How to troubleshoot the Jaguar XJ-S electronic fuel injection?

If you wish to understand or troubleshoot the Jaguar XJ-S electronic fuel injection system, it is highly recommended that you obtain a copy of “Understanding Electronic Fuel Injection, Ignition and Engine Management ” by Roger Bywater and available from AJ6 Engineering.

Why does my Jaguar XJ6 engine not start?

For a period of approximately a month, the engine became harder and harder to start, until one day, it wouldnt start at all. The engine would crank and eventually start at time though.

How do you stop a Jaguar XJ6 Series III?

Very carefully, with a sharp, straight edged razor, I cut away the brittle, now hard as plastic, rubber boot that protected the top of the connector. There are two wires leading into this connector. After carefully removing the spring retaining clip, I lifted the connector slowly, causing the engine to cease.

How does idle fueling work on a Jaguar?

The “match” of the fueling laws is therefore biased accordingly. Adjustment is provided on the ECU to enable the idle fueling to be optimised to give the required 1 – 2% exhaust CO emission. This adjustment has no effect apart from when idling with the closed throttle signal activating the idle fuel circuit.

What to do if your Jaguar XJ6 won’t start?

If your XJ6 or XJ12 won’t start, grab your voltmeter and follow this checklist. Covers checking spark plugs, coil, wires and distributor cap, ballast resistor, amplifier and distributor pick-up, fuel supply, fuel pump and relay, air flow meter, fuel injectors and ECU.

How to troubleshoot the fuel pump on a Jaguar?

Remove the relay plug-in socket and determine which terminal cavity corresponds to the white/green wire. This wire goes right to the fuel pump. Using your jumper wire apply 12 volts to this wire for just a moment (you are bypassing the somewhat tricky control portion of this circuit).

What do you need to troubleshoot a Jaguar?

You will need basic hand tools, a 12-volt test light or voltmeter, and a jumper wire with alligator clips. I believe this info to be accurate for all 4.2 Series III cars, but the very earliest models have a combination relay instead of the separate pump relay, main relay, and diode pack.

What kind of engine does a Jaguar XJ6 have?

The local mechanic Donnie Taylor, had done several engine swaps, where he replaced the Jaguar engine with either a Chevrolet Monte Carlo engine, or a Corvette engine. My father told the mechanic Donnie Taylor, to look for a good used Jaguar XJ6 for sale, to go and perform an inspection, and to bring it back if it was a good car.

Are there any recalls on the 1994 Jaguar XJS?

Once More, the 1994 model was recalled in May 19, 2006 for having a poorly fitting replacement fuel filter that inadequately seals components leading to fuel leaking from the engine compartment. This could pose a safety risk and also actively contributes to poor fuel economy.

Why is my Jaguar XJS not filling up?

According to the bulletins, the only solution should be delivered by the car dealer and it is to reroute the vehicles piping to release overstressed conditions that cause the hose joint to break and allow out fuel.

Why does my Jaguar XJ-S smell like fuel?

FUEL ODORS: Jaguars seem to be prone to fuel odors; the XJ-S was even recalled to provide a more positive vapor recovery system. Please note that while Jaguars often smell like fuel, they’re not supposed to; it is an indication of a problem, and should be addressed.

Why does my Jaguar XJS have poor fuel economy?

In summary, the fuel filter sold for the model was not manufactured to suit Honeywell’s specifics resulting in incorrect placement of the O-ring on the fuel line. Automatically, inadequate sealing will lead to leaking of oil out of the engine. Apart from being a fire hazard leaking fuel is a major cause of poor fuel economy.

When did I change the fuel pump on my Jaguar XJS?

I changed mine last year (1992 4.0 in tank pump) The original pump was made by Walbro and the one I replaced it with was also Walbro. Do you think if i can hear the pump run for its 3 seconds its most likely not the source of the problem?

What’s the RPM on a 1990 Jaguar XJ?

Last Saturday the following happened to my 1990 3.6 manual. Started first time and idled nicely. Took it for a 30 mile blast ( as you do ) and after some very spirited driving ( the manual does encourage it ) realised that the RPM was hunting at will betwwen 800 – 2800 RPM.

