Sometimes there is no fuel pressure and the relay does not click or activate and when it does not activate the check engine light does not light up with the rest of dash indicators when the key is turned on . When it shorts the check engine light starts to flash and short and the fuel pump relay makes buzzing sound with no field pressure. Then sometimes it starts just fine .
fuel pump relay buzzing no start
- Thread starter jarrod27
- Start date
6 volts at both connections with the fuel relay removed. Yes its new
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If your battery is still over 12 volts, then I'd say it's your ignition switch.
Repeated starts result in a buildup of carbon and with heat you get a high resistance. The voltage drop due to this high resistance will be evident on both sides of the relay. One side is direct from the ignition switch and battery. The other side is from the PCM which is fed through the ignition switch.
Repeated starts result in a buildup of carbon and with heat you get a high resistance. The voltage drop due to this high resistance will be evident on both sides of the relay. One side is direct from the ignition switch and battery. The other side is from the PCM which is fed through the ignition switch.
How can I test a ignition switch on 04 Pontiac Sunfire? Is there a thread on it. Also the green relay under dash clicks on and off when the problem happens. I just want to make sure its bad before I replace the ignition switch.
Try doing a search on it. I suggest you purchase a repair manual with electrical schematics for your car such as Hayne's. That would have a test method for your car but keep in mind by the time you remove the switch it'll be cooled off enough that readings may be OK. I know mine were but the contacts were black and pitted when I took the switch apart. New switch and everything's running great.
BTW, if you haven't done it already, check your battery connections and the connection to the main fuse box under the hood. When you took the voltage readings at the relay did you also confirm you had proper battery voltage to the main connection to the fuse panel.
When everything is working good, check the voltage at the relay and at other fuses that are only hot in RUN or START. Check those again when the problem occurs.
