I have a 94 XJ6, possibly a sovereign, that is giving me issues. I had the car parked because I usually ride my motorcycle. This morning I started the car and drove about 15 miles to my college. After I got out of class I got in my car and it would not crank over. Worked at it for a little bit in the parking lot and go the car to start by jumping the terminals on the starter. Drove about 3 miles down the road and the engine began to sputter like it was running out of fuel. The car finally died and had to jump the terminals on the starter to start the car again. The engine sputtered and would not stay running. Had the car towed home. After a few hours went out to the car and it would finally crank but when it started it would immediately die. The car has a full tank of fuel, new spark plugs, cap and rotor. Any help trying to figure this out would be great.

 

Hi David,

Welcome to the Jaguar Forums! It's great to have you with us.

The first thing I would suggest is to check the car for any stored Diagnostic Fault Codes (DTCs). Your '94 is OBDI, so it can't be checked with a standard OBDII scanner, but fortunately some diagnostics are built in to the system.

Without starting the engine, turn the key to Position II (Run). Now press the VCM button on the trip computer to the right of the steering wheel. VCM stands for Vehicle Condition Monitor. If any fault codes are stored, one of them will show up in the small display window below the speedometer. It will be in the form of "Fuel Fault 22" or "FF22," but the number may be different.

If a code is displayed, it is possible that additional codes are also present but will not be displayed until the top code is deleted. Let us know and if you find a code I'll tell you how to delete the codes one at a time so you can view them all.

Based on your symptoms, I would suspect one or more of the following:

Contaminated fuel
Clogged fuel filter
Weak or failing battery (see longer note below)
Fuel pump relay failing or socket corroded, fuel pump circuit wiring problem, or failing fuel pump - follow the diagnostic procedure in the post below:

https://www.jaguarforums.com/forum/x...3/#post1291811

Loose or corroded electrical connector in the ignition circuit
Loose or broken king lead from coil to distributor
Loose or corroded connector or broken wires at the ignition amplifier (below the coil)
Failing ignition coil (not unknown) or ignition amplifier (uncommon)
Failing crankshaft position sensor (CPS) or oil contamination of its electrical connector (it's a good idea to keep a known-working spare CPS in the trunk because they always seem to fail when you're away from home)
Failing Engine Management System (EMS) relay or corroded socket
Failing Ignition On relay or loose or corroded socket
Problem with the EGR system
Intake air leak / vacuum leak
Cold, starved or broken solder joints in one or more of the three fuse boxes
Corrosion on critical battery power connections and ground points

About batteries: Jaguars are notorious for demanding a lot from a battery. They have a relatively high quiescent current drain, so if the car is not driven regularly, they tend to deplete the battery's charge. Also, corrosion on the battery power cable connections and grounds can lead to poor recharging. And low battery voltage can cause all manner of hard-to-diagnose gremlins. I don't think low battery voltage is your primary problem, but it may be a contributing factor, so it would be worth load-testing your battery and checking the voltage while cranking - if it falls much below 12V that can lead to problems, and if it falls much below 11V the Engine Control Module (ECM (PCM or ECU in other manufacturers' terminology)) will not trigger the ignition to fire.

Sorry for the shotgun list, but since you're mechanically skilled I figure you would want as many ideas as possible. Hopefully other members will offer additional suggestions to speed up the diagnosis.

Let us know what you have in the way of service literature and we'll help you complete your library.

Please keep us informed and we'll try to help.

Cheers,

Don

 

I went out and worked on the car for a few minutes. Been a rough day. The battery is good, when i bought the car i made sure to put an optima red top in the car. The fuel relay in the trunk is good. I tried to pull any codes and the only one that showed for a second was a fuse 5 code probably due to the relay being bypassed in the trunk. No other codes have shown since that code cleared itself. I have a suspicion that the problem might be in the ignition itself. A while back I had a problem where the car would not start and then I would jiggle the ignition a little and the car would turn over. This had happened a few times in the past. This is also what initially go this problem started as well. Could this be an issue with the factory alarm as well. I have not gotten the remotes to work the alarm working since I got the car.

As for literature the only thing I have is a guide to clear the codes.

 

The ignition switches are known to go bad. You can test it at its electrical connector inside the steering cowl. Here are some photo albums that may help (knee bolster removal, steering column cowl removal, ignition switch replacement):

Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page

Some members have found that lubricating the ignition lock cylinder has helped if the problem is sticky tumbler discs.

As far as literature goes, there is a wealth available. I

The official Jaguar Workshop Manuals are available on DVD-ROM from the Jaguar Daimler Heritage Trust (they have recently updated the DVDs and appear to have combined the late XJ40s with the supercharged XJS - be sure to let them know the year, model and engine displacement of your car so they can send you the correct DVD):
Jaguar Heritage. XJ40 1992-94, XJR & XJR-S (JHM1152)

The Supplementary Information DVD-ROM contains Electrical Guides and a lot more information. I'm very glad I have it, but you may find most of the info you need from other sources:
Jaguar Heritage. XJ40 (XJ6 & XJ12) SUPPLEMENTARY MODEL & SERVICE INFORMATION JHM 1130

