Hi, I have just got my XJ6 on the road, had to replace the vacuum modulator to stop clouds of white smoke after stopping on downhill slopes.This has fixed that problem.
Trans is changing up gears when it is supposed to but not kicking down when it should except when coming to a stop,so having to manually shift to 2nd on up hill sections of road or when accelerating hard. On the bracket for the throttle cable is a micro switch angled back towards the fire wall,but looks like it should be upright where linkage would touch it when accelerating, Could this be a kick down switch that is not positioned correctly? And is it something I can play around with myself?
If it is not for trans kick down could someone enlighten me to it's purpose.

Regards,Clarke

 

Clarke,

I've moved your question from General Tech Help to XJ6 & XJ12 Series I, II & III forum.

Members here with the same or similar model will be able to advise on the kickdown switch.

(I've left a redirect in General Tech Help so you get double the chances of replies!)

Graham

 

Hi Graham,
thanks for that,just feeling my way around at the moment.
Clarke

 

I had similar issues. My gear changes were all over the place and never correct. I see you're in Brisbane. My series 2 car has a throttle kickdown switch and I had it positioned wrong. I dialed it all the way out and shifting and power improved.
Trying to find a detailed picture of the throttle linkage...

 

Hi Clarke - The BW 12 has a kick down solenoid that is operated by that switch you mentioned. It definitely should be operated by the throttle linkage - you should see it engage when you manually move the linkage. If it doesn't that is definitely the problem. Also if you have the ignition in run position with the engine off you should hear the solenoid activate when you push the switch closed either by hand or by moving the linkage. If it's angled back strangely and not screwed into the mount or the mount is bent there's something wrong with it.

If the switch isn't working it won't downshift for sure.

Tell you what though, even when it's working perfectly you'll probably still want to manually downshift on serious hills so you don't have to keep mashing the pedal to the floor. I live on a mountain and drive my Series 1's constantly... most of the time going up hill I just drop into 2nd and leave it there til it levels out.

Once you get the switch sorted another good thing to do to get the downshift working right is to replace the o-ring on the solenoid. Gotta drop the pan so best wait til you change the fluid for that one.

 

Hi Mike got the car back from paint shop today and got Haines manual in the post yesterday. Got black up to the armpits today,micro switch has been put back in correct posi, ran a test light on it,no power,switch is working on multimeter.
Green wire goes to a relay,no power from there with test light or meter, I'm assuming relay is the problem.
Green wire is on a double plug with a purple wire on relay. Purple wire has no power either,yet to study wire diag. Beer o'clock now so will wait to tomorrow.
Drove it in the mountains last week for 4 days,changing down with shifter,works sweet.
Throttle is sticking on uphill (at about 1500rpm)any ideas. Can replicate it in garage in D, but is fine in R or N. and if I shift to n it drops back to 700 rpm strait away.
Clarke

 

Hi Clarke,

The green wire is power and should come from the horn relay on the right inner fender near the coil. Do your horns work? This is all powered by fuse #4 behind the center instrument cluster. If the purple/brown wire is dead that is your problem. It's all switched power so the key has to be in run position.

The Red/Black wire goes into the transmission and is hooked to the solenoid. If you jump 12V+ to that Red/Black wire you should hear the solenoid click.

As far as your question about the throttle sticking... do you mean it physically sticks open or RPM's are high inexplicably? If the butterflies physically stick open it could be that the external return springs are missing or the 'y' shaped parts they attach to are gone - I've found that in several series 1's for some reason. Your Aussie market carbs are different than mine and you don't have the annoying secondary manifold we have to deal with either so it's kind of hard to say for sure. Series 1 linkage is simple so if it's something like that it should be fairly easy to diagnose.

If something else is going on besides the throttles just sticking I would suspect a possible problem with the distributor advance... maybe it's advancing as it should but sticks in that position? Check it with a hand vacuum pump.

Also does your car have an AED (automatic enrichment device) for cold starting? That could be an issue. I don't have much experience with that because US market cars don't have them. I do know they can be a pain though. Automatic Enrichment at the wrong time could jack up the revs...

