| TMC: SOUTHEAST CHAPTER |
 |  |  |  |  |  |  |
FEATURE ARTICLE: Lucas Fuel Injection Story
Dave Cox
There are people who can explain how to make the Lucas mechanical fuel injection purr like a kitten, and there are people who are experts
at explaining why any sane person will immediately convert a fuel injected Maserati to carburetors. This is neither. It is a diary of “How I
Spent the First Two Years with My Maserati and Lived to Tell the Tale.”
Like most newbies, when I dragged home my 3500 GTI I set about finding out what to do with it. The attraction of the car, for me, was, oddly
enough, the fuel injection, which was the very thing that kept the car from running and drove the price down. Craven greed played a part—
“Ah hah! I know how to fix this beastie!”—and part was curiosity—“I wonder if I can fix this beastie?”—but most of all, I had visions of gliding
around town in an aluminum-bodied Maserati which would wow my friends, befuddle my critics, and be a babe magnet to all the pretty girls
that had, for some reason, decided that I was a middle-aged, pot-bellied grandpa. But there is no denying the fact that the fuel injection itself
was the major lure, and memories of having great and singular success with a Rochester fuel injection system back in the day (late 60’s)
gave me confidence that the only good Maser was one with fuel injection.
Most folks told me to pull the unit off, put it in the trunk, and enjoy driving the car with carburetors. I listened patiently to these folks, and
even feigned interest in what they were saying. Meanwhile I contacted experts, and even trekked to Michigan for an audience with the nice
folks at Kinsler to chat about technical matters. The result was that I became something of an expert on the system, so long as by “expert”
one refers to anyone who happens to have a service manual. The great thing about the service manual is that, unlike the books for the car
itself, the Lucas folk wrote theirs in English.
After draining what looked like chocolate mousse out of the fuel tank, and removing petrified chocolate mouse and coffee grounds from the
fuel filter, I tackled the heart of the matter, the dreaded “bombs”, the Lucas fuel pumps.
Strategically located directly next to the battery, and wound up with miles of cracked rubber fuel hose, these high pressure pumps are
notoriously unreliable, and replacements are not easy to find. For some reason many of these pumps seem to have been destroyed by
fire. Go figure. My pumps looked just fine but refused to work, so the first order of business was removing them from their hiding place.
For most folks, removing these things would be a piece of cake. A few bolts, a few fittings and, voilá, the pumps would be out. For me, just
inserting myself into the trunk far enough to work on the things required the sort of effort that has earned many people awards for physical
endurance. Once inserted into the trunk area, I discovered to my dismay that for whatever reason, the selection of the correct wrench sizes
was nearly a deal breaker. Now I know enough to have both SAE and metric wrenches close at hand, but in those early days, it was my
naiveté that allowed me to assume that the Italians would stick to metric sizes. Huffing and puffing, blinded by sweat and chest pains, the
last thing a person wants is to find that the wrenches just don’t fit. Yikes. To this day I have folds and crease marks on my person that are
the direct result of stuffing myself into that trunk area and snagging my prodigious self on the unyielding trunk latch. Crikey.
Despite these challenges, the pumps finally succumbed to reason, and I began the task of disassembly. Fortunately, the chocolate mousse
had not made it past the large filters, yet the pumps had remained silent. A thorough cleaning and inspection revealed an impressively
robust device that, I later learned, was a clever combination of a windshield wiper motor, an aircraft-grade pump, and what looked like an oil
filter from an old Chevy. The combination led to the shape, and the shape led to the sobriquet “bomb”. Of course, there may be those who
would find a more literal etymology for the name, but there are always cynics around when Maseratis are being repaired.
In an unusual fit of reason, I tried a bit of electrical power to the pumps and, of course, they purred like kittens. Hmmm. A quick check of the
wiring in the trunk—again crawling into the pit of Hell—revealed that there was no electricity to be found. Considering the gasoline fumes,
this was probably a blessing.
