1952-59 Ford EFI conversion

Trying to design a fuel injection system to run my built Y block in my 1956 Wagon, but suffering from*****yzing anxiety. Hopefully, those before me can add some clarity, and I can get this project on the road this summer. If I am mistaken on anything let me know, I can handle criticism,I'm a married man.
Return or Returnless? I've come to understand that the main problem with a returnless system is the tendency for fuel to "deadhead" and percolate at the regulator( usually mounted in the engine compartment) with resultant vapor lock in high heat conditions. Understandable. However, I am so far planning to use the Holley in tank returnless pump that has a built in regulator, that, in theory, doesnt send excess fuel to the unit to sit there. It just seems likely that a 7ft long return hose filled with gas would absorb more heat from engine bay/roadway radiation, and our summer ambient air flow will do little to cool anything, I'm guessing. I am willing to use high heat shield fabric/coating on the exposed portion of the tank itself, and on lines running forward, and into the engine bay, so I'm hopeful that will keep the fuel cool enough. Curious what influenced others decision, as most installs I've found has used a return.

 

I'm running factory fuel injection for an '88 T-Bird in the roadster. It's a return system. Never had an issue.
And, I'll be running factory fuel injection in the '54 from a '93 Mustang, also a return system. Ford put millions into R&D in designing their fuel systems and the return lines are always the length of the cars. Not sure of the merits of returnless F.I. but I don't see anything wrong with a return system. Works for me!

 

I have heard of guys using a fuel filter from a Vette that has a connection for a return line. I have a return system in my 55 but after failing to ever get the FITech system tolerable I switched to a carb. That says something about my skill level huh.

 

I have heard of several people ditching the aftermarket FI in favor of returning to the carburetor. I have a fiend who just had one professionally installed and is having problems with it, too. Do any of them work well?

 

I worked for Chrysler (when it WAS Chrysler and beyond) and did technician training for 25 years. We traveled to the Detroit area for our training at least a couple times a year and had a chance to talk to the people that designed the fuel systems used on the new cars. In the early 90's they used a return system that had a regulator on the fuel rail (on the engine) that would dump the excess pressure back to the tank. In those systems fuel would absorb a lot of heat from the top of the engine and get returned to the tank. If the tank was low on fuel and the ambient air temp was high (as well as the road surface) the fuel in the tank could reach a fairly high temperature. The fuel in the tank was used to cool and lubricate the pump, so when it got too hot it could cause fuel pump issues. Once the fuel was past the pump and at high pressure (48psi) it wouldn't be prone to turning to vapor due to the pressure much like your coolant having a higher boiling point in a pressurized radiator. In the late 90's they went to a returnless system that mounted the pressure regulator at the top of the tank or on the pump, got rid of the long return line, and raised the pressure to 58psi most of the fuel supply problems went away. The low pressure in the return line along with the heat soak created most problems we saw, so I would recommend returnless regulator mounted as close to the tank as possible. Jeep Grand Cherokee used a filter with the regulator inside the filter****embly and the return line came off this filter mounted as close to the tank as possible. The pump was inside the fuel tank, this might be a possible solution to the problem for some? I wonder how many problems in the aftermarket systems are created by fuel system plumbing and fuel overheating issues rather than the unit itself causing problems. I have heard good things about the Holley Sniper throttle body system. Sorry for writing a book!

 

From what I have seem on a lot of forums the Holley gets a fair amount of praise the Fi-Tech have left a lot unhappy with bugs to work out.

 

This is exactly the problem I was referring to, and I learned that, as you say, some Manufacturers have gone to a returnless system of some design because of it so I wondered how. The Holley in tank unit has the regulator built into the pump, and returns fuel to the tank, so no fuel is exposed to heat except the outgoing. I would prefer not to have an external pump exposed to the elements here. The Holley Sniper is my choice n their line. Agreed that fuel overheating/system plumbing issues can be problematic. Thats why I detailed my thoughts on line/tank insulation.
I'm thinking that was just a chapter of your book, Thanks.

