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1997 Mpi Warm Start Issue


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#1 HertsMini

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Posted 21 July 2021 - 10:15 PM

Hi all, something I noticed today, wondering if you have any thoughts:

 

- cold start was fine fired straight up

- drove about 4 miles filled up and all was good

- drove for another 20 mins engine up to temp. Was a bit hesitant to start, one or two more cranks than when I set off

- got back home left the car outside for 40mins try to start it up and hesitant to start again.

 

I’m very new to Mini ownership and just want to get a few thoughts on this, the car starts up but seemed a bit more hesitant than when it was cold. Any ideas what this could be or things I need to check. As far as I know all the spark plugs are relatively new, HT leads seem ok, pump is priming, immobiliser is fine, haven’t been able to test the battery but the starter seems to be turning fine. Not really sure why it would be doing this only when warm.

 

thanks in advance!



#2 Alice Dooper

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Posted 22 July 2021 - 10:32 PM

Hi, I’d the same problem but only after the car got really warm.  The car is an MPI Cooper S.  Anyway, after a real thorough head scratch, I worked out that the fuel was evaporating off enough in the throttle body / manifold to make a warm start a bit more awkward.  She would start, just grumbled enough to have me worried a few times.  All was good when we would get going again

 

At the time, it was fitted with a Maniflow LCB, unlike the stock exhaust manifolds, these don’t have a heat shield.  I fitted a Burlen alloy 52mm throttle body as part of a tuning up thing and the warm start issue disappeared. Must be enough heat soak /dissipation in the alloy throttle body as opposed to the stock plastic.  The throttle body is a reversed item that’s also fitted in MG F’s and there was talk on their forums that the original plastic ones could warp slightly when hot, never heard of that in Mini’s.  I’ve since went back to a stock exhaust manifold with heat shield anyway as the O2 sensor is in a much better place.

 

Might be a good idea to start by plugging into the diagnostic’s to make sure all the sensors are working when hot and cold.



#3 HertsMini

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Posted 23 July 2021 - 09:38 AM

Hi, I’d the same problem but only after the car got really warm.  The car is an MPI Cooper S.  Anyway, after a real thorough head scratch, I worked out that the fuel was evaporating off enough in the throttle body / manifold to make a warm start a bit more awkward.  She would start, just grumbled enough to have me worried a few times.  All was good when we would get going again

 

At the time, it was fitted with a Maniflow LCB, unlike the stock exhaust manifolds, these don’t have a heat shield.  I fitted a Burlen alloy 52mm throttle body as part of a tuning up thing and the warm start issue disappeared. Must be enough heat soak /dissipation in the alloy throttle body as opposed to the stock plastic.  The throttle body is a reversed item that’s also fitted in MG F’s and there was talk on their forums that the original plastic ones could warp slightly when hot, never heard of that in Mini’s.  I’ve since went back to a stock exhaust manifold with heat shield anyway as the O2 sensor is in a much better place.

 

Might be a good idea to start by plugging into the diagnostic’s to make sure all the sensors are working when hot and cold.

 

Thanks for getting back to me on this, the issue you had does seem to be what I'm experiencing at the moment. What did you end up doing to resolve it? I'm very new to minis so anything more complex is probably going to be a bit beyond me so will need to take it to a garage. 

 

I'll try and get hold of pscan tool seems to be a bit more highly recommended compared to the T300. I'm going out for a drive later today so will see how that goes, cold starts always seem to be fine. 



#4 Alice Dooper

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Posted 23 July 2021 - 05:48 PM

 

Hi, I’d the same problem but only after the car got really warm.  The car is an MPI Cooper S.  Anyway, after a real thorough head scratch, I worked out that the fuel was evaporating off enough in the throttle body / manifold to make a warm start a bit more awkward.  She would start, just grumbled enough to have me worried a few times.  All was good when we would get going again

 

At the time, it was fitted with a Maniflow LCB, unlike the stock exhaust manifolds, these don’t have a heat shield.  I fitted a Burlen alloy 52mm throttle body as part of a tuning up thing and the warm start issue disappeared. Must be enough heat soak /dissipation in the alloy throttle body as opposed to the stock plastic.  The throttle body is a reversed item that’s also fitted in MG F’s and there was talk on their forums that the original plastic ones could warp slightly when hot, never heard of that in Mini’s.  I’ve since went back to a stock exhaust manifold with heat shield anyway as the O2 sensor is in a much better place.

 

Might be a good idea to start by plugging into the diagnostic’s to make sure all the sensors are working when hot and cold.

 

Thanks for getting back to me on this, the issue you had does seem to be what I'm experiencing at the moment. What did you end up doing to resolve it? I'm very new to minis so anything more complex is probably going to be a bit beyond me so will need to take it to a garage. 

 

I'll try and get hold of pscan tool seems to be a bit more highly recommended compared to the T300. I'm going out for a drive later today so will see how that goes, cold starts always seem to be fine. 

 

The larger metal throttle body cured it for me.  



#5 HertsMini

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Posted 23 July 2021 - 06:26 PM

Sounds good, I’ll see what the code reader brings up. Thanks buddy

#6 HertsMini

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Posted 25 July 2021 - 08:52 AM

Plugged a fault code reader in and no current errors were coming up. Strange things is I have been driving the car over the past day or two and the issue seems to have gone, starts really nicely when it's cold and warm now... As longs as things stay this way im happy  :D  I'll keep monitoring it moving forward.






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