Ed’s Jag

 

 

 

 

 

 

 

 

My Jaguar is a 1976 XJ-S, with a 12/75 date on the door post. It’s one of the first cars of the XJ-S type, the body style of which, except for a “facelift” in 1992, remained basically unchanged until 1996. It has 5.3 litre V-12, fuel injected engine. A carbureted version of the same engine powered the Series III E-Type, 1972-1974. In 1982 a new HE (high-efficiency) version was introduced to improve fuel economy. The early cars, like mine, are sometimes called “Pre HE.”

The car was originally driven by Henry Segerstrom. The Segerstroms were a prominent Orange County, California farming family but in current times they are mostly known as the developers of the preeminent South Coast Plaza shopping center in Costa Mesa, and as the primary benefactors of the Henry and Rene’ Segerstrom Concert Hall. I bought the car from Segerstrom Farms in December 1980 when Henry upgraded to the 1981 XJ-S of the same color, Regency Red.

I drive the car regularly. Several times a week I drive it to local hiking destinations and for errands.  I keep on top of maintenance so we can take it on longer jaunts with the Jaguar Owners Club of Los Angeles several times a year. Practical all the mechanicals have been rebuilt, including the front and rear suspension, brakes, transmission, and heads.

I also show it in JCNA-sanctioned Concours d’Elegance once or twice a year where it does well in the Driven Division. It was sanded down to metal and completely repainted Medium Canyon Red in1988. The upholstery has also been redone using the interior of a 1983. Several times since it has been in the body shop for touch-up and miscellaneous body repairs.

Maintenance Projects

Any 30+ year old car needs lots of attention, ranging from normal maintenance to major overhaul projects. For the first 16-17 years I owned my XJ-S I did virtually none of the work myself. When I took early retirement in 1997, dropping down to half-time work, I realized I was going to have to either sell the car or start doing some of the work myself.  Based on my auto shop training at Phoenix Tech several decades earlier and maintenance I had done on family cars in earlier times, I chose the latter. The Jag-Lovers online forums have been of immense help. After a while I found myself answering questions in addition to asking, and since the same issues come up again and again on these forums I began doing little write-ups of my maintenance and repair projects rather than answering the same questions repeatedly. These write-ups and other information on this page are the results of that effort. I should say that I do not do everything myself. If something is a really big project or requires a lift I take the car to trusted Jag shops in my area. In some cases these projects are documented here as well.

Notice

When an issue has to be revisited I might not take the time to update the write-up, even though I changed my thinking and approach on the matter. Consequently. some of the write-ups presented here are not up-to-date.  If you are going to undertake the project yourself and want my current thoughts don’t hesitate to contact me.

Engine Projects

Injector Harness Rebuild

We all know that the V-12 injector harness is in a severe environment—hot and oily. Often they become brittle after a few years, which can lead to breaking of the strands when servicing injectors and doing engine maintenance requiring moving the harness. Also, the connectors become brittle and break and corrosion can lead to poor contact and injector failure. After trying to patch mine by splicing in new connectors here and there, I finally decided to rebuild the whole thing. More…

FI Hose Damage Due to Crimping or Clamping

The Jaguar V12 HE fuel injectors and rail nipples were designed for a push on seal requiring no clamps. There is only a shallow, dished cap at each end. Arguments have long raged on the Jag-Lovers XJ-S and V12 Engines mail list as to (a) whether one should put a clamp over the joint “for extra insurance,” and (b) whether the caps are really necessary. Here I offer my perspective on these questions, along with some evidence that I believe supports these beliefs. More…

 Auxiliary Fan Control

The engine compartment gets very hot, as any XJ-S driver can tell you. It is especially bad after shutdown on a hot day after a bit of hard driving, perhaps in heavy traffic. This “heat soak-back” is theorized to be caused by cooling of very hot metal, such as the exhaust headers and downpipe. But regardless of the cause, the high temperatures tend to cook the soft parts under the bonnet, such as wiring and hoses. Moreover, I for one suspected it as a cause of hot starting problems, perhaps due to vaporization in the fuel rail or injector bodies. More…

Coolant Recovery Reservoir

Although later XJ-S cars are fitted with coolant recovery reservoirs, earlier models (such as my 1976) are not. I retrofitted an aftermarket unit in the body cavity behind the left front wheel, as on the later model cars. More…

Flushing Tee— Don’t do it.

