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Idle is to be adjusted with the engine warm, and in ‘N’ or ‘P’, Sierk - and should be set at some 800 - 900 rpms. 500 rpms hot is simply too low - xk engines requires miracle to idle smoothly at that…
Following Doug’s inputs is the right course of action - and a complete idle adjustment should include cleaning the throttle body first, and checking throttle gap. Then verify that the AAV is fully closed with the engine hot - and about half open with the engine cold. All that verified; the idle is adjusted with the idle screw as described…
But as Doug also remarks; low idle may have many causes, but if the engine does not respond to idle adjust - it is aponter to possible causes…
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Band adjustment must adhere very strictly to the adjustment procedure, Sierk - it is not a slap-dash affair, a small torque wrench is required…
Access is a bit awkward, but if the box is slipping; action is required to avoid downstream damage. If it is slipping only in ‘D’ (second and third) the front band is the first suspect - and band adjustment is the only available external adjustments available…
Doug has covered the AAV - it provides extra air during start and warm-up overcome cold engine ‘drag’. Generally; if idle is too low, the engine will be recalcitrant in starting, particularly cold - internal friction prevents idling, and without idling the engine cannot run…
Incidentally; idle properly set and the AAV the xk is a ‘feet off’ starter - any pedal input during cranking will cause the engine to baulk…
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Like many things there’s the ‘official’ method and there’s the “this seems to work method”
The procedure calls for loosening the locknut, loosening the adjuster 2 turns, then tightening the adjuster to 5 ft-lbs, then slackening the adjuster 2.5 turns. That’s it.
In my book 5 ft-lbs = 60 inch-lbs = one nudge. I seat the adjuster and give it one nudge, then slacken to prescribed 2.5 turns. Slap-dash, yes, but if something bad is supposed to happen I’ve yet to discover it. Perhaps I’ve just been lucky.
Ideally, of course, one would have (or buy) and inch-pound torque wrench and have (or buy) a socket to fit the square-head adjuster. And following the official procedure is surely the most responsible advice.
On the other hand, driving around with loose bands is ill-advised as well. Personally I’d rather take my chances with the non-official adjustment method.
On the other, other hand there’s risk in adjusting the bands even if the official method is used. If the bands are very worn, to the point of little or no friction material remaining, tightening them might damage the drum that they bind against…which would add to the expense of the inevitable transmission overhaul. Of course we have no way of determining the condition of the bands without transmission disassembly.
Gearbox
Frank and the lot is absolutely correct. Something to check before jumping into wrenching; is the fluid. pull the stick and smell it. if it smells like gear lube IRS or manual gearbox gear oil, then bust out the spanner and follow the sound advice from Frank and the others. If not, if just smells like a light oil, then its got the wrong transmission fluid in it.
History.
two years ago this was dropped off, with a note "Save me!! There going to take me a part and me to the crusher!
Keys in the ignition. well went down, fired it up. Awesome! it runs!! dropped it into gear, Not so awesome it doesn’t move. lots of bad words… Popped the bonnet pulled the dipstick, Low on fluid, gave it a quick sniff… Hmmm… Dextron (GM fluid here in the states). well that’s not right. put two quarts of ATF (the ford variant) dropped into gear, and a way we went! Yippee quick fix! I like it!!
Hmmm… A bit of slipping up the drive way; more bad words. Let the car sit for a couple weeks, it pissed out some more fluid. Filled it back up with ATF now the car shifts fine. Oddly enough if I drive the car every day it doesn’t leak if I let it sit for more than a week, then it pisses out about a quart.
A bit long winded to say, check the fluid type before you start wrenching. It made a difference to for me. Essentially the Dextron is too thin and the ATF is thicker and I believe what is spec’d as the proper fluid.
XJS well they use General Motors transmissions so Dextron is the proper fluid.
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Fluid type quantity and quality is of course first check, Mark - but will usually cause anomalies in all gears; either prolonged slipping or shift harshness…
Fluid is both a lubricant and a cooling medium. As hydraulic actuators are engaging bands and clutches there is a very slight slip as fluid is squeezed out between bands and drums (or clutch equivalents) to effect soft shifting. The different fluids have slight differences in ‘grabbiness’ to suit difference in gearboxes. Oil companies use different names for identical types, which are mixable - but name differences are sometimes confusing. And sometimes they ‘upgrade’ that are interchangeable - with new names…
Doug, I assume you meant 2.5 ‘flats’ which is what the FSM says. Its a square nut so 2.5 flats turns out to be about 3/4 turn which is what Haynes says. Anyway, I adjusted the bands and this corrected the slipping. This weekend - time permitting - I will do a compression check and then clean the AAV. If that fixes my cold start and idle I will be very happy. Its smooth if I put my foot on the gas and get it to 800-900 RPM in P. If it only fixes the cold start i will adjust the idle speed.
Thanks for the help.
Mark,
That’s a good story. My first xj6 was and 86 series three I got for free 17 years ago. A friend had it in his garage and it needed to go. All tires were flat and he said it had over heated and the power steering had gone out. It occurred to me (in the shower) that maybe - a belt had broken. Sure enough, a new belt and four used tires had me on the road with a free Jaguar xj6. I used it for a while and passed it on to my younger brother who drove it for a year or so before it did go to the wreckers. It was an Ohio car so had lots of rust.
