Holley Sniper install keeping the stock fuel system

[waggin_around]

Starting this EFI conversion

Just received the Sniper in the mail. Had this 1980 Waggy in the shop and $2300 later it still has a "bad ground" so the dash gauges and dash lights don't work(yet). I'm seeking any advice on electrical install. Due to this forum, I installed an electric low pressure fuel pump near the coolant overflow tank, and its been working off oil pressure sending unit and a relay off the wire to ignition relay. But looking for recommendations how to wire the Holley Sniper EFI. I have the McRobb on backorder and an ebay pump/2 liter surge tank on the way too..

Any easy-button suggestions for wiring the sniper?

[acct21]

Thank you kindly for posting the purchase links for each of the components for the RobbMC to EFI install.

I am trying to replicate your order and installation, and would be helpful if you can specify the quantity of each specific piece that is required. I am trying to decipher that from your instructions, but it's not entirely clear. In particular, it's unclear how many fittings, adapters and hose ends of each type I should order.

Thank you very much if you can add that or specify that additional quantity information to the post.

I built it out hose-by-hose on the parts list. Every fitting listed is x 1.

I'm just north of Austin. Sent you a PM.

[Riozilla]

Thank you kindly for posting the purchase links for each of the components for the RobbMC to EFI install.

I am trying to replicate your order and installation, and would be helpful if you can specify the quantity of each specific piece that is required. I am trying to decipher that from your instructions, but it's not entirely clear. In particular, it's unclear how many fittings, adapters and hose ends of each type I should order.

Thank you very much if you can add that or specify that additional quantity information to the post.

[Fury5]

Thanks for this update, and especially the parts list for the fittings. Super helpful. My head always starts to spin when I try figuring out all the various fittings a project like this requires. Gonna start ordering and try to set this up in the new year.

[Achilles]

This will be a great resource for people going this route. Nicely done.

[acct21]

So am adding this section so I can refer folks to it from the other forums (FB, etc).

So with 18+ months on my Sniper -- which is on my DD -- here is how I would set it up if I had to do it over again. I have not run into any issues; this is just 18+ months of seeing other people do it, and picking up some of their advice (and having a few forehead-slapping moments of "why didn't I think of that?"

This applies to most all of the later FSJs -- as long as it came with the factory Motorcraft/Autolite 2bbl, and 1/4" fuel return line.

The fuel system is completely, totally, bone-stock from the fuel tank to the hard fuel lines in the engine compartment. I completely rebuilt my entire fuel lines, fittings, sending unit, vents/rollover valves, etc -- but that was maintenance -- not necessary for the Sniper install.

LOW PRESSURE FUEL FITTINGS

I used "gasoline safe" teflon tape -- ONLY ON THE NPT FITTINGS -- but have since been advised that any teflon tape is potentially bad news in a high-pressure fuel environment. Even the slightest fragment of tape breaking loose runs the risk of clogging an injector. So have had seen several folks that use Permatex Aviation Form-A-Gasket on the NPT fittings instead. This is apparently the way to go. Never use any sealer on barb fittings, or on the -AN fittings mentioned later.

From the stock mechanical fuel pump (or hard line attached to the mechanical pump, if still present), run 5/16" fuel-rated (EFI/high pressure rated NOT necessary) rubber line up over the engine to the RobbMc lid. Insert a 5/16" hose barb x 1/4" NPT male fitting into the low pressure feed port on the RobbMc. Attach with stainless no-pinch hose clamps. I placed a 5/16" glass pre-filter just before the fitting on the RobbMc, BUT THESE ARE GARBAGE. Use A 50 micron WIX or similar.

Place a 1/4" hose barb x 1/8" NPT male fitting (with sealer) to the low pressure return port on the RobbMc. Attach 1/4" rubber fuel-rated hose with stainless clamps, and route back to the hard return line on the driver frame rail. Low pressure fuel feed/return is finished!

Fittings:
https://www.summitracing.com/parts/edd-831450
https://www.summitracing.com/parts/edd-831240

Clamps:
https://www.summitracing.com/parts/ear-750005erl
https://www.summitracing.com/parts/sum-390541

Wix pre-filter:
https://www.wixfilters.com/Lookup/Pa...spx?Part=49161

Sealer:
https://www.summitracing.com/parts/ptx-80019/


HIGH PRESSURE FUEL FITTINGS

Here is another place where I had one of those "why didn't I think of that?" moments...

I used 45 degree NPT x AN fittings for the high pressure lines, and would not do that again for a very simple reason: if the fittings don't index POINTING AT THE TBI, neither will your hose! In order to get them to index correctly, they might need to be over-tightened, or left more loose than they should be. Both of these situations can be easily avoided.

