Holley sniper install questions

[codfish]

Hi all

Will be installing a Sniper master kit in the near future. 84 K10 with 700r4. Current Qjet and stock iron manifold. Keeping the manifold. This is going to be my daily driver.

Been reading the install guide online, and have a couple questions for anyone that’s done the swap already.

Where have you guys been getting the switched power ( while cranking I believe)?

Does the sniper base have provisions for PCV and power brakes? Can’t tell from the pics I’ve seen online.

My truck has the coolant sensor for the gauge in the DS head. Is there a way to piggyback the sniper sensor and the stock gauge sender? Manifold has no provision, just a bung on the thermostat housing.

I don’t have the sniper yet. It’s on the way from Summit.

Thanks
Codfish

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[Vbb199]

Hi all

Will be installing a Sniper master kit in the near future. 84 K10 with 700r4. Current Qjet and stock iron manifold. Keeping the manifold. This is going to be my daily driver.

Been reading the install guide online, and have a couple questions for anyone that’s done the swap already.

Where have you guys been getting the switched power ( while cranking I believe)?

Does the sniper base have provisions for PCV and power brakes? Can’t tell from the pics I’ve seen online.

My truck has the coolant sensor for the gauge in the DS head. Is there a way to piggyback the sniper sensor and the stock gauge sender? Manifold has no provision, just a bung on the thermostat housing.

I don’t have the sniper yet. It’s on the way from Summit.

Thanks
Codfish

1. Fuse block, labeled "IGN"
2. Yes. Theres provisions for PCV and pb.
3. The oem sender for coolant temp is probably 1 wire , the sniper is 3 wire.

I imagine you could piggy back off of it if you wanted to.
The sky, your creativity, and your wallet are the limit with the efi system .


Im doing things on my sniper that holley doesnt even have instructions or support for. You can make whatever you want work, just know going too far (I.E. changing injectors) will void the warranty.

 

[CalSgt]

I don't know anything about the sniper system but...

You can put the Holley temp sender in the other head, it should just need to have a plug removed.

You can get the 12 volt hot while cranking lead from the starter solenoid under the hood or the ignition switch under the dash

 

[Shawn Watson]

I've seen many recommendations to use the wire that currently feeds the coil to trigger a relay that would then provide the Sniper with clean, switched power directly from the battery.

 

[bluex]

Do not "piggyback" sensors, it makes for bad readings on both ends. Put the temp sensor in the other head. It will perform better during warm-ups.

I would avoid the master kit, instead invest in an 87 tank, sending unit an a fuel pump from a 96 C1500 5.7l. In tank pumps are much more reliable an longer lasting.

There should be several ignition sources you can use in the fuse box, just make sure its hot in run AND crank. Otherwise the sniper will power off when you try to crank an it will be very hard to start. Yes I've seen this alot unfortunately.

Power an ground need to go straight to the battery, NO EXCEPTIONS!

O2 sensor, have a bung welded onto the exhaust, don't use the clamp on unit that it comes with. 6-8" after the collector with a minimum of 18" of pipe after it.

Your engine and current wiring need to be in good shape for the system to perform at its best. The units work well as long as the installation is done properly and your willing to invest the time to learn the system and to make it work its best. I've had a sniper on my truck since 2018, I'm still on all the original sensors an I've probably put 30k miles on it.

 

[CheemsK1500]

Make sure your exhaust has provisions for an 02 sensor. The Sniper system isn't particularly complicated, just don't half-ass it. If you do the install correctly, you'll love it. If you make a mess of this install, you'll miss your Q-jet dearly.

 

[Frankenchevy]

…where’s @SquareRoot ?

This is a sniper post after all.

@codfish , Disconnect your battery. Take your multimeter set to the tone setting of continuity. Attach one lead to your firewall junction. Take your other lead and probe your under dash fuse block for something that has power in the run position—it’ll tone out for continuity. You’ll have open accessory fuse locations on the left-hand side (driver side). Get the probe in there so you have a solid tone then cycle the key to the start position and back to the run position. Once you find a location that tones in both run and start, listen to the quality of the tone. You should have no disruption in that tone. If it is at all scratchy or breaks up, you need to install a new ignition switch or use one of the other methods to get a clean 12 V to the sniper.

 

[Elliot W]

Do not "piggyback" sensors, it makes for bad readings on both ends. Put the temp sensor in the other head. It will perform better during warm-ups.

I would avoid the master kit, instead invest in an 87 tank, sending unit an a fuel pump from a 96 C1500 5.7l. In tank pumps are much more reliable an longer lasting.