 

Hi Mike,
Jumped the red wire,can hear solenoid. Horns work so connected red wire to green and can hear solenoid. Multimetre on micro switch with key on and green wire connected shows no voltage then 12.4 v to the terminal red wire was on red when clicked in. But replace red wire to terminal and solenoid doesn't work.
There is a third terminal that had no wire to it, it has 12.4 volts constantly then drops to zero when switch is pushed in,connect red wire to this and can hear solenoid working when depressing micro switch. Maybe previous owner put wires back on wrong terminal.
This means solinoid will be constantly powered until linkage pushes switch in and cuts power to it and is powered again when throttle is backed off. So if solenoid is supposed to be constantly powered that is my problem,but I won't road test it until I know for sure
that is how it should be working(don't want to damage trans). Will have research that one further.
Re sticking throttle:All return springs are connected,thought it might be cable so took that off ,all mechanical parts are moving freely and nothing sticking. But when driving it sticks sometimes. Timing doe's need checking as engine over runs when turning off, the other thing I have changed is vacuum modulator on trans. I have guy across the road who is a retired mechanic so going to get him to set timing/dwell and check vacuum when I get a chance.
Twin SU hd-8 carbs,manual choke,no secondary manifold. all parts and springs look like they are there going by exploded views of carbs in Haines book and Intereurope book.

Clarke

 

Hi again Clarke - your kickdown switch configuration is different than mine - probably because of our left hand drive configuration - but I can tell you for sure that the solenoid should only operate when the throttle is nearly wide open. Definitely isn't supposed to be normally powered and then cut off at kick-down. I'm surprised your switch has another terminal... maybe a PO replaced it with something generic?

If you can you should get a copy of the Bentley XJ6 manual. Haynes is okay but the Bentley version is really much better and the wiring diagrams are WAY bigger. Here's a link to one on ebay.com.au Jaguar XJ6 Service Manual Series I 2 8 4 2 Litre Publication NO E 155 3 | eBay

This is expensive but sometimes you can get them much cheaper. Gotta keep watching. I paid $80 USD for my first one but then I found one in even better condition for $15 USD a few months back.

HD8's with manual choke is the way to go. You guys are lucky that you don't have to deal with all the emissions stuff we have. I just rebuilt a set of triple HD8's from a 420G that are going on the '72 when the weather gets nicer

 

Hi Mike,
Just bought the manual you gave me the link for,thanks for that.
Going to check out a couple of parts cars tomorrow and Tuesday, one of them is complete so I check out kick down configuration(mine looks different to both books I have)

Sorted the sticking throttle today,someone had bent the bracket for master cylinder back so it was almost touching firewall. So when accelerating hard in drive the torque was pushing the engine to the right and cable was getting a 90 degree bend in it when it was jamming up against master cyl. and would only release when it was put in N or r dropping the engine back to centre. Made a new bracket,all sweet. I have very steep driveay straight up into my garage,so it is nice to drive into garage without full throttle(scary) .
Hopefully I can sort kickdown in next couple of days, although it's not urgent like sticking throttle was.
Cheers,Clarke

 

Tried uploading some pics of micro switch,hope it works.

 

Hi Clarke,
Your kickdown system is different to the ones I have in my PDF of the Series 1 XJ6 parts manual as well... odd. The configuration of the switch itself looks right (except for the 3rd terminal) but it appears that someone zip-tied that roller-arm to the original arm of the switch? I'm assuming from you pics that the U-shaped clevis at the end of the throttle cable is supposed to activate the switch at around full throttle by contacting the roller-arm.

If you're lucky enough to find a parts car in the breaker's with that unit intact and un-messed with that'll definitely solve it. If not you can get yours to work by hooking it up so power is applied to the red/black wire at full throttle somehow... might have to bend/manipulate the bracket holding the switch but it should be pretty easy.

Glad to hear you got the Bentley book - it'll be worth it. Also good that you sorted the sticky throttle without too much trouble. Previous Owners are the bane of our existence - I can't even list how many ridiculous things they did to my cars before I got them

Let us know how it works out.

 

Hi Mike, The zip tie on the arm is a piece of plastic tied to so it moves enough to trip switch. If don't get one from the wreckers I'll play around with one until I get it to work now I know it supposed to be powered when depressed. As you say it won't be to hard.
The clevis doe's activate the roller arm at about 80% throttle.

Thanks again,you have really helpful with this. I think that big cat in my garage and myself are slowly becoming friends,speeds up the process when you get pointed in the right direction from someone with the experience that is happy to share their knowledge.
I'll keep you informed about the kickdown, I'm also passing an auto trans shop today so I'll drop in and see what they say about my switch(he is a friend of a friend so should be helpful)

Clarke

 

Hi Mike,
Talked to Trans guy today, my set up is not original and solenoid should be powered only when engaged as you said. So I will find a new switch and get it sorted.
Both wrecks had no linkage to check out ,but I got a full set of lights and indicators,grill,hood ornament,wipers,washer motor,panel that holds washer,window winders,all gauges and dash
switches,fuse panels,fuel caps,radio with mp3 input and alumium surround that is better than mine,dash mat,indicator switch. All for $100.(& my time to remove it all)
Feel like a I had a little win today. Motorcycle & Jeep parts will have to shuffle over a bit for incoming jag parts, at least I sold one bike to ease the grief from upstairs.
She's pretty good really,I've usually got a few projects on the go. But only the one at the moment,rest of fleet are all good to go and registered. I think that's why I started looking for a Jag, 4 days off a week and everything in garage totally sorted.

