This winter's project was to join the 400 EFI club, so thought I would share some of the details. Maybe it will give somebody an idea.
Basic concept of the setup:
- Megasquirt MS3-Pro
- Edelbrock 2171 intake w/ injector bungs added
- Edelbrock 4 barrel throttle body w/ PWM IAC
- 5.0L Explorer fuel rail & 6.2L injectors (33 lb)
- 7.5L TFI distributor (remote style)
- 7.5L Mass Air Filter
- 80mm Lightning MAF
- 1985 7.5L tank fuel pump senders
- LC-1 wideband & other standard Ford sensors
Intake up first:
Using a new intake I made a rig to hold the intake in a fixed position so I could drill the intake bung holes with a drill press. Ford seems to have tilted the injectors over 22.5 degrees side to side on 5.0L's but that wouldn't have left enough room at the center for the throttle body. So I compromised with a 15 degree angle to have the best compromise of angling towards the back of the intake valve while keeping enough room for the throttle body. The drill press table was then angled 15 degrees to match the angle that Ford used for the injector front to back tilt. I was able to find a good distance away from the flange that let me keep the vacuum ports (not too far inboard) and entering the port right at the top (not too far outboard).
With a fence on the table I was able to drill a hole, slide the intake to the next runner and drill the next. I had to go slow and it vibrated a bit more than I would have liked but it got done pretty quickly.
The holes turned out accurate enough but the bungs needed to be held in place due to them sliding too deep or not quite keeping in line. It was also a balance of the lower runners having the bung not too high and higher runners not too low. To make sure the welding shop didn't have to think about it I made up a way too complicated rig to hold them in line. The square tube was drilled with the same angle so it forced everything to the right spacing. Chunks of copper tubing were cut to set the depth, and then the nuts just kept things snug. (BTW they were parallel but the camera made them look not)
I don't have a TIG so a local shop welded it up for a surprisingly low price. All I had to do after they were done was knock down the extra bung material in the runners with a carbide bit.
I liked the 5.0L Explorer fuel rail setup so I had picked up a junkyard set. I changed the cross over tubing (with Aeroquip 4AN socketless) to compensate for the extra intake width.
Couldn't help mocking it up. I can even sneak the cruise control through it all.
I knew I wanted to run MAF so one day I wandered a junk yard for a couple hours and grabbed a few air filter assemblies that I thought may work. In the end one from a 96 F350 MAF 7.5L worked the best. It was narrow enough to sit between the battery and radiator with a simple bracket and had the same MAF bolt pattern as a Lightning. On from there was a duct and a TBI hat from a Dodge.
From the Diyautotune kit I received 8' of unterminated harness and so I went about adding in power wires, grounds, connectors, etc. Fuel injector subharnesses were made (not pictured so it looks a little too simple). There are many wires that I don't need so they were terminated at Delphi GT150 connectors so I can easily plug something into it in the future.
BTW even though its a TFI distributor I never used the actual TFI module. The ECU picks up the signal directly from the distributor sensor and then commands the MSD when to fire.
I mounted the ECU where the duraspark used to be and from there the harness runs across the top of the firewall and then down along the passenger side of the intake. A power wire from the battery gets everything power, and the vehicle duraspark connector triggers the relay with key on.
I figured out that fuel senders from a 1984-85 F350 7.5L were a great match as they had:
- same small fuel tank mounting hole size
- low pressure pump
- return line
- fuel level sender with the same resistance sweep
The rear sender was a direct swap other than the extra harness pin to power the pump. (Airtex E2089S)
The center tank was slightly more work but not too much. The flange hole on a 79 F150 is more on the side of the tank than an 85, so right above the sender card I bent the tubes to match my original. (Airtex E2091S) The filter sock now sits on the bottom of the tank and the float sits at the right spot for empty & full. (Before & after)
The in tank pumps only provide low pressure, so they connect to a switching valve and then on to a frame rail mounted high pressure pump (front tank not yet reinstalled).
The factory fuel line was used as the return and I ran a new supply line using socketless hose (6AN). Unfortunately the only fuel rail spring lock connectors I could find with a 3/8 barb & through hole was AN type so had to go that way but it looks nice (and expensive
). Other joints are all plastic quick connect type.
After final assembly we got it running without too much difficulty. I had a few settings wrong that took a little time to figure out but now its driveable and the tuning is ongoing. The only things left are to loom some of the remaining wiring, connect the kickdown lever, and see if I can get a progressive throttle pulley to make it less sensitive (hitting bumps demonstrates throttle response quite well and my inability to hold my foot still enough).
I'm still amazed how it can happily idle at 15:1 AFR and rev like a modern engine.