Sniper EFI conversion

[alignman88]

alignman88 so I am behind you a little ways on the conversion. my harness is spread out on the table. so on the factory harness I just need to eliminate the engine control items to start with. obviously the ecu will need power and ground. so the wires I already clipped (oops) going to the HVAC I need to splice back together. On the fuel side are you tagging into the stock relay and using the sniper to trigger the relay and then supply power to the fuel pump.

I’ve cut no wires out yet so you’re ahead of me. I’ve sorted out all the injection and emissions and MAP sensor spaghetti will try to maintain as much OEM process control while minimizing and making the engine bay clean (hate tons o wires).Looks like I will be able to put everything I need for top of engine (2 water temps, alternator, few others in a 1/2” loom)Don’t ditch ECM it may transfer info, one coolant temp goes to computer (now Sniper) while the other goes to gauges. ECM will basically be a body control module, and it will still transfer data to the systems like AC and heat not sure if it will control trans but easy fix there.

Im running a Walboro 255 in tank pump same location as factory, and will allow the original signal process to take place if possible. Pump just needs a hot for start/run and the relays are there so really want to keep if possible. Some FiTech guys have done that I think. Stock fuel lines match required spec throttle body has regulator all ya need is the metric to AN adapters to TBI from factory lines.

The Chiltons manual is easy to follow, at any parts store and they have a ton of info on the emissions electrical I may be able to completely eliminate those depending on check engine light work around or may have to tune out. Can’t be too hard.

Trying to finish interior before drivetrain or it would never get done. Hope to be full bore on drivetrain next week or so. I’m

 

[Davin Reckow]

Guess I will stop cutting wires then. LOL sounds like I should connect up what I have and shake out issues after that. I am using an in tank pump from a vortec truck. should give me 60psi and fit into the stock location of the low psi pump. I have a chiltons but I am not finding wiring for the heater or trans. I know exactly what you mean on the interior. finishing up upgrade stereo and speakers, include an under seat sub. swapped in a 98 seat and a fresh headliner. looks like new not that is was tore up. also added hydoboost and rear disk brakes. Thanks for the help keep me posted on your progress and findings.

 

[alignman88]

If you want your Sniper to control your timing also (and you should) you might want to read this article. Its the way Im going to go...

https://www.onallcylinders.com/2017/01/20/ask-away-jeff-smith-rotor-phasing-relates-efi/

I found that same article when leaning toward FiTech. Simple and affordable and Fitech ECM would control timing without a CD box. Sniper requires a CD box so I’m biting the bullet and using their dizzy, cd box and coil. Keep it all same same.

 

[Dubs]

I found that same article when leaning toward FiTech. Simple and affordable and Fitech ECM would control timing without a CD box. Sniper requires a CD box so I’m biting the bullet and using their dizzy, cd box and coil. Keep it all same same.

Correct, with FiTech you lock the dizzy set timing and put the value difference in the hand held them you're good. But you have to set your own timing curve.

 

[LC2NLS6]

I have the sniper with hyperspark box, hyperspark coil and dizzy. It's almost plug and play and you can control the timing. Put me in the group that cut some factory wires only to have to reconnect them when I saw one a/c wire that needed to go back on. For all the bad things I've heard of Sniper, I've heard even worse about FiTech. Summit sells a cheap branded efi kit as well.

 

[ccreddell]

All the product manuals Ive read on the Sniper say it comes with a coil driver to run a dizzy without an ignition box. I plan on running one, but was pretty sure you didnt have to.

 

[alignman88]

All the product manuals Ive read on the Sniper say it comes with a coil driver to run a dizzy without an ignition box. I plan on running one, but was pretty sure you didnt have to.

According to the tech on the Holley support line their dizzy still needs a cd box. He was familiar with the MSD pigtail PN used if a stock TBI dizzy but had no knowledge about that setup being used with Sniper and stated regardless of dizzy config the Sniper ECU can control timing but only through

All the product manuals Ive read on the Sniper say it comes with a coil driver to run a dizzy without an ignition box. I plan on running one, but was pretty sure you didnt have to.

You’re correct the Sniper can be set up with a traditional inductive ignition and a canister style ignition coil which requires a little more wiring or set up to run through a cd box, or as stated with the Hyperspark box and it’s plug n play. For the $250ish I’m using their box.
Here’s an article that’s very explanatory:
https://www.holley.com/blog/post/ho..._to_your_holley_sniper_fuel_injection_system/

 

[aaronb]

I've been running the coil driver with the hyper spark distributor to control timing for over 2 years now on the 406 in my 66 nova with no issues.

 

[AG2320]

Has anyone made any progress on these builds? I bought the cheaper Summit Racing EFI system, and so far, it is identical to the FiTech system. I am curious how you guys plan on doing your factory cruise control, throttle cable, and TV cables?

 

[LC2NLS6]

I removed cruise control. For the brackets, I used the FAST EZ efi bracket (100 bucks but works), Holley throttle arm extension (a must on the sniper with gm pedal travel, though you have to grind the bracket to fit). I have a 4L80E so no TV cable, but the FAST bracket has mounts for that in that kit.

The vortec delphi fuel pump has held up so far, I ran it out to 5500 on a cammed and 9.2:1 454.

I did some tuning on the laptop, right now I have too much timing cranking when cold under 30F mat, and too much fuel at say 30 mph load in the neighborhood. Rest of time it is spot on. Tuning is fairly easy now.