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So its 2010 R56 model. The battery, starter is good and tested well. However, it takes several crank cycles for it to start. Initially i used to do 7 or 8 short cranks (4 seconds) each for it to start.

Today I noticed that if I continue the first crank for say 9 - 10 seconds, it will start on the second crank.

I read through mini forums and they mention that it could be HPFP issue, but why would the car start in second crank when it fails to start on the long first crank duration?

So even if I continue the first crank duration for say 15 seconds it wont start! This doesnt sound like HPFP issue, right?

After further research online it does look like HPFP issue more specifically: source

The problem with the Mini Cooper S High Pressure fuel pump failing is an internal non return valve which fails and allows pressurized fuel to leak back into the fuel tank and as a result upon start-up has a lack of sufficient fuel to the injectors causing misfiring until the pump has built up sufficient pressure.

This looks like to symptoms I am facing, once the car starts after several attempts or cranking, the HPFP must have built enough fuel pressure to cause ignition and once the car starts the RPM continually supplies the fuel faster to HPFP

Upon diagnostics the following fault codes were given off:

P1105: (ECM) has detected a fault or malfunction with the Manifold Absolute Pressure (MAP)/Barometric (BARO) pressure switch solenoid valve.

P111A: not sure what this is exactly

P0420:

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    Does it make any difference if you leave the ignition on for 10 seconds before starting to crank?
    – HandyHowie
    Jun 21, 2022 at 22:25
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    @findwindow - I'd bet if the car is ultimately starting, it's not the ignition which is at fault. I'd highly suggest this is a fueling issue, but the OP would need to test the fuel pressure.
    – Pᴀᴜʟsᴛᴇʀ2 ♦
    Jun 22, 2022 at 0:33
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    @findwindow I added new iridium spark plugs as well as tested coils. They are fine. I doubt that spark is an issue
    – user0193
    Jun 22, 2022 at 8:50
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    You can always test this theory by spraying flammable liquid (starting fluid) down the intake during first startup. If it fires right away, it's a fueling issue.
    – Pᴀᴜʟsᴛᴇʀ2 ♦
    Jun 22, 2022 at 10:45
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    Is this starting behavior consistent, or does it vary if the engine is hot or cold?
    – GdD
    Jun 22, 2022 at 13:55

1 Answer 1

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It could be a check valve (aka non-return valve) causing your problems, the challenge is that yours is built into the high pressure fuel pump. The HPFP is an expensive part, you would want to exhaust other options before you spend on it, and do more diagnostic work.

You may be able to get fuel pressure readings using an OBD reader, I would start there and see what readings you get before and after starting when hot and cold. If the fuel pressure is very low before starting then it's very possibly the check valve. Your options would be to get the pump repaired (not sure if that's possible or economical), replace the pump, or you may be able to add a non-return valve in-line. It could also be that your low pressure or high pressure pump is starting to fail and don't operate well until they run for a bit.

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  • Ok, So I was unable to confirm the fuel pressure using OBD because it wasnt supported in my device. The fault codes I got were P1105, P111A and P0420. So it could be MAF, HPFP or something I yet have to figure out
    – user0193
    Jul 17, 2022 at 19:35
  • They could be old codes, did you clear them? If you clear them and they don't come back they aren't a concern. P111A is an injector circuit failure code, but it can trip because of low fuel pressure. P0420 is an emissions code and is almost certainly unrelated.
    – GdD
    Jul 18, 2022 at 7:50
  • yes, I did clear them and got P1105 & P111A as "pending fault codes". The ECU would confirm it after successive runs i guess.
    – user0193
    Jul 18, 2022 at 8:10
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    If you had a problem with an injector or the maf you'd be having rough running or other issues after start. P1105 could be a pressure differential sensor, not a MAF, or you could have a leak in the intake system, a common fault is a cracked breather tube. It's probably a problem of some kind but I'm not convinced it's the source of your starting problems.
    – GdD
    Jul 18, 2022 at 8:42
  • this makes so much sense! I am gonna get better OBD to get additional readings on sensors.
    – user0193
    Jul 18, 2022 at 8:45

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