Question on Fuel Pump Testing

[racemini]

Hi Nick! I have a base model r56, and I'm trying to diagnose why my car intermittently coughs and loses power at highway speeds and while going uphill on the highway. Right now, I suspect the engine isn't getting enough fuel on the highway.

I checked the voltage at the fuel pump relay during starting, and I got around battery voltage ~12.6 volts. However, when I check pin #2 of the fuel pump connector figure 8 of your instructions during starting, I get only 11.3 volts. Does this mean there's an issue with the wiring, as the pin is not receiving the full battery voltage? I tried measuring resistance from the relay to the fuel pump connector, and from the fuel pump connector to ground, but didn't measure any significant resistance.

If there is an issue with the wiring, how can I access the wiring to inspect it? I have the bentley manual, but I'm unsure where the fuel pump wiring runs through.

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This post was auto-generated based upon a question asked on our tech article page here: MINI Cooper R56 Fuel Pump Testing (2007-2011) | Pelican Parts DIY Maintenance Article

[Nick at Pelican Parts]

Could be low depending on where your ground is. Make sure the ground is on battery negative when testing.

If you suspect an issue with the wiring, confirm it via testing, loading the power and grounds or voltage drop test them. Then replace the wires if found faulty. Don't repair, just run new wires. It is faster.

- Nick

[Luccia at Pelican Parts]

Just to give you some other options and ideas: You could attempt to run some fuel cleaner through your gas tank to clean out the injectors possibly. I do this to my personal vehicle every once in a while. Any fault codes present or a check engine light? How many miles are on the vehicle?