 

As others have mentioned, my research was generally unfavorable with Fi-Tech also, how was their tech support?I chose Holley for their pump design, among other reasons. Everything is critical in getting EFI (any brand) to run properly, max spark, grounds,clean fuel, from my understanding, (EFI neophyte, but learning). I did see a post somewhere that mentioned that Corvette filter, but never pursued that.

 

The Stig, in this social group has a Fi-Tech (I think) on his 56 Fairlane. He spoke highly of it and the tech support he received. Maybe he will chime in? If the Holley pump is in the tank and the regulator is on the pump you are correct that there would not be any return line so that should be the best possible system as far as fuel delivery.

 

If it works well, that's all that matters. If I was swapping in a factory engine with all the existing system, I wouldn't break the design, but I'm building from scratch, and I would like to eliminate one more line. Following and enjoying your build, waiting to see more.

 

I was planning on doing exactly the same thing for the y block in my wagon. How "built" is your y block? One thing I found out from personal experience through a friend and from ALOT of research on the net is cam size makes a big difference. My engine only makes 10 hg at idle and at cruising speed. Not enough vacuum to get a proper vacuum signal for the throttle body injection to work properly. From what I have seen in my friends car it only ran decent when wide open. Might be something to inquire about with Holleys technical department. Also if your looking to pick up performance a well tuned carb will produce more hp.

 

I have 5.0 H.O. in my 33 Coupe with a return line. No big deal to put in a return line. Have run it since 80’s with no issues. Grafted a Mustang fuel pump to my gas tank. Recently removed the stock computer system and put in a Holley Terminator FI System. Good results and car runs great.

 

You are correct that engine Vacuum is the main input along with RPM that the most of the aftermarket systems use to calculate fueling to the engine. Using Ford as an example 80's Mustangs had two different systems, early cars had a "speed density" system and later cars had "mass airflow" system. The big difference was how the system measured how much air was flowing into the engine so it could calculate how much fuel to mix with the air. Mass air cars could be modified (cams, heads) more than speed density. Speed density systems use a manifold pressure sensor that looks at manifold vacuum (pressure) to determine how much load is on the engine, low vacuum = open throttle, high vacuum = closed throttle. Then it looks at engine RPM and does a calculation to decide how long to open the injector to spray fuel, this is why the fuel pressure is important. If the pressure falls low then less fuel will be sprayed during that injector "on time" and the engine will be lean. Here is where it gets weird, the self learning systems have an oxygen sensor downstream of the engine to see what happened during the last injection cycle. If the sensor sees excess oxygen it****umes that there wasn't enough fuel to burn all the oxygen so it adds more fuel to the calculation next time. There is more to it but that is the basic calculation tree, look at RPM, vacuum, add fuel based on the program chart (cell) then look at the oxygen sensor to see if the calculation is correct. If not modify the chart (add or subtract fuel) for the next time it sees that same RPM and Vacuum then again check the output (oxygen) till it gets the results it needs. NOW, engines with big cams and low vacuum have a particular problem and that is what is called overlap or the intake and exhaust will be open at the same time and this is what is causing low vacuum. The problem is the EFI computer sees this low vacuum and****umes that the engine needs more fuel (low vacuum = high load) so it adds more fuel. The oxygen sensor ONLY sees oxygen, it does not and cannot see fuel but the missfire caused by the excess fuel causes the oxygen sensor to see oxygen (it didn't burn) and enrich the mixture MORE when it is already rich. This is why on new cars the check engine light will come on when there is a missfire, the system will start adding fuel which can and will burn down the catalyst so missfire must be addressed quickly. Again I have written a book and there is more to this story but I tried to hit the basics why vacuum and lumpy cams are very hard to tune into a FI system unless it is a custom tune written by someone that knows what they are doing. Expecting a "self learn" system to be able to address all engines modifications is a***** shoot in my opinion. Just my LONG two cents.

 

I like what you did with your air filter! Where's the MAF?

 

Thanks. No MAF. Using Holley Terminator X Injection System which eliminates the MAF. After installing I had it Dyno Tuned and wow, what a difference!

