Product Description
Genuine Cummins
Cummins 3991518 — AFC Boost Reference Hose / Air Fuel Control Tube
MPN: 3991518 | Also Known As: AFC boost reference hose, aneroid line, air-fuel control tube | Length: ~7.5" (measure original)
Why This Part
- ✓ Restores proper fueling by carrying boost pressure to the AFC (aneroid) on P7100 pumps.
- ✓ Direct-fit for 2nd-gen 5.9L 12-valve P7100 trucks (1994–1998).
- ✓ OE materials resist heat and under-hood degradation.
- ✓ Simple, low-cost fix for drivability issues caused by cracked or missing hose.
OE Fit Stock Replacement 1 Per Engine
Quick Specs
| Type | AFC boost reference hose / air-fuel control tube |
|---|---|
| OE Part # | 3991518 |
| Length | Approx. 7.5" (verify against your original) |
| Qty Required | 1 per engine (sold individually) |
Verified Fitment (Automotive)
| Year Range | Engine | Chassis |
|---|---|---|
| 1994–1998 | 5.9L 12-Valve (P7100, AFC/Aneroid) | Ram 2500/3500 |
Industrial/Off-Highway: Listed by Cummins as an Air Fuel Control tube on select non-certified C8.3 applications—verify by ESN before ordering.
Often Paired With
- AFC Straight Male Connector: Cummins 3920803
- AFC 90° Elbow Adapter: Cummins 3910265
- Silicone boost/vacuum line for adjacent connections as needed
What’s In The Box
- (1) Genuine Cummins AFC Boost Reference Hose / Tube (3991518)
- Fittings sold separately (see “Often Paired With”).
Install Tips
- Measure original (~7.5"). Route away from sharp edges and heat; avoid kinks.
- Inspect/replace fittings (straight or 90°) if brittle or leaking.
- After install, road-test to confirm proper AFC response under boost.
FAQ
WILL THIS FIT MY 1994–1998 5.9L 12-VALVE?Yes—designed for 2nd-gen 5.9L 12-valve Rams with the P7100 injection pump and AFC (aneroid) system.
WHAT DOES THE AFC BOOST REFERENCE HOSE DO?It carries boost pressure to the AFC/“aneroid” on the P7100 so the pump can fuel correctly under load.
WHAT’S THE LENGTH?Approximately 7.5"—verify against your original line before ordering.
ARE THE FITTINGS INCLUDED?No—order the straight (3920803) and/or 90° elbow (3910265) adapters separately if needed.
IS THIS A GENUINE CUMMINS PART?Yes—OE Cummins 3991518.
Product Videos
Custom Field
Vehicle Year 1994-1998
Vehicle Make DODGE
Vehicle Model 5.9L 12V CUMMINS
Part Type AFC Boost Reference Hose