Next to the official Workshop Manual, the Haynes Manual is the bible for maintaining an XJ40. You can download a pdf scan of a U.K. version at the link below, but it is missing a couple of chapters. If you can find a printed copy of the U.S. version, ****** it:
https://www.mediafire.com/?hx8bttsy4kxxr#3267xri9vx4v6

You can download the 1993-94 XJ40 Electrical Guide here:
http://www.jagrepair.com/images/Auto...ec%20Guide.pdf

There are lots of files available in this thread:
https://www.jaguarforums.com/forum/x...ck-links-5911/

The XJ40 eBook at the Jag-Lovers forum is full of helpful info - you'll have to join to view the contents but it's free, and there are lot of knowledgeable XJ40 experts who frequent that forum and the archives is a treasure trove of owner experience:
Jag-lovers' Ebooks Book Index

There are a few good files here:
JagRepair.com - Jaguar Repair Information Resource

And lots of Technical Service Bulletins here:
JagRepair.com - Jaguar Repair Information Resource

You can download the Jaguar Electronic Parts Catalog (EPC) and install it on your computer by following the instructions in this thread:
https://www.jaguarforums.com/forum/x...uctions-48194/

And get to know the jaguarclassicparts.com website, where you can view parts diagrams and part numbers, and when you need to purchase parts, we'll be happy to suggest the reputable sources, which include our forum sponsors.

See my signature for links to lists of Jaguar Acronymns, Terms and Abbreviations and Jaguar OEMs, as well as photos of some of the work I've done on our '93, which is very similar to your '94.

Cheers,

Don

 

Today I go out and as soon as I turn the key it starts and runs for about 45 seconds then sputters and dies. Then it goes right back to start and immediately die.
This problem is getting annoying and I don't have the money to replace the part I suspect is the cause. I have an eerie feeling that the ECM is the cause of all the problems.

I went out again today and got it to run for a minute and throw a fit. Eventually it decided to throw a code. It flashed a Fuel Fail 12 and then went to Fuel Fail 18. This tells me that the Air Flow Meter is no go.

 

from the XJ40 book on jag-lovers:

Hows the fuel filter on that car?, $12 gets you a new one btw

Larry

 

The fuel filter is brand new just replaced it a couple months ago while I was doing a tune up

 

There are two relays on a 94 that affect the fuel delivery - the fuel pump relay in the trunk and the oxygen sensor heater relay, yellow base on the firewall. You could try swapping it out with one of the others next to it and see if that makes a difference. Cleaning the MAF plug is also a good idea.

Larry

 

David,

One of the things you'll learn about Jaguars is that just because a fault code points to a sensor often does not indicate the sensor has failed. Far more often the problem is with the electrical circuit: corrosion or oil contamination of an electrical connector, corrosion on the associated ground point, cracked insulation or a broken wire, etc. In the case of the MAF sensor, it appears to be grounded via the ECM on the Black/Yellow wires. The ECM uses three different ground points: At the intake manifold studs for either cylinder #2 or #3, and on the firewall/bulkhead right behind the cylinder head. It would be worth cleaning those ground points, as well as the one on the intake manifold at cylinder #1, which grounds some sensors and the ignition coil and ignition amplifier. Here are some photos showing ground identification and how I service them (as well as the fuse boxes):

Welcome to Jag-lovers - Members Photo Viewing Page
http://www.jag-lovers.org/snaps/snap_view.php3?id=1388098570
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page

All that to say, the 45 second run time is curious, and makes me wonder if the engine is dying when it goes into closed-loop fueling. When the engine is first started, it runs in open-loop mode, with the ECM using a default fueling map. But after a sufficient period of time for the O2 sensors to reach operating temperature, the ECM goes into closed-loop fueling where the ECM now relies on the signals from the MAF, Coolant Temperature Sensor (CTS) and O2 sensor to adjust the air-fuel ratio (AFR).

If your O2 sensor is stuck at one resistance, the ECM may think it needs to either enrich or enlean the fueling unnecessarily, causing the engine to stall. You can back-probe the O2 sensor's electrical connector, which is clipped to the oil dipstick bracket, to check for voltage that swings between just above 0V and just below 5V. If it stays at one voltage, the O2 sensor is bad. I would think this would trigger the FF44 code, but possibly not.

If the CTS is stuck at a resistance that constantly tells the ECM the engine is cold, the ECM will apply start-up fueling enrichment even after the engine has warmed up.

If the MAF sensor signal is not reflecting the volume of air being inhaled, the ECM will not be able to correctly manage the AFR.

Sorry to be so long-winded, but is there any indication that the engine is running rich or lean?

Don

 

The car has always run a little rich, especially on start up. I will go through the electrical and see if I can find any issues. Did not get a chance to take a look at it today.

I also plan to go through the codes and clear the computer to see if there are other stored that did not show.

 

I got into the car today and the car started and ran great. Not sure what the cause was but the car now acts like nothing happened.

 

Sounds like you had a bad connection that you fixed by plugging/unplugging - not an unheard of fix btw - still, best to clean up as many connections/relay seats etc as possible to avoid future gremlins!

Good news anyway,

Larry

 

The car started acting crazy again today. I pulled the Mass Air Flow Meter and see that the connector is got some gunk in it. Going to get some cleaner tomorrow and clean it out.