Fuel System - Noise From Main Fuel Pump
88peugeot05BULLETIN NO. 248
DATE: August, 1987
SUBJECT: NORMAL NOISE FROM MAIN FUEL PUMP
A positive displacement high pressure main fuel pump as used in our Bosch fuel injection systems will characteristically emit a "buzzing, screeching" sound when ambient temperatures exceed 30~C (85~F). This noise is usually heard from outside of the vehicle only with the radio off and A/C blower on low speed, under the following conditions:
1. Lowering a window while entering a toll booth or garage.
2. Exiting an idling vehicle after one or more hours of highway driving.
3. Exiting an idling vehicle after periods of prolonged idling in stop-and-go traffic.
4. Driving very slowly near fences, walls, underpasses, etc. with one or more windows open.
The volume of the noise will increase as the ambient temperature increases above 30~C (85~F).
This characteristic noise is not a reason to replace the main fuel pump, as the replacement pump will only begin to make the same noise under the same fuel/temperature conditions.
Main fuel pump noise should not be confused with in-tank priming pump noise.