Engine cranks but does not always start on first attempt?

Tiny
DCROUCH92
  • MEMBER
  • 2007 MINI COOPER S
  • 1.6L
  • 4 CYL
  • TURBO
  • 2WD
  • MANUAL
  • 95,000 MILES
I have a 2007 R56 N14 mini copper, for a long time now the car has struggled to start on the first attempt once it has been sat for a long period of time. I have replaced the low-pressure fuel pump, HPFP, fuel filter, spark plugs, camshaft position sensor and changed the battery but none of these seem to have solved the issue. The car appears to run fine and starts on the second attempt but struggles on the first one. I have had the fuel pressure measured at 5 BAR but am now running out of ideas for what could be causing this issue. Any help you could give would be greatly appreciated. Thank you
Friday, February 7th, 2025 AT 3:11 PM

13 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 52,235 POSTS
I have seen the engine coolant sensor get weak and give false readings to the PCM which will cause this issue. We can tell for sure if we scan the computer to see what the readings are, this guide can help:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

I have also seen a dirty throttle body cause this issue as well. Here are two more guides to help us see what's going on:

https://www.2carpros.com/articles/throttle-actuator-service

and

https://www.2carpros.com/articles/engine-cranks-excessively-before-starting

Here is the coolant sensor location in case the readings are off. Check out the images (below). Please let us know what happens.
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Saturday, February 8th, 2025 AT 10:47 AM
Tiny
DCROUCH92
  • MEMBER
  • 7 POSTS
Hi Ken thanks for your reply, I took the throttle body out and gave this a clean as it was dirty however I don’t think this has resolved the issue. The thermostat has recently been replaced so I don’t believe the issue lies with that as it was like it before and after the replacement. I have brought some injector cleaner which I will put into the fuel from tomorrow to see if that helps anything. Otherwise, do you have any more ideas of what could be causing the issue?
Also, I forgot to mention before I have also replaced the Vanos solenoid.
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Tuesday, February 11th, 2025 AT 10:04 AM
Tiny
KEN L
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  • 52,235 POSTS
Did you run the codes? Like I say, I have seen the engine coolant sensor cause a hard starting issue.
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Tuesday, February 11th, 2025 AT 10:16 AM
Tiny
DCROUCH92
  • MEMBER
  • 7 POSTS
The car isn’t currently showing any codes.
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Tuesday, February 11th, 2025 AT 10:42 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 52,235 POSTS
I would use a scanner to see the engine temperature and then if it is off change the sensor out.
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Wednesday, February 12th, 2025 AT 9:02 AM
Tiny
DCROUCH92
  • MEMBER
  • 7 POSTS
I checked the coolant temperature after I drove home today, and it was at 105 C this was after a 30 minute journey.
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Thursday, February 13th, 2025 AT 1:09 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 52,235 POSTS
That's seems a little high to me, was it a hot day?

Normal operating range: 85°C to 97°C

You might to try swapping the sensor out to see if the reading changes.
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Friday, February 14th, 2025 AT 10:15 AM
Tiny
DCROUCH92
  • MEMBER
  • 7 POSTS
Hi Ken, I fitted the new temperature sensor. I haven’t checked the reading yet, but it hasn’t changed the starting issue.
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Wednesday, February 19th, 2025 AT 1:28 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 52,235 POSTS
Okay, let's do a compression test to see if it is low which will cause hard starting.

Please go over this guide:

https://www.2carpros.com/articles/how-to-test-engine-compression

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Wednesday, February 19th, 2025 AT 10:18 AM
Tiny
DCROUCH92
  • MEMBER
  • 7 POSTS
I completed the compression test and the readings were a lot lower than the guide said. The first cylinder I tested was at about 103/104 PSI and the other 3 were exactly the same at 95 PSI.
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Monday, February 24th, 2025 AT 3:57 AM
Tiny
KEN L
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  • 52,235 POSTS
Yep that is low. The engine can be worn out, the timing chain has jumped one tooth or the camshaft Vanos are not working/worn out, I would do a leak down test on the engine to see if the valves/rings are leaking or if it is a timing issue.
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Monday, February 24th, 2025 AT 11:38 AM
Tiny
DCROUCH92
  • MEMBER
  • 7 POSTS
I did have the timing chain replaced and have replaced a Vanos solenoid. How would I go about a leak test or is this something a garage would need to do?
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Monday, February 24th, 2025 AT 12:03 PM
Tiny
KEN L
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Here is a video to show you how but it sounds like the engine is worn out. Let me know how is goes.

https://www.youtube.com/watch?v=h993q16Oul4&pp=ygUJbGVhayB0ZXN0

Please go over this guide and get back to us.
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Tuesday, February 25th, 2025 AT 9:28 AM

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