Fuel solenoids
Generator Fuel Solenoid Repairs
We test and replace the fuel solenoid on diesel generators: the electrical valve that opens the fuel when the engine should run and shuts it off to stop the engine. A failed solenoid can leave the engine cranking with no fire, stop it seconds after it starts, or keep it running after you press stop.
Callout fee waived when you accept our written quote. 1-year workmanship guarantee. See prices
- Coil, wiring and signal tested
- Start, run and stop proved
- Diesel sets of all sizes
- Onsite across Gauteng
Testing the solenoid
How do we test a fuel solenoid?
We measure the voltage at the solenoid while the engine cranks, check the coil’s resistance, and watch the plunger move the fuel lever. Those three checks show whether the solenoid, its wiring or the controller signal has failed.
Many solenoids have two coils: a strong pull-in coil that opens the valve and a lighter hold coil that keeps it open. If the hold coil fails, the engine starts and then stops within seconds. If the pull-in coil fails, the engine cranks and never fires.
We repair the wiring or replace the solenoid, adjust the linkage, then test start, run and stop. We never tie a solenoid open to keep an engine running, because that removes the normal way to stop it.
What we fix
Fuel solenoid faults we repair
Cranks but will not start
The solenoid does not open, so no fuel reaches the engine. We test it alongside the fuel supply, the filters and the lift pump.
Starts then stops
A failed hold coil, or a stop signal from the controller, cuts the fuel seconds after the engine fires.
Will not stop
A sticking plunger, or a stop solenoid that does not pull, leaves the engine running after a stop command. We fix it before the set runs again.
Wiring and connectors
A broken feed, a poor earth or a burnt connector leaves a good coil without power. We check the supply at the solenoid itself.
Controller run signal
The controller has to send the run signal. An alarm or a failed output can look like a dead solenoid, so we test both.
Solenoid replacement
We fit the correct solenoid for your engine, set the linkage and test start, run and stop.
Related Pages
Fuel system, starting and the controller
- Fuel System Repairs Our main fuel service: filters, contamination and polishing
- Fuel Pump Repairs Lift pumps and fuel delivery
- Cranks But Won't Start Turns over but does not fire
- Starts Then Stops Fires, then shuts down
- Controller Repairs The run signal and shutdowns
- Generator Fault Finding How we find the failed system
Common Questions
Questions about generator fuel solenoids
What does a generator fuel solenoid do?
It opens the fuel supply when the engine should run and shuts it off to stop the engine.
Can a bad fuel solenoid stop a generator from starting?
Yes. If it does not open, the engine cranks but never fires. A blocked filter, air in the line or a failed lift pump causes the same sign, so we test all of them.
Why does my generator start and then die after a few seconds?
A failed hold coil is a common cause: the pull-in coil opens the fuel, but the hold coil cannot keep it open. A controller shutdown can do the same, and we test for both.
Can I tie the solenoid open to keep it running?
No. That removes the engine’s normal way to stop and ignores the fault that closed it. Call us instead.
Does a click mean the solenoid is working?
Not always. A click shows the coil tried to move. We check that the plunger actually opens the fuel.
How is a fuel solenoid fault different from a fuel pump fault?
The solenoid lets fuel through or shuts it off, while the pump moves it. A closed solenoid leaves a healthy pump with nowhere to send fuel.
What does a callout for a solenoid fault cost?
The callout fee is R400 – R700 in business hours and R700 – R1,400 after hours. The callout fee is only payable if you do not accept the quotation. If you accept the quotation, the callout fee is waived. The written quote is free, and the diagnosis is included when you go ahead with the repair.
Still unsure what the fault is? Call or WhatsApp 082 057 4605 for onsite diagnosis.
Service Areas
Onsite visits across Gauteng
We come to your generator anywhere in Gauteng, 24/7. Choose your region for local suburbs, call-out details and the faults we see most there.
What to send before we attend
These details help us plan the visit and bring the right parts. Send what you can on WhatsApp; if you can’t find the model number, we still book the visit.
- Location
- The suburb or site, so the visit can be booked in the right area.
- Make and model
- The generator brand and model, if they are known.
- kVA
- The size printed on the data plate.
- Fuel type
- Diesel, petrol, LPG, natural gas, or dual-fuel.
- Controller model
- The module name on the panel, when it is visible.
- Fault or alarm
- What the set does, and any text on the screen.
- Photos
- The generator, the data plate, and the controller or alarm. Send these on WhatsApp.
Book a Visit
Tell us whether it fires at all
A crank with no fire, a start that dies, and an engine that will not stop are three different faults. Tell us which one you have, plus any alarm on the controller.
- Call
- 082 057 4605
- Message us on WhatsApp
What happens next
- We reply with questions about the generator, or to book a visit.
- A technician comes to you. For a breakdown we arrive within 1 hour.
- The fault is diagnosed on site and you get a written quote. No work starts until you accept it.
Charlie, lead technician: Degree in Mechanical Engineering, Degree in Electrical Engineering, Diesel Plant Fitter. Generator specialists since 2000.