7 replies to this topic

[Rui paulo santos]

 

Olá a todos.

Não tenho um mini, mas um Rover 214 GSI (SPI) 1992 com 87.000 km. É o carro para sair do caminho aqui em casa e está quase abandonado porque raramente é necessário, mas me forçou a entrar no mundo da injeção eletrônica por causa dessa falha.

Só que agora começou a dar problemas, cano de água estourado, sensor do volante do motor e agora isso.

Às vezes não funcionava ou funcionava de forma muito irregular.

Através deste fórum descobri que era possível acessar a unidade de controle, então fiz o respectivo cabo e tive que aprender como tudo funcionava.

Resultado, falha no sensor de mapa localizado dentro da unidade de controle.

Procurei em todos os lugares e não encontrei ninguém que tivesse trocado esse sensor, eles apenas trocaram as unidades de controle por outras usadas, mas eu não queria isso porque me sujeitaria a comprar uma ainda pior do que a que eu tinha.

Então decidi desmontar o meu, remover o sensor e, como não consegui encontrar um sensor ou folha de dados idêntico, decidi tentar com o que estava disponível.

Com um potenciômetro simulei esse sensor (em marcha lenta) e o motor ligou novamente.

Então adquiri o sensor MHK100820 do Rover 25, criei uma caixa de nylon para ele e montei-o fora da unidade de controle, criei o respectivo plugue (cabo elétrico) e soldei os fios à unidade de controle. (+5v, gnd, sinal)

Este sensor tem mais um pino de sensor de temperatura que não usei.

Eu não sabia se funcionaria, só sabia que também era um sensor de 5 V e 0-100 kPa, mas a curva característica de kPa vs voltagem poderia ser diferente da original e funcionar mal.

Depois de tudo conectado, com o motor desligado, a central registra 87kpa, deveria estar em torno de 100kpa (o sensor está bom, pois testei em um Rover 25 e ele mostra valores corretos), mas assim que o motor é ligado, ele funciona muito bem e vai para 30 a 40kpa.

A sonda lambda começou a funcionar novamente e começou a trabalhar em um loop fechado. Impecável.

Preciso apenas de um conector rosqueado para conectar ao tubo de vácuo (temporariamente é com um tubo e fita isolante)

Só dirigi cerca de 50 metros e parece funcionar bem.

Desculpe pelo texto longo, mas resolvi aproveitar esse tempo, pois acredito que pode ajudar muita gente.

 

cumprimentos de Portugal

 

Aqui estão as fotos:

Infelizmente recebi uma indicação de que não tenho permissão para postar as imagens aqui...

 

[madazv8]

Well done,  I thought this was possible also.  I was lucky to find an original sensor on e-bay.

 

 

https://www.theminif...sor-in-the-ecu/

[Designer]

Hi,

 

Well done on repairing your problem and thank you for posting your procedure on the forum.

If you reply to this comment you may be able to upload your pictures by clicking on the More Reply Options bottom right of the reply box.

 

Paddy

[brivinci]

This is really interesting and could be quit helpful down the road. Not sure I ever knew what the MAP sensor looked like inside the ECU. Makes it even more interesting when you hear of people suggesting sticking cotton up there and putting on heater to dry up/clean. Seems a little far fetched to think any strand of material could 1: make it all the way up to the sensor, and 2: do anything in the way of cleaning it. 

Looking at this, is there any safe cleaner one can use to spray into the outlet pipe on the ECU to clean these? I know they make specific sprays for MAP sensors but are these different and would break if used?

[madazv8]

This is really interesting and could be quit helpful down the road. Not sure I ever knew what the MAP sensor looked like inside the ECU. Makes it even more interesting when you hear of people suggesting sticking cotton up there and putting on heater to dry up/clean. Seems a little far fetched to think any strand of material could 1: make it all the way up to the sensor, and 2: do anything in the way of cleaning it. 

Looking at this, is there any safe cleaner one can use to spray into the outlet pipe on the ECU to clean these? I know they make specific sprays for MAP sensors but are these different and would break if used?

Would tend to agree after you look at the pics.  It would be helpful to remove any build-up in the inlet tube,  but not the sensor itself. From what I could tell it was just a MEMS type pressure sensor with a silicone membrane over the top.  Without trying I can't say,  but something which wont destroy silicone.... and then the heater trick to dry it out afterwards.

[hungdynasty]

This is really interesting and could be quit helpful down the road. Not sure I ever knew what the MAP sensor looked like inside the ECU. Makes it even more interesting when you hear of people suggesting sticking cotton up there and putting on heater to dry up/clean. Seems a little far fetched to think any strand of material could 1: make it all the way up to the sensor, and 2: do anything in the way of cleaning it.

Looking at this, is there any safe cleaner one can use to spray into the outlet pipe on the ECU to clean these? I know they make specific sprays for MAP sensors but are these different and would break if used?

Would tend to agree after you look at the pics. It would be helpful to remove any build-up in the inlet tube, but not the sensor itself. From what I could tell it was just a MEMS type pressure sensor with a silicone membrane over the top. Without trying I can't say, but something which wont destroy silicone.... and then the heater trick to dry it out afterwards.

Just wonder from your picture of the open sensor, is it possible to replace the silicon membrane to rebuild the sensor?

[madazv8]

 

 

This is really interesting and could be quit helpful down the road. Not sure I ever knew what the MAP sensor looked like inside the ECU. Makes it even more interesting when you hear of people suggesting sticking cotton up there and putting on heater to dry up/clean. Seems a little far fetched to think any strand of material could 1: make it all the way up to the sensor, and 2: do anything in the way of cleaning it.

Looking at this, is there any safe cleaner one can use to spray into the outlet pipe on the ECU to clean these? I know they make specific sprays for MAP sensors but are these different and would break if used?

Would tend to agree after you look at the pics. It would be helpful to remove any build-up in the inlet tube, but not the sensor itself. From what I could tell it was just a MEMS type pressure sensor with a silicone membrane over the top. Without trying I can't say, but something which wont destroy silicone.... and then the heater trick to dry it out afterwards.

Just wonder from your picture of the open sensor, is it possible to replace the silicon membrane to rebuild the sensor?

 

I would imagine that would be hard.  Silicone elastomers come in a wide range of durometers when cured, so even if you could replicate the thickness you would not be guaranteed a good result.   I think the 3 wire solution with a suitable generic MAP sensor is the best - when the originals can't be bought any more.

[brivinci]

Just need someone to list out which wire is which. Also, would there be any benefit to having the sensor closer to the manifold? Does it matter that its a bit of a distance away currently?