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On the '97, there is a fuel pump relay. Likely a relay on the 2004. Swap out a non-critical relay (for wiper fluid or some such) and see if she starts.
You can read the story up to now in my previous post -Starts and shuts down in 2 seconds.
I got the car home and tried various suggestions that came in from all you great folks.
Hard resets, fuel pressure, charges battery etc. while I have been waiting for the delivery of the Diagnostic software and cable from British Diagnostics.
Software installed and functioning, I hooked it up to the OBDII and ran a diagnostic and it can't see any of the modules. Then I see a note in the bottom right-hand corner of the screen.
Mongoose cable not connected.
I have attached a photo of my OBDII connector before the jag tech cleaned it up. I suspect it may have gotten like this because I leave an ELM327 plugged in all of the time and have for the seven years I have had the car. Perhaps a warning to others.
Any way the technician was able to get a hook up to download the old software and reinstall it. I am suspicious however that it may still not be that good a connection as the Mongoose isn't seeing my car.
Is anybody parting out a car and would like to cut off the OBDII plug and 6 inches of harness? It is all I can think of and the most logical next step I can think of. The photo of my OBDII connection that the repair tech at Jag sent me. He cleaned it up before he downloaded the software from the old module.
I have merged your new thread with your pre-existing one. Please do not start any new threads on this topic since it is most helpful to have all of the relevant information in a single thread, both currently and in the future when other members find your thread because they have a similar issue.
Regarding your Mongoose cable, are you using WDS, IDS or SDD on a laptop? If so, do you have the correct Mongoose cable drivers installed, and if you are running your software in a virtual machine, have you "Attached" the Mongoose in the USB menu?
Like they say on a lot of YouTube videos, disclaimer... Blah blah blah, do what I suggest at your own risk...
It's time to get a bit midevil on the car... I would.
Remove and have a look at the SWITCH for the key. It's a little red plastic thingy on the (US car) LH underside of the steering column... Could be corroded inside and when the key snaps back in the run position, the power supply is insufficient or crappy. Remove two tiny screws and you'll have it in your hand... Clean and inspect. Use a bit of electrical parts cleaner, spray it right into the switch, operate it with a large screw driver.
I would dig into the boot on the RH side, find the PWM control module. Aka the fuel pump control module. You will find a Red (R) and Yellow Red (YR) wire. I would take a lighter and melt a small section of the yellow red insulation and run a short stretch of wire and run it to a GROUND somewhere in the trunk. Here, if the fuel pump is functioning, at key turn, it will run full blast, you'll hear it, you'll know it's working and that will eliminate the question as to whether or not you are getting fuel pressure after the initial start prime at key turn. I think (repeat think) the 2 second prime is independent of normal PWM control.
THEN, try starting it.
If the same thing happens, I would DIG into the area on the LH front corner where your foot LH foot goes when your sitting in the driver's seat. If you grab the kick panel, the small vertical one that kinda tucks with a little tab under the tread plate in the door jam, and either push forward on it, or pull back on it, it will release and from there you can get to the inertia switch. By clipping two wires and stripping off the insulation, you can connect the two wire and completely bypass the inertia switch. Do that, start the car, see what happens. If you want to try this let me know and I will supply a wiring diagram so you can see which two wires.
Swap out relays on both door jam fuse boxes. Use the relays from the O2 sensor heaters, or something. Spares if you have them. Clean the fuses, clean the relay posts.
From there, I would dig into the steering column and replace the exciter ring in the column. They are cheap, at least check the connector. From there, I would go into the area on the dash heat vent closest to the LH window (US car), remove the molding, the heater vent, the instrument cluster, and the heating duct that runs behind it,,, and begin the process of swearing and cursing to remove the KTModule that is hidden in the dash. Small torx screw holds it in place.
The water and corrosion that you found in the OBD port,,, that moisture came from somewhere... The KTM lives right above it, as does the LH door fuse box. My KTModule was fried once with a leak in that area. Long story - window left open a crack and the KTM turned into a small bucket of water - toast at next start up. The inertia switch also lives in that area as well.
I would also add a redundant ground to the body control module. The housing of the BCM acts as a ground. If it's not bolted down tight, other ground is rotty, it can cause problems.
Clean out the BCM plug. Clean out the IC plugs. Clean out the ECU plug...
And keep trying.
I think you have a bad electrical connection somewhere. I really can be as simple as that. Ask me how I know, 😂
They are perfect for making temporary (or permanent) connections to test wiring, punching only a small hole in the insulation (and without risking setting fire to your wiring loom with a naked flame). Its also worth investing in a set of cheap back probes, which you can use to test at harness connectors etc. Something like this:-
Melting back, with a cigarette lighter, a 3/4 of an inch of plastic insulation on a wire will not result in starting a fire and burning down a wiring loom... It would be hard to do that,,, even if you were trying to do it on purpose...
My car had been in a flood - under water... And just to say quickly - there was no real test or report generated by the cars computers to tell me that my inertia switch was completely fried, that my KTM had shorted internally, that my ignition switch with its few internal (vital) contact surfaces were toast, that the BPM was not well grounded, etc etc etc. These issues needed to be found by hand, and eye, and I suffered for not really knowing that. There can be evidence that points you in some directions, often there will be....
The cars systems will TELL you but so much, but when it gets mysterious,,, ya gotta go digging, take some big swings with a big stick, kinda go shooting in the dark - if ya dare. That's been my experience. And that's just me.
Now let's just stop here ....A spark plug needs 40% more volts to fire it when its cold . So in the old days 1970s they used ballasted ignition ..a 6v coil operated on 12v during cranking.