 

There you go! Good computer, custom tune, amazing results!

 

This issue may be what ends this project, I am looking at that, plus the issue of mounting the in tank pump in the
wagon, because of the spare tire well. Not looking for more HP. Since I hope this build to be a long distance cruiser, and I'm now at Zero sea level, I don't want to adjust for altitude changes, plus reliability, starting ease. This was planned for the future, right now I just want to get on the road with carb, but EFI is a big, expensive modification and needs to be well thought out if a custom application. Rebuilding the stock brake system(dual master of course) and hoping I wont need a booster. So far to go.

 

What seems long to me is the 3 months I've been talking to EFI techs that never put the whole "scenario" out like that, like cause and effect. Thanks for doing that. Even if this never happens the education is invaluable.

 

There is even more to the FI than I put in my explanation, coolant temp, air temp, throttle position sensors, then the good systems will control timing curves. A carburetor running with that low of vacuum (10in hg at cruise) will also need careful tuning to run right and will be off with altitude changes (can't compensate) while a good fuel injection system will compensate for changes in altitude, air temp, air density.... each system has it's advantages and drawbacks! Like everything else in life pick what you can live with. I am pushing 70 now and have gave up on the really lumpy low vacuum cams and have gone to some moderation in cam choice for drivability and tuning ease. If I have about enough power to get in trouble and a good V8 sound that's enough for me!

 

“I am pushing 70 now and have gave up on the really lumpy low vacuum cams and have gone to some moderation in cam choice for drivability and tuning ease. If I have about enough power to get in trouble and a good V8 sound that's enough for me!”

I agree. I’m pushing 81 and long ago gave up the lumpy cams in all of my cars. A pleasure to drive, smooth runners with lots of power, auto trans, power brakes, ac, EPS and most importantly, reliability.

 

Well, I'm 75, and looking for the same, a strong enough motor for highway cruising, reliable, and stayed with the y block partially for its unique sound. When I get feeling like this project will outlast me, I fire it up sans mufflers, and I'm renewed. Discussed my needs at length with my engine builder and let him build it, but wasn't contemplating EFI at the time. Getting true 300 HP from a 292 requires much modification. Attached is my cam spec sheet. Valve lift was calculated with rocker ratio of 1.5, but I am running Harland/Sharpe 1.6 roller rockers.
Spent several late nights delving into all the nuances of EFI you mention, plus. Speed/density systems, MAP, MAV., N'Alpha, proper O2 sensor placement, injector sizing on and on. It seems that if you run a speed/density system, you can reprogram the ECU( I think) get to run in N'Alpha mode for the low end , changing settings to work with a "lumpy" cam, and reverting to original program after certain RPM. Do I have that right, anyone?

 

A lot depends on the ECU you are using and how much tuning capability is available with the sensors being used. An example would be a car using boost (turbo or supercharged) will need a MAP sensor that reads the positive pressure as well as low pressure (vacuum) based on the amount of boost being used. From that a tuning program can be created that will allow the correct amount of fuel to be injected for the air being forced into the engine. Most times I have seen a program that ignores the O2 sensor (I think what you call N'Alpha) only occurs at boost conditions when you want a rich condition to prevent meltdown of pistons. Most modern ECU's can be programed to do this at any point desired in the fuel map (map being the tuning chart used by the programmer). I am very confused at this point as to why the vacuum in your 292 is so low at cruise RPM, the cam card does not seem to me to be so radical as to only have 10" hg at cruise let alone idle. Lobe center at 110 degrees even with the duration shown should not be that radical. (NOTE: I have not built a y block like this). I have built small block Fords (289's) with similar cam specs and pulled more vacuum, like 15" at cruise. Most cams for fuel injection like more lobe separation, like around 113 degrees for the self tuning systems. FiTech claims their system will work with idle vacuum of 10" however this is on the very ragged edge of needing a custom tune. CRUISE vacuum of 10" seems really low to me with your cam unless you are trying to pull a really high gear ratio at cruise. I would contact John Mummert or Tim McMaster and ask for advice as I believe they have used this cam in several builds and may have some dyno results on vacuum on hand. There are several dyno charts on line from 292 y blocks they have built but don't think the vacuum numbers are on the charts. You could also call ISKY and talk to their tech****ist line and see if these numbers seem all right to them. So again I have talked too much but yes you can get a custom tune to do pretty much anything you want with a decent quality ECM.