Some XJ-S owners advocate adding a so-called “flushing tee” in the right heater hose  in order to help bleed air out of the coolant when filling an empty system. The reasoning is since this is the high point in the system an air bubble will stay there if not bled out at that point. Click here to see the one I installed on my car. However, it is no longer there. I removed it for several reasons. First, these things are of poor quality, with mold joints where the cap fits causing leaks. Second, if you use the OE heater hose you will find that the diameter at that point is too large for the available fitting nipples so it’s impossible to get a reliable, leak free clamped joint. In summary, the thing will frequently be leaking. At least that was my experience, and I had it installed for several years. And finally, it is totally unnecessary. The standard bleeding procedure described in the ROM does an adequate.

Front Crankshaft Seal Replacement

In a 25-year-old car, you can expect crankshaft seals to leak. In fact, I think my seals were leaking noticeable well before its 25th year. When I decided to replace the front seal was when it got so bad that it would spot the driveway while waiting for the garage door to go up. More…

Cam Cover Gasket Replacement

In a 25-year-old car, you can expect various gaskets and seals to leak. My cam cover gaskets, and probably the associated notorious half moon seals, have been leaking for years. In addition to leaving oil on the garage floor, it tends to dribble down to the exhaust manifolds where it vaporizes, filling the engine compartment with oil vapor. I believe this is a major cause of a grimy engine compartment. And, it is at first disconcerting, then later simply embarrassing, when smoke begins billowing up from under the engine at a stoplight. Drivers in other cars honk and shout “your engine is on fire! So, these were the motivating factors when I finally tackled this job. More…

Coolant Crossover Pipe Hose Replacement

The coolant crossover pipe is a black, steel pipe running across the front of the engine, right below the air-conditioning pulley. It connects to the engine at ports beside the thermostat housing on each bank, and connects to the water pump a little to the left of center. Its function, according to the Repair Operations Manual (ROM), is to carry coolant from each bank back to the water pump inlet when the thermostats are closed during warm-up. All three connections points for the pipe are close coupled with short hoses. This, together with the cramped space at the front of the engine, makes replacement of the hoses difficult. More…

Installation of a Crane XR700 Ignition System

For a long time I had noticed my car ran better first thing in the morning. Then it idled smoothly, while later on it idled rough and had spells of popping for a bit for a block or so two after a brief rest.  I’d done many things in hopes of fixing this problem, every time thinking it worked only to have the symptoms return later. Then I noticed some discussion on the XJ-S Lovers forum about the ignition amplifier failing and exhibiting this failure most noticeably at high temperatures. To deal with this, several pre-HE owners on the list had replaced the stock amplifier, timing rotor, and magnetic pick up with aftermarket electronic ignition systems. The Crane XR700 appeared to be the most widely used. Since it costs only about $130 including shipping I decided to give it a try. More… ( The write-up shows the Crane amplifier mounted on the right bank air filter housing. I later moved it to the shelf in front of the radiator. Photo).

Distributor Overhaul

I did a halfway overhaul of my distributor about 3 years earlier as one of my first DYI projects on the car, but had misgivings about some things I didn’t do. Among these concerns were the internal seal and bearing. The seal was suspect because I had an explosion of some kind that destroyed the cap (literally) a few months ago.  I was concerned about the bearing because my mechanic once mentioned some “wobble” in the shaft. Frankly, I now believe both were red herrings of sorts, but nonetheless I have now replaced both seal and bearing. This was an easier decision to come to because I had already resolved to install a Crane ignition system. More…

Installation of HE Rail in 1976 (PreHE) XJ-S

 The Jaguar V-12 engine in the early XJ-S has dual fuel rails, one for each bank. Each of these is in a “race-track” configuration, with rather complicated plumbing apparently designed to maintain good flow and equal friction pressure drop to all injectors. However, there are multiple parallel flow paths that can allow vapor collection in sections with consequent rough running. Since Jaguar had made several rail modifications over the years, I decided to retrofit a latter model rail. There were many challenges, but I’m happy with the result. More…

Fuel Injector Testing

Fuel injectors last a long time but, like everything else, are eventually subject to failure. The can fail in various ways, some of which can be fixed and others not. While there are places where you can send your injectors for professional cleaning and testing, here are some ideas for assessing possible problems yourself. More…

Radiator Drain Valve Repair

 The early XJ-S has a radiator drain valve that looks like one of the most solid components on the car. It is a solid brass “plug” style valve, about 5/8″ diameter and 3″ long. An extension rod connects to the stem and runs up the right side of the radiator so it can be operated from above. A 90-degree turn of the valve stem goes from fully open to fully closed. But despite its robust appearance, the valve has problems. After several efforts to fix mine I wound up replacing it with a generic from McMaster-Carr Hardware. More…

