Problem after rain fall.

Hi Shimizu,
I have some adds to what Volker posted before.
As he does, I'm awaiting your answers with great interest.

- It is essential to know which ECU ('main unit') is used because they often differ not only in the internal design but in the outer BUS layout.
Some of the connections are all the same, but some differ - and this is essential.

- If you can tell us the number  of the ECU we can tell you about the readings you can do / have to expect at the  25-poled BUS.

It's not helpful to read values  directly at the components, because faults in the wiring harness are not detected this way.
Therefore we do all the readings at the plug towards the ECU, mostly with the ECU unconnected.

You find a list of all ECUs known to us and their external connections here:  jetronic.org/index.php/en/cars/d-jetronic/56-connector
 
Regards
Norbert
 

Dear All,

Thank you for sending messages.

Attached are the photos of ECU and MPS sensor and trigger point contact and distributor. 
In the past I heard from Bosch guy that initial "B" of ECU AND MPS sensor parts number means to made specific purpose such as test, Rally, or something like that. ECU has 25 poles.

Yes, distributor has trigger contact point as attached photo. 

Regards

Shimizu

ECU AND MPS sensor photo are attached.

Hi Shimizu,

thanks for the pictures. Indeed ECU and MAP sensor as well as trigger contacts look like original Bosch D-Jetronic. B means special application. Could be that Bosch did not consider Isuzu as big enough to justify a fully qualified product. Only guessing.

Should I once have the chance to read out ECU and MAP sensor, I would do so. Do you know whether your MAP sensor has a diaphragm and is of type 2. I believe so. From pictures it could also be a type 1. But my guess is no. And it is not anywhere close to Citroen. It is a mixture of everything. It would be goof to have the chance to read your MAP sensor before diahragm tears one day. If only you would live inside EU. Transport to and from Japan is so expensive and takes so long.

Hi Shimizu,
unfortunately we don't know much about the system - but it's a genuine Bosch D-Jetronic as you told us,

You want to do some readings - and this will be possible.

You can take the harness-connector out of the ECU (Take off the plastic cap, remove two screws <maybe a part like a frame made of plastic> and pull the plug...)

The connector is 25-poled, but not all of them are used - some are NC. <It could be helpful to know which are NC>
The pins should be numbered from '25' (harness-side) down to '1'.
Maybe the leads themselves are numbered, too - or coded by colours.

You can't damage anything if you take care not to connect other lines towards '16' and '24' that are positive (+).
All others are ground, signal or output lines, can cause no harm when the plug is not connected to the ECU.

For some of the readings like the one you intend to do you can disconnect the accumulator.

For reading out the engine temp sensor you have to read the resistance between pin 23 (all the same at all ECUs) and pin 11 (ground).
Values should be (tolerance within 15%)
                       
0° C        32° F         5,9 kOhm
  20° C     68° F        2,5 kOhm
  40° C    104° F        1,2 kOhm
  60° C    140° F       600 Ohm
  80° C    176° F       325 Ohm
100° C    212° F       190 Ohm

Regards
Norbert


 

Dear Norbert,

Thank you very much for your detailed suggestion.
This Sunday, I checked the value of engine temp sensor between pin 23 and pin11. It was as below.

13.5° C   3,5 kOhm

It seems it is no problem, right?

Regards

Shimizu