Sierk
The 5 ftlbs is the critical factor; it clamps the bands to the required level, ensuring that the ‘back-off’ then gives the required clearance to ensure the proper gap between band and drum. If too tight, the drum is not properly released, not allowing the drum to rotate freely - which will cause lining wear, or may cause the box to engage two gears simultaneously - and something will give. Don’t ask me how I know…
First test of the AAV; remove the top hose and look at the slide, alternately with the engine cold and hot. If it stays in the same position; gently manipulate the slide with a small screwdriver - it is spring loaded, but sometimes stick in years of accumulated gunk. The AAV is not designed for internal cleaning; that requires drilling out the 4 corner rivets, replacing them with screws - but solvent applied to the slide externally may sometimes help to free the slide…
If the AAV reacts normally; clean out the throttle body and verify throttle gap - then adjust idle with the idle screw. using the idle screw to adjust idle without verifying AAV and throttle body first invites trouble…
An update - I have not yet cleaned the throttle body or the aav. I did however replace the coolant temperature sensor. This did not help the cold start difficulty all that much (though it hadn’t been started in a few days). It did make a big difference to the cold running idle which is now at 800-900 and steady. The hot idle is still low - around 600 but is steady. So changing the temp sensor has eliminated the lumpiness of the idle - but its still too low when warm.
If I take the throttle body off to clean it - I assume I will need a new gasket. Any particular gasket better than another? After cleaning the TB, should I go straight to warm idle adjustment, or should I still mess the the aav.
Thanks,
Sierk
No actual need to remove the TB to clean it. Some rags and toothbrushes and aerosol carb cleaner will do he trick. Then check the blade gap, should be .002"
The go ahead and try the idle speed adjustment. If there is no response/change when making the adjustment then the air distribution block might be clogged.
Sierk,
Just in case you are wondering how to make the idle speed adjustment, the three attached pictures should help. It is a bit of a challenge to get the tool in the right place and also to make the adjustment with the engine hot which is when you are supposed to make theadjustment. The allen wrench is 7/32" and I use a small 7/32" wrench to turn it. If you want to increase RPM turn the tool counter clockwise (anti-clockwise). If you want to decrease RPMs turn it clockwise. It’s best to make a small adjustment (2 or 3 flats) and then rev the engine a bit and let it stabilize. Keep adjusting until you get it where you want it. I recommend trying about 850-900 RPMs to start with and then increase or decrease to get what works best for you. You don’t want the RPM too high because you will get a clunk when you shift into gear. If it is too low then the idle will be lumpy. Spec is 750 RPM, but that was with a new engine.
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The engine reaction to the change of the CTS is a bit strange, Sierk - but as a back-up test; measure the resistance of the ‘old’ CTS. At room temp it should be between 2 - 3 Kohm - generally the CTS should be tested before changing it. There may be a connector problem, temporarily ‘fixed’ while fiddling - but may recur - needing some remedial action…
The difference between hot and cold idle implies that the AAV is working - so cleaning throttle body and checking throttle gap is the next step. As Dug says, no need to remove the throttle body - just disconnect the air duct at the throttle body for access…
Then adjust idle, it’s recessed in the silvery air distribution block, looking down under the AFM. AndPaul is perfectly right: ‘It is a bit of a challenge to get the tool in the right place’ - as is turning it in the tangle hoses and wires…
Yes, I dropped that small 7/32” wrench many times as I tried to adjust the RPMs in my 2 Series III XJ6s in their hot engine bays. Finding it again was rarely easy. Then I decided to put a small piece of wire on it and a piece of blue masking tape on the wire so that it was easier to find and retrieve when dropped. And I dropped it a lot because it is so hard to get my hand in there and the pieces of metal around it are all hot. It has worked for me pretty well and the blue masking tape, which is barely visible in the second picture, makes it easy for me to locate in the drawer with all my other wrenches when I am looking for it.
It is difficult to access the adjustment when you hardly see the hole. A development on the tool to adjust idle is to put on an extension at the right angle. The picture shows what I use for my xj6 S3
Paul,
I just wanted to let you know that because I did not attach blue tape and a wire to my wrench - I guaranteed myself that I would drop it. I got lucky - I heard it clink on the garage floor under the car. Anyway - I cleaned the throttle, gapped it, and then turned up the hot idle. Hot start is tremendously improved, cold start is somewhat improved, it now idles well cold and hot. It actually shifts better too. So to summarize for other reading the thread:
I did not touch the AAV
I did not do a compression check - have the tools just haven’t gotten to it, and I don’t suspect anything there
I adjusted the front transmission band with a torque wrench which eliminated the slipping. I adjusted the rear partially with a torque wrench until I feared rounding out the square nut. I don’t know what I gained with the rear band.
I changed the water temperature sensor and this made an immediate improvement to my cold idle speed as well as improving/removing the lumpiness from cold and hot idle
I cleaned and adjusted the throttle body butterfly plate
I turned up hot idle to 800 rpm
The car is now much more fun to use - I still need to improve the cold start - haven’t checked the cold start injector.
Thanks for all the help from so many on this forum.
Sierk
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If the cold idle is now 200 - 400 rpms higher than hot idle set, Sierk; the AAV does what it should…
However, checking the AAV in-car is very simple. And the xk is a strictly ‘feet off’ starter - requiring that idle components are working properly for easy starting at all temps…