Rebuilding the Jaguar 5.3L V12 Fan Jockey Pulley

This is an article I plan on submitting to The Journal of Negative Results. The upshot is I spent a lot of time and money putting a new bearing in my noisy jockey pulley only to have it fail almost immediately. I’ve since replaced it with a rebuilt one. I leave the write-up here just to remind myself of my limitations. More…

Servicing the Throttle Capstan

The throttle capstan, Figure 1,operates the two throttles in synchronization in response to the throttle cable. When the pressure is released from the accelerator the capstan, under action of a coil spring within it, is supposed to snap immediately back to the idle stop position.  Over time the lubricant on the capstan shaft hardens so the capstan no longer rotates freely. When this happens you may notice the engine not always returning to its proper idle speed; sometimes it will return to 750 RPM, other times 800 or 850. The solution is to remove and disassemble the capstan so it can be cleaned and lubricated. It’s an easy job, taking about two hours at most. More…

The D-Jetronic Throttle Switch

The early Jaguar 5.3 L v12 used the Bosch D-Jetronic Electronic Fuel Injection (EFI) system. An important element in this system is the throttle switch, located beneath the throttle capstan, Figure 1. The red arrow in the photo points to the connector to the switch, peeking out from under the capstan. The switch provided several throttle-related signals to the ECU, including idle state, full throttle state, and cceleration state. It is a simple, fairly reliable device, although it sometimes needs attention. This document shows how to disassemble and clean the switch, as well as how to test and adjust it. More…

Inspecting, Cleaning, or Replacement of the Front Power Buss

The positive battery cable on the XJ-S runs from the battery in the boot to a terminal post on the left side of the firewall. From there a cable, called the Post Cable in the parts book (C 44183), runs to another firewall post in the same position on the right side of the car. In this write-up I call that cross-over cable the Front Power Buss, or simply the Buss, as that seems more descriptive. This document shows how to remove, inspect, clean and if necessary replace the buss. More…

Calibration of the Temperature Gauge

Whenever the XJ-S driver sees the dash temperature gauge creeping up higher than he/she is comfortable with the first question is generally “Is the gauge right?” One way to answer this is to make some kind of independent measurement. Some have gone so far as to fit additional sensors to the engine and mount a separate gauge or gauges in the car. More commonly, an infrared radiation (IR) “gun” is used to measure temperature of various surfaces on the engine, e.g., the top radiator hoses or thermostat housings. Presented here is another method that’s not very difficult or expensive. More…

Retrofit of an HE Fan to the pre HE XJ-S V-12

When my temperature gauge was still reading a little high after recoring the radiator I began to get suspicious of my clutch, even though it was only 7 years old and had only about 15,000 miles of service. Rather than replacing it I decided to convert to the fan used in the later HE engines. More…

Valve Train Noise (Head Rebuild)

My XJ-s was 37 years old and had 137,000 miles on the clock when it developed serious valve train noise on the right bank in early 2013. Several Jag techs made a preliminary diagnosis of imminent valve seat drop. It turned out to be something else entirely. Exhaust valve A4 and to a lesser extent A6 had apparently stuck open and overheated. The springs, valve stems, tappets, and guided were all burned, and the cam cradle and cam worn so badly they had to be replaced. The noise was the cam lobes pounding on the tappets. The root cause of the valves sticking open will never be known with certainty. The shop that did the R/R and rebuild work attributed it to loss of oiling due to sludge build-up. While there was much evidence of sludge,  only A4 & A6 getting badly damaged remains a mystery under that theory. Two other highly respected Jaguar engine specialists believe carbon build-up started the process, gradually worsening to the point where there was no seat contact, leading to overheating. Once the springs were overheated they lost their temper and couldn’t close the valve at all. But regardless of the cause, the fix was the same: complete rebuild of the heads. Shown here is an annotated photo album of the episode. More…

Body Projects

Jaguar XJ-S Bonnet lock maintenance

The bonnet locking systems is covered in the ROM beginning at 76.16.20. However, general maintenance and adjustments are only vaguely described. Here I will try to be more specific on the procedures for adjustment and general maintenance. More…

Inexpensive Cup Holder

An often-voiced complaint about the XJ-S is the lack of a cup holder. Several aftermarket solutions have emerged, as outlined in Kirby Palm’s Book . Described here is a very inexpensive, inelegant alternative. More…

Keyless Entry

The early XJ-S has electric door locks are controlled by a rocker switch on the console. The boot lid lock is manually operated only. The goal of this project was to fit the car with a remote, keyless entry system allowing doors to be locked and unlocked, and the boot lid to be unlocked, with a key-fob remote. More…

