air. ATC (Climate Control Module) threw two codes B1263 and B1266, Vent Servo motor circuit failure and Left air intake servo motor circuit failure.
5.- The DDM (Driver Door Module) and the PDM (Passenger Door Module) both threw the B1236 code, indicating a door window glass feedback, loss of signal. The 20A fuse (#1) for both seat modules was found deceased. Both windows seemed to operate normally.
6.- What is the best diagnostics software for my late build 2003 XK8 (Vin=A32xxx)? I am interested in constructing a laptop computer dedicated to the diagnostic task. The Panasonic ToughBook is no problem. Does the Forum have access to any of the iterations of the ISD / SDD software? I had previously built a system dedicated to the BMW Z3 running the GT1 / DIS software.
Lastly, since this forum has convinced me that I have gotten myself involved with a service money pit. (I once owned a boat and currently have a BMW Z3 daily driver. I know what a money pit is !) Problem is, like John55, I really like this car. As a young man in my mid twenties, I fell in love with the 67 Jaguar XKE, a love affair that has withstood the tests of time. I could have bought it then for around $5500, Today, a 67 goes for $55,000 or more. I believe it is the most beautiful car ever designed. The XK8 and others with the same styling come in at a close second but, at least, one I can afford.
So, if I understand your steps 1-4 above, you now have a second fuel pump control module feeding the fuel pump, and the original control module is still in place and connected (other than to the fuel pump)?
I thought that you could get fuel pressure by feeding the original fuel pump control module with a simulated PWM signal? In which case, would that not have permitted you to drive the car as you are doing now. I don't see the difference between the two configurations. What am I missing?
A 'watchdog' is a device that monitors a processor for a crash and will send a reset signal to restart the processing. They're used where there is no human intervention (no way to press Ctrl-Alt-Delete, essentially).
The 'P1236 - Fuel pump not working when requested' *may* be a result of the original fuel pump control module noticing that the pump is not now connected. Perhaps check the 1Hz hearbeat? The others may be historic or transients and I suspect that you can ignore them for the time being.
Normal fuel pressure is maintained at ~55 psi when everything is working as it should.
I thought that you could get fuel pressure by feeding the original fuel pump control module with a simulated PWM signal? In which case, would that not have permitted you to drive the car as you are doing now. I don't see the difference between the two configurations. What am I missing?
A 'watchdog' is a device that monitors a processor for a crash and will send a reset signal to restart the processing. They're used where there is no human intervention (no way to press Ctrl-Alt-Delete, essentially).
The 'P1236 - Fuel pump not working when requested' *may* be a result of the original fuel pump control module noticing that the pump is not now connected. Perhaps check the 1Hz hearbeat? The others may be historic or transients and I suspect that you can ignore them for the time being.
Normal fuel pressure is maintained at ~55 psi when everything is working as it should.
Doing it your way, I my demented mind, might have disrupted the conversation between the ECM and the driver module. I saw no conversation between the pump and the driver.
Your comment on the P1236 code clearly shows that I wasn't thinking correctly. In my mind, I was maintaining system integrity. Oh, well !
Thank you for the info on watchdog, normal fuel pressure and the link to Motorcarman's post on the Flight Data Recorder.
WHOOP ---- WHOOP ---- WHOOOP ! !
Somebody, I think jrnsr or jayjagjay, kept pressing me to check to see if there was any voltage ot the open ends of the cut wires. I did ! And, lo and behold, there was ! I connected my old pump to the cut ends and the pump was spinning ! I immediately disconnected my additional pump driver & associated circuits and reconnected the tank pump to the driver talking with the ECM. ! CRANK / NO START ! ! So I REVERSED THE WIRES ! ! IT STARTED RIGHT UP AND RAN LIKE THE BEAST SHE IS ! ! Fuel pressure just a little over 50 lbs. Drove it 4 miles around the neighborhood and got one new code, P0191, so I will be hovering over the Fuel Rail Pressure Sensor for the next few days.
While I am elated that the car is operational in its original condition (no tricky stuff), I am still concerned that there are problems yet to be discovered (what caused my original limp home mode). For now I shall enjoy driving my beautiful black panther around the neighborhood.
See attached diagram of the fuel pump wiring schematic. The fuel pump wires were cut at the X's and the pump was wired to the 2nd driver module as shown. When I checked the voltage at the X's, and the rest is in the post. My conclusion is that the Chinese harness wires (W & B) from the pump to the internal connection on the tank lid were reversed.
