Fuel injection return line

[ktwhite]

Ok, for those of you who have installed fuel injection, how did you plumb the return line into the tank(s). Also, where did you locate the pump. I am interested in putting one (Holley, Fitech) my Tiger. Any real world experience would be appreciated.

 

[woody6]

I installed the Holley Sniper last year with my resto-modded Tiger, and am quite happy with it. I had Renu coat my tanks, and they installed a return line in the top of the right hand tank, extending inside to near the bottom of the tank (to prevent aeration). The pre-filter and pump in the spare tire well, the post-filter in the location of the Tiger pump, hard lines forward to the bellhousing, then two separate stainless hardlines from the bellhousing to the front of the engine, up past the alternator, and back to the throttlebody.

The car starts cold on the turn of the key, and the idle settles down to 700 RPM within seconds. Throttle response is great hot or cold. The only issue I have had is an occasional stall when I come off the throttle at a stoplight, and I've been told by others that driving it is the key. There are also parameters I can tune to help this, but for now I'm letting the sytem 'learn'. Here's some pictures:

http://hermitagewood.com/tiger/index.php?blg=2020_0801_fuel

http://hermitagewood.com/tiger/index.php?blg=2020_1001_injection

http://hermitagewood.com/tiger/index.php?blg=2020_1101_injection

One thing about the Sniper setup is that the pump that comes with the kit is noisy. On modern cars, these pumps are usually in the tank where the noise is muffled, but that is tricky with the Sunbeam saddle tanks. I'll eventually upgrade to Holley's more quiet pump.

I'm gladly try to answer any questions that I can.

--Woody

 

[woody6]

Looking back at my photos, there's a few other details to the install:

• You will need a second coolant temperature sensor, I bought a pipe thread tap and installed it in the heater hose fitting
• You will have to add an O2 sensor, the Sniper kit comes with provisions to clamp a bung to the pipe, or you can have one welded in.
• The Holley Sniper unit can control spark timing. I used one of the Hyperspark distributors. If you buy one, be sure and get one already equipped for the camshaft you will run. I had to change the gear for my ford roller cam, and it would have been cheaper to get the right distributor up front.
• The Sniper tach wire worked perfectly with my new electronic tachometer, but I can't tell what it would take to work with an original tach
• The wiring looks complicated at first, but there are only about 4 or 5 to connect to the car (power, ground, ignition, fuel pump - not sure what else from memory). There are provisions for multiple types of ignition (like MSD), and for the Sniper to control other items (like electric fans).

 

[woody6]

 

[65beam]

I installed a FITECH unit on my 302 and had nothing but problems. Jegs took it back and I got a second unit. It was worse than the first one. The engine now is fitted with a carb. The FITECH control units are junk. Their folks on their tech line have no clue as far as figuring out the problems. We would talk to one person and call back later to find that person quit. This happened a couple times. Joel Griffin also had problems with the FITECH unit. Holley seems to get good reviews.

 

[Austin Healer]

I have a client who had the pump and the return line installed in the RH gas tank. Rmoveable with 6 Allen screws for servicing and filter changes. a boss was welded to the top of the tank, then the unit just drops into place

 

[woody6]

I have a client who had the pump and the return line installed in the RH gas tank. Rmoveable with 6 Allen screws for servicing and filter changes. a boss was welded to the top of the tank, then the unit just drops into place

I really like this, and several companies make the drop in units for retrofitting to older cars. But I think you would never want to get low on gas.

Funny story. I can remember running out of gas in the 80's and having the car on the right shoulder, which was also sloped to the right. I walked to a nearby gas station and came back with a gallon of gas. When poured into the filler on the right, went immediately to the left tank - where it still could not reach the center pickup. After wondering for a couple of minutes how many walking trips I might have to make to the gas station before the center feed fuel line would get fuel, I put the car in first gear and pulled it up onto the asphalt with the starter. The pump primed and I was on my way.

So with the pump in just one tank, I suspect the effective tank capacity might go down to 9-10 gallons. Below that, I'm guessing that fuel pressure would drop whenever the pickup got air instead of fuel.

Someone suggested putting the fuel pump in the tank balance tube, and adding some baffles at either end. It wouldn't be simple, but might be the best solution to keep the pump cool, fuel supply stead, and muffling pump noise.

 

[Austin Healer]

I really like this, and several companies make the drop in units for retrofitting to older cars. But I think you would never want to get low on gas.

Funny story. I can remember running out of gas in the 80's and having the car on the right shoulder, which was also sloped to the right. I walked to a nearby gas station and came back with a gallon of gas. When poured into the filler on the right, went immediately to the left tank - where it still could not reach the center pickup. After wondering for a couple of minutes how many walking trips I might have to make to the gas station before the center feed fuel line would get fuel, I put the car in first gear and pulled it up onto the asphalt with the starter. The pump primed and I was on my way.

So with the pump in just one tank, I suspect the effective tank capacity might go down to 9-10 gallons. Below that, I'm guessing that fuel pressure would drop whenever the pickup got air instead of fuel.

Someone suggested putting the fuel pump in the tank balance tube, and adding some baffles at either end. It wouldn't be simple, but might be the best solution to keep the pump cool, fuel supply stead, and muffling pump noise.

The displaced area from the fuel pump was no larger than 1 quart. The pick up is at the very bottom of the tank to prevent starvation, or cavitation.

 

[woody6]

The displaced area from the fuel pump was no larger than 1 quart. The pick up is at the very bottom of the tank to prevent starvation, or cavitation.

Sure. I wasn't worried about displacing volume, but rather all the gas moving to the center tube and left tank on an extended right hand turn (when down to the couple of gallons). But I do like that the install cools the pump and muffles the noise.

 

[0neoffive]

View attachment 14810

Nicely done .

 

[Austin Healer]

Sure. I wasn't worried about displacing volume, but rather all the gas moving to the center tube and left tank on an extended right hand turn (when down to the couple of gallons). But I do like that the install cools the pump and muffles the noise.

we never had any issue with it.

 

[ktwhite]

Thanks for all the help. It has been helpful.

 

[theo_s]

I ran a BossEFI for a number of years, but didn't come to a happy place with respect to tuning. Their mapping software was pretty quirky, and then the company got bought by Professional Products. I now run a carb but I still have all the EFI gear... Might put the throttle body back on with a different controller at some point when I have time to play with it.
I initially installed a cast aluminum replaceable-element primary filter in the spare tire well like Woody6, and plumbed the return line into it along with the fuel feed from the crossover pipe; then I also had the pump and high pressure pump in there. One thing is that if you have any leakage at all then the trunk will smell like fuel all the time.
I ended up going away from that setup and now have the primary filter, pump, and high pressure filter all mounted on a piece of 1/8 aluminum under the trunk, just behind the spare tire well. The return line tees in just ahead of the pump. Going forward, the return line ends up following pretty much where the original feed line went. The feed line runs more outboard, and it ends up going through the right front fender well to come out to the engine compartment about level with the front of the right cylinder head. Then the fuel line runs rearward past the carburetor inlets, and then to the pressure regulator mounted on the firewall, where it plumbs into the return line.