Question:    1989 Jaguar XJS V12 Two Wheel Drive Automatic 65000 miles I have removed my alternator and the bench tests okay. Reinstalled, the dash gauge still reads discharge while running...even at high rpm. The idiot light lamp is working and does not go out. I've checked the wiring and it looks good, as do the fuses. Where do I look to solve the problem? I am stumped. A traceable wiring diagram would be very helpful.
I have not used a site such as this for help before. I promise to make a donation if the information you provide helps me find and repair the problem.

Answer:    If you have a voltmeter test the battery open voltage-meaning no load on the battery.
it should read 12.4 or higher. If not you need to recharge the battery to get up to read atleast 12.4 volts. If you got it-Start the car turn the lights On, and read the battery again it should be reading 13.5-15.5 volts if not the alternator is not putting out. See your EWD below

Question:    1989 Jaguar XJS V12 Two Wheel Drive Automatic 98,000 miles. Hello I'm having trouble getting a jag I just bought to pass smog. The tech say's it's pumping too much fuel way too rich. The tech say's mabey not coming out of cold startup loop mode. I did a full tune up myself changed all filters, replaced the fuel pressure regulators (2) and also replaced two of the cats. still no pass. some people seem to think computer replacement how do I tell if it's a bad computer and is the one I have adjustable I heard some are mine is a DAC 6337 LUCUS 16 CU CONTROL UNIT 8478B with a date code of 4588. the unit does have a hole on one side with what looks like a recessed stainless steel rod?? If the one I have is adjustable how do I do it

Answer:    this computer is adjustable. but you have to have a special machine to hook up too watch the mixture. chances are it is ok. is the car getting warm enough. a bad thermostat can cause a car to run rich. also remember your car has two thermostats. also if the coolant temp sensor is bad it too will cause fueling problems....

Question:    1993 Jaguar XJS 6 cyl Wheel Drive Type unknown Manual 63800 miles My battery went dead and my security system started beeping and I could not shut it off. I replaced my battery and the security system will not stop beeping until I disconnect from the battery. How do I stop the beeping I do not have the key less entree device?

Answer:    Close all doors and lock-unlock drivers door with the key.

Question:    1982 Jaguar XJS V12 Two Wheel Drive Automatic 36,375 miles. hi there. I am restoring an xjs and I want to keep the motor running while I do this. I have changed all the spark plugs and she fired up but is blowing grey smoke from the right exhaust and takes a long time before I can give it any revs, it also only seams to start on hot days. someone told me to check the brake fluid and it is empty leading me to believe that it is sucking fluid through the manifold. dose this sound right to you. also can you remove the air conditioning unit and belt and still run the car or will this affect the motor cheers Giles.

Answer:    for brake fluid to enter the motor your brake master and booster must be faulty, and brake fluid smoke is usually dense white in color. I would be chasing a faulty injector. As for the A/C system, you can remove it with out affecting the engine operation and performance. If it is still charged up, it must be decommissioned by an authorized shop with the correct equipment to remove the gas.

Question:    1995 Jaguar XJS 6 cyl Two Wheel Drive Automatic 85,000 miles I had the engine washed. It was left running while being washed. It stalled suddenly. Dried everything possible, still no spark. All fuses good. Let sit for two days still nothing. What could have shorted or gone bad? Any suggestions?

Answer:    Check all fuses, just to be sure. When you dried it out, did you unplug connectors to blow them out? Hot engines make steam when wet and it can get into everything. Start with all ignition connectors and the MAF plug. Do every sensor you can find. Might need to scan it to see if the PCM stored a failure code

Question:    My Jaguar XJS V12 1980 model has poor cooling in the A/C. I have had the compressor, drier, condenser, expansion valve and evaporator replaced. At startup from cold, the air is about 40F, but as soon as the condenser warms up, it goes to nearly 50F.
When I compare the hand-felt temperatures along the cycle with those on my other vehicles, I find:
1. The discharge from the compressor is very hot, too hot to touch on the Jag. I would guess above 180F, but I can just hold my hand on the other vehicles, about 120F, I think.
2. The condenser discharge temperature is still very hot, though I can just about hold my hand on it, perhaps 120F or more while on the other vehicles, the condenser discharge temperature is barely above my hand temperature.
3. The temperature at the low pressure filling point just before the compressor is cool, but not cool enough to condense water from the air on the Jag, but is cold and cold enough to condense water from the air on the other vehicles.
Can you suggest a cause? My guess is a blockage or restriction somewhere producing a high back pressure. The original refrigerant was R-12, but this is illegal in Australia, so it was converted to R134A.

Answer:    You will need to have the High & Low pressures read & recorded so we can establish what is going on. I have had mixed results with R134A It may be a problem in the compressor, but a pressure reading will help.

Question:    I have a 1995 XJS - 4.0L AJ16 - 90,000 miles. MY muffler guy says one of my cats is beginning to show early signs of blockage. I have changed the plugs, fuel filter, and had the throttle body and fuel system cleaned. I feel a random and inpersistant rough idle and my mileage is not what others get with this car. I get codes P0420 and P0430. Do I have a bad coil (there are 6 coils), a bad O2 sensor, a bad/dirty MAF, or bad injector? At running speeds, I notice no roughness or hesitation. Thanks for the advice. PS, any way to home test the items?

Answer:    The two codes you have are catalyst efficiency codes. the mean yes the catalyst are going bad and it is necessary to replace.

Question:    Heater has stopped working already replaced the control valve worked for a while then stopped again just blows cold air thought it could be an air lock but can find bleed screw any suggestions please

Answer:    yes there is a bleed valve under the throttle body but be careful it will break easy. also the s types had wiring issues. for the heater valve. check for voltage in the center wire of the connector. if there is no voltage you have a wiring issue. the wiring is located under the drivers inner fender good luck

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