Use straight NPT x AN fittings, and then use 90 degree fittings for the hose ends at the RobbMc. This way you can appropriately tighten the fittings into the lid of the RobbMc, and then attach your hoses -- which will point in any direction you wish.

You will need two (2) 3/8" NPT male x -6AN male fittings for the high pressure feed and return into the RobbMc. Sealer ONLY ON THE NPT SIDE -- never on the AN fitting side.

For high pressure hose, I only needed a single 6' length of high pressure AN hose. I used Summit house brand, and used half for the high pressure feed, and half for the high pressure return.

At the RobbMc end of the high pressure hoses, attach a 90 degree hose end (-6AN hose end x -6AN female) to the high pressure feed and the high pressure return hoses.

At the other end of the high pressure return hose (the end that attaches to the -6AN fuel pressure regulator port on the Sniper), I recommend a 45 degree hose end x -6AN female fitting.

For the high pressure feed, you will need two additional considerations: a high pressure, fuel-injection rated filter -- and a fuel pressure testing port. Recommend attaching an -6AN fuel pressure port fitting to the Sniper fuel intake fitting.

For the filter, recommend a RobbMc fuel filter, as well as some -6AN fuel hose x 3/8" NPT fittings for the filter. Run a straight fitting into the filter, and a 90 degree fitting that you can attach to the Earl's pressure port fitting.

Fittings:
high pressure feed line (from RobbMc to Sniper fuel inlet port)
https://www.summitracing.com/parts/sum-220648b
https://www.summitracing.com/parts/sum-220687b
*section of high pressure hose goes here*
https://www.summitracing.com/parts/sum-240101b/
*filter goes in here*
https://www.summitracing.com/parts/fra-499466-bl
https://www.summitracing.com/parts/sum-220675b

high pressure return line (from RobbMc to Sniper return port)
https://www.summitracing.com/parts/sum-220648b
https://www.summitracing.com/parts/sum-220687b
*section of high pressure hose goes here*
https://www.summitracing.com/parts/sum-220686b

High pressure filter (recommend model 1072)
https://www.robbmcperformance.com/products/filters.html

Fuel test port fitting (Schrader valve for use with the fuel pressure test kits you can rent from the big box stores -- can be replaced with 1/8" NPT direct screw-in gauge).
https://www.summitracing.com/parts/ear-9616sverl/

High pressure fuel line (determine how much you need and order correct length)
https://www.summitracing.com/parts/sum-230606

Obviously, your mileage may vary with this setup -- but it WILL get you pretty close. Comments welcome.

[BamaWagoneer]

Running this same setup as well thanks to this thread.

Been about a month and love it. Can't believe how much better the engine appears to run. So smooth. Much more responsive on the throttle.

[acct21]

I've run mine like this since August, and it is smooth as glass. I'm down to about 1/16th of a tank, and as long as I can see fuel in the sight glass of my pre-filter, I know the surge tank is full - and I can make it to the nearest gas station!

[SOLSAKS]

GREAT JOB

I REALLY LIKE THE IDEA
OF KEEPING FUEL PUMP
AND USING THE holding tank.

really neat engine area.

I bet the EFI will be super.

dave in NC

[acct21]

That looks great. Exactly like I set up mine (except I'm cheap, and used rubber lines for the low-pressure side!).

Since you used the RobbMC (red) bracket, you definitely have some room for a wrap (or two) of some foil insulation. It will keep the heat from the exhaust manifold off the side of the surge tank.

Congrats on the EFI setup!

[PBG928]

Finally got Robbmc and Holley Sniper installed. Engine actually started. Have to fix a few other things before I can let it warm up and start learning. LCD screen is way cooler than the 1950 style box that comes with the Howell EFI. I went with the stainless lines and they are tough to work with but look sharp. Keep you posted. Sorry for large images havent been able to resize yet.

[Mikel]

What about a buffer tank after the pump?


The tank would have a considerable internal volume and both the inlet and outlet would be at the bottom. When pressurized, the internal air would act as a spring, providing fuel pressure for short periods while the pump is sucking air.


The only problem I see is with longer fuel system priming times. But I bet a check valve would shorten that time...

[asphaltrockdweller]

I to would love to see your fuel pump/lines when ya get better weather.

[PBG928]

Getting ready to install the Holley Sniper and the Robbmc mentioned above. with this set up do I really need the charcoal filter?

[acct21]

When I pulled the regulator, it was missing the o-ring seal on the neck. Suspect it was pushing out and blocking the return flow out of the return outlet.