So, my dad's Fairmont, with the 347 Stroker, had a very problematic 650 Holley DP on it. I think the issues we had was from it sitting with old gas in it, since my dad hasn't been up to driving it and keeping up with it. First we tried rebuilding the carb, got it to at least run again but not very well, so we pulled it back apart and soaked it some more and put it back together. It still wasn't right though.
So, we decided we were through messing with a carburetor and wanted the easy starting and smoother running of a fuel injected motor.
I had been looking at these newer "self-learning" fuel injection systems that have come out recently, and the most popular ones lately seemed to be the FiTech throttle body system and the Holley "Sniper" system that is very similar. From my research, there was more favorable comments about customer support from Holley with about the same amount of performance from each system, and the same amount of customer satisfaction with the way the systems worked from the reviews online. So, we decided to go with the Holley kit. We also decided to go with the Holley fuel system, with the external fuel pump plumbed to the stock fuel tank outlet.
The Holley Sniper throttle body looks very much like a AFB or Edelbrock carb, laid out in a somewhat square architecture. And it bolts on the same as the carb. The Holley throttle body has a 800 cfm rating, and has injectors rated for up to, I believe, 650 HP, normally aspirated, or as low as 200 HP. So, it is good for a wide range of engines. The ecu on the system, which is built into the front of the body, also has the capability of controlling the ignition as well as a wet nitrous system, and it will also control electric fans. It also has some extra controls for anything else that can be triggered by a single wire. Holley has also now released tuning software for their efi systems that can be used on the Sniper for advanced tuning.
We didn't use the ignition control on dad's car, just the fuel injection.
Pic of the engine with the Holley carb
And, with the new Holley Sniper
Dad's car had the Lokar throttle cable and the kickdown cable kits already on it, and they swapped right over to the throttle body, brackets and all with only minor adjustments.
The wiring on the Sniper, at least when using just the fuel injection is fairly simple, only 4 wires to connect from the throttle body, battery +, Battery -, ignition signal and one wire that goes to a hot source that is hot in run as well as start. For the ignition signal, you either have a wire that goes to the negative coil post, or a wire to the CD ignition box. Dad's car has the MSD 6AL so we ran the proper wire to the tach output on it. Then there is a wire from the Sniper to trigger your tach. The only other required wire is the power to the fuel pump, and this wire is already run through a relay in the sniper harness, so it just connects directly to the fuel pump + post. The system also comes with a small, 3.5 inch, display and programming unit that hooks to the throttle body with a cable run through the firewall. Since the display is not required to run the car after the initial setup, I tucked the cable behind the dash and put the unit in the glovebox.
The Sniper ecu also needs a dedicated temp sensor, which is provided, but you have to have a port to put it in, either in the intake or the head. There are no ports available in the AFR heads on the car, and both ports on the water crossover on the intake were being used, one by the sender for the temp gauge and the other for the heater hose. I ended up using a "T" fitting and putting the second temp sensor in the port along with the heater hose connection. Then the sensor just plugs into a harness lead on the throttle body.
Next thing to tackle was the O2 sensor. The kit comes with a sensor bung that is installed with no welding, it just clamps in place with a gasket over a 3/4" hole drilled into the exhaust pipe.
[IMG] OOPS! Forgot to take that pic! [/IMG]
Next is the fuel system, and it was the most difficult part. The system comes with an external 255 LPH pump, 40 feet of 3/8 fuel injection hose, and a number of 6AN fittings for slip-on hose and a bag of fuel injection hose clamps.
Most of you guys know that these pre-fuel injection cars came with a very simple fuel system, the tank having a 5/16" pipe coming out of the plate on the fuel level sender to supply fuel to the mechanical engine mounted fuel pump, and no return line, and a simple vapor recovery system. The Sniper fuel system has the above mentioned 3/8" supply and return hose sizes, so a little extra work was required to make the system work with the Fairmont tank.
I first tackled the return line. One of the fittings supplied with the fuel system kit is a bulkhead fitting, which is intended to be placed in the fuel tank to connect the return hose. This would, of course, require the draining and removal of the tank, drilling a hole, mounting the fitting and flushing the tank out to remove any metal shavings left from drilling the hole. I had no wish to do all of that, so what I did was to remove the fuel filler pipe and drill it to mount the bulkhead fitting. Boy, I thought that would be easy! Not quite. If any of you guys have had the filler neck out, you know it is divided with a plate along the entire length that provides a space for air to escape the tank as you fill it with gas at the pump, and, of course, it has the little flapper on the cap end. This leaves no access to mount the fitting, so, what I did was get a nut with the same thread size as the bulkhead fitting, 9/16-18, and drill a hole in the side of the filler neck, then weld the nut over the hole, then the bulkhead fitting with its sealing washer, screws into the nut. And, just to make sure it was all sealed up, I covered the base of the nut with epoxy.
The next issue was to fit the 3/8 fuel hose to the 5/16 fuel supply pipe on the tank. The solution I found for this is a Russell fitting that has a 5/16 compression nut and ferrule on one end and a 6AN on the other end. To get the 5/16 compression end to go on the tank supply pipe, I had to cut off the very end that has the bulge that keeps the hose from popping off. But, when In tried to slip the compression nut and ferrule on, I found that it wouldn't slide on far enough to get it all put together. So, what I did was to cut part of the compression nut off the back side so it would slide onto the pipe further. This did finally allow me to get it put together and tightened up, and then connected to the 6AN fitting and fuel hose.
Next up was to figure out where and how to mount the fuel pump. The system also comes with a pre-pump 10 micron fuel filter, and a post-pump 3 micron fuel filter. The fuel pump needs to go as low as you can get it, preferably below the tank level, or as low as you can get it, and as close to the fuel outlet on the tank. I had some aluminum angle on hand, and cut a piece of that, then mounted the pump and both pre and post filters to the angle. I then took some aluminum flat stock and bent up some brackets to bolt it all to the car by some available bolt holes. I then ran all the hoses, tank to pump, pump to throttle body, throttle body to return fitting. I did also heat wrap the fuel hoses where they come near the tailpipes.
That completed the install of the components, all that was left was to do the initial setup for the ecm, flush the fuel line, hook that back up and fire the motor up!
Here is a video of a cold start and a few warm throttle blips.
After the initial setup, you have to drive the car for a while and let it self learn. The more you drive it, the better it runs as it learns what the engine needs.
The car now starts with no fuss, and it really screams when you tromp on it. So far, I can say that it was definitely a great mod for the money! And, I can tell you that the fuel economy has gone WAY UP! It used way less fuel on our initial trip than it ever did before.
The kits we used are the 550-511 black sniper kit and the 526-7 fuel system kit. We bought them separately off amazon, but they do offer a complete kit with both the EFI and fuel system, but they were out of stock at the time. It will save you some $$$ by buying the complete 550-511K master kit.
I have some video of our first trip down to the Saturday night get together, but still need to edit it some and put it together before I can post it.
So, that's it for now!
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