I just bought the Sniper Quadrajet efi, and have a few questions for some of you that have installed it on the early C3's. mines 72. I'd like to run it with the stock fuel tank. what fuel pump and filters do I need to use? Where did you access to the power for cranking/run 12v? If I understand the instructions correctly, it says a regulator should be installed in the return line. Why there?
thanks

 

Holley makes a fuel pump/sender combo. You can use stock fuel tank and lines #Part# 12-311. https://www.holley.com/products/fuel...s/parts/12-311.

 

Agreed. You will need a return line though, They recommend the same size as the fuel line, so I did not use the stock return line. I ordered the Holley tank with the fuel pump and filters. I do not have a regulator on the return line.

 

This is not correct. The in tank unit has the regulator and return inside the tank. No return line required. I have this installed in my 68. After hearing of problems with injectors possibly due to contamination I pulled my metal feed line out and replaced it with Vibrant Performance flexible line. So I have a 4 inch efi rubber line from the tank to the filter and another short piece with a barb to -an fitting. Vibrant line with -an fitting run all the way to a metal line I fabricated in front of the right head. You could probably remedy this possible problem by putting the 10 micron filter after the original metal line also.

The only problem with the Holley in tank unit is that the gauge did not work. The float would not float. I had to bend the bottom 90 degree so that the float had a bit more leverage to get the lever to move. The float itself seemed small in comparison to the original so I replaced it with the old one. Works fine now.

 

No return line? hmmm.... that is definitely contrary to all of the installation guides I saw. I went ahead and ran a return from the throttle body back to the tank as directed. My wife says I never follow directions but in this case I did. Then again maybe I missed as optional part in the instructions.

 

Theres nothing wrong with being an overachiever. I go out of my what to complicate it if I can. There are lots of posts here about using a LS filter/regulator at the tank and using a short return off of it back to the tank.That is what I was going to do until I saw Holley's newest offering.. You simply cap off the regulator port at the Sniper. The regulator is just above the pump in the tank and dumps the return back onto the hydromat fuel pick up. In theory you should not really need a baffle. Well for cruising anyway.

 

I was wondering what provision is made that in the event of the misfortune of having a crash that the electric fuel pump is shutoff? I can see scenarios where the pump is still running you have a leak somewhere and the fuel pumping out out at 60 PSI.

 

You can put and inertia switch on it.

 

thanks I talked to Holley today and they have the in-tank fuel pump in stock

 

https://www.holley.com/products/fuel...s/parts/12-311

 

There are 2 options. Single line is fairly nes for Holley and uses an external pump and gegulator at the tank. Traditional is in tank pump with 2 lines.
Regarding regulator on return.
You have 2 options
1: Fuel line into sniper, return out of sniper into regulator, regulator return to tank - In this case the 3rd fitting on he regulator is blocked.
The fuel simply flows into the sniper input and out the output unrestricted. the regulator keep the line pressure at 60 and this the sniper works.


2: Fuel to regulator, return from regulator to tank, pressure line from regulator to sniper. Sniper
in the case the fuel goes to sniper input at 60PSI, output side is capped. Unit has fuel at 60psi.

Either works.

Note:
My sniper unit does not work. It is just dumping fuel into the car. Been with several Holley techs, - waiting 20 minutes on hold each call.
At this point I have sent the a data-log from the sniper to the last tech I spoke with... and they have not gotten back to me. Last email is unanswered....

Not sure where to go now..... is my only option to pull the entier system and send it back????

I am shocked at their service.....

Hopefuly they get back to me today.

 

Contact these guys.
https://www.efisystempro.com/?utm_so...eid=bf48d4fd87

 

Thanks! I'll try

It is a sad day for Holley when I have to elsewhere and pay someone to solve their problem.
I have been a big Holley fan since the late 70s....
very disappointing..... I advise all to be careful with these guys....

 

With this Virus BS going on staffing and such at Holley I would assume is just as difficult as at other companies. No guarantee the person on the other end gives a ****.

 

Did look through the troubleshooting guide on pg 74 ? Or this may help.
https://documents.holley.com/199r11369.pdf

 

It's bad.... I spoke with a tech about this. They are running half in office half remote.
No excuse for not getting back to me. Hell, I had one tech who was trying to figure this out tell me:
"I need to go check a notebook" He put me on hold and never came back.....

