Category: Fuel Injection

One of the proposed solutions to my EFI cranking problem is to wire a relay into the ignition system which will provide constant power to the Sniper head unit. Apparently it’s pretty common for old vehicles to have a voltage drop between the Run and Start positions in the switch, which the Sniper unit isn’t designed for. My first course of action will be to swap out the ignition switch with one of the spares and see if that makes any difference. It could be something as simple as a poorly made modern switch, which wouldn’t surprise me.

If I can get one of the two to work reliably, then problem solved. If not, the next step will be to wire in a simple relay to the ignition circuit which will provide constant power to the head unit and keep it live. There are two types I can use: a simple 30 amp on/off type like I’m using for the auxiliary fuse panel. The other is an adjustable design with a potentiometer which allows for the amount of time the circuit holds a charge. I don’t need it to stay on for 30 seconds after the switch is turned off, just enough to keep the head unit working.

A proper inlet fitting arrived in the mail on Friday and I had to wait until Sunday morning after the rain had passed to do a test fitting on the carburetor. I could only get one in blue, but you’ll never see it under the air cleaner. Thankfully, it cleared the water neck with about a half an inch to spare, so I tightened it down and made a list of preflight checks that had to be done before fired off the engine. First, I replaced the existing positive battery cable with a bigger fatter one. I’ve always wondered if I’m not getting enough cranking amps from the existing cable and decided to improve that situation. This took a little more time than I thought because the starter is in a really lousy position on C series trucks. It’s in between the engine and the frame rail and directly over the front axle so it’s going to be very difficult to swap out if that has to happen.

Then I pulled the plugs and put a borescope down into the cylinders one by one to check for any water in the cylinders. I did this because I drained a bunch of water out of the gas tank and I was afraid I’d pulled a bunch into the engine and possibly done some damage. I found no evidence of water or rust, just dirty piston heads that need to be cleaned up with a long idle and some time on the road.

Next, I had to get a bunch of new gas and get it into the tank, which is harder than it looks because I don’t have an angled funnel. After visits the three different stores I found something that mostly worked and put about 4 gallons of gas in the tank. Interestingly, the first time I turned the key to the accessory position, the fuel gauge worked, but it worked  intermittently since then, so I’ll have to figure that out. With that done and the wiring to the Sniper connected, I cleaned out a jug and set it up in the engine bay to catch fuel.

The first test of the system is to boot it up and program it for the type of engine, cam, idle speed, and a couple of other settings. Then you program it, and do a couple of fuel system flushes to run clean gas to the system. After I did this, I connected the fuel lead up to the carburetor, said a prayer, and cranked it over for the first time.

It didn’t immediately catch, and I noticed that the Sniper control unit had rebooted itself; this should remain on constantly. Doing a little Internet digging I learned that other people have had this problem and it’s got to do with a gap in continuity when turning the key. Walking back through the main points of failure, I tested the jumper to switched power on the fuse panel and verified that was OK. The power leads to the harness were connected correctly. That left the ignition barrel.

This ignition barrel is brand new. I bought it the first year I had the truck, and I believe it’s been wired correctly, but clearly I’m going to have to pull it out of the dash and check it over again. I’ve got two spares I can swap in for testing—the original and the one out of the ’67. I’m going to go out and take some detailed pictures of the ’67 barrel and the one in the truck and compare them, along with the diagram I have from the service manual. I’ve been thinking about pulling that one apart and swapping in one of the new ignition cylinders (I don’t have a key for either one) so that could be a cheap way to test the system, with the added benefit of getting the entire truck to work on one key.

Finally, I checked for spark while I was turning the engine over on the #5 cylinder and didn’t see anything on the indicator, so that’s another thing to check.

I’ve got the week off from work to burn up excess PTO time so I’ve been focusing mainly on the EFI install and procrastinating by tackling some smaller projects on the side. The EFI install is intimidating because it includes lot of things I’ve never done before and presents some mechanical problems that are proving difficult to solve. The instructions begin with the simple task of installing a fuel pump and two fuel filters in between the gas tank and the engine. This also includes a return line, something modern fuel injection needs, but my truck never came with. So that required dropping the tank again, drilling a hole somewhere in the tank, and plumbing a new line. Another complicating factor, as mentioned earlier, was that there’s little to no room in between the outlet on the tank to the engine compartment, which made the fuel pump location a huge question mark.

Dropping the tank was easy; I’ve already done that once. But when I drained the tank, I found a pint of what I can only assume was water, which was very disturbing. I know I emptied this tank out completely before I reinstalled it and I know I capped off all of the inlets so I don’t understand where this water came from. What I’m most concerned about is that I’ve been trying to start it and I’m afraid I may have hydrolocked the engine by squirting water into the cylinders instead of gasoline. After some deliberation, I’m going to continue with the EFI install on this engine, assuming I haven’t bent any pushrods, and we’ll see.