Headliner Replacement

I had the headliner, front seats, and carpets redone for the first time in 1988. By 2000 the headliner had begun to sag in a couple places, and by late 2001 it was around my shoulders. This time I decided to do it myself. Not that it’s terribly expensive to have it done (about $200 labor and materials at local shops), but I decided I would rather save the labor money for having things done that I really could not do myself. As it turned out though I didn’t save much, as the materials cost about $150, as explained below. More…

Spoiler Undertray Repair

Perhaps due to sagging front springs, the front of my car rides low. Once or twice I have pulled too far into a parking place, so that the spoiler under tray has ridden up over the parking curb. Then upon backing out, the undertray was ripped from the screws that attach it to the car body. Subsequently, the back edge began to droop, making it susceptible to even more damage. The drooping may have been due to the lip, which provides stiffness, having also been broken. Or, perhaps it was due to oil damage from a leaking front crankshaft seal. At some point my mechanic put in some cable ties to support it a bit. When I had to remove the undertray to replace the front crankshaft seal, I thought about replacing it. However,  the cost of a new one inspired me to try to repair it instead. More…

Rewiring Front Speakers

For years my stereo would cut out intermittently. First, I replaced the speakers to no avail. I then replaced the stereo, only to have it still cut out. A few years later I took it to Circuit City to let the experts fix it. They convinced me to let them put in yet another stereo and new speakers, arguing that the wiring was probably OK so it had to be either the stereo or the speakers. Great stereo, but still cut out. Several times I did continuity checks but without success. Whatever gremlins were there were hiding whenever I looked for them.  But, applying the Sherlockian process of elimination I decided to replace the wires. And, guess what, it fixed it! More…

Rebuilding Front Seats

As part of spiffing up my interior I decided I had to rebuild the drivers seat. I had both of them reupholstered in 1988 so the leather was good. However, the foam was collapsing a bit both in the seat and the back bolsters, and the diaphragm was torn. Also, the piping on the seat back was worn in the usual spot from getting in and out of the car. More…

Fixing Sagging Doors

Like many 28-year-old cars, my driver’s door was sagging a bit and clunking against the striker when closing. Also, it would squeak as the door rubbed against the seal on bumpy roads. The problem was wear between the hinge pins and the hinges, particularly the upper pin. The upper pin from my driver’s door is shown in Figure 1. The lower pin showed hardly any wear. More…

Installing Aftermarket Bonnet Struts

Like everything else, bonnet struts eventually wear out. Sometimes they fail by no longer holding the bonnet open. My original ones did that after about 15 years, and the tech that did my work at the time finally just replaced them and told me later. Guess he figured he had his neck on the chopping block! After another 10 years that set were still holding the bonnet up, but had become so stiff on the uplift that sometimes I had to really struggle to get it up. Time to replace them again. More…

Replacing Side Bumper Strips

The original XJ-S did not have a protective bumper strip along the sides and was therefore subject to door dings. These dings are very and hard to repair because of the ridge. After my wife did it to our 1976 XJ-Sin our garage (the day after it returned from the paint shop), I had them installed at a local body shop. They consist of aluminum channel riveted to the body and vinyl insert strip. The vinyl eventually deteriorates in the sun. This article explains the simple process of replacing them. More…

Rust Damage Due to Rear Window Seal

The rear window seal was replaced when the car was repainted in 1988. Unfortunately, the glass tech didn’t know how to do the job. A Circuit City tech installing a new antenna in the mid 1990s must have known about the problem, since he took advantage of the rust hole in the parcel shelf to run his wires, saying nothing of course. By the time I discovered the leakage in 2001 it had done extensive damage to the parcel shelf and the rear floor pans. It coast over $1,000 to fix the damage. More…

Rear Window Seal Replacement

The XJ-S rear window is notorious for leaking. I recently had it resealed for the third time. An annotated photo album shows the process. More…

Tail Light Problems

The tail lights on the early XJ-S were, to be frank, terrible. One problem is the ground for the lamp sockets was through the metal plating on the plastic so cracking and peeling results in dim and blinking lights. The other problem was, at least on my car,  the body cavity into which the tail light assembly fits only roughly approximates the shape of the tail light.  Moreover, there is no proper register holes or pins. The mounting screws go through oversized holes in the body and one is supposed to jockey it around till it’s snug and then tighten the nuts. This is a difficult process, and when the car was painted the body tech failed miserably. He tried to close the gaps simply by tightening the screws, breaking the plastic tail lights at the mounting pads, and still left a gap. It was years before I knew this had happened and rain and car washes got in the cavity and did serious rust damage. More…