At this point, a considerable dissertation on the safety circuit switch-- when the oil pressure goes down, electricity is cut off the to the fuel
pumps—could be inserted, but this story is too long as it is, and besides the whole wiring system is clearly shown in the wiring diagrams of
the owner’s manual. A few hours of study will reveal everything, and offer the added bonus of giving the student a good start on learning to
read Italian. Suffice it to say that once power was restored to the pumps, fuel flowed, but not before several more trips into the horrible
depths of that trunk, and, as an added bonus, the opportunity to get acquainted with the underside of the dashboard.
With a consistent supply of fuel at 100 lbs. of pressure, the fuel injection should work just fine. My car tended to smoke so much that I was
pretty sure there were no rings in the engine. There was so much smoke that mosquitoes several streets away were falling out of the sky
like rice at a wedding. The fact that the engine ran like poop was a factor, but one tends to overlook the dodgy throttle response when the
sun is being blocked out by blue clouds of smoke. There was a real danger of asphyxiation.
Days of diagnosis revealed that the smoke would come and go, but so did the fuel pressure. It should be said at this point that even the
most basic information about the engine was still MIA, which added to my reluctance to try to diagnose the fuel injection while it was on the
engine. Reluctantly, I took my neighbor’s advice and built a test bench. This was in 1999.
This opens the discussion to the pros and cons of listening to neighbors when working on a Maserati. In my defense, most of my neighbors
had long since taken to hiding indoors whenever I worked on any of my cars, so my reluctance to run off someone who was sympathetic to
me and enthusiastic about my Maserati should be understandable. Still, there is the matter of qualifications: He is an engineer and I am
not. True, he is an electrical engineer, and from the beginning wanted to install a MegaSquirt system, but having anyone in the garage was
preferable to going it alone. The result was a jim-dandy test bench, with a variable speed DC motor to run the fuel distributor, an old
refrigerator pump to pull a vacuum, and six glass baby food jars with rubber grommets in their lids to accept the injectors and to catch the
mineral spirits. Look out Kinsler, your days are numbered.
As it turned out, their days were numbered, at least as far as the Lucas system was concerned, but my efforts had nothing to do with that. I
did learn that each injector had its own style—one sprayed like a shower head, one like a partially plugged shower head; one sprayed like a
garden hose with a thumb over the end, and another like a pin-hole in a copper water line—and none sprayed the same way for long.
Money was spent on experts—“Golly, Mr. Cox, I have never seen injectors behave this way.”—and efforts were made to replace them.
Finally, we cut the end off one and found a likely culprit: A petrified o-ring. One kind fellow explained, voice full of pity, that metallurgy was
the culprit, and even if the o-rings were new, the softness of the seats would still cause problems. The obvious conclusion was that the
thirty-five-year-old injectors were probably worn out. The test bench was beginning to pay off with concrete proof of the obvious.
Rebuild-able injectors were available for the later units that used plastic fuel lines, but early units like mine used smaller fittings and jazzy
chrome-plated metal fuel lines. Aesthetic concerns like this just muddied up the problem, but the injection’s appearance should count for
something. At one point we fiddled around with Bosch mechanical injectors from a Rabbit, and concluded that various alternatives were
possible if one were willing to re-engineer the system. More test bench dividends.
Along the way, tests on the fuel distributor revealed that it was extremely well made, had a wide range of adjustment, and, apparently, would
enjoy a long, happy life even after some of the clearances were less than optimal, which is just what one wants on an airplane. Still, there
was the matter of all that fuel dribbling out of the unit and into the engine, and there was the matter of figuring out those funny little rollers.
We finally concluded that, baring severe changes, there was no reason the rollers would need much attention, but that still left the matter of
the fuel leaking into the cam area. Not good. It seems they do not start and stop airplane engines as often as we do with our grocery-
getters, and the folks at Lucas figured that any dribbling fuel would be of little concern on long flights. When the system was adapted to
automotive use, someone accepted this idea of using oil pressure to counteract the fuel pressure to keep the fuel in the fuel injection and
out of the crankcase. The fact that later model Maseratis used a “dry system” which relied on a seal rather than the differential between oil
pressure and fuel pressure speaks volumes about that original decision.
Fitting a later unit became a possibility, so a few of those systems were acquired, and other possible scenarios were also explored. At one
point, even the MegaSquirt system got some attention, though, to my eternal credit, not much. Finally, I was faced with the following
conclusions:
1. Replacement injectors were a requirement.
2. Oil leaking into the crankcase had to be stopped, either by redesigning the “wet” unit or by switching to a re-calibrated “dry” unit.