What kind of fuel injection did the XJ-S use?

FUEL INJECTION SYSTEM TYPES: The 1976-80 XJ-S used a type of Lucas fuel injection system based on a Bosch D-Jetronic design. From 1980 on, the cars used a system referred to as a Digital P, also similar to Bosch.

How many injectors are in a Jaguar V12?

When being developed via Lucas for the Jaguar V12, the inability of the original D Jetronic ECU to drive twelve injectors was easily overcome by adding an amplifier, mounted over the radiator, conveniently dividing the injectors into four groups of three.

When did the Jaguar XJ 12 ” he ” come out?

The “HE” revisions debuted in 1981 and significantly increased fuel economy, bumping power by about ten percent as well. Seventies-era Jaguar twelves are, to put it mildly, nightmares to own. Mechanically, they can be fragile and service access underneath the long bonnet is difficult.

How much horsepower does a Jaguar XJ-S V12 have?

The original 5.3L V12 was smog-strangled to just over two hundred and forty horsepower in the States, but again, this was in an era where American five-liter V8s often claimed one hundred and twenty horsepower or less. The “HE” revisions debuted in 1981 and significantly increased fuel economy, bumping power by about ten percent as well.

How many oxygen sensors does a jaguar have?

The V12-equipped cars have two oxygen sensors, while the six-cylinder cars only have one. See our Jaguar Parts Store Catalog to order parts. Can’t find the new or used part you need?

What causes rich fuel mixture on EFI XJ6?

The coolant temp sensor is a common culprit. The main purpose of this sensor is to “tell” the ECU that the engine is cold so that a richer mixture, required with a cold motor, will be provided. In this sense it is similar in intent to an automatic choke on a carbureted engine.

How to diagnose rich running on Jaguar XJ6?

Diagnosing rich running on the fuel injected 4.2L engine, covers checking of the coolant temperature sensor, fuel pressure regulator, oxygen sensor, fuel injectors, cold start circuit, fuel changeover system, air flow meter (AFM), and ECU. This information pertains to the Jaguar XJ6 Series II-III models with the fuel injected 4.2 engine.

Why did my Jaguar go into limp mode?

Thown into limp mode on highway last night HELP! Hey all, I am new to the Jag community coming from a Porshe and an Infinit FX45. I recently bought an 05 black SType R and had a serious issue last night. Crusing home on the highway going about 70MPH, not accelerating nor coasting, just maintaining speed.

Can a Jaguar S-type thown go on the highway?

Crusing home on the highway going about 70MPH, not accelerating nor coasting, just maintaining speed. The engine basically shut down, and I had to pull onto the shoulder, it was very dangerous and frankly, it freaked me out.

Why is my air con leaking in my Jaguar?

Accordingly, when there is a leak, the area usually looks wet with oil. This is a large ‘radiator’ mounted in front of the engine coolant radiator, which cools the hot refrigerant gas enough to cause it to condense to a liquid. Due to its position it tends to be most damaged by stones thrown up from the road and by corrosion.

What kind of aircon system does a Jaguar XJ have?

The following refers to aircon systems fitted to Jaguar XJS, XJ Series 1,2,3 and will have some relevance to later cars. See also our R134a conversion mythbuster.

Where is the hot water heater on a Jaguar?

Replacement is very difficult! Situated in the engine bay, close to the bulkhead (firewall) with two coolant pipes and a small vacuum pipe, this shuts off hot water to the heater matrix when max cold is demanded. It can become stuck open or shut but is fairly easily replaced.

How does the air con work on a Jaguar A6?

Later A6 installations used a pressure switch in the same location on the backplate of the compressor which open-circuited the clutch drive if the pressure of refrigerant gas fell below a certain point (about 100psi). In either case, the compressor will not run again until the gas has been re-charged.

Can a Jaguar XJ-S V12 overheat?

