Waking a 27-Year-Old Giant: Wiring, the "Mojo" Slump & First Fire

It is early November 2025, and it has already been an incredibly demanding, busy year here at Car Builder Solutions. Between consolidating our massive parts catalogue down to a compact, "at-a-glance" A5 format, and condensing the main A4 master catalogue from 435 pages down to 356 pages to save on the sky-rocketing printing and postage costs for 20,000 copies, my desk has been buried under paperwork.

Truthfully, I’ve also been struggling with my build mojo. I’m not getting any younger, and finding the time and raw motivation to tackle what is, for me, the most complex and difficult phase of the project has been tough. Preparing to fire up the engine requires a serious amount of both.

However, logic dictates that getting a 27-year-old engine running right now—even for just a few seconds—makes absolute sense before diving into the massive expense of bespoke exhaust fabrication and permanently bonding the main composite tub. A couple of days ago, I gave myself a strict talking-to, walked into the workshop, and decided to confront the beast head-on: the wiring.

I’m writing this log just as much for my own future sanity as I am for the public CBS blog. If you're currently staring down a daunting wiring project of your own, I hope this chronicle provides some clarity, reassurance, and perhaps a bit of motivation.

The Engine's History: A Long Hibernation

To understand the stakes, we have to look back at where this engine came from. I bought it back in 2006, but even then, it had already been sitting patiently in its shipping crate for eight long years. The original invoice from 2006 details a complete package: the engine, transmission, exhaust, and all vital ancillaries including the starter, alternator, air-conditioning compressor, original wiring loom, and factory ECU.

Fast-forward to 2010. To get this power unit through the rigorous UK IVA (Individual Vehicle Approval) emission regulations, the factory management system simply wasn't going to cut it. I turned to the specialists at Ron Francis Wiring in the USA. They reprogrammed the ECU and custom-designed a standalone engine wiring harness to my precise specifications. At the time, the exchange rate was a healthy $1.60 to the pound.

Unboxing the Harness & Laying the Groundwork

The first step was removing the original factory engine loom. I carefully unwrapped, labelled, and unclipped it from the block to preserve it for future reference.

In stark contrast, the replacement Ron Francis loom arrived neatly organized as a collection of individual wire bundles separated into labelled bags. It included factory-correct, pre-wired plugs for the ignition coils and every single engine sensor. The kit provides an incredibly generous length of wire for each circuit, ensuring ample slack to route cleanly to the designated fuse panel, regardless of where you choose to mount it in the chassis.

Astonishingly, every single wire has its specific function and matching fuse box terminal number printed clearly along its entire length. Fool-proof instructions link each bag number to its operational purpose and layout path.

I began by laying out all the wire bundles loosely across the engine, plugging each connector into its corresponding sender. In this initial layout phase, you can see the new fuse, relay, and connector panel sitting at the base, with its short output bundle routing directly to the multi-pin block and the re-flashed ECU on the right. Each bundle contains three or four wires, cut to roughly eight meters long. This gives total freedom to route wires via the most indirect, well-hidden paths around the engine bay.

An Incredibly Clever System

The attention to detail from Ron Francis is genuinely impressive. To prevent eye-strain and mistakes, each wire is inkjet-printed along its entire span using white ink on dark insulation and black ink on light insulation. For instance, the red wire servicing the Left Ignition Coil reads clearly: "CONNECT TO TERMINAL 10", accompanied by a small arrow indicating the correct direction to read the text. The same applied across the board for the Throttle Position Sensor (TPS), Mass Airflow (MAF) sensor, and Front Left Oxygen (O2) sensor. It is as close to foolproof as wiring can get (in theory!).

• Builder's Tip: If you are tackling a comprehensive rewiring job like this, every single specialty tool, crimper, heat-shrink sleeve, and terminal block used in this build can be found directly in our catalogue or on our website at www.carbuilder.com.

The Loom Connection Panel & Temporary Rig

The heart of the engine management routing is the main connection panel, featuring four rows of 30 sequentially numbered terminals—giving a grand total of 120 potential termination points. Connections are made using pre-insulated forked crimp terminals. Because this is purely a trial run to confirm the engine's mechanical integrity, I left every single wire at its maximum length. Doing so sacrificed a clean layout temporarily and meant using an entire set of terminals, but it preserved my options for the final install.

Crucially, this panel manages only the engine's powertrain. The instruments, lights, cockpit options, and HVAC will all run safely off one of our standalone CBS Wiring Modules down the line.

