A diesel engine is only as healthy as the fuel that reaches it.
A plugged filter, water in the fuel, air leaking into the suction side, a weak lift pump, or a cracked line can all produce the same symptoms: low power, surging, hard starts, stalling, or a fuel pressure fault. Left alone, some of those problems damage expensive high-pressure pumps and injectors.
Arkansas humidity is the local twist. Warm, damp nights put condensation into partly empty tanks, and water in diesel is a leading cause of separator warnings and injector trouble. Then, a few mornings each winter, a hard freeze can gel untreated fuel and wax up filters. Filters and water separators are the first line of defense, and they need attention on schedule — not just when the truck quits.
Our Fuel System Repair: what the mechanic handles
- Primary and secondary fuel filter replacement
- Draining and servicing fuel/water separators
- Water-in-fuel sensor and warning lamp diagnosis
- Gelled fuel and waxed filters — warming, filter changes, and getting the engine running
- Priming the fuel system and bleeding air after filter changes or running dry
- Finding suction-side air leaks — loose fittings, cracked lines, and bad O-rings
- Lift pump testing and replacement
- Fuel line and hose repair
- Crossover line and tank fitting leaks
- Fuel pressure sensor diagnosis
- Fuel heater and filter housing problems
- Pulling a fuel sample when contamination is suspected
Jobs that belong in a shop
- High-pressure fuel pump replacement on many engines, which can mean major teardown and timing work
- Injector replacement on engines where it means pulling major components — some injector work is possible on site, many jobs belong in a shop
- Tank removal, cleaning, or replacement after heavy contamination
- Flushing a system contaminated with gasoline, DEF, or water all the way through the injectors
Put DEF in the fuel tank? Don’t start the engine — on many trucks, don’t even turn the key on, since that can run the fuel pump. DEF in the fuel system can do very expensive damage. Call before you touch the key.
Fix it on site or tow it?
Filter changes, water separator service, priming, gelled fuel, lift pumps, and most line and fitting leaks are standard mobile work. If the symptoms point to filters or air in the lines, the truck is usually running again on the same visit.
A tow may make more sense when contamination has already reached the high-pressure side, when a high-pressure pump or injectors have failed, or when a big fuel leak makes the truck unsafe to work on where it sits. Diesel dripping onto a hot exhaust is a fire hazard — shut the engine down and move away from the truck.
What to tell dispatch
Give us these details on the first call so the mechanic shows up with the right parts and finishes in one trip.
- Symptoms: low power, stalling, surging, hard start, or no start
- Whether a water-in-fuel lamp is on
- Any fuel smell or visible leak, and where it seems to come from
- Fault codes on the dash
- When the filters were last changed and where you last fueled
Trucks & engines we service
- Freightliner
- Peterbilt
- Kenworth
- Volvo
- Mack
- International
- Western Star
Class 6 through Class 8 trucks, with engines from Cummins, Detroit Diesel, PACCAR, Volvo, Mack, Navistar, and Caterpillar.
Fuel System Repair across Little Rock & Central Arkansas
We handle fuel system problems at truck stops, fleet yards, and on the shoulder. Low-power complaints usually show up under sustained load — pulling I-40 up from the river toward Conway, or running loaded down I-30 in summer — when a partly plugged filter can’t keep up. Water-in-fuel calls follow humid stretches and trucks that sit with low tanks.
Interstates we cover
Cities we cover
Fuel System Repair FAQ
What are the signs of a clogged fuel filter?
Power loss under load, surging, hard starting, and low fuel pressure codes. A filter can flow enough at idle but starve the engine when it’s working hard.
Why do I keep getting water in my fuel?
Condensation in partly empty tanks is common in humid weather, and water can also come from a bad fuel source or a leaking tank cap. Keep tanks fuller when parked, drain the separator when the lamp comes on, and have the source checked.
Why does my truck die right after a filter change?
Air in the system. After a filter change the system has to be primed correctly; skipping that step, or a filter that isn’t seated, lets air in.
I put DEF in my fuel tank. What do I do?
Don’t start the engine, and on many trucks don’t turn the key on either. Call right away — the tank and fuel system may need to be drained and flushed first.
Can fuel really gel in Arkansas?
Yes, during hard freezes. A truck that cranks but won’t start on a frigid morning may have gelled fuel or waxed filters. Winter-blend fuel or an anti-gel additive, added before the cold arrives, prevents most of it.
Do you replace injectors?
It depends on the engine and access. Describe the symptoms and engine model and dispatch can tell you whether it’s an on-site job or a shop job.