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Now what might be possible, subject to the electrical gurus on here's OK, is to use the capstan microswitch for TWO purposes:
to operate the fuel enrichment as normal, and
to operate the kickdown.
I believe, as long as both the input 12v live wiires for each circuit are on the same terminal of the switch, and the outputs also both on the other terminal, it would do both circuits. The only question would be the current carrying capacity of the switch, but I would be very surprised if that was more than about an amp.
By "live" I presume you mean "12V positive".
The enrichment switches operate by completing a ground/earth circuit.
The kickdown requires 12V+
What I did is use an ordinary ice cube relay to operate the kickdown, with the enrichment switch providing a ground/earth trigger.
Would it not be possible or even more desirable, to do away with the 'Micro Switch' idea altogether and instead 're-purpose' the part of the Steering Column Stalk Lever that is used for Flashing the Headlights, as a sort of a 'Paddle Shifter' to operate the 'Kick-down' at any time decided by the driver, who might base that decision on the reading of the 'Tacho' at the time
Giving 'Total Flexibility' as to when to operate the 'Kickdown' and for how long
If there's a will, there's a way.
However Jaguar already provided the capability of selecting lower gears whenever it strikes your fancy. Just move the gearshift to "2" or "1".
I nearly always use the Shifter as the floor mat often gets crumpled up under the accelerator pedal, which prevents the kickdown operating, even though I always try and keep that Carpet Flat, maybe I will try and Velcro it or something
In any event I think the Shifter is a lot more fun!
Since we're tossing around ideas to increase performance and response via the kickdown......
It's quite easy to fabricate a compressor cut-out circuit, using the kickdown to trigger it.
I did.
I dunno the exact amount of horsepower the A6 compressor saps but they're notoriously parasitic. When using the kickdown it's presumed you want maximum power, and every little bit helps, so.......
I am wondering if you could have something like a Jubilee Clip Clamped around the Capstan, with a Cam like 'Thingy' on the Outside. so that you could turn it to any position before you Clamped it up. so you could find the 'Sweet Spot' before you filed anything off
I have a S3 XJ12 that would benefit from these mods. It has the 3.31 diff already.
I hadn't thought about modifying the shifter, but I have always thought the orginal gates were clumsy.
Mr Bywater is slowing down a little I think, I'm not sure if I should send an ECU.
Thanks,
Rob
Give him a call, if he says he will do it, he will do it.
I am wondering if you could have something like a Jubilee Clip Clamped around the Capstan, with a Cam like 'Thingy' on the Outside. so that you could turn it to any position before you Clamped it up. so you could find the 'Sweet Spot' before you filed anything off
Alex
The column stalk/foot operated switch would work, but the problem would be that you have to maintain switch contact to keep it kicked down. So as the thing leaps forward, as it most certainly will, i think you will need all your attention on the steering/driving!
I also always found the stick shift from D to 2 rather cumbersome, and definitely nothing like as quick as a properly working capstan setup, and once again I think both hands on the wheel will be needed in the context of rushing past a slow car on a normal two lane road.
I do agree that organising the setup so as to make it easily adjustable is the ticket. In my setup, which is basically a prototype, when I have used it a bit more, and if I decide it needs softening a bit and coming on later, the i think that slotting the bracket is the easiest fix to making it easily adjustable:
In the above photo: the blue loop shows the heel on the capstan that trips the switch; the orange box shows where the bracket needs to be slotted, orange arrow direction makes it kickdown later, green arrow direction makes it kickdown sooner.
I think this is probably the easiest way to make it adjustable to just right.
Now all I need is to scrounge a nice bit of 10mm thick stainless to make the bracket smarter with a nicely machined slot. One for Louis the Lathe King...
Last edited by Greg in France; 02-03-2022 at 08:45 AM.
The enrichment switches operate by completing a ground/earth circuit.
The kickdown requires 12V+
What I did is use an ordinary ice cube relay to operate the kickdown, with the enrichment switch providing a ground/earth trigger.