There should be several ignition sources you can use in the fuse box, just make sure its hot in run AND crank. Otherwise the sniper will power off when you try to crank an it will be very hard to start. Yes I've seen this alot unfortunately.

Power an ground need to go straight to the battery, NO EXCEPTIONS!

O2 sensor, have a bung welded onto the exhaust, don't use the clamp on unit that it comes with. 6-8" after the collector with a minimum of 18" of pipe after it.

Your engine and current wiring need to be in good shape for the system to perform at its best. The units work well as long as the installation is done properly and your willing to invest the time to learn the system and to make it work its best. I've had a sniper on my truck since 2018, I'm still on all the original sensors an I've probably put 30k miles on it.

I second all of this advice. If I had to do it over again, I'd get a corvette fuel pressure regulator (set to 58 psi) instead of having to run the full length fuel return line. Be patient when "breaking in" the system as it takes driving time to self learn. Be sure you know how to properly set your TV cable brack when you mount it on the sniper as an improper setting could lead to a broken trans. And finally, if you are struggling to get it to tune properly, look in to RF noise that can occur when sensor wires are too close to other wires i.e. spark plug wires and other high voltage wires.

 

[Matt69olds]

I have a Sniper EFI on my Olds, sometimes I really wish I had left it alone with the Q-Jet. I have had more than my fair share of warranty issues, lack of customer support, and one VERY expensive tow bill. If you absolutely have to have EFI, go with the better ECU. There are many parts of sniper that can’t be serviced individually, requiring throttle body replacement.

I’ll share more details if interested, but I’m guessing the OP isn’t interested in turning his thread into a Sniper bashing session.

The pink wire labeled ignition is just a “wake up” wire, it doesn’t have any serious current draw on it. You could tap into the same pink wire that powers the ignition, with no loss on ignition efficiency. Another option, find the wire coming out of the firewall that supplies power to the electric choke. Don’t use the wire that goes directly on the choke, that wire is powered by the choke relay and goes thru a oil pressure switch. If you find the power wire that supplies power TO THE RELAY, that would work perfectly.

I would second using a later model fuel tank with internal pump. External pumps always seem to have problems with gravity feeding, overheating, having the pump submerged in the fuel solves those problems.

There is a reason every aftermarket electrical company recommends the power and grounds go directly to the battery, and EMI/RFI isn’t the reason!! It’s because most gearheads have no clue how to run wiring, and make good solid electrical connections. Holley, MSD, etc know running the power cables directly to the battery is the easiest way to minimize technical troubleshooting and customer complaints. There is not ONE OEM automaker that runs every control module and computer directly to the battery, they almost all have a fuse/relay and power distribution panel under the hood near the battery.

I have a “brand X” (ford) starter solenoid mounted near the battery. The MSD ignition is powered from that starter battery stud (and has for 20 years) and the sniper is also powered there. For grounds, I have a 3/8 bolt welded to the frame, the battery cable negative goes to the engine, with another cable from the engine to the welded bolt. The Sniper is grounded there.

 

[codfish]

Just getting into the wiring finally for the sniper. Pink wire question.

I know it needs power while in run and while cranking. That’s understood.

I have a couple empty terminals in the fuse block that are hot in run and while cranking. Only thing is, the volts drop from 12 to about 8.5 while cranking. Is this sufficient?

I’ve searched this topic on many different sites, and EVERY answer just says the source has to be hot in run and crank, not necessarily 12 volts.

Thanks again for the help
Codfish

 

[Elliot W]

I'm fairly certain that voltage drop while cranking is ok for the pink wire. The important one to not have voltage drop is the red wire that goes straight to the battery, along with its companion black wire to the battery ground terminal. I could use some backup on my response though.

 

[codfish]

Thanks

I’m waiting for the Holley tech line to open. I’ll ask them as well. I’ll report back with what they say.

Codfish

 

[codfish]

Finally got through to the tech line at Holley

He said any voltage drop below 10 is not advisable. He said it may work, but could lead to further issues. Said that a voltage drop of 3-4 volts while cranking indicates that that power source(the spare ones in the fuse block) may still be associated with the starting system somehow, and if you have starter issues at sometime, it will affect the efi system.

He did say however that that power source would be fine to hook a relay into, and just use pure 12v from the battery. I guess that’s what I’ll do.

Figures. The ones on the fuse block would be too easy to use lol.

Thanks
Codfish

 

[Elliot W]

Is the battery old? I thought normal crank voltage drop was between 10 and 11. If you think you might need a battery or more CCA, it might be worth getting a new one instead of running another line and relay to the battery terminal.

 

[Brett77]

I agree do not go off thermostat for temp its looks bad and incorrect readings when learning is going on.