XJ6 died on a short drive

Con

The same ignition switch (Jaguar part number DAC1607) was used throughout the Series III production. So an OEM ignition a 1980 XJ6 should work in a 1985 XJ6, assuming that it is a good ignition switch.

Paul

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Agreed, Paul - but there might be some slight differences in wiringā€¦?

Frank
xj6 85 Sov Europe (UK/NZ)
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Double ditto on Paulā€™s points:

  1. the S57. The clearest electric schematic Iā€™ve ever dealt with. It has solved so much for me. Iā€™ve shared pages with others to help them. Many thanks to Bob Loftus.

  2. Yup, when I switched out my ignition switch, I found the buzzer disconnected. Clear signs of a visit under the scuttle by a PO. I reconnected it. The buzz does not bother my ears !!!

  3. Tape wrapped splices are asking for trouble. If one must splice, as I did in my conversion, I stuck to solder and shrink wrap.

  4. A NOS ignition switch via David Boger fixed a lot of things on my car!!!

  5. While wrestling with starter issues, I installed an emergency crank wire in my engine bay. merely a wire to the solenoid. Open on the top engine bay. Bare end protected, though, Jump 12v here and the engine will crank,

Carl

Hi all, I appreciate the help I am getting here on this problem. I have just got a copy of the relevant electrical schematics from jagschemes here in Australia. These are just a good clear copy of the relevant circuits that have been colour matched to make the circuits easier to follow. I have no problem with schematics, I used to repair TVs, VCRs and Audio equipment, but the copies I originally had were rubbish so these are making life much easier. I am a little time poor at present so may not get to the car in the next day or so but I will need to sort out the fuel leak before I try starting the car again, otherwise I better get some good insurance to cover the damage if it goes whoosh! :wink:
Talk to you soon
Con

So hereā€™s an interesting thing, I received my noid today and just for the sake of trying it out plugged it in to one of the injector plugs. On cranking I noticed that the light was pulsing. The light was quite dim though. Is it supposed to be a bright light or does it mostly only just glow? I donā€™t know why I did not get this result with my test lamp but am wondering if the pulse current is just very weak as Frank has suggested. Am currently removing immobiliser wiring from under the dash. I have two wires that I cannot see where they go so am trying to get some info from the manufacturer re installation diagrams. Not holding out much hope on that though. Still waiting to get under the car to sort that fuel leak, need to get some decent car stands. Not sure if bricks will suffice especially with me under there. :wink:
Con

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The grounding in the ECU, to open the injectors, only last for milliseconds, Con, once every engine revolution - too short for the noid to light up muchā€¦:slight_smile:

Adding that the deliberate resistance in the resistor pack further reduce current flow through the injectors/noid. And with ign on, engine not turning, there is 12V on both injector wires - no lightā€¦

So the ECU seems to do its stuff - making lack of injector action still a focus of vital interestā€¦

Frank
xj6 85 Sov Europe (UK/NZ)
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If the injector has 12V on one side and ground on the other it will open, period, no high tech thereā€¦
Maybe a bad ECU ground, or severely corroded cables with high resistance letting enough current through to just light the Noid light, but not enough to fire the injectors ?
And if wiring and Resistor Pack test OK, maybe the ECU is not doing its stuff good enough ?

Best
Aristides

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Certainly possible, Aristides - each injector draws around 1,5A, and they fire simultaneously. Indeed, during the noid test the other injectors should fire, confirming ECU proper functionā€¦

The internal working of the ECU is convoluted - and sometimes a bad solder has caused malfunctions. But generally, the ECU is very dependable, and not a first suspect - testing with a replacement is a quick-check, of courseā€¦

Frank
xj6 85 Sov Europe (UK/NZ)
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Frank
xj6 85 Sov Europe (UK/NZ)
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Hi the security system wire removal continues. I have pulled the ignition switch out, given the innards a spray of contact cleaner and given it a good work out, removed all the tape, cut all the extra soldered bits of wire from the ignition switch wires, soldered, covered the joints in heat shrink and as an extra insurance policy also wrapped the joint in cloth tape. (the heat shrink seemed very thin after shrinking) One wire on the back of the switch was barely on the terminal so I cleaned the terminal and soldered the wire back on. Does anyine know what the Brown/Red wire on terminal 6 does? None of my wiring schematics show this wire.
Con

Making good progress there Con !

I searched my manual and I donā€™t even see a terminal 6 on the ignition switch (!!?)
Does it look original ?
The only Brown/Red cable I could see is for the Seat-belt warning light, which is Battery fed.
But it also connects, via Fuse # 2, to the Brown/Orange cable from the Hazard switch.
So maybe an other security system modification ?

Best,
Aristides

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#6 terminal is powered with ign ā€˜offā€™, Con - the brown/red was used on carbed engines with ā€˜anti run-onā€™ fittedā€¦

To simplify assembly line Jaguar wired all cars the same, catering for various equipment levels - wires not needed was just left disconnected.

