I have a mini cooper S JCW 2012 model. Recently the cars engine block was damaged and changed in a local shop with a used engine. Since the used engine was installed there seems to be a problem of high pressure fuel pump(check engine light is on mentioning Fuel tank valve activation line : disconnection). Even after changing the fuel pump there seems to be no changes in the cars issue. The car cannot rev for more than 4 RPM. It is what a specialized garage says. After checking the engine he said that the current engine which is installed in your car is of a Mini Cooper S rodster. It is not the same engine of your car. Since it is not the same engine this check engine light is on and cannot give high accelaration. SO now he is telling me to change the complete wiring system. Once the wiring system is changed and the ECU has been reset, there is a 70 percent chance it may work. Guys I would like to know on your thoughts. Will it work?

  • Are you translating what the mechanic said from another language? Is it possible the mechanic was talking about the ecu for the engine?
    – Solar Mike
    Dec 20, 2021 at 8:37
  • Do you know what was swapped? Was it just the block, or were all the ancillaries swapped too?
    – HandyHowie
    Dec 20, 2021 at 8:38
  • Hi, The full engine was swapped. a new ready engine was placed on to the car. The fuel pump is not the same as the previous engine that is why the garage guy is mentioning to change the wiring and can do some softwaring to reset the ECU and it can be ready. Dec 20, 2021 at 9:04
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    If this were my situation the first place I'd go is to the local shop that you had do the work. Generally it would be up to them to procure the correct replacement engine, install it properly, and verify the installation.
    – jwh20
    Dec 20, 2021 at 11:08

1 Answer 1


The mechanic sounds like he is guessing, which is not good enough.

What model of mini the engine block came out of shouldn’t make a difference if it is the same size and same engine type.

If there is a difference with an ancillary component on the engines, for example the fuel pump or fuel pressure regulator, then that should be swapped from your old engine to the new engine.

You need to find out exactly what he thinks is different. Changing the full wiring harness doesn’t sound like the correct fix to me.

  • The down-voter, maybe you could point out what is wrong with what I have said.
    – HandyHowie
    Dec 20, 2021 at 8:45
  • The complete set engine was changed, not only the block. He showed me the difference in the fuel pump of the same car, that my car has a different fuel pump design that is why the ECU is not getting the correct anaylsis in its system due to different fuel pump design because the engine is not the same of a Mini cooper S JCW instead it is of the roadster which have the trunk space. Please advise what can be done. Dec 20, 2021 at 9:09
  • If I had the same issue, I would be trying to identify what the differences are. Maybe the injectors are different, or some sensors. Is the actual block different? It could end up costing a lot of money if guesses are made and parts changed without knowing what the exact issue is.
    – HandyHowie
    Dec 20, 2021 at 9:49
  • This guy is mentioning that since the engine is of a different car he is changing the wiring and the ecu system to make it work. The head looks different. The fuel pump on the right side of the engine is different. Dec 20, 2021 at 10:17
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    You should have put this extra information in the question. It sounds like the engine is significantly different. I am not surprised that there are issues. Unless someone on here has detailed knowledge of the engine differences, you are unlikely to get a very helpful answer. Edit your question to include the information in your comments.
    – HandyHowie
    Dec 20, 2021 at 10:53

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