Re.: Where is the OBD II connector on a California Spec 1990 12cyl XJS?

Thanks Doug

I imagine adding an amount of oil would increase the pressure somewhat, especially since it's a liquid. I just have to figure out how to get it into the same device / syringe that I used to inject the dye into the system and hope that it will work against the 50psi pressure that is already in the system.....

Should I use Pag 150?.... 6 oz?...

Tom , oil can be added into a charged system via the charging ports, similar to adding freon. What I'm not sure about is if doing so upsets the existing charge in any way.

As for the control/vent problems, I'd suggest starting a new thread

Cheers
DD

Should I use Pag 150?.... 6 oz?...

Thanks Doug.

Well. I got it all working, but I forgot to add more oil to the compressor. Do I have to drain the 134a again to put oil in it or can it be added to a pressurized system. Seems like you can add dye to a pressurized system?... There also seems to a be problem with the opening of the air flow vents inside the car. I'm guessing this ahas a fully automated climate control and that the vents are controls with servos that can go bad. Mine seems to be stuck to where all the cold air is coming out through the defroster ducts by the wind screen, but hardly any out of the bottom or center vents. Is there any way to just get in there and manual set things to where the other vents are at least partially open as well and then leave it at that. I don't want to spend a fortune and tear apart the whole dash.

Nah, nuttin' to be nervous about. It just presses into the hole with a bit of a wiggle. Use a new o-ring to prevent a leak

Cheers
DD

I feel like I'd be nervous to transfer the switch, as I seem to remember that is exactly where the old compressor was leaking...

Often a replacement compressor has a blanking plug installed where the HSLP switch goes. Take a good look. It's probably held in with a cir-clip. Just transfer the switch from your old compressor to the new one

Or, yes, as you say, ground the wire that goes to the switch.

Cheers
DD

Doug. I think I may have made a mistake that I discovered too late. The compressor does NOT have an electrical terminal at the back. I'm guessing this means that the HSLP switch is missing and the system won't run unless I ground the loose lead or the Ac system works without connecting that lead? Does anyone know? I'm not even sure whether I could swap the old switch to the new compressor easily. As far as I could see that was where the old compressor was leaking in the first place.

Thanks, Tom

Hi Doug

Thanks for the excellent history lesson. I ended up getting a reman unit (new aren't available, of course) for $199 which wasn't too bad considering that most places wanted a lot more or were not able to get one. I'll install and charge it today and keep my fingers crossed that I caught all the leaks in my system....

Although the old GM/Harrison "A6" compressor was used in millions of cars the demand for replacements may well be dropping to the point where few if any parts stores keep any inventory on-the-shelf. By the early 80s only a few GM cars were still using it...leaving only Jaguar, Rolls, and perhaps a couple other low production makes.

Still, though, any ordinary parts store should be able to order one for you if they don't have it in stock.

The last one I bought.....probably in 2002 or so.....was a new unit from AC Delco. It was about $330 as I recall and had to be special ordered. At that time rebuilt units ranged from about $75 to $200. I went with a new unit after having problems with rebuilts.

If you Google "A6 Air Conditioning Compressor" you'll get lots of hits. You might want to consider one of the new all-aluminum replacments for about $350 (Add "aluminum" to your Google search)

If the question of "superheat switch?" or "HSLP switch?" comes up, your 1990 should have the "HSLP Switch" type. (HSLP= Hide Side Low Pressure). This refers to which type of low freon circuit protection the compressor has.

(Don't let anyone tell you that "all" A6 compressors are the same. They are not. They are all *fundementally* the same, yes, but there are a few sub-variations, such as mentioned above.)

Also, be prepared to change fasteners from SAE to metric or vice versa

Cheers
DD

Tom try a different store. NAPA, CarQuest, not Autozone or such.

Hi George
They all seem to be out of those old compressors. The best I could get was $200 for a re-manufactured unit.... Unless you have a link?....

Excellent! Thanks George. Always good to know when a VW part will fit a Porsche :-)...

Tom Jaguar provided a tool for those 2 plugs--look in your boot kit. As far as the AC compressor that is a GM or Harrison unit--about $100 at your local parts store-new.

Good news Steven! I took the old distributor cap off and could already tell that it seemed to have all sorts of traces inside it that might conduct electricity under the wrong circumstances. The rotor actually didn't look bad and I also replaced 10 of 12 spark plugs which weren't horrible, but they had a wider gap. probably due to wear. Can you guess which plugs I didn't replace yet? Would I be able to sneak out the other two past the ac compressor with normal extensions and universal joints? The good news is, that I am now actually going to take the ac compressor out and replace it anyway because it has a leak. Does anyway have any good sources for who rebuilds these or does exchanges?

Steven, thanks very much for your help specifically and everyone else who had advice.