With everything connected, the engine bay looked like an explosion in a spaghetti factory, but everything was safely hanging clear of the exhaust manifolds and the front serpentine accessory belt. The final tasks of shortening, wrapping, neat looming, and permanent routing will happen only after a successful startup.

For fuel, I set up a temporary rig, borrowing the gravity-fed fuel tank from my Berkeley project, perched high up to feed down into a fuel filter, an aluminum swirl pot, and one of our high-pressure #INJP4 Fuel Pumps. I wired up a basic ignition switch, an alternator warning light, an ECU malfunction indicator light (MIL), a voltmeter, and a mechanical oil pressure gauge.

Power was drawn from a brand-new battery, routing the main +12V positive feeds through our #BDB3R Battery Clamp Distribution Board, and the negative ground returns via our heavy-duty #QDIS2 Battery Quick Disconnect Switch.

The engine coolant plumbing was also completed at this stage, though I deliberately held off on adding water. The plan was to let the engine fire for just a few seconds dry, ensuring it would actually run before committing to filling and bleeding the full system.

The First Attempt: Dead Silence

By Friday 28th November, everything was assembled. I asked our technician, Matt, to cast an expert eye over my wiring and plumbing work, and invited our Marketing Manager, Adam, to act as a second pair of eyes to watch for any unexpected smoke, stray sparks, or mechanical drama.

First, we isolated the high-pressure fuel pump feed, connected the main battery leads, and cranked the engine over simply to check for oil pressure. As I had half-expected, the modern gauge didn’t cooperate with the 27-year-old factory Ford oil pressure sender, giving us a completely dead reading. Undeterred, we peered down through the oil filler neck on the rocker cover; a few seconds of cranking confirmed a beautiful, healthy flow of oil washing over the valvetrain.

With lubrication confirmed, we reconnected the fuel pump, turned the ignition key, and listened to the satisfying hum of the fuel system priming its flow and return lines. Finally, we braced ourselves and spun the engine over with all systems fully live.

Nothing. Absolutely nothing. Not a single pop, bang, or sign of life. We cranked it for twenty seconds to ensure fuel reached the rails, but met complete silence. Nada.

Diagnosing the Slumber

We immediately broke it down systematically. Matt pulled a spark plug and grounded it—Yes, a bright, consistent spark. We had ignition. He then unclipped an injector plug and verified a clean voltage pulse with a test light—Yes, power was actively reaching the injectors. Matt unbolted the left-hand fuel rail and pulled out an injector. By connecting a temporary 12V power supply directly to the injector terminals to pulse it open while manually blowing through it, the issue was instantly revealed: a thick, stale-smelling, bright orange goo was packed inside. It had been sitting there for nearly thirty years, arguably protecting the delicate internal components, but completely sealing them shut against modern fuel pressure.

I reinstalled that single injector, cranked the engine, and immediately got exactly one cylinder firing consistently per revolution! That was all the proof we needed. I stripped off the air intake, unbolted both fuel rails, and pulled all eight injectors. Using a spare injector plug wired to a 12V battery, we pulsed each injector open repeatedly while flushing them thoroughly with pressurized brake cleaner and compressed air.

Seven of the eight cleared beautifully, atomizing a perfect, crisp, symmetrical cone of cleaner. Only one remained stubborn, delivering a slightly deflected, lazy sideways spurt. I put them all back in, hoping that a bit of heat and fresh fuel cycling might eventually clear the final restriction.

Signs of Life and Fuel Gremlins

A few more revolutions on the starter motor and the big V8 suddenly coughed, spluttered, and roared into life! We let it idle for about ten seconds. It sounded mechanically pristine—no ticks, knocks, or untoward noises. Confirmed that it was a healthy engine, we shut it down to fill the cooling system with 20 litres of water. As is typical with mid-engined vehicle layouts, it took a fair amount of time and patience to bleed the air bubbles out through to the front radiator and heater matrix.

Once happy with the water level, we fired it up for a longer run. It idled beautifully for roughly twenty seconds, before suddenly popping a massive flame out of the left-hand catalytic converter and dying. We restarted it with the pump isolated; it ran for an instant on residual pressure and cut out. We were clearly facing a fuel delivery breakdown.

Suspecting a drop in fuel pressure, I cobbled together a diagnostic gauge onto the fuel rail test valve. It showed a rock-solid 2.7 bar (39 psi)—exactly where it should be. The primary suspect turned back to the injectors sticking or heavily over-fueling as they warmed up. Given their 28-year hibernation, it wasn’t a surprise. I pulled all eight once again, and a helpful customer arranged to run them through a specialist ultrasonic cleaning and diagnostic batch.