Miscellaneous Projects

Backup Lights Repair

Being out of the driver’s view, backup light (reverse light) failure can go unnoticed for months or even years. I did not discover mine were not working until I entered my car in a JCNA concours event in early 2003, although when I tracked down the problems (two, not just one) I came to know they had been out of service for at least a year. Here’s how I tracked down the problems and fixed them. More…

Cleaning AC Condensate Drains

If you sometimes experience water splashing on your feet while making right turns it is probably because the tubes that are supposed to drain the condensate from the evaporator are clogged. They tend to clog due to disintegration of the thin foam used as flap seals in the AC unit behind the dash, or simply dirt from years of dust washing off the evaporator. When I cleaned mine for the first time recently it seemed to be the latter, as there was lots of fine material rather than chunks. Regardless of the source, the problem is easily solved. More…

Refurbishing Early XJ-S Kent Wheels

The early Jaguar XJ-S had the so called Kent wheels, Figure 1. These are cast aluminum alloy with five “spokes” created by depressed areas around the lugs. These area are painted anthracite gray which eventually fades in the sun. Repainting using readily available spray can paint is not difficult. More…

Fuel Odors in the Boot

There are frequent complaints about gasoline odors in the boot of the XJ-S. Several causes have been identified, including leaky tank, leaky fittings where various fuel and vent lines attach, bad filler neck seal, sump tank leakage, hoses joints, and last but not least permeation through hose walls. In this write-up I try to discuss all of these issues, and tell what finally worked for me on my ’76 coupe. I documented my experience with this problem in this write-up. In the end, my problem stemmed from use of common fuel hose, the walls of which have high permeability for some of the components of modern gasoline. This is discussed in the write-up. Also, this video clip shows a hydrocarbon sniffer being used to confirm this source of fuel odors in the boot.

Overhauling Girling Front Brake Calipers (contributed by Richard Dowling)

Richard gives tips and step-by-step procedures for front brake caliper overhaul. More…

Windscreen Motor Replacement (Lucas with parking solenoid)

Two different Lucas wiper systems were used on the early XJ-Ses. The earliest model used a solenoid operated parking mechanism. Later, the solenoid operated mechanism was replaced by a reversing mechanism for parking. This write-up describes the solenoid model, although much of the information also applies to the reversing model. More…

Other Technical Information

Fuel System Pressure Tests

Pressure test results for the EFI system are presented. Shows how fuel rail pressure holds after shutdown. More…

Windscreen wiper assembly mounting

Windscreen wiper assembly mounting diagram from ROM. More…

 Special Spanner for Starter Upper Bolt (Richard Dowling)

Fifteen years ago when I had to pull the starter motor to fix a leak in the exhaust gasket above it, I was puzzled at how to get at the bolt at the top. You just can’t get at it with any standard tool in the box. Perhaps Jaguar has a special tool, but the typical DIY can’t afford to invest in very many “special tools.”  More…

PreHE Power Amplifier Disassembled

A few years ago I picked up a spare EFI power amplifier. While chasing daemons I changed out my original, replacing it with the spare. Didn’t solve whatever problem I was having, but I never reinstalled the original unit which is now on the shelf. One day out of curiosity I opened up. More…

Injector Firing Sequence (Richard Dowling)

Richard Dowling has created this more easily read version of the Injector firing sequence: More…

 

 

2 thoughts on “Ed’s Jag

  1. Ed Sowell says:

    I am slowly transcribing the write-ups from my old website. In the meanwhile, you can still see all the articles at http://www.efsowell.us/ed/myJag.html

  2. Ed Sowell says:

    After fairly smooth running after replacing the distributor vacuum advance a few weeks ago, it’s now running a bit rough. Checked fuel rail pressure: solid 32 psi, and holds after shutdown.

    Pulled plugs 1A & 2A. Tips clean. A bit of darkening on the metal, but not wet or oily.

    New finding: Just happened to notice arcing between the 2A plug wire and the 4A injector lead. Tried to reroute the 2A wire but it’s not long enough to do anything but squeeze it between the 3A injector mounting clamp and the distributer cap. Replaced it with the longer Magnacor wire (that the tech at JP European had replaced with my old Lucas wires). It runs noticeably better but then got a jolt while fiddling with the CTS connector! I’ve now ordered new boots for my Magnacors and will reinstall them. Maybe a new cap?

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