3. It made sense to replace the fuel pumps with more modern units. Although I had managed to get consistent performance from the original
pumps by adding a small Fawcett pump to push fuel from the tank to the fuel pumps, everyone assured me that the pumps were problematic
in hot weather. By this time, I was willing to take any advice that was offered.
The new millennium had arrived.
These challenges were at least a proximate cause of the six year hiatus that passed before I finally returned to working on the car. Turns
out that all those folks—wonderful, bright and helpful folks—were right when they advised me to switch to carburetors if I planned to drive
the car. It was I who was the doofus, a hoople of the first order. A newbie through and through.
In 2007 I installed a set of original 42 DCOE Weber carburetors on a genuine Maserati manifold, and I promptly discovered that my engine
started easily, did not smoke, and despite lovely compression readings and plenty of spark, could not run more than 1.5 miles, the distance
around my community’s main road. (Memories of the fuel injected motor conking out at exactly the same place are currently being
suppressed, but that is another story for another day.) Suffice it to say that the carburetors put my car back on the road after decades of
hibernation, caused in part by the dilemma of the fuel injection. Switching to carburetors was the best thing I have done for my car. Period.
Still, whenever and wherever I drive my car, I find myself wondering about the fuel injection that beckons from its storage shelf. It is clean, it
is shiny, and it worked on my test bench. Best of all, it frightens the poo out of most mechanics.
Knowing what I now know, would I put the injection back on the car? Would I go for a (gasp!) modified system that would have the show
judges pointing and condemning? How can I resist? After all, the best Masers have injection.
Dave Cox
There are people who can explain how to make the Lucas mechanical fuel injection purr like a kitten, and there are people who are experts
at explaining why any sane person will immediately convert a fuel injected Maserati to carburetors. This is neither. It is a diary of “How I
Spent the First Two Years with My Maserati and Lived to Tell the Tale.”
Like most newbies, when I dragged home my 3500 GTI I set about finding out what to do with it. The attraction of the car, for me, was, oddly
enough, the fuel injection, which was the very thing that kept the car from running and drove the price down. Craven greed played a part—
“Ah hah! I know how to fix this beastie!”—and part was curiosity—“I wonder if I can fix this beastie?”—but most of all, I had visions of gliding
around town in an aluminum-bodied Maserati which would wow my friends, befuddle my critics, and be a babe magnet to all the pretty girls
that had, for some reason, decided that I was a middle-aged, pot-bellied grandpa. But there is no denying the fact that the fuel injection itself
was the major lure, and memories of having great and singular success with a Rochester fuel injection system back in the day (late 60’s)
gave me confidence that the only good Maser was one with fuel injection.
Most folks told me to pull the unit off, put it in the trunk, and enjoy driving the car with carburetors. I listened patiently to these folks, and
even feigned interest in what they were saying. Meanwhile I contacted experts, and even trekked to Michigan for an audience with the nice
folks at Kinsler to chat about technical matters. The result was that I became something of an expert on the system, so long as by “expert”
one refers to anyone who happens to have a service manual. The great thing about the service manual is that, unlike the books for the car
itself, the Lucas folk wrote theirs in English.
After draining what looked like chocolate mousse out of the fuel tank, and removing petrified chocolate mouse and coffee grounds from the
fuel filter, I tackled the heart of the matter, the dreaded “bombs”, the Lucas fuel pumps.
Strategically located directly next to the battery, and wound up with miles of cracked rubber fuel hose, these high pressure pumps are
notoriously unreliable, and replacements are not easy to find. For some reason many of these pumps seem to have been destroyed by
fire. Go figure. My pumps looked just fine but refused to work, so the first order of business was removing them from their hiding place.