Me too - are you not now back to the original state and the issue has vanished?
Exactly so, Mike, as to square one ! I am not so sure that the original issue has vanished. Right now, I am enjoying the pleasure of driving this beauty around the neighborhood, missed over the last three and a half years. Pessimist that I am, I fully expect the original issue that caused the limp home mode will re-appear. The new code, P0191, may be a clue to that problem or the result of my playing with the wiring. As I now re-register this car, clear the codes and continue driving it through the needed drive cycles, I await the problem's return.
Again, I want to thank all the members who jumped in to help this newcomer to the Jaguar community. It has been a truly pleasurable experience and look forward to a continued association.
It's frustrating as hell when this happens, but it does and you can't continue to trace a fault that has vanished
The FDR data might give you a clue when you get to read it.
I would clear all the codes other than the P1582 (I think that needs the Jaguar diagnostics in any case) if you can and see what happens. The P1000 will morph to P1111 once the drive cycle has completed.
Paul,
Before you go out for another test drive in your Jag, hook up the OBD2 scanner. Before starting, just out of curiosity, check the throttle position at full throttle and see how close it is to 100%. (If you embark on readjusting pedal cable, it is not as described in the post in the post TPS and PPS ADJUSTMENTS VIA OBD.). Make sure the floormat isn't interfering. Take particular note of the throttle position closed cold, before starting. Then observe how high the rpm runs up to starting, and that it settles down slowly. What is the rpm fully warmed up? Now what's the warmed up throttle position? How smooth is the idle? You might keep an eye on the fuel pressure, too. If you have nothing better to do, take a few minutes to remove the throttle body snorkel from the air cleaner and the breather tube from the valve cover. Check to see if the TPS says Denso, which could indicate it is the original. Does it have goofy 5 sided security screws or now have Philips, hex or Allen screws? If it appears to be all original, maybe leave a sleeping dog lie. You might get a feel for how the throttle position approaches zero when gently pushing the throttle plate closed, as pointed out in TPS and PPS ADJUSTMENTS VIA OBD. If it goes into limp mode again, or if the butterfly doesn't register zero as it touches closed, you might want to adjust the TPS.
It's frustrating as hell when this happens, but it does and you can't continue to trace a fault that has vanished
The FDR data might give you a clue when you get to read it.
I would clear all the codes other than the P1582 (I think that needs the Jaguar diagnostics in any case) if you can and see what happens. The P1000 will morph to P1111 once the drive cycle has completed.
I cleared the codes and did get an explanation of the P1582 code needing Jaguar diagnostics for it to clear. Thanks for the info on the P1000 code.
It is mildly frustrating that the limp mode message has not yet re-appeared. It leaves me concerned about the car's trustworthyness to go beyond my immediate neighborhood. Hopefully, that will abate with continued use.
Paul,
Before you go out for another test drive in your Jag, hook up the OBD2 scanner. Before starting, just out of curiosity, check the throttle position at full throttle and see how close it is to 100%. (If you embark on readjusting pedal cable, it is not as described in the post in the post TPS and PPS ADJUSTMENTS VIA OBD.). Make sure the floormat isn't interfering. Take particular note of the throttle position closed cold, before starting. Then observe how high the rpm runs up to starting, and that it settles down slowly. What is the rpm fully warmed up? Now what's the warmed up throttle position? How smooth is the idle? You might keep an eye on the fuel pressure, too. If you have nothing better to do, take a few minutes to remove the throttle body snorkel from the air cleaner and the breather tube from the valve cover. Check to see if the TPS says Denso, which could indicate it is the original. Does it have goofy 5 sided security screws or now have Philips, hex or Allen screws? If it appears to be all original, maybe leave a sleeping dog lie. You might get a feel for how the throttle position approaches zero when gently pushing the throttle plate closed, as pointed out in TPS and PPS ADJUSTMENTS VIA OBD. If it goes into limp mode again, or if the butterfly doesn't register zero as it touches closed, you might want to adjust the TPS.
Looks like all good info. Currently, replacing front shocks tower mounts ( put on back burner when original limp home appeared ) and, noticing a deteriorated lower shock bushing, shocks. Should improve the ride and lower the TAP TAP TAP noise coming from under the hood. LOL !
Thanks for your help, Jim, it is very much appreciated.