After the tank was down, I measured and test fitted and measured again and found the best possible place for the return line, right next to the sender hole at the top of the tank. This is the only place I could get fingers inside to tighten any bolts. I filled the tank with water, drilled a pilot hole, and then used a stepped bit to widen it out. The fittings that come with the kit were all aluminum, so I needed a wire to fish them back out after dropping them in the tank the first fourteen times, and found that using the wire was the best way to help guide the parts into place. I also fabricated a bent wrench out of 16 gauge steel to help tighten the fitting up inside the tank. After flushing it out with more water, I installed the return line and bench-tested the fuel sender, but wasn’t getting reliable readings. When I got the truck, the fuel sender actually worked, but I’m not sure what happened after I pulled it out. My multimeter is the $9 Harbor Freight special, so I decided I needed to upgrade that to something a little more legitimate.

Underneath the truck, I found the best possible place for the fuel pump and pre-filter was on the inside of the frame rail. That was all still filthy, so I scraped and wire brushed it, then painted it with encapsulator. The only way I could figure on routing  the fuel line was to direct it backwards to the inside frame rail, do a 180° curve to the pre filter and pump, then go up to the engine bay. I ordered aluminum fuel hose for the bends because I didn’t want the hose kinking up over time and restricting the flow.

While I was puzzling over those problems, I was fixing smaller things like a sagging driver’s door. After lifting it up with a bottle jack, I loosened then tightened the hinge bolts and it closed cleanly. Then I bent some 16 gauge steel into an L shape, drilled it out, cleaned it with a file, and used it as an under dash bracket to install a USB charger.

Thursday started out being a gloomy, rainy day, but after about 2 o’clock, the weather cleared, the sun came up, and it warmed up to about 75°. In the morning, I drove up to a locksmith in Towson to have them look over the rear door handle and help me understand the problem I was having with the new lock cylinders falling out of the assembly. The guy behind the counter was super helpful, but he couldn’t figure out what we were missing. After talking it through with him, he agreed that I needed a spring loaded retainer clip at the back of the regular door handle lock cylinder, and that the ignition cylinder wouldn’t work in the door. I was hoping I would have more answers than that, but he got me to thinking about a way to solve the problem. I stopped off at Harbor freight for a better multi tester and then headed back home.

I took full advantage of the afternoon, warmth and pulled the old carb off the engine, cleaned up the intake, and dropped the sniper in place. After reading and rereading the installation instructions, I started roughing in the wiring in the engine bay to begin to understand where things need to go. Alternating between the engine and the frame rail, I sorted out most of the main electrical harness and crimped and soldered leads for the positive and negative battery terminals aligned for the controller is fished into the cab, and the main fuse and relay harness is roughed in on the firewall. I did find that the temperature sensor included with the kit is one size larger than the threaded hole in the water neck. I have a spare manifold sitting on the floor of the garage that I can examine to see how hard it would be to drill and tap a wider temperature sender. Of course, I’m of getting metal shavings in the engine, so this is the nuclear option. The other installation issue is that both the fuel inlet and return outlet on the carburetor are right up against the water neck and coil so I put a pair of 90° fittings on my parts list.

Under the truck, I finished the fuel pump install and with a handy delivery from Amazon, I had 10 feet of coiled aluminum fuel hose in my hands. It just so happened that they had coiled the inside loop at a little less than 6″ so all I had to do was cut off a section of the inner coil and I already had a clean 180° bend in my hands. I flared the ends and installed that, then started looking for a way to get the fuel line to the inside of the frame rail. I found a factory-drilled hole large enough to feed another 90° bend just above the spring perch and threaded an another length of aluminum through to join up with the rubber hose. It feels Mickey Mouse, but I think I’ve solved the fuel routing problems and I was happy that I was able to use the brake flare kit I bought two years ago on this aluminum. Then I used a punch to put a divot in the exhaust pipe, drilled out a hole, and installed the O2 sensor. The clamps provided with the kit were too small so I used a set of pipe clamps from my bench for the time being until I can get factory clamps in hand. When I get those I’m going to pull the 02 sensor back out and wire-brush the pipe for a better mating surface.

I got back up and worked in the engine bay on the wiring until it got dark and then brought some parts in to the workbench in the basement. The first task was to modify one of the door lock cylinders to accept a snap ring at the very back using a Dremel. I carefully cut a channel out of the rear of the cylinder and trimmed a snap ring down to the same diameter. Inserting that into the channel and inserting it into the button, I used a pair of snap ring pliers to widen it out so that it stayed in place but spun freely. Reassembling the handle, it finally worked as designed and I had something I could put back on the truck.

Next, I spent a good bit of time testing the original fuel sender with the new multimeter and found that it did work, but that was dependent on the angle of the float arm. Sometimes it made contact with the rheostat and sometimes it didn’t. Doing a little more research, somebody on the Binder Planet posted that the sending unit for a ’57 Thunderbird would work with a little bit of modification, so I put that on the parts list.

I’ve been itching to just get it done but have been practicing my patience as much as possible, and as of Friday I’m pretty happy with where I’ve gotten to. The biggest hurdles now are to understand the wiring setup, and I’m going to take my time to understand what I’m doing before I start hacking things up.