The specialist testing report confirmed our suspicions:

While waiting for the professional injector rejuvenation, I kept myself busy. I sourced a scrapped section of the original Ford donor exhaust, carefully cut out one of the redundant threaded oxygen sensor bosses, and drilled a hole to fit it into my custom, modified collector pipe right before the left catalytic converter. Once welded, this would allow me to run the dual factory oxygen sensors properly for accurate closed-loop fueling.

The Breakthrough: Friday 19th December 2025

Exactly 27 years and 11 months after engine number G6443 was hand-assembled by engine builders Vaughan Herbert and Bob McIntyre at the Romeo Engine Plant in Michigan, USA, it was time for the final showdown.

I reinstalled the professionally reconditioned injectors, bolted up both catalytic converters, fitted both oxygen sensors, and turned the key. Still not right. The engine would catch, run roughly for a handful of seconds, lose its rhythm, misfire, and stall out with another loud pop from the exhaust.

I spent several sleepless nights tossing and turning, trying to recall the fundamental principles of electronic fuel injection and engine management that were second nature to me twenty years ago. I went back to the garage and systematically hunted for faults. I discovered and repaired a loose crimp terminal on the coolant temperature sensor and found an un-tightened vacuum union on the manifold reference line to the fuel pressure regulator. Neither fault was critical enough to cause a complete shutdown, but fixing them was progress. I hooked up a temporary vacuum gauge to the plenum: it pulled 19 inches of mercury. Absolutely rock-solid engine vacuum.

I decided to painstakingly verify every single strand of wire on the Ron Francis harness against the connection panel. While carefully uncoiling and feeling along the taped sections of the bundles, I spotted a section wrapped in electrical tape containing four colored wires, but only three lines were emerging to connect to the terminal board.

I had missed two critical connections. One un-terminated wire belonged to the Mass Airflow (MAF) sensor, and another belonged to the Throttle Position Sensor (TPS). They were basic, simple oversight mistakes that I likely wouldn't have made years ago, but finding them brought a wave of relief. I crimped them, secured them to their respective terminals on the board, and took a breath.

Sweet Success & Next Steps

I turned the key one more time. The starter engaged, and the big V8 instantly fired, stabilized, and settled down into a beautifully smooth, rhythmic tickover.

As the block gently warmed up, I took one of our CBS Infrared Laser Thermometers and began scanning the engine bay to monitor thermal performance. I scanned each individual exhaust runner to verify even combustion temperatures across all cylinders, tracked the catalytic converter light-off temperatures, checked the thermostat housing to ensure it opened at the correct design temperature, verified the flow and return paths to the radiator, and even checked the hot water rushing cleanly through the heater matrix. Everything was operating perfectly.

It has been an incredibly long time since I last felt that immense rush of satisfaction and profound relief when a modified engine wakes up and runs flawlessly for the first time. The feeling is just as intoxicating as it ever was. In standard factory trim with all restrictive emissions equipment active, this power plant was rated at 305 horsepower. Deleting the surplus ancillary items and running this clean, optimized configuration should release a few extra horses. That will do nicely.

Mission accomplished—at least for this milestone. I’ve proven beyond doubt that the engine, custom wiring, and cooling modifications work in harmony.

What's next? 1. I will wire the radiator cooling fans into the circuit.

2. Run the engine up to full operational temperature for an extended period.

3. Fill and bleed the hydraulic clutch system to ensure clean release, drive engagement, and proper selection of all gears out to the hubs.

Once those parameters are verified, I will systematically disconnect the engine loom wires, drain down the coolant, remove the temporary Berkeley fuel rig, and finally face the highly anticipated challenge of dropping the main cockpit tub into position for the final time.

As a final note, Matt made an excellent point: it would be highly prudent to check our exhaust emissions for strict IVA compliance before moving further along with the build. Luckily, our friend Dave from AEON drove over with his Sun MOT emissions testing rig. He hooked it up and found the engine running just a fraction on the lean side. He suggested swapping out the factory fixed fuel pressure regulator for an aftermarket, fully adjustable unit, allowing us to bump the fuel rail pressure up a fraction to dial the mixture in perfectly.

If all goes well, these temporary lines will soon be permanently shortened, tidied into a neat engine bay loom, and re-terminated to the distribution board, which will be safely mounted inside the body sill section.

Thank you for following along with this massive milestone. Stay tuned for the next update, and happy building!

Do you have questions about custom loom installations, high-pressure fuel setups, or finding components for your own IVA compliance? Leave a comment below or explore the full range of electrical and plumbing supplies over at www.carbuilder.com.