I will post an accurate and complete review video on youtube. I do a lot of videos some are over a million views.
I hope Holley can resolve this. I do like their stuff but at this point I am being pushed too far....

 

Good Luck

 

Yes.... I think the unit is defective. It is dumping fuel into the engine.
At this point I am hesitate to start it. Let time I have it running for a while for a tech on the phone. Raw gas was dripping out of the exhaust system.....
It is a fire hazard at this point.

 

I am wrapping up the installation of the Holley Sniper Stealth 4150 on my 1968 C3 with it's 427. I bought one of the Holley Fuel Tank modules for my '68 and it was so simple to install. The hole that allows you to install the sending unit is now pumping 60 psi of fuel as well as telling me the fuel level in my tank. I found on my Corvette that the hole was on the bottom of the tank and not on top like so many cars. I simply drained the fuel tank and removed the old fuel level sending unit and installed the new module with the sending unit, fuel pump and Fuel Pump Regulator. On the Sniper Stealth there is no return line IF you use the Holley Module with built in regulator inside the fuel tank. I paid $340 for the module and I would recommend it to anyone who wants to go to EFI. It took 20 minutes to set up the fuel system in my Corvette. One of the best things about the Holley Module is that they come with a small piece of the new Holley Hydra Mat which is the best absorbing pick-up filter that I have ever seen. The instruction I got with my system were 76 pages long and pretty well written. After getting the parts I did not have to make any trips to the auto parts stores for anything, they included Everything I would possible need to install the Sniper on my Corvette.

I was hesitant to buy an EFI from somebody who does not provide installation help. I bought mine from the EFI System Pro and get 2 years of Incredibly helpful and knowledgeable Tech support. The Tier 3 Holley technician is available 24/7 and gave me his personal cell number and email address. Every time I have a question the answer is right away. The folks at EFI System Pro are incredible at their customer service. I bought my entire system from them and I saved some money. Their service is extraordinary and I am very pleased with my transactions with EFI System Pro.

The best part is that since the Sniper Stealth looks like a Double pumper and is the same size and location it works with my Factory L88 Hood. The L88 hood is the best way to get cooler air into your combustion chambers. Several people have seen under the hood and can't tell it is an EFI system. It starts runs and works very well in my 1968 C3. After connecting all the wires and the O2 and CTS I turned the key and set the system up. Following the setup the Corvette came to life within one or two seconds of cranking. The hardest time I had was getting the IAC to be set properly. Once the engine hits the operating temperature of 160* the system starts learning. It was a little rough in the first few minutes as you could hear the system changing things around. You set the idle speed where you want it and then you are ready for action.

The people at EFI System Pro will help others with Holley EFI systems purchased from other sources but they might charge if it gets complicated. Tom K you might try calling them or better yet text them and ask away. Their Web Site also is a wealth of information from the Tech. People ask him questions and he will answer them even when they bought it elsewhere. The technician knows these systems inside and out. I am still so glad that I bought it from EFISystemPro.com as they had in my hands 2 days after the order. I had planned on using a new fuel tank with the fuel pump installed, they cost several hundreds more than the module does. The folks at EFI System Pro suggested that if my tank was okay just to use the module and save a few hundred dollars. I was amazed that I bought the entire system for close to $300 hundred less than I had budgeted.

The Holley Sniper like mine has data logging and has a couple different input and output connections for you to use as you see fit. The Sniper is also ready for Nitrous if I chose to do that to my C3. It also controls the fans, fuel pump and will also operate your ignition system for you. I have an MSD Ignition system that works just fine with the Sniper. The Sniper's Software is amazing as it will do a lot of different things for you. I use a Snow Performance Water/methanol injection system and that will be controlled by the Sniper when I am finished. The only thing it does not have is a knock sensor, but with the various available inputs I suspect I can connect it in somehow.

Tom K maybe take a look at their website EFISYSTEMPRO.COM and see if they can help you. Once you get the system working properly you will be very happy with the results. It is a great design and it does work once it is set up properly.

Stay healthy!

 

Just sent a note through their website tech support.... they will respond by next Monday...... Time to move on people.....
Keep your quadrajets!