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Cummins 4089981 is the fuel pump timing actuator: a black solenoid housing with a two pin connector on a cast aluminium base with a two bolt flange, supplied with its gasket and three screws. It is used on Cummins ISX15 and QSX15 engines. This aftermarket version is made to the same mounting and connections as the original, so it fits where the old one came off.
Sold as one unit. Check the number on your old part, or in the parts manual for your machine, before ordering.
| Part Type | Fuel Pump Timing Actuator |
| Replaces | Cummins 4089981 |
| Engine | Cummins ISX15, QSX15 |
| Supplied as | Actuator, gasket and three screws |
| Fits | Cummins ISX15 and QSX15 engines |
| Condition | New, aftermarket |
| Stat. HS-Code | 850590 |
| Country of Manufacture | China |
Cummins machines
Check the part number on your old unit before ordering.
| Cummins Part No.(SPM Part No.) | Fits |
|---|---|
| 4089981(SPM-HEP-5167) | Cummins ISX15 and QSX15 engines |
Engine derate and fault codes
A failing fuel or timing actuator sets fault codes and the engine drops power or runs rough.
Hard starting
An actuator that sticks or leaks upsets fuel delivery and timing, and the engine cranks longer before it fires.
Fuel leaks
Leaks at the actuator base mean the gasket or body has failed. Replace the actuator with a new gasket.
Fitting tips
Clean the mounting face, fit the new gasket, torque the screws evenly and clear the fault codes before testing.
We check what other aftermarket sellers charge for this same part. Their prices on the date we checked:
| Seller | Price | Checked |
|---|---|---|
| eBay, aftermarket seller | USD 350.00 | 2 Nov 2026 |
| SINOCMP | USD 439.00 | 2 Nov 2026 |
| Fab Heavy Parts | USD 744.80 | 4 Nov 2026 |
| YEM Parts | USD 1,428.93 | 4 Nov 2026 |
| MyMROmarts | USD 1,501.61 | 4 Nov 2026 |
| Buy Machinery Parts | USD 1,682.51 | 4 Nov 2026 |
| Spare Part Mart | USD 238.27 | Today |
Our price of USD 238.27 is 32% to 86% less than these sellers.
Found this part cheaper somewhere else? Send us the listing and we will beat it by 5% under our Price Beat Guarantee. Every order is also covered by our 30 day money back guarantee.
Yes, it was made for the Cummins ISX15, and 1 more listed under compatible equipment. Check the old fuel actuator is marked 4089981 or one of the cross references, because makers change parts between serial ranges.
On the Cummins ISX15, it depends on hours and working conditions. Follow the machine service schedule, and change it when it shows wear rather than waiting for it to fail.
Leaks, noise, loss of performance, or visible wear compared with a new part. If in doubt, measure it against the sizes in the specifications.
Yes. Every order is covered by our 30 day money back guarantee. Keep it unused and in its packaging.
Keep it until the new one is fitted and running. It is the quickest way to compare sizes, connectors and mounting if anything looks different.
No. It is an aftermarket fuel actuator made to replace the Cummins 4089981. It is not made by the original manufacturer; the number only shows what it replaces.
Live rates for the quantity selected, delivered to your door. Confirmed at checkout.
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