Now if you move forward is it reasonable that the jag designers apply a higher voltage to the coil for 2 seconds and then reduced to normal ... Hence the Normal circuit is not working.
If its an old one with two ignition modules then its probably in that or a later model in the ECU ...or in the ECU on both early and late models.
since it shuts down after 2 sec I'd like to know how it shuts down?
ie, does it feel/sound like someone turned off the ignition (it immediately quits running) or like it just ran of fuel (a little slower before stalling)????
if the latter I like the fuel pump activation probability, if the former well...I dunno.
The only way I can see to test this would be with an oscilloscope ..you would see pulses to the coil which then stopped.
Maybe an old analogue meter ( one with a pointer/needle) would respond in the first two seconds and then stop reading.
I cannot see that a method used for years to aid starting would be abandoned on the jag. Afterthought.
Just looked and yours is a 2004 so the ignition modules are inside the ECU which you say is not programmed right .
so you have found the problem. Get that original ECU back and get someone with a brain to look at it.
Last edited by Pistnbroke; 10-01-2022 at 10:00 AM.
I did some research on this...The later motors with the 4 pin ignition coils have a +12 an earth and two wires to the ECU.
These wires can only be earthed by the computer, that's what it does.
I suspect that one of those two wires is pulsed to earth during starting to provide the extra volts required for cold plugs and the other is the signal for normal running. What's in the coil I don't know ..multiple or tapped primary, voltage dropper etc.
Sounds like the start signal stops and the run signal does not take over .
Last edited by Pistnbroke; 10-01-2022 at 10:02 AM.
The car can be immediately restarted for 2 second time and time again.
That does sound like something shutting off after a time delay. From what you have described, it doesn't sound like fuel starvation if the engine simply cuts out without faltering.
You can monitor fuel pressure over OBD on the 4.2 to check that it's holding up. I agree that replacing that OBD connector is a good move.
The extra pair of connections on the 4-wire plugs feed a 'spark confirmation' pulse back to the ECM. If any are missing, the ECM will disable the injectors for the offending cylinders after a short time delay.
The feedback wires are spliced into two groups of four - that's two cylinders on each bank.The ECM deciphers which cylinder each pulse relates to as it knows where the crank is in its cycle at any point in time.
A problem on one of the two ECM feedback lines could theoretically take out 4 cylinders, but it's unlikely both would fail together.
You could try a 'noid' lamp for spark:- Gus sent me a short video he had made while checking out his car. That might work for the injectors too, but I'm not sure how accessible they are with the SC motor? A 'scope is the best tool, as pistnbroke states, if you have access to one.
Last edited by michaelh; 10-01-2022 at 04:54 PM.
Reason: grammar
I've been pondering your issue and one thought keeps nagging me: you have not mentioned that any network (U-prefix) or body (B-prefix) diagnostic trouble codes were stored. You mentioned some ABS codes, which I presume were chassis (C-prefix) codes, but in my experience, an X103 without at least some U- and B- codes stored is rare. I'm wondering if your issue could be due to a communication problem on the CAN or SCP networks. It seems very odd that your symptoms do not trigger any Powertrain (P-prefix) codes, which may support the suspicion that something is unhappy in the networks.
If you can get your Mongoose working, please let us know ALL the DTCs you can scan.
you say The extra pair of connections on the 4-wire plugs feed a 'spark confirmation' pulse back to the ECM. I dont think that can be right ....two of the pins are a steady 12v and earth when the ignition is on. So what switches the coil primary to induce the spark ? If your two wires are feedback then it leaves nothing for switching ( 2003 diagram consulted)
you say The extra pair of connections on the 4-wire plugs feed a 'spark confirmation' pulse back to the ECM. I dont think that can be right ....two of the pins are a steady 12v and earth when the ignition is on. So what switches the coil primary to induce the spark ? If your two wires are feedback then it leaves nothing for switching ( 2003 diagram consulted)
One of the two wires is the trigger, the second is the feedback. From the AJ27 Technical Guide:-
Coil-on-plug Operation
The ignition control module is triggered directly from the ECM and drives the coil primary circuit, controlling current amplitude, switching point and energisation period. Each ignition control module also provides a monitor output to the ECM. When an ignition trigger signal is received, an acknowledge pulse is sent to the ECM if the current drive to the coil primary is satisfactory. This pulse is initiated when the current reaches 2 Amps and is terminated at 4 Amps. If the trigger pulse is not received or the coil current does not rise to 2 Amps, the monitor line will remain at logic high, signalling an ignition failure to the ECM. Two ignition monitor inputs are used on the ECM as before, but with each group of four monitor lines wire spliced together.
In other words this fault is nothing to do with the coil packs.
Interesting to note that its a constant energy ignition system ie the primry resistances are low and if put on 12v would probably draw 8A but this is terminated at 4A giving a constant energy spark.
Clearly does not apply to the 2 wire which may use a different system.
I have been waiting a few days to digest all of the suggestions and have just gotten into it this morning. My first problem is that I cannot get the computer to see the Mongoose so when I run a diagnostic I I just get back red x's on all of the modules. I have sent a message to Jaguar Diagnostics seeking help.
Does it run smoothly and shut straight off, or does it kinda run smooth then kinda chug chug and shut off. My xjs was starting and shutting off and then i found a vacuum leak in the intake tube. Well to be exact, i found a hole in my intake tube that I accidentally made lol smh
09-29-2022, 10:44 AM
Starts and shuts down in 2 seconds - continuation
