Holley Sniper Stealth EFI - Part 6 (Throttle Body Feed Lines)

After a little trial and error, I've selected a regulator and braided fuel line for the throttle body that will be perfect for the Mustang

I originally purchased an Aeromotive 13130 regulator and Holley 534-236 braided fuel line.  I selected the Aeromotive regulator due to numerous bad reviews of the stand alone Holley regulators on the Summit website.  The Aeromotive regulator was a well built part but required a completely different fuel line configuration.  This version doesn't regulate in-line before the throttle body but afterwards which wouldn't work with the braided fuel line I purchased and would create a more cluttered appearance.  

When searching for other options, I decided on using Holley part number 534-237.  This is the exact same style braided fuel line I had before but the regulator is integrated in the line which makes for a cleaner installation.  I'd seen this one before but skipped over it due to reviews stating the regulator hit the intake or valve cover on a small block Ford.  After looking at the picture for a bit, I didn't think that would be the case and ordered the part anyway.

The part is actually a series of parts that you assemble.  The regulator bolts to the back carburetor stud to hold it securely in place.  I took a few minutes this morning to put it all together and tighten it up properly.  I think this is going to work as I need.  

I have a fuel filter to install just after the tank (left) and one to install at the throttle body (right).  The one at the tank is a Summit 220170B which has an integrated 90 degree fitting and a 100 micron filter.  The one for behind the throttle body is a Summit 230123B and is a 10 micron filter.  The plan is to put the filter at the throttle body right behind at the back of the intake.  You can see it in the picture above but I've not built a bracket yet to hold it secure.  I'll work on that in the days to come.

Holley Sniper Stealth EFI - Part 5 (AC Idle-Up Feature)

The Sniper system has the ability to increase RPM when the air conditioning is running so that it does struggle at idle.  This will be a considerable improvement over the former system I was using.

What I had in place was a Holley 46-74 solenoid that was quite expensive ($134).  The solenoid was arranged to push on the throttle linkage at the carb when the AC was running.  However, it was not strong enough to move the throttle linkage if it was presently closed.  It was only strong enough to hold it farther open if it were activated and the throttle was returning closed.  It was hard to align and seemed to have varied results on the RPM, required a relay and wiring, and just wasn't a great solution for me.

The old wiring configuration required a relay.  The compressor provided a 12v output but it wasn't strong enough to operate the solenoid.  I wired in a relay as shown below to use an adequate 12v power supply from a white wire run from inside the cabin to the former location of the voltage regulator.  

This is wired using the orange wire (Input #1) on the 10 pin optional I/O harness.  When there is a ground input to this wire from the compressor, it will increase RPM based on your settings in the Sniper system (under Tuning -> Advanced -> Advanced Idle -> IAC Kick).

I rewired the relay to provide a negative trigger for the Sniper system so that it would know when the system is running rather than the former setup which provided power to the solenoid.  I also changed the trigger wire color to orange so it matches the Sniper system.  I don't intend to leave this as it is for the long term but this was a quick fix to change the wiring, mount the relay back where it was, and have it functional despite it being the middle of winter.

This is the new wiring for the relay.

This is a picture of it during the wiring process.

Holley Sniper Stealth EFI - Part 4 (Temperature Sending Unit)

The Sniper kit came with a coolant temperature sending unit (232R14A).  Unfortunately, I have only one temperature port in my Edelbrock RPM Air Gap intake and it is being used by my current temperature sender that operates my AutoMeter temp gauge (ATM-3531).  My AutoMeter sending unit (#2258) reads 1123 ohms at 100 degrees and 65 ohms at 250 degrees.  Despite all my research, it seems you must use both sending units.

Using both sending units will certainly clutter the under hood appearance. I would need to either find a new thermostat neck or something that goes into the heater output.  For now, I decided to just use the Sniper sending unit and watch my temp on the Sniper display.  However, at some point, I'm going to want both of them working again.

With that decision made, I drained out a good amount of coolant, removed the AutoMeter sending unit, installed the Sniper sending unit, and then put the coolant back in.  Afterwards, I replaced a little black plug in one of the intake runners as it was leaking.  I had a new plug in my spare parts and used Permatex 85420 which is fuel resistant sealant.  I then swapped out the carb studs for a shorter set since I'm not using the old carb spacer.  Lastly, I took the Trans-Adapt (TRD-2178) air cleaner stud I purchased and but about 1/2" off before installing it with a locking nut.  

Holley Sniper Stealth EFI - Part 3 (Starting Slowly)

I started today by removing the AutoMeter Sport Comp AFR gauge (ATM-3370) from under the dash that I've used for years to tune the carburetor.  I'd always planned to use it to tune and then remove it.  I was always questioning if it was right so the gauge stayed in place permanently.

I removed the wiring under the dash that fed power to the current electric fuel pump.  Instead of it running to an ignition source at the circuit panel, I ran it out the firewall to connect to the Sniper system.  I had coiled up all the extra wire from connecting it which made it more than long enough to reach under the hood.  The Sniper system will now tell the pump when to run.

Inside the car, I took apart the RAM mount I used to hold my phone on road trips and expect to use it as a mount for the Sniper display.  I used the 3M adhesive pads they provided and fastened the display mount to the RAM mount.  It holds it just under the radio which will be perfect.  When I don't plan to have it out any longer, I can put the cell phone holder back in place.

The last thing I did was pump all the fuel out of the tank, remove the existing fuel tank, and the fuel pump.  I expected to pump all the fuel out without making a mess of the floor but that didn't happen.  It started perfectly as I filled a 5 gallon gas can.  I left the hose in the can while I went to get a funnel to put the gas into another vehicle.  In the minute I walked away, the fuel line came out of the gas can, fell to the floor, and I suppose the siphon effect caused it to just keep pulling fuel as the entire floor was covered.  I thought I had laid the best plan.

I spent quite a while cleaning up the floor so that it didn't overwhelm me with gas fumes.  I'll be gone for work the next few days so I put the gas tank outside to vent and dry out.  When I return, I'll get back after it.  I might order a few small things between now and then to continue making progress.

Holley Sniper Stealth EFI - Part 2 (Parts Arrive)

The Holley Sniper Stealth EFI system arrived in the mail today.  I quickly opened it and spread out all the items that came as part of the kit.  I'll need much more to make this work but everything I expected to receive was included in the box.

I placed the throttle body on the intake and it seemed slightly taller.  With some quick measuring, I found the Sniper unit was a 1/4" taller than the Street Avenger carb.  I placed my air cleaner on and found that it now makes contact with the hood.  I've been using a 1/2" phenolic spacer which I can remove.  I added the spacer to address issues with vapor lock.  Since the Sniper doesn't have bowls to store fuel in, the spacer will have much less benefit.

I also noticed that due to the design of the top of the Sniper, the threaded hole for the air cleaner stud is lower.  As a result, my former air cleaner stud is too small.  I need one that has a 1/4"-20 thread pitch and that is hopefully around 3.5" long.  I'll add that to the list of things to purchase.

Before the Holley Stealth kit arrived, I decided to go ahead and purchase the gas tank I'll use with the Stealth EFI system.  I purchased a Tanks brand kit (TNK-MU-HT-KIT) which includes everything that I will need associated with the fuel tank.  The tank is a 16 gallon tank with internal baffles and is powder coated silver (TNK-MU-HT-KIT).  The tank came with the pump (TNK-GPA-4) and a Ford style sending unit (TNK-TAN-ORG).  Despite ordering the tank several days after the Stealth System, it arrived first.