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Not been anywhere near the car for a while...life caught up. Anyway, despite the fact that I was never convinced that the battery was the problem, I kinda felt that everybody kept shouting and was gonna get annoyed with me if I didn't change it. So I bought a new battery ...no difference.
The only thing I'm thinking about now is this CKPS ....I took it off and measured about 5k ohms which suggests it's knackered ( But I'm also a bit surprised., I assumed it'd either go open circuit of closed ....just going high resistance seem a bit odd?) ...
Which then leaves me confused about this stray 3.3V dc on the CKPS connector ( with sensor removed ) ..if the sensor really is dumb then there shouldn't be any voltage on that wire...and that is more likely to be the problem than anything else? Even if the sensor is dead...did that 3.3v kill it?? Earlier in this thread i think is the info that the sensor is dumb?
OR ... is that 3.3v MEANT to be there to turn the sensor on? Again , rather like wasting my money on a battery , I'm keen to avoid replacing the sensor ( which appears to be either £100/$130 for a decent make from the motor factor or £50 off ebay for what is presumably something manufactured by a Malaysian four year old for a pound) if the real problem is this 3.3v ...does anyone have a definitive answer as to whether the 3.3v should be there or is it induced or shorted into the line somewhere?
OH ..another thing ...folk said 'check the ECU for corrosion on the pins' ..I pulled the ECU ...and the connectors on the top and the plugs look absolutely factory fresh ...couldn't be any cleaner?
The inertia switch has three wires going into it...I pressed it to no avail....I should short that out yes?
Don't take apart the inertia switch as you will have parts flying everywhere , done that myself . Just jumper the 2 white wires to bypass it .
The CKPS will read about 1300 ohms and not 5000 as a fundamental reading . A functional reading is a wave form you would have to have equipment to see .
the 3.3 volt reading will have to look into . The CKPS is a inductance sensor and not a hall effect sensor like the 3 wire camshaft sensor which needs a power source to function .
Mr. Q in Hong Kong for the wiring bundle as it goes over the fuel rail and through the firewall as a round bundle high on the firewall on the right side had some wire damage in the firewall area ..
Last edited by Lady Penelope; 06-27-2018 at 04:13 PM.
Sorry...I'm not getting what you mean in the last line of your reply.
Before I waste any more time or money I'd really like to establish if this 3.3v in the CKPS feed is normal ...if it's not, then I need to solve that problem
In reading mine I saw 1400 ohms on the sensor and no stray or unwanted voltage AC or DC on either of the 2 wires with a confirmed meter ground . This with the Key on position and engine not running . I saw about 0.15 volts change as I read the wires which validates the test configuration . But this small signal is inconsequential in the big picture .
Mr. Q in Hong Kong is " Qvhk " as I can't always remember his name and you may ask him as a Personal Mail as he had his eyes on what he found on his
Last edited by Lady Penelope; 06-27-2018 at 06:02 PM.
Im sorry to hear the new battery didnt do the trick, but as I was trying to say before, even if it isnt the solution, it creates a good starting point for further checking of the electrics (and of course a good starting point thereafter!)
As for the Crankshaft position sensor, many years of reading this forum have led me to the conclusion that its ability to cause problems transcends all reason and logic. It is right up there with coils as a major cause of grief, ranging from non starting through stalling to uneven idling.
To put it another way, If X300 coils and Crankshaft position sensors were 100% reliable, this forum would be about half of its size! With the passage of time as the cars become older new patterns of faults begin to emerge, coils and Ckps have been prevalent from the outset. Coils dont tend to cause a sudden "blackout", Ckps can.
That said, I well appreciate your lack of enthusiasm for shelling out for parts to fit speculatively, especially as you are already out of pocket for the battery. Can you borrow a known working CKps or buy one and return it?
In my opinion the resolution of the 3.3 volts he found on his CKPS wires need to resolved first before installation and testing of a new or borrowed CKPS . I see 2 issues in this car's example of the stray 3.3 volt signal already present in the 2 return signal wires as well as the higher resistance of the currently installed sensor which has the effect of reducing the amplitude of the wanted AC intelligence signal and if the ECU can discern a count with this lower amplitude or if the stray signal is a AC signal and overpowers if not alone modifies the shape of the curves depending on the stray and the wanted signals frequency . This is based on the phenomena of more then one signal can exist in a wire at the same time .
How the ECU interprets this compromised signal vs. a pure AC signal is unknown to me .