Yes, of course I’m talking about regular oil changes, changing all the plugs when needed and making sure the cooling system is up to scratch. It’s famous as the golden rule for the XJ-S V12 ‘Don’t cook it’; yes because if a V12 overheats, the valve seats can loosen when it cools back.

How many miles does a Jaguar XJ-S V12 get?

Dear Jaguar lovers, many of us love the great XJ-S V12; but this classic Jaguar deserves maintenance, care and love. A V12 can clock up 300,000 miles if we keep it with respect and correctly maintained. Yes, of course I’m talking about regular oil changes, changing all the plugs when needed and making sure the cooling system is up to scratch.

What should I do about my Jaguar XJ S?

As well maintained XJ-S should never be short of braking ability in general driving. Up front the four-pot calipers should be checked for perished dust boots, while heavily-lipped discs should be replaced rather than machined, otherwise they’ll be undersize and will distort.

When did the Jaguar XJ V12 come out?

Examples rolling off the production line after 1981 boasted improved performance and economy, greater dependability and the ability to cover 50 miles without going on fire – courtesy of an improved HE V12 engine. However, for a true taste of Jaguar V12 magnificence, the improved 1980s design diluted the twelve-cylinder’s velvety gruffness.

Is the Jaguar XJ still a good car?

However, for a true taste of Jaguar V12 magnificence, the improved 1980s design diluted the twelve-cylinder’s velvety gruffness. There is no doubt that the re-invented XJ-S HE remains an impressive machine, but it’s the original design that radiates Jaguar’s trademark blend of gentleman racer with out-and-out cad.

What kind of car was the XJ in 1979?

Examples such as this 1979 pre-HE XJ-S are a rare beast on today’s market, with the majority of Series 1 cars having been gifted to the crusher after one failed MOT too many.

How big is a 5.3 litre V12 Jaguar?

We won’t kid you on, these 5.3-litre V12s do not suffer fools gladly. Nor do they appreciate long periods of hard use without a thorough service. Yet, treat your big cat with respect and you’ve got the perfect tonic for a modern world where simplification and streamlining rule.

Is there a problem with my Jaguar XF club?

I have just had the same problem on my 2011 50,000 mile XFS without driving hard. It is obviously a regular fault as the replacement at over £200 was immediately ex stock. Worse still I purchased a used car warrantee but it is restricted to moving parts and those containing oil not air.

Who is the best service advisor for a Jaguar?

I say that with a heavy heart because of a life long love affair with Jaguars, and despite the fact that my Jaguar Service Advisor since 1988, Bob ** at Jaguar of Willow Grove, is one of the most knowledgeable, and courteous in the business. Read full review Helpful

What are the best reviews of a Jaguar?

Top 322 Jaguar Reviews Trending Car Warranties Home Warranties Medical Alert Systems Invisible Braces Gold IRA Movers Buyers Guides News Login Write a review Follow us: Find a Car Brands partner Help me decide Home Automotive Car Brands Updated on 06/07/2021 Jaguar 4.0/5 (322 ratings) 5 stars 119 4 stars

Can a bad fuel injector cause a misfire?

FUEL INJECTORS: If your engine is running or idling rough, one possible problem is a plugged or bad fuel injector. This may be indicated if the misfire always seems to be the same cylinder, although a bad spark plug or wire or mechanical problems in that cylinder are other possible causes.

How many injectors are in a jet engine?

INJECTOR GROUPING: The wiring harness is set up to operate the injectors in four sets of three. However, within the ECU these circuits are combined to form two sets of six. Reportedly, in the early D-Jetronic systems, each set of six injectors includes three on each bank.

Why did my Jaguar XJS have an engine fire?

Earlier cars can have engine fires due to the fuel injector hoses getting brittle and leaking due to the heat in the Vee of the engine. ALL of them can have distributor explosions due to how they’re arranged.

Is it safe to buy a Jaguar XJS?

Apart from that they are lovely cars, he should have a lot of fun. For me, the answer is mostly “don’t buy a V12 XJS” because they do have a *lot* of problems. The 5.3L V12 had several problems involving dropped valve seats (which immediately wreck the engine and require a rebuild) if they’re run the least bit hot.

