Electronic fuel injection conversion

I was really just pulling numbers to show that cost wise it’s an investment. Reliability? Convenience? Some performance improvement? More efficient?
I’ve weighed this on one of my Streetrods for several years. There simply isn’t a way to cost justify it. My rod will gradually appreciate in value as long as it remains in good shape. 4 sp OD and or port EFI probably will make little difference in value or saleability. For me the car is an incredible daily driver. I’ve already put 15k absolutely trouble free miles this year on it with a “quadrajunk” as we say. Mpg is no better that the original got 42 years ago.
Now my semi classic 94 Buick RoadMaster Wagon got 20-24 mpg some 5-600 pounds heavier and with 40 less hp, yet it could eat the el Camino’s lunch 0-60. However it’s now been in the shop off and on for 6 months with mysterious EFI issues that simply defy solutions. I sure would hate to see this in a boat. This car is all original with nothing but OEM parts used. it’s left my stranded twice in only 5k miles in two years. I have a laptop, software and connection cable dedicated to this car for deep scanning the computer.

Newer boats have EFI and I’m sure they are well thought out by factory engineers. As long as they are operated correctly they are probably very good. But these things age and with that comes a host of issues. Water and corrosion being a couple of them. More so in boats than cars. My boat gets a daily bath in condensation in the summer. I’ve already had water in the fuel tank even using non oxy premium from the fuel dock. I don’t know how many fuel/water separators I’ve gone through. I buy a dozen at a time. I’ve pumped the tank
Too.

So should you go through with this be sure you understand the EFI system and have at least a scanner capable of reading codes.

I looked back on the previous posts (please forgive spelling, I do check but it self corrects...sometimes )
You noted looking at different systems. I favor port injection as I think you can get more even fuel distribution as you don’t have to deal with wet flow in the manifold. A couple mfg sell port EFI. They generally run about $1800 but do require a high pressure fuel pump. They usually have some kind of mini fuel tank that your motor’s standard fuel pump supplies, regulated by a float. Then within this is the EFI high pressure pump. I like the Edelbrock Pro Flo 4 system. They use OEM parts so they are relatively easy to service. They have a forum on their site.

https://www.edelbrock.com/pro-flo-4-efi-system-for-1986-earlier-small-block-chevy-engines-35760.html

https://forums.edelbrock.com/forum/pro-flo-efi/pro-flo-4
 
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Newer boats have EFI and I’m sure they are well thought out by factory engineers. As long as they are operated correctly they are probably very good

Except nobody told the enginer that it has to work when water, salt or fresh get into the tank
 
Well I did the swap to the Holley spread bore kits on my 454's and happy I did. The quadrajets were leaking and required too much cranking to fill the float bowls. First plan was to rebuild them then carry on but decided to jump in and do the conversion. I set up the engine mounted fuel pumps to supply to the EFI fuel pumps added the O2 sensors at the riser and did some fabrication for the throttle mounts. The engines now start like a modern car and the handheld monitors tell me exactly what each engine is doing. And now more fuel smell at shutdown. Not a small project but worth it for me.
 
Bread box do you have any fuel consumption data to share? If so how does it compare to the before #s?
 
I did not record consumption before and have only done one longer trip on Lake Ontario from Port Credit to Wilson and back. Default AFR is 13.5:1 at a cruise of 2500 so we used more fuel than I think is necessary. I plan to change my target AFR to 14 or the low 14's as I develop confidence. Changing fuel ratio is dead easy on the handheld touchscreen.
 
Thanks to all , I have been slow in responding. Too busy with family events, vacations and weddings, etc. Then the holidays, barely managed to find time to close up boat. Now with beginning of a new year, I plan on getting back to my marine pursuits. The replies have made me rethink just what I will do. I will definitely ensure the engines are tuned correctly. Then test how well everything operates, Thanks to Playdate. I may decide to do the conversion later , budget dependent. Many of the upgrades and improvements I see on this site that many have done seem very interesting. Again thanks to all. I am very appreciative of the info everyone gave.
 
I have a pair of Q Jets for sale.
There is a reason the entire world has gone away from carbs. Fuel economy is part of it for sure but I think a bigger consideration is how much longer engines last now than when carbs were used. Regardless I get it and if you come back to the project I would be happy to help with what I learned as I took it on.
Cheers,
Dave
IMG_5512.JPG
 
Breadbox, looking to do a similar conversion on my twin 3.0’s have been looking at the Holley Sniper EFI kits. Did you use the supplied O2 sensor or something different? Any issues you had with the conversion?
Thanks, Chris
 
Hi Chris, I used the O2 sensors and some plates i found on Amazon or eBay that sandwiched in the risers. So that meant longer bolts and fresh gaskets. One of the O2 sensors failed early on and as the install was really fresh I spent a fair bit of time trying to figure out what I did wrong. New sensor and all good, had I had a few more hours on the set up I would not have assumed it was my error and the fix would have been far more quick. You need to really plan the swap.
-Fuel pump and filters, i used the engine mounted pumps to fill and recirculate fuel into one of these, 2 of these and back to the tanks https://www.summitracing.com/parts/...Qk6WPv7eOGBGcDKkg3N__-MlobyX9tZ4aAvmdEALw_wcB all with marine rated fittings and hose. Not difficult but time consuming.
-the other important thing is good solid power and ground also easy and makes everything else work better like alternators and instruments.