Cheers
DD
Doug yep. This is what I was thinking last night. Just a simple single throw relay wired in line to the enrichment switch. When the enrichment arm is closed via the capstan the kickdown will operate. You could then adjust the enrichment switch on the capstan via the filing and relocation if you felt around 75% throttle wasn't low enough for kickdown. I like it and it would look standard which is what I'm going for. Great thread. We all seem to gravitate towards the performance mods. Hahaha
Went down the easy route and just swapped the kickdown wires onto the enrichment switch. Greg is sooo right ... it is like driving a different car.
Now for a permanent solution. Automotive electrics are a dark art to me, so I will need help. Is it simply a matter of adding a relay where the 12V wire from the kickdown is wired to the enrichment switch via terminals 85 and 86, and the enrichment circuit is closed using terminals 87 and 30?
I have accomplished the same thing by a different method but I fully agree, having the kickdown operate at about 3/4 throttle really transforms the car. I did not go with the location you have selected because of the need to grind the capstan to prevent switch operation at idle but I may eventually go that way. Here are photos of my current setup, working off the left throttle rod. First picture is closed throttle, second is about 3/4 throttle.
I have accomplished the same thing by a different method but I fully agree, having the kickdown operate at about 3/4 throttle really transforms the car. I did not go with the location you have selected because of the need to grind the capstan to prevent switch operation at idle but I may eventually go that way. Here are photos of my current setup, working off the left throttle rod. First picture is closed throttle, second is about 3/4 throttle.
Greg. Well that's another option. Well done. The possibilities are endless it seems. I'd like a setup that was adjustable with slotted holes so you could adjust where you'd like it but you could do that with the way you have it also.
I haven't really driven my car other than putting around the driveway to test the drive line, gearbox and brakes etc as I'm in the middle of a resto, but I'd like to hear feedback about the actual performance and drive experience the difference makes. Ie is it worth it.....
1989 XJS v12 he Lucas—- when I turned the ignition on I HAD 12v at the switch. So I thought “GREAT”. Switch works fine. I started the car and now I have NO more 12 v at the switch. I do need to replace the switch as it is cracked. I pulled the green wire off and still 0 volts. Fuses on the inner fender well are all good. What am I missing?
PS- . I do have to free up the frozen throttle for the kick down
Thanks. The 10a fuse # 5 was blown, the brake lights and directional also did not work also. All on that 10 amp fuse. Thanks! Problem # 2 reared it’s head as I had the key on. I smelled fuel and noticed the minor fuel leak on the left side fuel rail at the sensor that has 2 vacuum lines connected to it. I removed one hose and there is fuel at the edge of the fuel line. One vacuum line goes to the intake runner the other to a actuator on the fuel supply for the B bank. It is brown in color. Does this need changing. ( I’m assuming so ). No leaking while she’s running but the B bank (drivers side) is running more rich than the A bank. ( US model). Lucas
Thanks. The 10a fuse # 5 was blown, the brake lights and directional also did not work also. All on that 10 amp fuse. Thanks! Problem # 2 reared it’s head as I had the key on. I smelled fuel and noticed the minor fuel leak on the left side fuel rail at the sensor that has 2 vacuum lines connected to it. I removed one hose and there is fuel at the edge of the fuel line. One vacuum line goes to the intake runner the other to a actuator on the fuel supply for the B bank. It is brown in color. Does this need changing. ( I’m assuming so ). No leaking while she’s running but the B bank (drivers side) is running more rich than the A bank. ( US model). Lucas
If you have a fuel leak at that sensor, you probably have a broken diaphram in the fuel pressure regulator, allowing fuel into the vacuum line. The sensor you describe does not touch fuel. It is a temperature actuated vacuum switch to aid hot starting. You should be able to remove it, and see that there is no hole in the fuel rail, just a blanked off threaded boss for the sensor to screw into.
It is highly likely your B bank fuel pressure regulator is leaking, making that bank run rich from the gas being sucked into the vacuum port.
02-03-2022, 06:44 AM