 

My wife had a ‘67 390GTA Mustang that I built for her. I put a MSD Atomic FI Kit on it along with a new Tanks Inc. tank and Aeromotive in tank FI pump system. I set it up to run “return-less” as per MSD’s instructions. They do the return-less by pulsing the fuel pump. Had both starting and idling issues. Switched it over to a return system and the problems went away. Also I don’t know if it’s a common problem, but something you might want to be aware of is thermal shock to your in tank pump. We’d gone to a car show on a 107* day, stopped and filled up with gas to come home. Made it about 5 miles and the car quit just like you’d shut the key off. Long Story Short, had a friend tow the car home, checked everything. Had power and ground clear to the pump, no pump. Contacted Aeromotive and sent the pump in to them. They sent me a new replacement unit and sited that the failed unit had failed due to “thermal shock” from the high ambient temperature and the cool temperature of the gas...

 

My 54 Merc with 92 EFI, hope to have it running in the near future

 

..Thanks for the input. My dyno sheet starts at 3000 Rpm, and I haven't hooked a vacumn guage to the manifold to get an idle vaccumn. I don't remember claiming only 10"hg. Went and got fresh gas to fire it up today and will check hopefully tomorrow and repost. I've been waiting to get idle vacumn before talking with Holley and Ted Eaton, my builder. Engine build/trans build up (4r70W)/rear gearing were designed together to be a good daily driver/ long trip cruiser. But I hadn't considered EFI at the time. I believe my cam will be workable with the the right tune. Never asked for a race engine, built a stroker because all I had good out of the 312 block was the crank--whatcha gonna do?
I do know that I will be using the Holley Sniper, the rest I need to discuss with them. My understanding of "N-Alpha" is that it takes its reading from the TPS at low rpm and the "tune" reverts to (MAP or MAF-forgot right now)at set rpm on. I dont think I want the ECU to control the timing, but if my current 57- up Ford distributor/ Petronix II, isnt up to the task, that could change. I have a trans controller, so EFI wiring should be pretty basic.

 

Thanks, never heard of thermal shock. Great! now I've got to engineer a pre- fuel heater? Just kidding, but I will mention this to Holley before purchase. Real life experiences are most valuable, thanks.

 

Nice looking project, hope you get on the road soon. The best part of swapping in a whole later system is that you can go to the dealership to get diagnosis.

 

"swapping in a whole later system" is really difficult to do unless you go aftermarket harness such as Ron Francis, then you're not really using the "whole system". A '57 Ford forum member years ago pulled the entire wing harness from the donor '94 Lincoln Mark Viii when he did his 4.6 conversion. It took him 2 months just to separate out the wires on the harness, and he was a retired Ford electronics technician.
A major consideration..........not much can be done to modify computers on the OBD1 systems, at least in comparison to OBD2. Trying to find someone who can is almost impossible. Most performance shops won't/can't touch an OBD1 system. First year for OBD2 was 1996 (for Ford). Might want to consider that when choosing a "later system" BTW, aftermarket harnesses include a code reader connection. It's nice to be able to go to a shop and be able to plug in, doesn't have to be a dealer. OBD1 digital readout code readers are difficult to find for a reasonable price, but I found one at the tri-state swap meet in Denver. $100-150 ish? can't remember.

 

Sorry, my mistake, I confused your post with a follow up post from 56 longroof where he said he had 10" hg at idle and cruise. Got my wagons mixed up! Ted Eaton is an expert for sure and if you are getting advise from him I would ignore most of what is noise in the background, he built the engine he should know what it should be able to do.

 

Looks like some good deals this month if you are looking at the Holleys. https://www.holley.com/products/clearance_parts/