Fuel Injection on a 73

[kkkaiser]

I was watching  car show today,  and they putting a Fuel injection in a 69 rivera.. and saying how much nicer the milage would be and better this or that,,

i have asked this on the 63 forum, and thought i would throw it out for the 73 eldo... is there a benefit.. more so than just a regular carburetor, for say MPG, or starting or what ever they may be good for??  I'm  putting gthise questions in my possible things to do over the next two or so years, so just looking for some consensus on virtues or not,,

[The Tassie Devil(le)]

I also have been looking at putting my '72 Eldo on Fuel Injection, but ruled it out due to the cost of the overall fitting.

I have also looked at converting the vehicle to wholly run on LP Gas, gut ruled that out because of the problem with the size and shape of the container/s in the trunk, which had a restriction on the capacity of the trunk to carry baggage.

But, I have converted the car to running a Predator Carburettor, which in itself giver the instant throttle response of fuel injection, the fuel economy from the variable venturi, and the extra engine braking when taking the foot off the pedal.

Bruce.

[kkkaiser]

revised heading

[The Tassie Devil(le)]

I changed the initial heading for you.

Bruce.

[TJ Hopland]

I would not do it just hoping to gain mileage.   Just do the math.    Here is an example.   Say you can get it done for $2000 which would be pretty cheap and you go from 13 to 15 mpg which I would not guarantee.  Lets say you drive 5000 miles in a year which is high for a classic,   5000/13= 385 gallons.   5000/15= 333 gallons.     Lets say $2.50 a gallon   385-333= 52   52*2.5=  $130 savings per year in this case.   At those rates you are looking at a 15 year break even point.

I think I am going on almost 10 years between my 78 CDV and 73 Eldo.   Started out with a analog Holley Projection system on the 78 which was a daily driver and worked pretty well.  Moved it to the 73 which didn't work well.  The projection I think was optimized for a 350 so going to a 500 I think was kinda a stretch.  I ended up keeping the throttle body but running it with a Megasquirt ECU.    Megasquirt is a open source DIY ECU system.   It appears to have fallen off a little but back when I did it it was a fairly large fairly active community.   You often assembled the circuit boards yourself then had to configure the system yourself running software that other users wrote.  It was quite a process that forced you to learn a fair amount about EFI and tuning.

About the time I got it running pretty well work went from a fairly normal average out to 40 per week to more of a 70 thing so I barely had time to drive the car over several years plus had a major setback on my rebuilt engine that cost me time and money.   More recently I started to have some issues that I blamed on the system so I started to mess with the program.    After really screwing things up I realized my fuel pressure was high due to a restricted return line.  Got the line fixed but was never able to get the program quite right again and I didn't have a backup of the original.   Also had a hesitation backfire start up so I just kinda gave up.

Was reading about the new at the time $1000 self contained auto tuning systems and decided to just make the time and budget to do it.   Did it and it went fairly well but I still had the backfire which turned out to be a distributor issue so once again nothing wrong with my original system.     Replaced the distributor and went to timing control and things were looking up for a while but now I have a minor hesitation issue that I have some theories on but just have not had any time to look into. 

One of the biggest issues with aftermarket add on EFI is the fuel delivery.  There is good reasons that every factory EFI system since 1980 has had the fuel pump in the tank, it just works.   Besides just being in the tank the tanks or sending unit itself has baffles in it to help the pump stay in the fuel when the tank level is low.   This is difficult to DIY retrofit so you often end up with other options that have downsides and more potential issues.    EFI is popular enough on popular cars that you can buy new tanks with the baffles and pumps.    Mustang,  Cheville, Charger  no problem but Cadillac not so much.     

Would I do it again?  Probably.    Would I recommend it to others?   It really depends on your abilities and expectations. 

[kkkaiser]

you see,, all that back and forth,, the tinkering,, that is what i would hope to avoid,, its not a gas mileage thing for me,,, it a time thing,, i know they advertise greatness,, and i have read many reviews, particularly on installation on older cars.. 70s and 60s, and for most part, people seem pleased,,,now,  they are new, and long term reliability has not been assessed.  but I read your discussion and that is what scares me.. i want to learn how to maintain, but reading about backfire due to distributor, restricted fuel lines,,, at this stage,, I would NEVER be able to figure that out,, so i am looking at it from a simplification POV

[Eric DeVirgilis CLC# 8621]

On the great day of Judgement - as it always comes, sooner or later - when these altered machines get put up for sale, the owners will soon be treated to an education in Alterations 101 when either nobody wants the car, or be sold at a heavy discount if they do. Then we'll see how long the smiles last. 

Unless such economic considerations are of no concern nor are likely to become so - it should be left stock.

The car was born as a  1973 - it should be left as a 1973. The market values it most... as a 1973.

A 1973 Eldorado is not, nor will it ever be - a 2002 Eldorado with all goodness that 30 years of intervening technology, compliments of the the people at GM can who design and build cars for a living. 

