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Going to check out an XJ81 tomorrow. Advice?

XJ6Paul
Posts: 64
Joined: Tue Jul 01, 2014 2:29 pm
Location: Atlanta, Georgia USA

Going to check out an XJ81 tomorrow. Advice?

Postby XJ6Paul » Mon Mar 23, 2015 10:20 pm

It's a flamenco 1994 Jaguar XJ12. 105,000 miles. Current owner has had it about 10 years and seems to have driven it and cared for it based on the items he said he's addressed over the years.

VIN ending 700xxx. It does not have the SLS. Only have a couple photos so far, but cosmetically looks promising. I'll get more details and take photos when I see it, but he claims to have put a lot of $$ into it about 4 years ago - new shocks, brakes, some suspension parts, new driver's seat leather, new paint job, and then within the last year, new injectors and oxygen sensors and tires.

Current issues: he says the check engine light comes on and has done so for a while, although it runs and drives fine. He replaced the O2 sensors and made other efforts to fix but each time it came back on. He couldn't tell me a specific code is showing up. This may be pure salesmanship BS, but he claims only the dealership can clear the codes. As I understand it, and as he explained, it's not a true OBD I or II system, right?

Could use a new headliner he says. Transmission light came on temporarily yesterday he said. It had not been driven in 3 weeks at the time. Limp mode did not kick in and shifts were normal per seller.

For what it's worth, I have experience working on a friend's 5.3L XJS (marelli ignition) and did a full tune up - dist cap, rotor, plugs, coils, wires, as well as some brake (front) and suspension work for him, and a few electrical issues. Did the silicone squirt mod to the rotor.

Anyway, I'll go shake it down and see how it looks. Priced at $3,500. Initial thoughts?
1994 Jaguar XJ12

abercanadian
Posts: 1281
Joined: Tue Oct 16, 2012 6:50 am
Location: Vancouver Island

Re: Going to check out an XJ81 tomorrow. Advice?

Postby abercanadian » Mon Mar 23, 2015 10:41 pm

If there's a check engine light on, there's a code (at least one) stored. The car can read its own fault codes via the VCM. Turn ign on then press VCM button. Code will be displayed. Codes can be cleared several ways but the way I do it is to disconnect the neg battery terminal for a few secs. Remember to make a note of the radio code first though!

Trans light on? Sounds like this car may have a few issues alright. :o

good luck

Larry
Image
94 XJ40 VDP vin 701729
Oyster Metallic/Doeskin on Aero Alloys
230,000 Kilometers 143,000 Miles
Daily Driver

94 XJ40 SOVEREIGN vin 703632
Diamond Blue Metallic/Barley
111,000 Kilometers/69,000 Miles
Parts Car

david
Posts: 6586
Joined: Wed Aug 06, 2008 8:09 pm
Location: Cheshire, UK

Re: Going to check out an XJ81 tomorrow. Advice?

Postby david » Mon Mar 23, 2015 10:47 pm

XJ6Paul wrote:It's a flamenco 1994 Jaguar XJ12. 105,000 miles. Current owner has had it about 10 years and seems to have driven it and cared for it based on the items he said he's addressed over the years.

VIN ending 700xxx. It does not have the SLS. Only have a couple photos so far, but cosmetically looks promising. I'll get more details and take photos when I see it, but he claims to have put a lot of $$ into it about 4 years ago - new shocks, brakes, some suspension parts, new driver's seat leather, new paint job, and then within the last year, new injectors and oxygen sensors and tires.

Current issues: he says the check engine light comes on and has done so for a while, although it runs and drives fine. He replaced the O2 sensors and made other efforts to fix but each time it came back on. He couldn't tell me a specific code is showing up. This may be pure salesmanship BS, but he claims only the dealership can clear the codes. As I understand it, and as he explained, it's not a true OBD I or II system, right?

Could use a new headliner he says. Transmission light came on temporarily yesterday he said. It had not been driven in 3 weeks at the time. Limp mode did not kick in and shifts were normal per seller.

