* Pump Pushrod Adjustment: The most common cause. The pushrod connecting the camshaft to the fuel pump might be improperly adjusted. Too much or too little clearance can cause the pump to "tick" or "tap" against the camshaft lobe. This is a relatively easy fix, requiring adjustment of the pushrod length.
* Pump Mounting: An improperly mounted pump can cause it to rub against the engine block or other components, creating a tapping sound. Make sure it's securely fastened and seated correctly.
* Internal Pump Issues (Less Likely): While a *new* pump is unlikely to have internal problems, it's possible there's a manufacturing defect causing a component to intermittently contact another inside the pump housing, producing a ticking sound. This is less likely than the adjustment or mounting issues.
* Loose or Damaged Pump Arm: The pump arm itself might be loose on the shaft or slightly bent, leading to irregular contact and noise.
* Other Engine Noise: Sometimes, a noise *similar* to valve tapping can actually originate elsewhere in the engine. It's important to carefully listen to pinpoint the exact source and be certain it's the fuel pump before making adjustments.
Troubleshooting Steps:
1. Verify the Sound's Source: Use a mechanics stethoscope or even a long screwdriver held against your ear (carefully!) to pinpoint where the noise is coming from.
2. Check the Pushrod Adjustment: This is the primary suspect. Consult your Edelbrock instructions or a reputable engine repair manual for the proper adjustment procedure. It often involves measuring the pushrod length while the cam is on its base circle (when the lifter is at its lowest point).
3. Inspect the Pump Mounting: Ensure all bolts are tight and the pump is seated correctly on its mounting surface.
4. Listen Carefully: Does the tapping change with engine speed? Does it only happen at idle or under load? This information can help diagnose the issue.
If you're unsure about any of these steps, it's best to consult a qualified mechanic. Improper adjustments can damage your engine.