If you want FI, buy one that was born that way.

[kkkaiser]

i would agree, but even still, whether stock or modified.,, but so much time is spent getting it to run better in a stock situation, and yet, we are constantly reminded that we will never get out the money we put in, so if there is a modification that would improve a time and function, its worth exploring,, and as far as designing engines,, we know that many many recalls have been issued over the years for seemingly simple things, often financially motivated, but that, in the end, affects function,  .. i would say people here have as much knowledge of engines as the engineers, maybe not designing, but certainly maintaining, but it has come with a lot of sore bleeding knuckles  fixing design flaws,, improving fuel lines and  in line pumps to combat vapor lock,,etc,, they are not stock, but they improve the drivability and function and reliability  that is the route i am researching, it may not be worth a hoot to make the change, but for my interest in the cars, i want to research the possibilities and get input from those who have other opinions..just part of the learning process for me.  what might work, and what may be just fluff in the market to extract my money,,

["Cadillac Kid" Greg Surfas 15364]

If it means anything to you, I too had thoughts of adding FI.  I began and collected a complete 76 FI system with new sensors, new TPS, had the intake powder coated, got the correct fuel pumps, FI HEI distributor, have a full factory wiring harness, etc.  That was about 15 years ago and all the parts are still sitting on the shelf.  I cannot justify going from  my properly jetted and set up Quadrajets to an FI system for the minuscule increase in mileage that might be possible (but not guaranteed, remember the amount of fuel used works out to about .48 pounds of fuel per horsepower hour. Don't use the HP don't need the fuel).
I went so far as to work out a scheme for multiport injection using the factory intake and basic system. So far the shelf is the best place for me.
Greg Surfas

PS anyone interested in a complete FI system might PM me.

[Eric DeVirgilis CLC# 8621]

If we were talking installing a newer radio - and it was done without hacking up the dash so that it could readily be returned to stock - I wouldn't ask questions. Changing to FI is a completely different level of surgery. There are no Service Manuals published for "Joe's FI conversion".   

Expertly tended, there's no reason the original setup should not perform as well as anything. In order to obtain any tangible fuel economy benefit, you'd need a 4 speed transmission with lock up torque converter before having a prayer of  making dent in consumption - the benefits of which would primarily be seen on the open highway only.

Pretty difficult to get around the physical laws of the amount of energy consumed moving 5,000 lbs around.

Previous poster well qualified for the task at hand, yet upon the shelf his FI system sits. That pretty much says it all. 

[TJ Hopland]

I have not done anything to the car you can't reverse someone wanted to.   If someone wanted to turn my car into a show car they would have a lot more time into replacing all the hose clamps and hoses back to correct than pulling off the EFI stuff.   We are not talking about welding in a Chev motor with hood scoop and tubed out for drag slicks.  I got the original carb on the shelf along with the original 8 track and AC parts I got with the car which was not a mint show car when I got it 20 years ago.   

When I sold my 78 I wanted to keep the EFI parts for my 73.    I think it took me about an hour to remove it and bolt the carb back on.  You could have more time into swapping radios.  The mechanical part with a throttle body system is pretty darn simple, its a carb with a wiring harness coming out of it.   Many of the new systems have the ECU built into the throttle body so you don't even have the hassle of running a big harness through the firewall and mounting the ECU inside anymore.   FiTech Go 400 or 600 and Holley Sniper are popular examples of such systems. 

My point with the backfire distributor and return line issue is EFI does not solve good old fashioned mechanical issues.   Both cases I mistakenly blamed the EFI system and tuning when the actual cause of the problems had nothing to do with EFI.   I would have had the same issues with a carb.    The fuel line was likely due to being 40 years old.   Distributor was an HEI.   If I had just put a new cap and rotor on I would have masked the problem till I got some miles on it and it got humid again.   

If you had a mustang or camaro were you can buy a 100% complete system matched to your engine either stock or crate performance I think you would have a pretty decent chance of a trouble free and good performing setup.  I think it would be as reliable as if it was stock.   For those cars you can also pretty much buy an complete factory drive line out of a newer model that bolts in too which could give you an edge because at that point you more or less have a factory designed and engineered system.     For those of us that don't have those cars we don't have those options and that is where you start adding variables that stack up to possible issues and more screwing around. 

[kkkaiser]

makes sense,, lots to think about,,,thanks for all the input,,

[TJ Hopland]

Ya.   Figured you would want to hear from someone with years of real world experience on a similar car.  I'm not saying I'm any kind of car or EFI expert so your mileage may vary so to speak.  I'm sure there are people with no skills that just bolt em on and it works perfect but for me it wasn't that way.   Overall its been good and its never left me stranded its just annoying sometimes and because I built it I get fixated on trying to fix it and make it perfect.    If it was a carb some of it I would just say its a carb so it is what it is.   Lots of EFI guys say they get fixated on trying to tune out every little thing which sometimes makes things worse.

