Product Description
| Feature | Specification |
| Primary Part Number | MOTORCRAFT DY-258 |
| OEM Part Number | D9TE-CA (Ford Engineering Number) |
| Function | Spark Delay Valve (Slows the vacuum signal to the distributor's vacuum advance unit during quick acceleration, altering spark timing for emissions control) |
| Voltage | Not applicable (Mechanical/Vacuum component) |
| Ignition System | Used on vehicles equipped with DuraSpark II electronic ignition distributors. |
| Construction | Small Plastic Barrel/Cylinder, often color-coded or stamped |
| Typical Use | Original Equipment (OE) Check Valve installed inline with the vacuum hose leading to the distributor. |
| Vehicle/Truck | Years | Engine Type | Notes |
| Ford Trucks (F-Series) | 1979 - 1980 | Various V8 and I6 | Used on the distributor vacuum line of F-150, F-250, F-350 pickups. |
| Ford Bronco (Full Size) | 1979 - 1980 | Various V8 and I6 | Used on the distributor vacuum line. |
| Ford Passenger Cars | 1979 - 1980 | V8 302, 351W, 400 | Used in full-size models like LTD, Thunderbird, and Fairmont for emissions control. |
| Mercury Passenger Cars | 1979 - 1980 | V8 and I6 | Used in models like Cougar, Marquis, and Zephyr. |