I really disliked the smell of fuel in the bilge and while running, that is all gone.
And the long cranking to fill the carbs always made me feel like I was killing the starters, also gone.
A few other benefits are accurate tachometers and gauges.

Truth is there is no real solid justification.
Regardless very happy I made the swap,
Dave
 
Thanks for the quick reply!
Mine runs pretty good now (as long as i start the day before i head to the lake) with the exception of having to crank the hell out of it after I’ve ran for awhile and then shut her down. I also get very nervous of any sort of fuel smell in the bilge.

Biggest concern was the O2 sensors in a wet environment.

Did you have any issues with stock spark arrestors mounting to top of new throttle body?
Was there enough length in wire to run the ECU monitors up to the Helm?
Thanks!
Chris
 
I used K&N spark arrestors because the original units looked so restrictive, pretty sure originals would have fit just fine as the unit basically is a Quadrajet in dimension and mounting. O2 sensors live hanging on the bottom of cars driving in the rain and snow which is more harsh than an engine room in a Sea Ray.
Yes I added length to the wires for the monitors. Grabbed some computer wire from an electronics place and was very careful with my soldering and routing, all worked no issues. Before I did it I asked the Holley tech guys if it would work and they had no knowledge. I added enough to go from the engines to the helm which more than doubled the original length.
Cheers,
Dave
 
Sounds great! I’d love to see any photos if you have them!
Emmett281@gmail.com

looking forward to getting mine converted!
 
Hi, I am thinking over doing the conversion from Carbs to Fitech or Holley sniper throttle bodies too. What are your sailing experiences with that conversion so far?
Thanks, Gerhard

Bread Box said:
I used K&N spark arrestors because the original units looked so restrictive, pretty sure originals would have fit just fine as the unit basically is a Quadrajet in dimension and mounting. O2 sensors live hanging on the bottom of cars driving in the rain and snow which is more harsh than an engine room in a Sea Ray.
Yes I added length to the wires for the monitors. Grabbed some computer wire from an electronics place and was very careful with my soldering and routing, all worked no issues. Before I did it I asked the Holley tech guys if it would work and they had no knowledge. I added enough to go from the engines to the helm which more than doubled the original length.
Cheers,
Dave
Click to expand...
 
What can I say.
Bigger job than expected & very happy I took it on. I also did a few things twice because I didn't chose the best distributors are the beginning.
Along the way I started working with Chris at https://www.efisystempro.com/
He supplied some the parts I have used and even gave me a full timing map to make everything run as it should.
At the beginning I when with HEI mechanical advance distributors and that was a mistake, now that I am running the full Holley kit life is great. The old girl starts and runs like a modern car.
Fuel was straight forward as I had a fitting on the top of my tanks for the return.
https://www.holley.com/products/fuel_systems/fuel_injection/sniper_efi/sniper_4bbl_tbi_kits/
https://www.holley.com/products/fuel_systems/fuel_injection/sniper_efi/hyperspark_ignition/
The fuel pumps I used are no long available and have been replaced with this
https://fitechefi.com/product/force-fuel-system/
You can likely get everything from Chris.
I also went with the Holley digital dash which you can set up in many configurations.
IMG_7304.JPG


this is at idle and it's easy to see the starboard engine is still in warm up, coolant 146 vs 149 and AFR 12.5 vs 14.2.
fuel flow both at 9 lbs / hour so you would need more decimal places to see the difference between the two AFR's at idle. Underway it is dead easy to sync the engines and come up with a cruise speed that is efficient.
Also in retrospect I think I would have gone with square bore and an adapter plate rather than the Quadrajet spread bore primarily as Holley does not support the Quadrajet as well as the square bore. Different software and firmware.
Happy to answer any questions,
Dave

just noticed on the small handheld units you can see the fuel flow difference more accurately
 
Thanks Dave for your reply.
Unfortunately my boat lies 450 km away from me in Croatia. I will go there next week to do some work on the interior. So I can check the tanks for fittings for the return line. Do you use two force fuel systems with separate return in each tank? Why not just inline high pressure pumps?
Whats wrong with the original ignition as it is electronic anyway?
They say the electronic is self-learning. Is it easy to set up?
Did you notice better fuel economy?
Did you have any issues, failures etc?
Sorry for lots of questions. I want also to figure out if I should better put the work into improving/refit my carbs or go for a simple EFI.
Gerhard
 
Yes two separate fuel systems so that both engines are independent of each other.
Original ignition might have been OK and perhaps I should have left it alone.
The self learning is for fuel mixture and dead easy to set up. Ignition timing is not self learning.
The boat simply works better, I did not do a study and believe that if you plan to save enough on fuel to pay for the conversion you will be disappointed.
I had one of the Holley units fail, they replaced it under warrantee.
The thing I really enjoy is jumping on the boat and simply starting the engines on only a few seconds cranking.
And no fuel smell ever on the boat, with the carbs the boat smelled of gas after shutdown.
Dave
 
Nice - What did you do to meet the explosion proof requirement for electrical in a gasoline boat's engine room?
 
there are no exposed electrical components added in the system.
the explosion proofed alternator and distributor is sealed for marine use.
 
How about the FI things like IAM, TPS, and ECM?
If they are certified "hermetically sealed", "Intrinsically Safe", or rated for marine engine room installation per ABYC you will be OK.
 
from the Holley specs,
  • Certified to ISO 8846, SAE J1171 & United States Coast Guard Requirements for Ignition Protection & Fire Resistance. Making Sniper EFI the perfect choice for carburetor to marine fuel injection conversions!
 
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