Adding Fuel Injection

Adding Fuel Injection Fuel Injection Close Up

Fuel-injection swaps seem to be catching on for all types of off-road vehicles these days. The aftermarket support is incredible when it comes to fuel-injection swaps, but what if you want to do a junkyard fuel-injection swap?

At first glance it would seem like it’s not too difficult, but appearances are not what they seem when it comes to fuel injection. Most fuel-injection swaps involve either a multi-port fuel injection (MPFI) or throttle body fuel injection (TBI). For cost and simplicity reasons a large number of the swapped-on fuel injection kits are TBI kits that fit on existing intake manifolds. These TBI kits are very affordable and reliable for off-road use. One of the biggest reasons to add one of these is never having to worry about stalling out on a steep climb. Well, that and the fact that retrofitting fuel injection (usually) improves fuel economy, engine power output, and gives cleaner emissions out of the tailpipe.

Have you ever tried performing a junkyard fuel injection swap only to quickly realize it was going to take more than just plugging in the harness to a power source? The factory harness has various wires that are not needed and need to be removed to simplify installation. Be prepared to spend at least a few hours taking apart the harness and labeling the various plugs.
Have you ever tried performing a junkyard fuel injection swap only to quickly realize it w
Most TBI kits are designed to run a fuel return line to the tank to alleviate some of the excess pressure at the TBI. This can be done by splicing a T-fitting into the overflow fuel hose if you don’t already have a return line to the fuel tank.
Most TBI kits are designed to run a fuel return line to the tank to alleviate some of the
When you’re doing a junkyard TBI swap, you’ll likely have to run an inline fuel pump which is pretty easy to install. The difficult part is having the right one. Our friend made the mistake of running a higher pressure pump that would make the engine flood out within a few seconds of running. TBI units run a fuel pressure of 12 to 14 psi.
When you’re doing a junkyard TBI swap, you’ll likely have to run an inline fuel pump which

Adding Fuel Injection Junkyard Parts Installation Problems

If you’re trying a junkyard swap with a GM TBI, the ECU has to be run inside the cab since it is not intended to be mounted in the engine bay. Here you can see why installing junkyard parts will create troubleshooting problems that will be difficult to diagnose with the factory tangled mess of wires. Aftermarket kits come in longer lengths with everything pre-labeled to ease installation.

If you’re trying a junkyard swap with a GM TBI, the ECU has to be run inside the cab since

Many companies offer self-contained TBI systems that are very affordable and user friendly for the average person. Companies like Howell, Holley, Fast, First Fuel Injection, Edelbrock, and Affordable Fuel Injection all have EFI systems that will easily outperform any junkyard fuel injection system and they are guaranteed to work!

A cheaper, but riskier way to attain fuel injection is by piecing together a GM TBI unit along with all the necessary sensors, relays, ECU and wiring harness from a junkyard. You should plan on spending at least $400 for everything you need, but if you have faulty parts the price quickly goes up. If you’re planning on installing it into a non-Chevy V-8 be prepared to spend endless hours trying to get it to run. If you want the system to control the timing advance, some distributors will not be compatible with this system.

If you’re not fully prepared to wire up, modify parts, and troubleshoot problems that will no doubt arise, junkyard swaps are just not worth the hassle! Take it from someone who saw a good friend drop more than $1,200 trying to retrofit a factory GM EFI system onto a Ford engine. You’ll end up spending more money on troubleshooting, labor, parts, and time. Not to mention that your truck will be hung up for weeks as you try to make it run correctly.

Unless you have extensive knowledge of computer-controlled fuel injections and how to properly input every reading they get, then we’d highly suggest leaving the creation of a retrofit fuel injection system to the professionals. You can find professionally built EFI kits for under $1,000 these days. And some EFI kits are self-learning systems so they don’t require dyno time and tuning to make them work great!

An oxygen sensor must be added to the exhaust in order to properly run the system. All you need to do is drill a hole in the exhaust big enough to fit a spark plug extension and weld it in place. Make sure you route the wire up and away from the exhaust.
An oxygen sensor must be added to the exhaust in order to properly run the system. All you
In order to get the TBI system to work you’ll need to run a coolant temperature sensor since the ECU uses a reference voltage from it to adjust the fuel mixture. The ignition control module on the right needs to be wired up to the distributor in order to deliver a pulse signal to fire the injectors. If the reference voltage from a GM pick-up coil doesn’t match your distributor’s pick-up coil, the injectors may fire at the wrong time causing the engine to lock up or backfire. It’s obvious that an aftermarket fuel injection kit is the better choice when performing a swap like this. The aftermarket units are ready to run and are guaranteed to work with your engine. The same cannot be said for a junkyard system.
In order to get the TBI system to work you’ll need to run a coolant temperature sensor sin
This Holley self-learning TBI system throttle body bolts directly onto an existing manifold. After inputting a few engine specifications, the installer is able to turn the vehicle on, drive it, and have the fuel injection system tune itself. For now, Fast and Holley seem to have the leading self-learning systems, but we’re sure to see more companies offering these kits in the future.
This Holley self-learning TBI system throttle body bolts directly onto an existing manifol

Sources
Howell Engine Developments 6201 Industrial Way Marine City MI 48039 810-765-5100 www.howellefi.com	Holley Performance Products 1801 Russellville Rd P.O. Box 10360 Bowling Green KY 42102 270-782-2900 www.holley.com