If only we lived in TV Land where the cars never rust.   Bolts never get stuck or break.  Shop full of tools.   A new air filter gets you 30% more horsepower if its chrome.

[bcroe]

Good advice above.  If your car has issues, the first step is get them all
fixed.  Fuel injection is NOT a magic bullet that will cure any existing problems. 

If you are concerned about gas mileage, the last car to be driving is a 73 Eldo. 
I actually helped my mileage, by using a transmission with a switch pitch
converter.  This, coupled with a 2.41:1 axle ratio, and a very free flowing
exhaust.  For FWD the lowest ratio final drive is 2.73:1, but I put in a 65:57
reversed POWER DRIVE chain unit, that gave me an equivalent 2.40:1 overall
high gear.  good luck, Bruce Roe

[kkkaiser]

as i said earlier, it wasnt about mileage,, that is what the show stated,,,and while i wouldnt sneeze at an increase, my interest was in the potential of consistency and reliability with less maintenance,, if that was at all a possibility with these systems..thats all

[35-709]

"Previous poster well qualified for the task at hand, yet upon the shelf his FI system sits. That pretty much says it all.   " 

If Greg Surfas (and basically all other responders) advise (in a nutshell) don't do it, I would say the question has been well-answered.  To add my 2 cents --- don't do it.  You will be creating for yourself more problems and headaches than you will be solving.

[V63]

There have been great improvements with the 'slap on EFI' systems. Technology and price. There are also systems satisfying the requirements of big blocks of monster HP.

Having recent first hand experience installing EFI on a 57/365cid and 71/500cid (hi performance build).  I remain extremely satisfied with both vehicles performance. The transformation in smoothness and performance is nothing less than amazing. The systems will be fitted to 2 1974 472's next without ANY hesitation. The conversion can be done comfortably in a weekend.

I do recommend 'in tank' fuel pumps over rail. the rail pumps are annoyingly noisy, and life expectancy is reduced. They also make new fuel 'Reserve tanks' that a standard fuel mechanical pump fills the reserve tank ..and the EFI electric pump is mounted inside of it.  We did this on the 71/500cid that's in a 1941 coupe.

Better fuel management GREATLY reduces engine wear!

It would be hard for me to buy a carbie again.

[TJ Hopland]

Which systems(s) did you install?    Which 'reserve' tank?  And where were you able to mount it?   My first was a low pressure system which makes things a lot less complex.    My current I used a RobbMC surge tank.   Originally I had it mounted where I think it was catching too much heat from the radiator.   I recently moved some stuff and now have it behind the headlights.   Have not had a lot of drive time to see if it made a difference yet.   

[curly]

T

I do recommend 'in tank' fuel pumps over rail. the rail pumps are annoyingly noisy, and life expectancy is reduced. They also make new fuel 'Reserve tanks' that a standard fuel mechanical pump fills the reserve tank ..and the EFI electric pump is mounted inside of it.  We did this on the 71/500cid that's in a 1941 coupe.

Got any pictures or links to the Reserve tank?  Sounds like a good idea, I've been meaning to switch my Full Size Jeep to EFI, but I hear to many reports of fuel pump failure (frame mounted).

Thanks

[TJ Hopland]

The concept has been around for a long time but until more recently you had to build them yourself.   

FiTech is one option.  About $400.   Doesn't have the best reputation,  more miss than hit. 
http://fitechefi.com/products/40003/

Edelbrock makes one.   Looks to be about $600.   It doesn't appear to be widely popular, not tons of info out on the web on em.
http://www.jegs.com/i/Edelbrock/350/3605/10002/-1?&ref=paid&brand=Non-Brand&channel=Search&gclid=CJ3OveX96tQCFcm4wAod0iALOA

Both of those use a float which seems like an odd design choice and a source of possible problems.   Both say you need to run a 'vaopr' line back to the tank so its not like it saves you from running an extra line in some cases.   Basically the mechanical fuel pump feeds the tank and when it reaches the preset level the float shuts off the fuel just like the float in a carb.   In theory there is then just a vapor space at the top of the unit that gets vented back to the tank.    What seems to happen is for one reason or another you end up boiling the fuel which then kinda overflows into the vent line.   Problem is now you end up with fuel in that line so when things calm down the normal venting can't happen because the line is blocked with fuel. 

I'm running a RobbMc unit that doesn't use a float.   The canister just fills up and anything extra fuel or air just gets pushed back to the tank.  Another possible advantage of this setup is the constant flow may keep things a bit cooler.   Another bonus $300 for the 500hp model its cheaper than the rest.    http://www.robbmcperformance.com/products/powersurge.html


The concept of these is great but there are downsides.  Finding a cool location to mount it seems important and is easier said than done in some cases.  Very few people seem to have issues with the in tank systems if you can get one or make one work for your car.