I'm new to this car and my electrical harness is in good shape electrically compared to other examples but the observation of degradation of specific devices is valid but I think it should include the wiring harness plus the grounds .
There must be a reason why Vee is changing his harness on his AJ16 powered XJS and Mr. Q in Hong Kong observations of damage in his XJR harness .
Everyone is looking for that magic bullet of it being this or that device to change based on percentages , cost , how X fixed his , or effort . But this is a electrical foundation issue .
Last edited by Lady Penelope; 06-28-2018 at 11:00 AM.
I’m going to pick my car back up on Monday, after getting it repainted. I’ll check my CKPS when I get it back.
It would be great if there was a way to record the bolts being read on certain circuits. For instance, the red wire should be at 4VAC at 700rpm, 8.60VAC at 1500rpm and 22.0VAC at 3000rpm. How can that be monitored? I would recommend having a copilot watch an analog gauge as the car is being driven?
The blue is a ground.
Both wires are shielded. As mentioned before, I wonder if he shielding is no longer grounded, and can that be checked?
Shields go back to LIG81. That’s one of the ground posts just inside the engine bay once the wires make it just outside the car. Unfortunately there’s a couple of splices along the way.
One splice is basically where the ground wire leaves the pair of red and blue wires and goes to another splice where it joins several other shielded ground wires. Those splices will be difficult to see, but they all occur inside the car, somewhere between the ECU and the rubber boot before the wires enter the engine bay.
Well....it was indeed the CKPS!!!!!! Just a sad coincidence that it went so soon after fixing the charge circuit, just coincidence I suppose.
Car started instantly, so the 3.35v is still a mystery, although I did speak to a local and very esteemed auto electrician who thought the ECU might put out a kind of 'search' voltage on start up in the sensor isn't connected. He said not to believe that voltage unless it was taken by tapping into a connected circuit, rather than an open one!!! Every day is a school day!
The car then did indeed start with the old battery too as an experiment, so it's a hundred pounds I could have saved at this point, BUT ... I appreciate everybody saying battery health is key, so I would have had to have done so sooner or later.
Since I wasn't convinced I went for the cheapest CKPS I could find ( 25quid , LEMARK LCS237 #263075538887 from tvrparts on ebay ) ... is it any better or longer lasting than the one the motor factor was gonna charge 100quid for...who knows? ...maybe I'll buy another and stick it in the glove box!!!!!
Anyway ..thank you everyone for your help and patience, and in many ways it's been a blessing, a bit of a baptism of fire but I feel like I know a heck of a lot more about the car now than I would otherwise have done. And at least I know all my earths are clean!!!! More so though, is I've gained a BIT of an understanding of what does what on this really quite electrically complex machine.
One thing to keep in mind on the CKPS is that before it completely fails and give a CEL code or the loss of a tachometer is that it will partially fail and not enable the fuel pump to stay commanded on . This is a safety / crash design feature that turns off the pump if it doesn't see engine rotation .
To further your understanding of the AJ16 engine control / regulation here is a different document . Don't expect to understand it immediately but over time .
Have you considered the use of a small luggage trailer ?
Do you have the distinctive leaping Jaguar hood ornament ?
The original AJ9500A stereo head can be modified yourself with a line in to be able to run a CD or MP3 device . This is different then a cassette device line in . The speakers foam surrounds other then the mounting foam commonly deteriorates over the 20 years and the foam can be replaced yourself for a much better sound .
The rear seat picnic tables of the more deluxe versions can be added but require the higher front seat back rear shells so color dependent .
ericjansen In Taiwan is modifying is higher up in the line rear seats for lighted Champagne and glasses holder . I'm going to do the same with the Sovereign rear seats with the smaller opening with the use of a electronic chilling device commonly available .
Last edited by Lady Penelope; 07-06-2018 at 01:04 PM.
If the inertia switch is tripped you WILL have no dash lights and no crank, turn the key to postion one and you switch on the relay in the trunk fuse box, position two enables ignition control relays under the rear seats and the right hand engine bay fuse box, the inertia switch allows a path to earth for ignition switch position two, if tripped no path to earth, then no dash lights etc etc, check the electrical diagram fig 1.4 and 2.1
100% False. Please delete this misleading post.
Tap Your switch with a screwdriver handle, then go start the car. Now try turning on the radio. Lights? Air Conditioning? Everything works except the car won’t turn over. She’ll crank forever, but she won’t turn over.
06-27-2018, 01:30 PM
