top of page

Greasecar Valve Troubleshooting

Valve Troubleshooting Intro

Greasecar Valve Types: SV-100 on the left, with the SV-98 3-Port in the middle and SV-98 6-Port on the right

Step One: Testing Ground connection with multi-meter

Step Two: Checking power into the valve using a multi-meter

Greasecar SV100/SV98 Valve Troubleshooting


Your Greasecar solenoid valves were designed to give you years of trouble free use. However there are a couple factors that can affect their performance and reliability. As both the SV98 and the SV100 feature a traditional electromagnetic coil with reversible flow which drives the solenoid, the valves are not polarity sensitive. This means either lead can be designated a ground or power supply.

The solenoid of both the SV98 and SV100 operates using a magnetic coil active with either negative or positive flow. Leads are interchangeable between power supply(either negative or positive) and ground.



The valves are built so that the default position of the solenoid allows for flow from the common port (stamped COM on both valves), to the normally open port (stamped NO). When energized, the position of the piston changes, and allows for flow to go from the COM port to the normally closed (NC) port. The valve will stay in this position until power is removed from the electromagnetic coil, at which time the valve will reset to it's default position. To ensure each users success, the valves are tested before they leave the Greasecar facility.


As the operation of the valve is simple, diagnosis of a suspected valve takes only a few easy steps.


Step One: Check the valve for a proper ground connection. One lead of your valve should be grounded to a clean ground source. You can double check the ground connection of the valve using an electrical multi-meter on the ohms setting (often represented by a horseshoe-like symbol). If not familiar with using a multi-meter, please read the included instructions, and do not proceed until you understand how it works. Touch one lead of the multi-meter to the ground connection, and the other to the negative terminal of the battery. You shouldn't have any resistance between these two points. A lack of continuity between these two points would indicate a poor ground connection.

Step Two: Check the valve for the power going into the valve. The lead that isn’t grounded to the body of the
vehicle will be connected to either blue or green power lead. With you ignition on and the engine off, activate the
valve by flipping the switch in “veg” mode, and by turning the CoPilot into “veg” mode. You should have battery
voltage at this blue or green wire. If you do not, trace the wiring back to your power source (which will ultimately
be the battery), checking for either a chafe or short in the wiring. While inspecting the wiring, check any fuses that
may be inline as well.

Step Three: Briefly hot-wire the valve. The Valve can be “hotwired” briefly by connecting the two leads on the
solenoid to the positive and negative terminals of the battery. An audible click indicates the valve is switching.

Step Four: Check the solenoid coil for continuity. The internal piston of the solenoid is driven into it’s energized
position using a coil. This coil is what the two leads of the valve connect to. Using the multi-meter, test for continuity
between the two terminals. While continuity between the two terminals indicates an operating coil, an open
circuit would indicate a faulty coil.


Step Four: Good SV-98 Coil Shown

Step Four: Bad coil shown

Flow through the valve

Flow through valve in Un-energized/Neutral Position

Flow through valve in Energized Position

As described on the previous pages, the flow through the valve operates in a particular way. The flow of the valves are illustrated below. Though the SV98 is shown, the SV100 flows in exactly the same way.

The valves will be activated as follows:




Mode:     Diesel (No Light)      Vegetable Oil (Narrow Light)     Purge (Light Light)

Valve A       No Power                       12 Volts                                           No Power

N.O. Port      Open                              Closed                                              Open

N.C. Port      Closed                            Open                                               Closed

Valve B      No Power                        12 Volts                                            12 Volts

N.O. Port       Open                             Closed                                             Closed

N.C. Port        Closed                           Open                                               Open



SV-98 Valve Maintenance

Greasecar's 98 Series valves are a bit different from our SV-100 valves in terms of flow, installation, and materials. The SV98 is a cartridge style valve that can be removed from its housing for inspection and maintenance. Because of the nature of these valves, routine maintenance is necessary.


Formation of vegetable oil polymers commonly occur with regular use in a vegetable fuel system. These polymers come in the form of a brown residue and can interfere with proper valve function. Periodic inspection and cleaning of the valve cartridge is recommended and will vary with application. Suggested maintenance interval is 6 months or 1000 gal of vegetable oil use.


The SV-98 valve is made up of several components which are held together by plastic tabs on the coil body. If the valve is not extracted from the Aluminum manifold body carefully it is possible to break these tabs which will effect the function of the valve.

To service the valve, first remove the two screws which secure the valve to the manifold body.  Then, in the case of the 6-port assembly, remove the fitting from the "N.O." port opposite to the cartridge valve.  With the fitting removed you will have access to the tip of the valve cartridge and will be able to push the cartridge out of the manifold body without straining the securing clips.


The manifold body design of our 3-Port assemblies does not offer access to the tip of the valve so it is necissary to gently pry the valve cartridge out of the body with a flat head screwdriver as shown. Be sure to pry at the base of the cartridge as shown not on the coil housing or mounting tabs.

Once removed, the cartridge can be cleaned manually with general solvent and a toothbrush. Be sure to rinse debris and lubricate o-rings before re-installing. Installation is the reverse of removal.

bottom of page