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Engine Dies When I Hit The Brake Too Hard! (Sudden Low Rpm)


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#1 edxkp

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Posted 07 May 2018 - 06:28 AM

hey all! i'm very new towards the Classic mini world and i have manual rover mini with airbag. currently, whenever i'm cruising and if i were to step on the brake too sudden, the RPM will drop ridiculously low and stall. did check the vacuum hose and no leak or whatsoever. 

i know it has something to do with the adjustment in the fuel injector but may someone tell me what am i suppose to actually adjust? 

 

i've brought my another mini ( which has similar problem) to a mechanic and what he did was remove the fuel injector cover, and told me a certain pin was not moving into place which result in the car not able to resume its RPM or something. 

 

would appreciate if someone can guide me along the way!!cheers!

 

 



#2 Ruckus

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Posted 07 May 2018 - 08:13 AM

Do you know if its a MPI or Spi model ? Before 1996 or after.

I would be looking at the stepper motor (SPI) Or idle control valve (MPI).

As the injection cars do not have carburettors they need a device to control the air when idling.

The problem you describe I had the same with my MPI mini, I chased it for a long time until it was found the idle control valve was out of position. Once it was reset I had no more stalling.

Edited by Ruckus, 07 May 2018 - 08:14 AM.


#3 edxkp

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Posted 07 May 2018 - 08:46 AM

Do you know if its a MPI or Spi model ? Before 1996 or after.

I would be looking at the stepper motor (SPI) Or idle control valve (MPI).

As the injection cars do not have carburettors they need a device to control the air when idling.

The problem you describe I had the same with my MPI mini, I chased it for a long time until it was found the idle control valve was out of position. Once it was reset I had no more stalling.

 

 

MPI as its a 40th anniversary Model. any idea how can i reset the idle control valve? is there any way for me to find some visual guide ? 



#4 Ruckus

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Posted 07 May 2018 - 10:45 AM

You need the right diagnostic equipment. The rover version is called the T4 testbook it a lot of money so only specialist tend to have them. Others system might do it but I dont know.

Mine was checked and set correct by a local MG/Rover specialist, I would recommend you do the same unless you want to start buying diag equipment.

Edited by Ruckus, 07 May 2018 - 10:45 AM.


#5 edxkp

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Posted 07 May 2018 - 01:31 PM

You need the right diagnostic equipment. The rover version is called the T4 testbook it a lot of money so only specialist tend to have them. Others system might do it but I dont know.

Mine was checked and set correct by a local MG/Rover specialist, I would recommend you do the same unless you want to start buying diag equipment.

any alternative recommendation as in malaysia, we do not have any MG/Rover specialist :/. i'm just trying to do this all DIY.
could it be some vacuum pipe to ECU/ induction pipe which has gone wrong? 



#6 cian

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Posted 07 May 2018 - 02:10 PM

As a start I would take the idle valve out and clean it with brake cleaner, the insides do get clogged

#7 buznout

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Posted 07 May 2018 - 08:53 PM

If your car is a Japanese import 40th, it will have SPi injection

#8 edxkp

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Posted 08 May 2018 - 12:28 AM

If your car is a Japanese import 40th, it will have SPi injection

oh alrigight alright. any advice on how i can solve my stalling issue at red lights, junction, slow speed etc.? i'm just so lost right now. no specialise mechanics, no mini-specialist. its just forums and forums and try and error 



#9 FlyingScot

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Posted 08 May 2018 - 06:14 AM

Right start with the basics.
Make sure mechanical set up is correct and serviced (tappets set, etc)
Vacuum pipes and fuel trap should be replaced as these deteriorate over time and are the most common issue.
Unless they have been replace recently do this as they are difficult to rule out as a cause otherwise.

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#10 owm

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Posted 09 May 2018 - 05:02 AM

For the other mini, the pin the mechanic is referring to is the plunger of the stepper motor. This is a great pinned thread by Sprocket explaining its operation:

http://www.theminifo...otor-operation/

 

And this is an excellent troubleshooting guide for the SPI:
http://www.theminifo...oint-injection/

 

 

As for troubleshooting your Rover Mini with airbag, is it a MPI or SPI? The MPI has an idle valve which as advised above, to remove and clean it thoroughly and see if that helps. Were all the vacuum hoses checked thoroughly? Might be a good time to change all of them out to silicone hoses.

 

 

 

hey all! i'm very new towards the Classic mini world and i have manual rover mini with airbag. currently, whenever i'm cruising and if i were to step on the brake too sudden, the RPM will drop ridiculously low and stall. did check the vacuum hose and no leak or whatsoever. 

i know it has something to do with the adjustment in the fuel injector but may someone tell me what am i suppose to actually adjust? 

 

i've brought my another mini ( which has similar problem) to a mechanic and what he did was remove the fuel injector cover, and told me a certain pin was not moving into place which result in the car not able to resume its RPM or something. 

 

would appreciate if someone can guide me along the way!!cheers!

 

 



#11 FlyingScot

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Posted 09 May 2018 - 05:20 AM

If it’s a JDM car it can have an airbag and the SPi system. The easy way if your not sure is where is the radiator - inner wing SPi , front MPi.

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#12 Sprocket

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Posted 09 May 2018 - 12:00 PM

The only way the brakes can affect the engine is through the brake booster. That is unless the original poster is describing another problem?....

#13 FlyingScot

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Posted 09 May 2018 - 12:06 PM

The only way the brakes can affect the engine is through the brake booster. That is unless the original poster is describing another problem?....

I assume he meant on lifting off the throttle....

FS

#14 jamesquintin

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Posted 14 May 2018 - 06:14 AM

If its an MPI check the wiring behind the air filter. It can rub through and cause this issue.






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