Clarke

Clarke

 

Hi Clarke - That's a great deal for all those parts... I can't even remember the last time I saw a series 1 in any breakers yard in the last 15 years. Thank goodness for ebay.

Interesting that your kickdown system was not original - I wonder if your intake is from an older car... I was surprised when you said your 73 didn't have the AED for cold start. Oh well, should be easy to get the solenoid working at this point.

BTW - here's something you might want to look at if you haven't already. Every Series 1 I've bought had an issue with brake fluid. The brakes will seem fine while driving around town but when you take it out on the highway for a serious high-speed shakedown of 20 or 30 miles the old fluid heats up, water in it boils and surprise! almost no brake pressure. It comes back after it cools down. Even my nearly perfect 72 which has been babied in a garage for 20 years had that issue because the PO never drove it like a Jag needs to be driven. He just drove it the ice-cream store or the local car show and that's it. The thing is, Jags (and pretty much all british cars of that era) have a vent in the brake fluid reservoir that is open to the atmosphere. Brake fluid's gotta be changed at regular intervals and no-one ever does it. So unless you know for sure someone's done it recently save yourself a few seconds of utter terror and change it. There is a Mitsubishi reservoir retrofit that has a more modern, sealed design that I do as a matter of course to avoid this - just came back from ordering one for the 72 as a matter of fact. If you're interested in that let me know and I'll get you the specifics.

It's a rare thing when all the vehicles are good to go - you owed yourself the Jag for that Wish I could say the same about mine... but I've been pretty good - only have the 2 Jags and an '86 Ford F150 XLT at the moment, way less than my usual inventory.

My trouble-and-strife's been pretty good too. We just bought a terrible, dilapidated house with an awesome garage (bigger than the house) - I think she got sick of Jag wheels in the dining room and 2 sets of triple SU's where the coffee table should be. My cunning plan worked.

 

Thanks for the heads up on the brake fliud, it doe's fade a bit after a bit of driving I thought it might be the booster or something else. PO had rear brakes out just before I got it. Will change fluid the next time I have days off. (next week)
Info on the retro fit would be interesting to see.
Regards, Clarke

 

Hi Mike, Could have had complete wreck for $350. Nowhere to store it unfortunately,but got my $ worth anyway.
It has a 253V8/t350 conversion(Holden 4.2 litre V8...Aussie GM),i'm thinking if I can find a place to park it he will give it to me for $300. Engine did run when he got it 6 months ago apparently.
But 253's are a dime a dozen here,not like trying to get a 350 small block.......like hens teeth. Can get reasonable 253 v8 for the price of a XK head gasket(lol) .
Not planning on molesting this XJ6 just yet,really want to keep it stock.But planning ahead at this price is cheap.

Wrecking 1971 Jaguar XJ6 | Wrecking | Gumtree Australia Logan Area - Hillcrest | 1031815571

Clarke

 

After 8 months of changing down manually I decided it was time to sort this problem
A $4 momemtary switch,a couple of connectors and 2 metres of wire.Done.
Installed it in the drivers side ashtray,easy to get at. And just the push of a button.
Linkages are not original and I have been playing around with various switches and brackets with no luck so decided I would give this a go. Simple,and works sweet.

 

A bit late, as usual.

Our S2 V12 BW12 needed a new modulator, so I sourced a "compact adjustable" unit from Kent trans spares (gone defunk a while back), and installed it and played with the adjusting screw up inside the vac snout.

That sorted, eventually, the shift, and kick down, to a very acceptable level, as the solenoid inside the trans was toast and I could not find one at the time, and also the micro switch arrangement on the V12 is LOUSY at best.

I did the same on the HE TH400, and sweet it was at all times.

 

Grant, Sourced the modulator from Motospecs for $30. (an FMX job). And adjusted it accordingly the first week I got the car, I was adding to my first thread.
The sticking throttle turned mentioned earlier in this thread turned out to be the broken engine mounts that I discovered trying to sort the rough idle when rebuilding the carbs.Cable was getting fouled bebind the Brake resivoir, PO had bent it all out of shape trying to sort the throttle problem I think. And I think that may have caused the non working kickdownm Micro switch as well.

All works now,sweet

Until I got home tonight to find a pool of PS fluid under the pump, I think I may have damaged an old hose when I moved the Pump to fit new water pump and belts. At least it is a job for Thursday..