Wiring

Both types on natural gas conversion kits have most of same wiring in common. You will need to locate these wires for the installation and some you will need to splice and others you will need to piggy back just to capture the signal for the kit to work properly. So here they are in no particular order.

O2 Sensor Wire- Your vehicle should have at least one if not two oxygen sensors. Each sensor typically has 4 wires coming off of it, 2 of them are ground wires, one of them is a heated signal wire and the other is simply a signal wire. Check your wiring diagram for which wire is which but you will most likely be looking for the non heated signal wire. If you are testing for the wire with a meter it will typically bounce between -0.5v – 0.5v or it will be a 0v – 5v signal. Depending on the year of the vehicle. (many times the oxygen sensor wires are grey or purple on the vehicle)Once you have located this wire note it down and you will be piggy backing off the wire for the signal not splicing. On newer injection kits this wire is optional because the system pulls most of its information off of a MAP sensor and this provides additional information. On the mixer kits or venturi conversions the O2 is more central to the idle of the vehicle but it can also run if you can’t locate it through the use of the software that should come with the kit.

Injector Wires- Most injectors have 2 wires going to them. If you have your manual look for the colors in it that are the individual injector wires. If your are testing to find it with a meter then there will be a common wire that goes to all of your injectors and a individual signal wire. You will most likely want the individual signal wire because if you use the common injector wire to splice into for your injector signal you could accidentally cut power to another function like the idle air control valve or throttle position sensor and your vehicle won’t run well. What i have found works best is to identify the individual injector wires at the source and splice right there above the injector. This one is probably the most time consuming part of the job depending on the number of cylinders your vehicle has. Most of my experience has been on V8 engines so there is a significant amount of time spent with the injectors alone. You must locate these wires for both the injector kit and venturi or mixer type of conversion kits.

Permanent Hot Wire- If you have your manual look for a permanent hot wire. If you are using a tester you need to find a permanently hot wire when your ignition is off or just attach a wire directly to the Positive post on your battery. Must for both kits.

Ignition Source- If you have your manual you need to find a wire that is hot when the ignition is turned to the on position and off when it is off. If you are using a tester you are trying to identify a 12v ignition source, so it will provide approximately 12 volts when the key on and approximately 0v when it is off. Must for both kits.

Ground Wires- You will need to locate a couple locations for a ground. On any given vehicle there are several ground sources that can be used without any extra drilling. However, depending on where you decide to locate your CNG ecu and feedback controller it may be easier to use a self tapping screw and drill it into the frame (which is the ground for the vehicle) and attach your wire to the screw. Must for both kits.

Throttle Position Sensor- If you have your manual look for the throttle position sensor wire. If you are using a testor, locate the throttle position sensor and there will be 3 wires typically coming off of it. One is a power wire, one is a ground, and one is the signal wire. The easiest way to confirm this wire that i have found is have your buddy turn the ignition on without starting the car and have him or her slowly push the throttle. It will give a signal that changes with the position of the throttle, hence the name. It has been my experience that this wire isn’t used on the injected kits but is used on the mixer/venturi kits.

RPM Wire- There are a couple sources that can be used for this wire. First and most common is simply piggy backing the signal from one of your coils. The software can convert the indivual coil signal to an RPM signal and use it for its purposes. Second, you can locate the actual RPM signal wire that is used on your dash dials with your manual and piggy back of it. Third if you can’t use the first two souces for what ever reason you can use a crank shaft position sensor wire. The software of the kits can then convert it to use that signal for an RPM signal. I have alway used the coil wire from the first coil on the vehicle (cylinder number doesn’t matter). It will have 3 or 4 wires attached to the coil and one or two will be a ground wires, one a power wire, and one is the signal wire. Just eliminate the ground wires and the power wire. If you have your manual then it will give you the wire you are looking for.

These are the primary signal wires that you will need to find for your vehicle conversion kits. Both kits use them to perform the fine adjustments to your vehicle. There will be other wires in the kit that will need to be attached but they will be things like the pressure sensor wire and your switch that will be in the cab. They will simply need to attach to their designated wires from the kit or cng ecu. They should be pretty straight forward.

Most kits have pretty good color coordination. I mean that they have done their best to find the most comon colors from current vehicles and made the appropriate wires that color. It makes it a little easier to understand what goes where.

In all the vehicles I have converted I solder the connections after I have positively identified the correct wires. I don’t like the cheap clamp/cut connectors because they can corrode over time and then eventually fail.

If i’m splicing a wire do it this way.

  • Cut the wire I need.
  • Strip both ends of the wire.
  • Place heat shrink tubing on the wire about to be soldered and slide it back so it doesn’t shrink from the heat of the solder.
  • combine the two wires and twist them together.
  • Solder the two wires together, then let cool.
  • Slide the heat shrink over the connection and shrink it with heat to protect the connection.

Watch this video on how to solder.

Sorry its a little blury.