For most folks, removing these things would be a piece of cake. A few bolts, a few fittings and, voilá, the pumps would be out. For me, just
inserting myself into the trunk far enough to work on the things required the sort of effort that has earned many people awards for physical
endurance. Once inserted into the trunk area, I discovered to my dismay that for whatever reason, the selection of the correct wrench sizes
was nearly a deal breaker. Now I know enough to have both SAE and metric wrenches close at hand, but in those early days, it was my
naiveté that allowed me to assume that the Italians would stick to metric sizes. Huffing and puffing, blinded by sweat and chest pains, the
last thing a person wants is to find that the wrenches just don’t fit. Yikes. To this day I have folds and crease marks on my person that are
the direct result of stuffing myself into that trunk area and snagging my prodigious self on the unyielding trunk latch. Crikey.
Despite these challenges, the pumps finally succumbed to reason, and I began the task of disassembly. Fortunately, the chocolate mousse
had not made it past the large filters, yet the pumps had remained silent. A thorough cleaning and inspection revealed an impressively
robust device that, I later learned, was a clever combination of a windshield wiper motor, an aircraft-grade pump, and what looked like an oil
filter from an old Chevy. The combination led to the shape, and the shape led to the sobriquet “bomb”. Of course, there may be those who
would find a more literal etymology for the name, but there are always cynics around when Maseratis are being repaired.
In an unusual fit of reason, I tried a bit of electrical power to the pumps and, of course, they purred like kittens. Hmmm. A quick check of the
wiring in the trunk—again crawling into the pit of Hell—revealed that there was no electricity to be found. Considering the gasoline fumes,
this was probably a blessing.
At this point, a considerable dissertation on the safety circuit switch-- when the oil pressure goes down, electricity is cut off the to the fuel
pumps—could be inserted, but this story is too long as it is, and besides the whole wiring system is clearly shown in the wiring diagrams of
the owner’s manual. A few hours of study will reveal everything, and offer the added bonus of giving the student a good start on learning to
read Italian. Suffice it to say that once power was restored to the pumps, fuel flowed, but not before several more trips into the horrible
depths of that trunk, and, as an added bonus, the opportunity to get acquainted with the underside of the dashboard.
With a consistent supply of fuel at 100 lbs. of pressure, the fuel injection should work just fine. My car tended to smoke so much that I was
pretty sure there were no rings in the engine. There was so much smoke that mosquitoes several streets away were falling out of the sky
like rice at a wedding. The fact that the engine ran like poop was a factor, but one tends to overlook the dodgy throttle response when the
sun is being blocked out by blue clouds of smoke. There was a real danger of asphyxiation.
Days of diagnosis revealed that the smoke would come and go, but so did the fuel pressure. It should be said at this point that even the
most basic information about the engine was still MIA, which added to my reluctance to try to diagnose the fuel injection while it was on the
engine. Reluctantly, I took my neighbor’s advice and built a test bench. This was in 1999.
This opens the discussion to the pros and cons of listening to neighbors when working on a Maserati. In my defense, most of my neighbors
had long since taken to hiding indoors whenever I worked on any of my cars, so my reluctance to run off someone who was sympathetic to
me and enthusiastic about my Maserati should be understandable. Still, there is the matter of qualifications: He is an engineer and I am
not. True, he is an electrical engineer, and from the beginning wanted to install a MegaSquirt system, but having anyone in the garage was
preferable to going it alone. The result was a jim-dandy test bench, with a variable speed DC motor to run the fuel distributor, an old
refrigerator pump to pull a vacuum, and six glass baby food jars with rubber grommets in their lids to accept the injectors and to catch the
mineral spirits. Look out Kinsler, your days are numbered.
As it turned out, their days were numbered, at least as far as the Lucas system was concerned, but my efforts had nothing to do with that. I
did learn that each injector had its own style—one sprayed like a shower head, one like a partially plugged shower head; one sprayed like a
garden hose with a thumb over the end, and another like a pin-hole in a copper water line—and none sprayed the same way for long.
Money was spent on experts—“Golly, Mr. Cox, I have never seen injectors behave this way.”—and efforts were made to replace them.
Finally, we cut the end off one and found a likely culprit: A petrified o-ring. One kind fellow explained, voice full of pity, that metallurgy was
the culprit, and even if the o-rings were new, the softness of the seats would still cause problems. The obvious conclusion was that the
thirty-five-year-old injectors were probably worn out. The test bench was beginning to pay off with concrete proof of the obvious.