For what it's worth, I have experience working on a friend's 5.3L XJS (marelli ignition) and did a full tune up - dist cap, rotor, plugs, coils, wires, as well as some brake (front) and suspension work for him, and a few electrical issues. Did the silicone squirt mod to the rotor.

Anyway, I'll go shake it down and see how it looks. Priced at $3,500. Initial thoughts?


A very late car. It does sound good for the money - provided the problems it has are solvable! The V12 is a magnificent machine, no doubt about it.

I would normally wait until someone who has actually owned a V12 answered this since I have no experience of them, but since you are looking at this tomorrow, time is pressing!

Assuming the V12 fault codes are the same as the six cylinder cars, then he is not correct that only a dealer can clear the fault codes - disconnecting the battery for a few minutes will clear any codes. If they then reappear, the fault code has been triggered again.

The fault codes are displayed on the dash - when a fault code is displayed, it is shown in the 'window' where the mileage is normally displayed.

He should be able to tell you what the code is, assuming he knows how to do it. When you see the car you can display the fault code(s) yourself by pressing the Vehicle condition monitor button. This button is on the black dash binnacle round the steering wheel on the right hand side - marked 'VCM'. It is sited together with an array of small on board computer buttons. Where the mileage is displayed will then show the fault code.

As far as I know, the fault codes are the same on the V12 as they are on the 3.2 and 4 litre six cylinder cars. (The 3.6 is different). Hopefully a V12 owner will confirm this.

The fault codes for the six cylinder cars are:

http://www.jagweb.com/aj6eng/fault_codes.php

JAGUAR 3.2 & 4.0 - LUCAS 15CU SYSTEM.

Code Display Procedure. When a fault has been detected the facia panel will display "Check Engine" warning. The relevant fault code can be identified with the vehicle stationary by using the following procedure:-
1.Switch off engine.
2.Wait 5 seconds.
3.Turn ignition switch to position 2 - do not start engine.
4.Press VCM button
5.Fault code number should be seen on VCM or trip computer display.

Fault codes can only be cleared by use of dealer JDS, PDU or similar (also to display fault codes) or by grounding the lead provided for the purpose from the ECU (see below). If more than one fault has been logged the first one must be rectified or cleared before the next will be displayed for which the above procedure must be repeated. Fault codes and related functions are listed below.

15CU Fault Codes and Functions - 3.2 and 4 litre AJ6 Engine


11.Idle pot. Looks for more than 4 volts on trim pot wire. Defaults to 2.5 volts.
12.Air flow meter. Looks for air flow meter signal less than 0.2 or more than 4.5 volts between 400 and 300 r.p.m.
14.Coolant thermistor. Looks for signal less than 0.1 or more than 4.9 volts fully warm; less than 3.54 volts after cold start; voltage change of more than 0.7 volt when fully warm.
16.Air thermistor. Looks for signal less than 0.1 or more than 4.9 volts.
17.Throttle pot. Looks for signal less than 0.25 volts.
18.Throttle pot/airflow meter signal conflict. Looks for throttle pot signal above 2.25 volts while AF signal indicates light load. Defaults to ignore throttle pot signal above 1.5 volts therefore open loop operation with full load enrichment is disabled.
19.Throttle pot/airflow meter signal conflict. Looks for closed throttle signal while AF signal indicates high load with speed above 1000 r.p.m. Defaults to ignore closed throttle signal therefor idle functions are disabled.
22.Fuel pump drive circuit. Checks for short or open circuit to pump relay.
23.Lambda sensor error - fuelling rich. Feedback signal high despite correcting weak by more than 12.5%.
24.Ignition drive circuit. Checks that ignition drive pulse exceeds 4.5 volts and is below 0.1 volts with no pulse.
26.Lambda sensor error - fuelling weak. Feedback signal low despite correcting rich by more than 12.5%.
29.ECU self test. Program data checksum wrong - corrupted.
33.Injector drive circuit fault. Checks that injector voltage during initial turn on period (1.3 milliseconds) does not exceed 1.2 volts.
34.Injector drive fault or injector dribble. Checks that feedback sensor is not indicating rich fuelling during over-run cut off above 2000 r.p.m.
37.EGR circuit check. Checks voltage across EGR valve for open or short circuit.
39.EGR temp sensor check. Looks for conflict between EGR temperature sensor reading and state (i.e. open/closed) of EGR valve. Disables EGR by default.
44.Oxygen sensor circuit check. Looks for absence of feedback signal. Also if weak fuelling error cannot be corrected by up to 12.5% enrichment, enrichment of 37.5% is applied and fault flagged if no corrective response is detected. Defaults to open loop operation.
46.Idle speed control valve coil 1. Checks that off voltage is less than 0.85 volts and on voltage exceeds 12.25 volts.
47.Idle speed control valve coil 2. Checks that off voltage is less than 0.85 volts and on voltage exceeds 12.25 volts.
48.Idle speed control valve error. Looks for idle speed being too high with valve closed (coolant temp below 35C) or too low with valve open (coolant temp above 75C).
66.Air injection relay drive circuit. Looks at voltage across relay to detect open or short circuit.
68.Road speed sensor. Looks for conflicting speed signal (less than 1.5 m.p.h.) with engine speed above 2800 r.p.m. and AF signal above 3 volts, with transmission not in neutral.
69.Drive/neutral gear selection error. Looks for engine start when D or N not selected, or for engine speed above 3550 r.p.m. and high load signal when D or N are selected.
89.Purge valve circuit. Looks at voltage across purge valve winding to detect open or short circuit.