Thanks again. My ignition rotor is coming in tomorrow and I will replace it along with the distributor cap. The odd thing is that the problem seems to be intermittent and gets worse the more the engine is driven hard. When it does happen, there is actually a strong smell and some smoke that comes from the engine bay, even though I'm not finding any sign of oil leakage or cooling system malfunction....

Thanks again. My ignition rotor is coming in tomorrow and I will replace it along with the distributor cap. The odd thing is that the problem seems to be intermittent and gets worse the more the engine is driven hard. When it does happen, there is actually a strong smell and some smoke that comes from the engine bay, even though I'm not finding any sign of oil leakage or cooling system malfunction....

Every new tidbit you discover seems to point in the same direction. Loss of ignition, for whatever reason, is causing serious misfires and consequently overheating one or more exhaust catalysts. You have four cats, two on each side. The odor and smoke you describe can come from the overheated cats. At temps way above normal [they can start glowing cherry red] they begin to burn off "stuff", dirt, dust and the like that collects on them, that can account for the smoke and odor. Hence my advice to run the car as little as possible until it's fixed. Catalysts are not cheap, and piecemeal diagnosis can result in much higher expense in the long run, than taking the car to someone experienced with the Marelli V12.

Good luck!

Thanks again. My ignition rotor is coming in tomorrow and I will replace it along with the distributor cap. The odd thing is that the problem seems to be intermittent and gets worse the more the engine is driven hard. When it does happen, there is actually a strong smell and some smoke that comes from the engine bay, even though I'm not finding any sign of oil leakage or cooling system malfunction....

Tom,

As I mentioned before, your car has no on-board diagnostics, and therefore no codes to read.

The manual you have must be for a 1992 model. That's when the clock display was first used to display the "Check Engine" message, followed by a FFxx. [Fueling Failure xx]

Cheers,

Hi Guys

I only just checked back in. I should have requested email notifications. Thanks for all the good advice, but especially Steve and Tom, as I was also leaning towards an ignition problem. The cutting out is just too severe for a fuel problem unless it was related to an faulty fuel injection/ ECu. I had already ordered a new cap, rotor, spark plugs and ignition wires, but Marelli is not longer available from my sources. I waiting with the coils until I try this first and then report back...

(Side note: The owners manual does say something about fault codes being shown after 5 seconds if you turn on the ignition. I'm not sure where the read-out would be, but I can't see which any fault code is shown. Maybe the system is quite rudimentary and doesn't cover this type of error, albeit quite severe?.....)

Thank you all for your help. Do you have any idea what could cause the severe misfiring at rpms above 3000 under high load, mostly in the kick down position?

Tom, Steve is dead on with his direction. My '94 actually started misfiring while it was idling in my garage, and noting a difference in its sound under load. I came to find one of the exhausts cold, as it ran and immediately stopped the engine. Steve Petry is a very wise sage, with his common sense advice, which is highly knowledgeable and skilled.

Since my vehicle was 18 years old when this occurred, replacements were recommended. I ordered from Coventry West, new: 2 coils, a Marelli rotor, and cap; do not go with any aftermarket products, get authentic Jaguar parts (Steve's advice as well). You may as well go with new wires and plugs (get OEM on the plugs too), if they have never been replaced, since you will be "in it" so to speak. You will find most everything easy to change out with a few minor obstructions. Recommend having a telescoping magnetic pick up tool when small nuts or washers fall out of reach. An oil change may be in order due to gas contamination if one bank was not firing. Safe is better than sorry. Another comment, my car sat without running for a few weeks, and I felt confident most if any raw gas had evaporated. I did get a large plume of white smoke as the heat burned off the residue.

All of your efforts will be rewarded once you re-fire with all new parts in place and I guarantee you will smile when task is complete, let alone find new life in the power, new parts can instill.

Edited on 2013-02-14 11:54:56

Tom, first thing I would do is get your Marelli distributor cap off and check the dual level rotor for burning through. That can allow the spark to jump to the distributor shaft and bypass the spark plugs.

A failing Marelli ignition coil can be the cause as well, you have two, one for each bank.

Be aware that severe misfires like you describe can be deadly to the catalysts on the V12......can get very expensive. I would try to run the car as little as possible until the misfires are pinned down.

Good luck!

Tom you might also want to check for Vac. leaks and the vac. advance module on your Dizzy. Fuel starvation is an issue as well as the purge system for the fuel tank.

Fuel starvation is one possibility. Check inline fuel filters for partial blockages.

Best, Harold ...

Thank you all for your help. Do you have any idea what could cause the severe misfiring at rpms above 3000 under high load, mostly in the kick down position?

The 1990 XJS had no on-board diagnostics, and therefore no diagnostic connector. The connector referred to by Steve was in the engine bay of the sedans with the AJ6 engine.

Cheers,

OBDII did not come on the cars officially until 1996. Some 1995 cars had the hook up. Your car should have a OBD1 hookup I believe in the trunk but it requires special Jaguar specific equipment to get anything out of it.