The connection may have been used for the alarm system, but likely not. However, #6 can be used for any item desired to be powered only with ignition off - which are rather few. Whether PO used it at all on your car is of course uncertain - but diagrams show no ex-factory useā€¦

Frank
xj6 85 Sov Europe (UK/NZ)
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Thanks Aristedes and Frank. Damn, I was hoping the Brown/Red wire was the one that would solve all my problems by giving it a decent connection. Still good to know if I want to power anything without the hassle of turning a key.
And the beat goes on!
Con

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Come on, Con - like housework, Jaguar work is never ending. With one difference; sometimes you are completely satisfied with you houseā€¦:slight_smile:

Frank
xj6 85 Sov Europe (UK/NZ)
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:grinning: yep Iā€™m starting to get what that means Frank.

Well the fault finding goes on. Iā€™m still working on getting this car up and running again. I am struggling to get the time at the moment to do the work but I can get a few hours here and there. Today I decided to pull the fuel injectors and see if they were indeed opening as they should. Well they are but the injector on number 1 cylinder was not functioning at all. While out, I used a 9v battery to check whether it was working independant of the car. It did, so while there, I sprayed carby cleaner through a pipette, so it was under pressure, into the inlet side and watched a fairly even spray pattern out the other side. Checked the others and cleaned the same way. After refitting the injectors I checked operation of each by removing the plugs from all injectors and plugging each one in one at a time and making and breaking the bullet connector. All functioned ok except number one. A carefull check of the plug showed that one of the connectors inside the plug was pushed out so I was only getting 1 wire connected there. This plug was the only one that still had the rubber boot intact so was masking the fact that the plug had pushed through. After refitting the plug I rechecked operation and it was all good. So now I know that that end of the fuel delivery system is good. Now I also noticed that the fuel being delivered did not seem to have a lot of pressure. I have a new fuel filter that I need to fit and then I will see if the pressure improves. I had a small disaster as well, The fuel temperature sensor which is on the fuel rail has two hoses attached. On my car the one that comes out the bottom was blocked off with a screw in the hose. I managed to snap this off the sensor with the spanner while removing the adjacent injector. The sensor has a cap that seems to just slide off and this cap is what has the hose connected to it. As this hose was blocked off, can I just put a thin piece of material inside the cap to block the hole?
I am fairly happy with the fuel side of things now apart from the fuel pressure so am going to start on the ignition system soon. I have some rewiring to do and maybe replace the coil. I think progress is being made,
Con

Hi Con, I hope things improve for you soon. Reading your posts makes me quite happy with my pedestrian old carbs - sorry I canā€™t help, Paul

Funny thing is Paul, I originally wanted and Series 1 or 2 with carbies. I think I would have had a better chance of understanding those. Iā€™ve had a couple of MGBs and restored a 1949 Singer 9 Roadster, the MGs with twin SUs and the Singer eventually aquired a pair of SUs as well. The car I bought just happened to fall in my price range and, at the time, was running. Oh well, nothing that time and money canā€™t fix.
Con

I have both, and Iā€™ve found the injection variants a bit easier to troubleshoot and get running well. Iā€™ve found carbā€™s are very susceptible to problems due to the methanol in the fuel these days, and here in the US itā€™s tough to find fuel that doesnā€™t have methanol. Thereā€™s some sort of chemical reaction between the metal the carbs are made of and the methanol which creates a petrol flavored aspic in the bowl. I also keep a stock of diaphragms on hand for the because the diaphragms appear to be good for about 1 or 2 years; until the methanol completely destroys diaphragms.

For what ever that was worth.

Today I finished the injectors refitting with replacing the short hoses from the fuel rail to the injector. I used 5/16" internal diameter as that seems to be the only size apart from 1/4" that the local parts store stocks. Fitted ok but wonā€™t know for sure until I repressurize the system. I removed the fuel filter and was a little surprised at what came out. Looked more like dirty transmission fluid than petrol. Looks like I am getting closer to my problem. Going to drain the tanks next and give them a slosh out. Found a label on the old filter stating that it was fitted late November in 2003, probably a little due for replacement

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The purpose of the thermal vacuum switch is just toā€™ switch offā€™ the vacuum to the fuel pressure regulator with high fuel temp, Con - which seldom occursā€¦:slight_smile:

I suggest you just connect a plain vacuum hose between the manifold nipple and the pressure regulator - simply omitting the thermal vacuum switch for the time being. The system will then work as intended - just blocking this hose will simply cause excessive fuel pressure for ā€˜normalā€™ conditions, which is overwhelmingly most of the timeā€¦

Without verifying fuel pressure; it is imprudent to pursue other matters - with incorrect fuel pressure the engine wonā€™t behave whatever else you doā€¦:slight_smile:

Frank
xj6 85 Sov Europe (UK/NZ)
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