Rebuild-able injectors were available for the later units that used plastic fuel lines, but early units like mine used smaller fittings and jazzy
chrome-plated metal fuel lines. Aesthetic concerns like this just muddied up the problem, but the injection’s appearance should count for
something. At one point we fiddled around with Bosch mechanical injectors from a Rabbit, and concluded that various alternatives were
possible if one were willing to re-engineer the system. More test bench dividends.
Along the way, tests on the fuel distributor revealed that it was extremely well made, had a wide range of adjustment, and, apparently, would
enjoy a long, happy life even after some of the clearances were less than optimal, which is just what one wants on an airplane. Still, there
was the matter of all that fuel dribbling out of the unit and into the engine, and there was the matter of figuring out those funny little rollers.
We finally concluded that, baring severe changes, there was no reason the rollers would need much attention, but that still left the matter of
the fuel leaking into the cam area. Not good. It seems they do not start and stop airplane engines as often as we do with our grocery-
getters, and the folks at Lucas figured that any dribbling fuel would be of little concern on long flights. When the system was adapted to
automotive use, someone accepted this idea of using oil pressure to counteract the fuel pressure to keep the fuel in the fuel injection and
out of the crankcase. The fact that later model Maseratis used a “dry system” which relied on a seal rather than the differential between oil
pressure and fuel pressure speaks volumes about that original decision.
Fitting a later unit became a possibility, so a few of those systems were acquired, and other possible scenarios were also explored. At one
point, even the MegaSquirt system got some attention, though, to my eternal credit, not much. Finally, I was faced with the following
conclusions:
1. Replacement injectors were a requirement.
2. Oil leaking into the crankcase had to be stopped, either by redesigning the “wet” unit or by switching to a re-calibrated “dry” unit.
3. It made sense to replace the fuel pumps with more modern units. Although I had managed to get consistent performance from the original
pumps by adding a small Fawcett pump to push fuel from the tank to the fuel pumps, everyone assured me that the pumps were problematic
in hot weather. By this time, I was willing to take any advice that was offered.
The new millennium had arrived.
These challenges were at least a proximate cause of the six year hiatus that passed before I finally returned to working on the car. Turns
out that all those folks—wonderful, bright and helpful folks—were right when they advised me to switch to carburetors if I planned to drive
the car. It was I who was the doofus, a hoople of the first order. A newbie through and through.
In 2007 I installed a set of original 42 DCOE Weber carburetors on a genuine Maserati manifold, and I promptly discovered that my engine
started easily, did not smoke, and despite lovely compression readings and plenty of spark, could not run more than 1.5 miles, the distance
around my community’s main road. (Memories of the fuel injected motor conking out at exactly the same place are currently being
suppressed, but that is another story for another day.) Suffice it to say that the carburetors put my car back on the road after decades of
hibernation, caused in part by the dilemma of the fuel injection. Switching to carburetors was the best thing I have done for my car. Period.
Still, whenever and wherever I drive my car, I find myself wondering about the fuel injection that beckons from its storage shelf. It is clean, it
is shiny, and it worked on my test bench. Best of all, it frightens the poo out of most mechanics.
Knowing what I now know, would I put the injection back on the car? Would I go for a (gasp!) modified system that would have the show
judges pointing and condemning? How can I resist? After all, the best Masers have injection.
The Tech section is open to members who have suggestions for other members which may be of help in the
repair of Maserati automobiles. We recommend that any repair be carried out under the supervision of a
qualified, licensed mechanic/technician.
repair of Maserati automobiles. We recommend that any repair be carried out under the supervision of a
qualified, licensed mechanic/technician.
Additional Tech Articles:
Tuning Your Weber Carbs Ivan Ruiz
Synchronizing Ghibli Carburetors Howard Kestenbaum
Leather Restoration Ivan Ruiz
Don't Leave Home without It Ivan Ruiz
Tuning Your Weber Carbs Ivan Ruiz
Synchronizing Ghibli Carburetors Howard Kestenbaum
Leather Restoration Ivan Ruiz
Don't Leave Home without It Ivan Ruiz
**For additional Technical articles, please see the bottom of this page
