SPN 94 FMI 1
Fuel Delivery Pressure — Value too low (most severe).
The reading is valid but far below the normal operating range, at the most serious 'too low' level.
What the SPN covers: Low-pressure fuel supply pressure feeding the high-pressure pump, after the lift pump and filters. More on SPN 94.
What FMI 1 usually points to: A real under-condition such as very low oil pressure or low fuel pressure, or a sensor that has drifted low. More on FMI 1.
Severity
HIGH — limit use, diagnose now
Low fuel supply can cause power loss, hard starting and pump damage. Address before working the engine hard.
Likely causes
- Clogged fuel filter(s)
- Failed or weak lift/transfer pump
- Air leak on the suction side
- Low fuel level or gelled fuel in cold weather
- Faulty pressure sensor
Checks & fixes (easiest first)
- Replace fuel filters and prime the system
- Check for air in clear lines or a sight glass
- Measure supply pressure with a mechanical gauge
- Check tank pickup and vent
FAQ
What does SPN 94 FMI 1 mean?
Fuel Delivery Pressure — value too low (most severe). The reading is valid but far below the normal operating range, at the most serious 'too low' level.
Is SPN 94 FMI 1 serious?
Low fuel supply can cause power loss, hard starting and pump damage. Address before working the engine hard.
What should I check first for SPN 94 FMI 1?
Replace fuel filters and prime the system; Check for air in clear lines or a sight glass; Measure supply pressure with a mechanical gauge.