Notes:

Because codes 26 and 44 can be activated by running out of fuel they only display once until the next ignition on/off event
Last edited by david on Mon Mar 23, 2015 10:49 pm, edited 1 time in total.
Image 1992 Sovereign 3.2 diamond blue (1993 model)

Jimbo
Posts: 855
Joined: Fri Mar 11, 2011 12:06 pm
Location: Leeds, West Yorkshire, UK

Re: Going to check out an XJ81 tomorrow. Advice?

Postby Jimbo » Mon Mar 23, 2015 10:48 pm

I've not had mine long, but from my brief experience, there are a myriad of pipes which can leak, and a myriad of electrical connections which can become dirty, or solder joints become dry, or wet if the inevitable leak gets to them, so take all warning lights as a potential simple / very tricky and long fix.

Once the car is running very well, with no warning lights etc, no leaks underneath, then it's a contender - these engines and gearboxes are tough, but there is so much complexity, that what is a simple fix on the four litre for example, can become an expensive, long and difficult job, just for that extra two litres.

The engine bay is a rats nest of potential problems, so spend a good long time looking for fluid leaks/ evidence of past leaks, and also after the long test drive to see if any have re-apppeared - take a decent torch too for illuminating the hard to see areas- from experience some of the oil pipes require a big stripdown to replace them, if you can get the pipes from Jaguar that is.

The rust issues are the same as other '40's - so get the carpets up and feel for the damp, especially in the front footwells, this will probably mean you need refurbished fuse boxes in the near future as well as welding. Same applies to suspension bushes etc, usual '40 issues - listen for bumps and bangs etc, and if the seller has decent service records, then take a good look at them to see if all aspects of the car have had money spent on them in the last decade.

These cars inevitably stand still for long periods of time, and like all cars, need driving regularly, I'm only just getting to the end of a list of faults which have prevented me driving mine, but now she's running reasonably, I'll keep on making trips in her to stop the gremlins taking a hold again.

Overall, spend as long as you can to ensure everything works as it should, get a long test drive, then go home and think it over. It will still be there the next week, and the price may well have dropped, unless it is a true minter.

Good luck anyhow, I'm sure others will have more useful advice to follow :D
1993 Daimler XJ40, 6.0 BRG
vin 685859

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david
Posts: 6586
Joined: Wed Aug 06, 2008 8:09 pm
Location: Cheshire, UK

Re: Going to check out an XJ81 tomorrow. Advice?

