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JDM to DSM ECU

Nabeel

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I have seen some where how to convert JDM ecu to DSM to accept the DSM Link. I searched & couldn't find how.
Any one know what mod to be done?
 

Brunoboy

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Vr4 ecu is the same as a DSM Ecu, 91-94 are the same and 90 is different. Ecmlink.com can have your board converted or you can purchase one there.
 

Nabeel

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I am talking about VR4 JDM ecu. Are you sure it is same as US VR4 ecu?
 

fuel

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JDM 89.10 onwards will be single board EEPROM like USDM VR4 and 91 onwards 1G
 

cheekychimp

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Yes but I believe the pinouts for the JDM ECU are the same as those for a 1990 DSM. You supposedly have to swap two wires over to run Link in a 1990 car (and hence in a JDM car). I have so far never been able to get Link working properly in my 1990 JDM VR4. As soon as I get my idle issues on the daily resolved 100% and that car is running perfectly, I will attempt to run DSMLink on 'that' car to satisfy myself that there is compatibility before messing around with the other car anymore. In fact I am now thinking I may just run an EVO 8 ECU on the other car put DSMLink in the daily (if it works) with the MAFT Pro and call it a day. It sounds from everything that I have read that this will work just fine for everything that I want to do.

Fuel: If you have any pinout diagrams in English for the JDM cars it would be extremely useful to compare with those of the USDM 91-92 VR4s and 90 DSMs. After battling for several years with this, I am convinced either my ECU to engine harness is shagged or there is something else to this conversion that has been missed for JDM cars.

For Nabeel, if you ever find that other post or get an answer PLEASE PM me. I have been struggling with this FOREVER.
 
Last edited:

RedTwo

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I seem to remember when the local guys were hacking at JDM EPROM images they found most of the data clusters to be at different addresses compared to the US EPROM images.
 

Nabeel

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FYI

Recently I am using JDM Ecu on US 91 harness. No problem so far. I dont remember if I swaped the two wires as 90 Ecu's. That can easily known as it will give error code & engine light will light up.


About the idle issue..You may right. I thought I am having bad Idle Air Control Valve..
 

fuel

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there are approx 6 different "JDM" ECUs so it helps to be more specific - ie provide a MDxxxxxx part number

According to CAPS/ASA

-87 to 89.09 pre-facelift dual board non-EEPROM 450cc TD05-14B 205PS in either std E39A or E38A RS - MD128618
-89.10 to 90.07 facelift single board EEPROM 450cc TD05-14B 225PS in either std E39A 5spd manual or E38A RS - MD150427
-89.10 to 90.07 facelift single board EEPROM 450cc TD04-13G 210PS in E39A automatic - MD153695 which was then superseded by MD169547
-90.08 to 92.03 facelift single board EEPROM 450cc TD04-13G 210PS in E39A automatic - MD165809
-90.08 to 92.03 second facelift single board EEPROM 510cc TD05-16G 240PS in 5spd Evolution spec E39A and E38A RS - MD165808

The first one will be equivalent to the 90 DSM ECU while the rest will be equivalent to the US 91 onwards DSM and GVR-4s.
 

cheekychimp

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Fuel,

This is helpful but to double check, do you have any pinout diagrams for any/all of those JDM ECUs to check with corresponding USDM pinouts. This MIGHT be the problem I am having and I have swapped wires I shouldn't have or vice versa.

Paul.
 

fuel

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Hi Paul, I don't I'm afraid. Just have access to CAPS/ASA.
 

cheekychimp

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Never mind, I'll check my ECU numbers, but are you sure on what you posted above? I had been told that ALL JDM ECUs had printouts corresponding to the USDM 1990 DSM ECUs. Consequently, I have been swapping wires in my harness, trying to run DSMLink in a JDM ECU ... I even paid over the odds for a hard to find 1990 Turbo DSM EPROM and had it socketed.

It sounds as if I should have left everything as it was and run the straight USDM '91 EPROM in the car.
 

FlyingEagle

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THE Ottawa
Quoting cheekychimp:
Yes but I believe the pinouts for the JDM ECU are the same as those for a 1990 DSM. You supposedly have to swap two wires over to run Link in a 1990 car (and hence in a JDM car). I have so far never been able to get Link working properly in my 1990 JDM VR4. As soon as I get my idle issues on the daily resolved 100% and that car is running perfectly, I will attempt to run DSMLink on 'that' car to satisfy myself that there is compatibility before messing around with the other car anymore. In fact I am now thinking I may just run an EVO 8 ECU on the other car put DSMLink in the daily (if it works) with the MAFT Pro and call it a day. It sounds from everything that I have read that this will work just fine for everything that I want to do.