Which is better a Jaguar XJS or a V12?

So, if you MUST get a V12, get a 93-96. That said, you will find that the XJS is more of a handful to own compared to the Jaguar sedans. The heat of the engine tends to mean more regular hose, belt, and component changes in the engine bay.

What kind of brakes do you get in a Jaguar XJS?

In addition, they also got the 4L80E transmission (4 speed overdrive unit from GM) so they get a little better gas mileage. They also have conventional outboard brakes, so maintenance is easier. So, if you MUST get a V12, get a 93-96.

How to adjust the ECU on a Jaguar EFI?

The ECU adjustment changes the base fuel mapping. The adjustment procedure is covered in Kirby Palm’s book, XJS: Experience in a Book, so I won’t duplicate it here at this time.

Is the Jaguar V12 intended to be fuel injected?

How they work, how they go wrong, and how they can be improved. An Historical Point. The Jaguar V12 was always intended to be fuel injected – the carburetor setup with which it was launched was hastily cobbled together when the Brico Directors suddenly scrapped the promising Brico EFI system at the eleventh hour.

The ECU adjustment changes the base fuel mapping. The adjustment procedure is covered in Kirby Palm’s book, XJS: Experience in a Book, so I won’t duplicate it here at this time.

Why does my Jaguar XJ6 not start up?

About half of the time, the reason why the Jaguar XJ6 will not start or quits running is because of the two main electrical problems that I described above. The other cause of the XJ6 not starting or quits running is the fuel system. Mostly, it is the fuel pump being killed by rust flakes from the two fuel tanks.

Where is the starter relay on a Jaguar?

The starter relay, Jaguar part number C36611, should be located at the right rear of the engine bay near the bonnet latch mechanism on the inner fender wall. The attached picture shows the starter relay in my wife’s 1990 XJ-S convertible circled in yellow.

Are there any problems with the Jaguar XJS?

In fact, there are other problems, more generalized than the ones discussed which affect the XJS performance. In this second section we will discuss these general issues and how they can be addressed. Because of the nature of the XJS body, it is prone to rust and rot on and inside various components.

Is there an electrical system for a Jaguar XJ?

Available for most classic Jags, with XJ and XJ-S available soon. The diagrams are laminated in plastic and color coded to match the actual wiring. The supplier is:

What kind of fuel injection does a Jaguar V12 use?

Jaguar had little option, in view of the substantial investment to which they were committed, other than to hurriedly introduce the V12 with the less thoroughly developed quadruple carburettor arrangement, which performed tolerably well, except from a cold start, when fuel consumption and exhaust emissions were horrendous.

How does a D Jetronic fuel injection system work?

The basic D Jetronic system employs a recirculating fuel system in which a constant supply of fuel is pumped from the tank and delivered through a fine filter to the injectors at constant gauge pressure (usually around 2 Bar / 30 p.s.i.). A spring loaded regulator valve (2 on the V12) spills off the excess fuel which returns to the fuel tank.

What causes a Jaguar XJ engine to stall?

In November 1994, Jaguar issued technical bulletin 44-23for Jaguar XJS vehicles with 4.0-litre AJ16 engines. In these vehicles, the engine may stall when the transmission is shifted to Reverse or Drive from Park; stalling was most likely to occur when the engine was cold.

Are there any recalls on the Jaguar XJS?

In March 1992, a recall was issued for Jaguar XJS V12 Coupe and Convertible models because the high tension lead from the ignition coil could move close to the #4A fuel injector hose, causing the outer and inner injector hoses to crack or split. If this occurred, fuel would be expelled in the engine compartment which could start a fire.

What kind of ignition system does Jaguar XJ-S use?

Three ingition systems have been used on the Jaguar XJ-S: the Lucas Opus Mark 2 system on non-H.E. engines prior to 1982; the Lucas ignition on H.E. engines 1982 to 1989; and finally the Marelli ignition on post-1989 cars. An ignition coil requires a certain amount of time to build up enough energy to produce a spark.

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