Postby david » Mon Mar 23, 2015 10:51 pm

Are the fault codes the same as for the 4 litre, Jim?
Image 1992 Sovereign 3.2 diamond blue (1993 model)

david
Posts: 6586
Joined: Wed Aug 06, 2008 8:09 pm
Location: Cheshire, UK

Re: Going to check out an XJ81 tomorrow. Advice?

Postby david » Mon Mar 23, 2015 10:58 pm

The Six litre V12 fault codes are listed here:

http://www.kwecars.com/wp-content/uploa ... ltBase.xls


I'm uncertain whether the codes marked for the 4 litre cars are also used on the V12.
Image 1992 Sovereign 3.2 diamond blue (1993 model)

Jimbo
Posts: 855
Joined: Fri Mar 11, 2011 12:06 pm
Location: Leeds, West Yorkshire, UK

Re: Going to check out an XJ81 tomorrow. Advice?

Postby Jimbo » Mon Mar 23, 2015 11:11 pm

david wrote:Are the fault codes the same as for the 4 litre, Jim?


I think so, I just cured fuel fail 14, by cleaning the temperature sensor, and I also went round every electrical connector I could find in the engine bay and squirted contact cleaner and scraped the connections with a small flathead screwdriver.

I suspect I need to do the same to clear the gearbox warning light fault, with the gearbox, but I live on an insane slope, so jacking her up needs a special run out with plenty of tools to my car club or somewhere similar.

I also have found yet another leaky oil pipe to the radiator, this time engine oil I suspect, as it's on the passenger side - that will teach me to ignore her over winter :oops:

If you work on the principle that every connection to every wire or black box, every hose and jubilee clip, needs checking and cleaning, at the beginning of ownership, whether you think it needs it or not, then you won't be caught out - these engines are very high maintenance, not to be confused with the very reliable four litre :shock:
1993 Daimler XJ40, 6.0 BRG
vin 685859

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david
Posts: 6586
Joined: Wed Aug 06, 2008 8:09 pm
Location: Cheshire, UK

Re: Going to check out an XJ81 tomorrow. Advice?

Postby david » Mon Mar 23, 2015 11:50 pm

Yes, it is easy to be blasé about the V12, given how easy the 4 litre is to own. In reality, they're a much more exotic beast. They have their rewards too, when they are running right of course!
Image 1992 Sovereign 3.2 diamond blue (1993 model)

XJ6Paul
Posts: 64
Joined: Tue Jul 01, 2014 2:29 pm
Location: Atlanta, Georgia USA

Re: Going to check out an XJ81 tomorrow. Advice?

Postby XJ6Paul » Mon Mar 23, 2015 11:53 pm

Thanks so much for your fast input! I had read about the VCM button to get a code so I'm not sure why the owner wasn't able to tell me if one is showing up. I'll clarify when I see the car.

I won't jump into this car without some thought. He's not marketing it very actively. As he was going though the list of items he had done on the car, it seemed he was having second thoughts about selling it. We'll see how it drives/sounds/looks and go from there. It's been a Southern USA car so hopefully rust won't be an issue.
1994 Jaguar XJ12

Simont485
Posts: 2185
Joined: Sun May 06, 2012 8:14 am
Location: Eye, Suffolk

Re: Going to check out an XJ81 tomorrow. Advice?

Postby Simont485 » Tue Mar 24, 2015 10:13 am

Hi Paul

Probably a bit late for a reply!

But anyway, check coolant. Check its been changed regularly (every 2 years is the advice I have been given) throughout the cars life...should be in the history files/ service receipts if it has FSH. Also the thermostats should be changed at the same time. Temp gauge should sit at N and not move and the additional cooling fans should cut in and run on after engine is switched off.

I assume it has cats? so ensure the ignition system, coils, plugs, rotor arm and dizzy cap have been changed too. Again check history. A note on the spark plugs:- The front two often get left as the a/c compressor has to be moved to change them!

Engine Vee mounts often need changing and the front shock bushes too.

Other than that treat it as any other car, don't be intimidated by the V12 its a great engine and will last a life time if looked after.

Well best of luck!!
Jaguar XJ12 1994 704165
Jaguar XJS V12 1996 196529
Rover SD1 TP Vitesse 1986