Fuel: If you have any pinout diagrams in English for the JDM cars it would be extremely useful to compare with those of the USDM 91-92 VR4s and 90 DSMs. After battling for several years with this, I am convinced either my ECU to engine harness is shagged or there is something else to this conversion that has been missed for JDM cars.

For Nabeel, if you ever find that other post or get an answer PLEASE PM me. I have been struggling with this FOREVER.



Hope this helps somewhat:




http://www.mediafire.com/file/5fhcuo1norhaudv/dsmchipscom jdm usdm info.zip
 

fuel

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Quoting cheekychimp:
Never mind, I'll check my ECU numbers, but are you sure on what you posted above? I had been told that ALL JDM ECUs had printouts corresponding to the USDM 1990 DSM ECUs. Consequently, I have been swapping wires in my harness, trying to run DSMLink in a JDM ECU ... I even paid over the odds for a hard to find 1990 Turbo DSM EPROM and had it socketed.

It sounds as if I should have left everything as it was and run the straight USDM '91 EPROM in the car.



I'm only speculating that the pre-facelift JDM 87-89.09 ECU (which is dual board non EEPROM) is similar to the 90 1G dual board non-EEPROM ECU. Of course they have different part numbers due to the different tune. I'm thinking the facelift JDM loom swapped over the two wires just like how the 91 DSM and USDM VR-4s did, seeing as the changes to US models appear to happen a year later (mostly because 91 models are released in 90 in US while that's not the case in Japan).
 

cheekychimp

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Tim,

Thank you. I had been looking for that table, I knew I had seen it somewhere. I'm just trying to confirm now if ALL JDM cars are essentially USDM 1990 DSM pinout compatible or if they changed to the 91-92 configuration as Phil is suggesting. The latter makes sense. At least now I have the colours of the wires and so I should be able to trace everything to make sure it is in the right position and fit a correspondingly correct ECU.

Phil, I think I need to get the chassis numbers of both my JDM 1990 cars and have you check to see if they are pre- or post facelift. I know that won't be 100% conclusive but it should give me an idea of which way the harnesses are configured. The daily harness is also virgin and unadulterated so I can experiment on that car in the safe knowledge that I haven't created any additional problems by swapping incorrect wires in the harness (I cannot say that with 100% confidence for the other car at this point).

In addition, if I do determine that either BOTH cars are post facelift or BOTH are pre facelift at least I can compare the two harnesses and rectify any mistakes I might have made.
 

fuel

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1990 will be facelift.
 

cheekychimp

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That means it was a mistake swapping wires then. No wonder it was an odd ECU that worked to get it running. I bet that's a pre-facelift dual board non-EPROM ECU in there now that works because the wires in the harness have been reversed. I bet all of the other ECUs we used whether JDM or USDM were the 91 pinout configuration.

Small wonder nothing ran right!

Still this should be easy to diagnose/rectify now. If that's the case. I should be able to put the DSMLink Chip in the 1990 DSM ECU and be good to go!
 

cheekychimp

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Quoting FlyingEagle:

Hope this helps somewhat:




I am glad you posted this Tim, but thinking about it, I am also sure that this was the table that lead to my downfall. It says 1990 JDM cars are identical to 88-89 cars and according to Phil that's not the case and what caused my confusion. Mine is a 1990 car but it looks as if it also has the 91 configuration because the facelift occurred mid 1990 and I presume mine is a late 1990 car.
 

fuel

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facelift occured in October 1989, so all JDM 1990 cars are facelift. You can spot the facelift by having the same tails as the US 91 xxxx/2000 models and the single lamp corner turn signals/headlamps with city lights, and instrument cluster which does away with the colour change switch.

If you're referring to the second facelift for 5MT vehicles (ie to Evolution spec), that happened in August 1990 - and you would definitely be able to tell by having the hood vents, 510cc injectors, 16G turbo, 3.909 diff ratios etc.

But all JDM 1990 models will be single board EEPROM.
 
Last edited:

cheekychimp

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Thanks for clarifying that Phil. I'm 90% sure this is my issue now since Ken said the only ECU he could get my other car to run with was an old dual board non-EPROM. Still it is comforting to know the fix is probably as simple as swapping back those two wires and not something more serious/sinister.

I didn't expect this thread to reveal as much information as it has and it has been very useful. In fact if it gets the project car running properly, it's a godsend.
 

fuel

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let me know chassis numbers and I'll let you know exactly what model(s) you have.
 
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