Install thread- Holley EFI Sniper on '72 402 big block

[Ekliptix]

Part 1 Video https://youtu.be/ZOTmKqEPsHo

Moving the truck into the shop


Old vs New



On the engine. Vacuum and throttle/trans cable connected.


3/4" hole drilled for O2 sensor. It's 10+ degrees above horizontal and near the collector.


Derp. Included 2.5" exhaust clamps for O2 sensor mounting don't fit my 3" exhaust. I'll need to go buy some 3" clamps:


Draining some coolant to install the new temp sensor


Temp sensor install location. May need to relocate it as I've read the reading back there can be too low.



To be continued!

[Skrilla]

God I love your truck, soo nice

[SKR]

I'll be following along, I want to do this to my truck too.

[Ca_Silvia13]

Very interested in how you end up running the fuel. It's the #1 thing holding my back on swapping the 455

[Ekliptix]

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Very interested in how you end up running the fuel. It's the #1 thing holding my back on swapping the 455

For the fuel source side (tank to elec fuel pump to throttle body) it should be straight forward.
For the return (throttle body to tank) I have a place near the tank where I plan to add a simple T fitting to a rubber hose (shown in video), but I have not yet figured out a hole in the cab where I want to run the return hose.

[Sentry]

Boom.
https://www.amazon.ca/Fuel-Diesel-Ga.../dp/B01F4CA0FS

Thank me later.

[Ekliptix]

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Boom.
https://www.amazon.ca/Fuel-Diesel-Ga.../dp/B01F4CA0FS
Thank me later.

I don't need to cut my tank to do this install, if I'm understanding the purpose of that thing. If I'm missing the point can you explain?

[Sentry]

It's a quick easy sump, if you want to sump the tank instead of using 45 year old lines.

[Ca_Silvia13]

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For the fuel source side (tank to elec fuel pump to throttle body) it should be straight forward.
For the return (throttle body to tank) I have a place near the tank where I plan to add a simple T fitting to a rubber hose (shown in video), but I have not yet figured out a hole in the cab where I want to run the return hose.

I didn't see the inline pump previously. Looks like a very complete kit, would you agree?

[Ekliptix]

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I didn't see the inline pump previously. Looks like a very complete kit, would you agree?

It sure is. So far, the only thing lacking is the exhaust clamps for the O2 sensor being suited for 2.5" dia exhaust, while I have 3". I bought the optional fuel kit with the EFI system. If I was going more hardcore, I'd get a new rear fuel tank with a build in electric fuel pump. However, this kit has the in-line elec fuel pump, hose, filters, fittings, etc.

[90_Shelby]

Is the system strictly for fuel delivery or can it control timing as well?

[Ekliptix]

I don't believe to, but this part can be connected to the Sniper EFI computer to control timing: https://www.holley.com/products/igni.../parts/565-100
It's on my 'later' list of things to add.

[CUG]

Looks good.

[carson blocks]

Nice project. If you're switching to fuel injection, have you considered doing the tank swap to a frame mounted tank? Keeps the gas and associated smell out of the cab, bonus points for safety if you're in to that sort of thing, and clears up room behind the seat for subwoofers, gun racks, whatever floats your boat. They make nice clean tanks for those that sit between the rear frame rails, and are already set up for FI.

[Ekliptix]

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Nice project. If you're switching to fuel injection, have you considered doing the tank swap to a frame mounted tank? Keeps the gas and associated smell out of the cab, bonus points for safety if you're in to that sort of thing, and clears up room behind the seat for subwoofers, gun racks, whatever floats your boat. They make nice clean tanks for those that sit between the rear frame rails, and are already set up for FI.

I don't have any issue with the factory fuel tank in the cab. I've never smelled gas. If I were starting from the frame up, I'd put a rear fuel tank in. I the case of what I'm doing here, that's too big of a pain in the ass and cost to bother with.

[Ekliptix]

Got the fuel tank drained in to jerry cans.
Removed the mech fuel pump.
Assembled the elec fuel pump and filters.

Found a factory return line I intend to use. Need to get a fitting to step down from the 3/8" fuel hose to the 5/16" steel return line going into the fuel tank.

I intend to keep the 2 3/8" hoses (green and red below) next to each other, along the frame rail before running them up the firewall above the transmission, around the distributor into the EFI unit. I'd use the factory hard lines along the frame except they terminate way at the front by the radiator. The headers will be approx 3" away from the fuel line at the nearest point. I suspect this is OK for temps, but I'll look into something to wrap parts of the fuel hose with to protect it from heat as an extra step: https://www.amazon.ca/Heatshield-Pro...70_&dpSrc=srch

Here's the plan:


High flow mech fuel pump vs electric fuel pump.

[carson blocks]

Mounting the fuel pump on the frame under the cab?

[Ekliptix]

Correct. Near the stock fuel hard lines.

[carson blocks]

Nice, just wanted to make sure it wasn't going in the cab with the tank, both for noise and safety.

[Ekliptix]

Part 2: https://youtu.be/hIClWrLBrBA

Got the fuel system installed.

Removed the mechanical pump and used the included plate to cover the hole. The original bolts were too long for the plate, so I had to find some shorter bolts.

The electric fuel pump is mounted along the frame using some existing holes (lucky).




I ordered some of these off amazon.


And after a bunch of looking found this 3/8" to 1/4" step down to connect to the factory return steel line into the stock tank. From the EFI unit in the engine bay, the 3/8" rubber return hose goes down the firewall, along the frame, through 2 of the rubber retainer clamps, into the 3/8" to 1/4" step down fitting, into a new 1/4" rubber hose, into the factory 1/4" steel return hose which goes into the cab and tank.


I heat tape wrapped some of the fuel line and post pump filter just as a precaution, and it looks cool.


Also got the 3" exhaust clamps from amazon so O2 sensor is installed.


- - - Updated - - -

Made some wiring progress tonight.


This is an optional 10 pin connector. Most of the wires are for nitrous, etc, so I cut and heat shrinked most of them. I only need the brown wire remaining to send a signal to my tach.


Started getting some things tucked away. I need to buy some black wire loom to cover those 3 wires at the top. I attached the fuse and relay to a screw by that AC box thing.


Tried to hide the wires as much as possible. This is the power from the battery, ran through the fender.


What's left is connecting a blue wire (power) to the fuel pump, grounding the fuel pump, ensuring the O2 sensor cable is secure, terminating the yellow wire to the distributor tach signal, connecting the brown wire to the tach, connecting the pink wire to 12v when the ignition is on.

Then put some gas in the tank, follow the start up instructions including priming the pump and dumping gas into a can to fill the source hose with fuel.

The end is in sight!

- - - Updated - - -

Good news and bad news.

The good: The truck is running!!! It idles super smooth and there's no unspent fuel coming out the exhaust.

The bad: There's coolant leaking from the intake manifold where a crack has appeared, likely from me over tightened the heat temp sensor.

Need to do:
1) replace/fix intake manifold where it cracked.
2) adjust throttle cable to provide 100% open throttle. Reads 85% position at peddle WOT.
3) wait 3 months for snow to melt

Part 3 Video: https://youtu.be/JSnHy1DTm8E

Finished engine bay


Running and warming up


Me "What's that sound?"


Green juice is good, right?


Random pic of chains used to get 1 car and 2 trucks unstuck from my driveway this weekend. 305 studded winter tires, love 'em.