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Discussion Starter #61 (Edited)
IMPORTANT NOTE: For people in the UK and possibly Europe!

I had a KLK7 ECU pulled from an 1998 Australian Eunos 800 2.5L (Xedos 9 / Millenia)... as far as I knew it wasn't paired with an immobiliser, but when I compared the internals to the KLH7 in my 1996 UK MX6 it had an identical circuit board. A few minor differences in resistors but 99% the same. I figured the differences were because of the MAF setup on the KLK7 and a VAF setup on the KLH7.

Here comes the kicker... I wired up the MAF and IAT sensors and then plugged the the KLK7 ECU in! .. got a few codes from the diagnostic port which I think they were 11, 23 and 24. Tried cranking the engine but it would not start. Later found out that there was an immobiliser for my KLH7 (the original ECU). Which meant it was highly likely that the KLK7 ECU also had an immobiliser including valid keys, which I did not have, only the ECU.

What I discovered is the 1995+ OBDII versions of the Mazdas came with a Temic Immobiliser box that uses a coil antenna in the ignition lock to read a chip in the key. Once it finds a valid programmed key it then sends a code word to the ECU to enable fuel and spark.

Unfortunately when I put the original ECU back the car would not start, then I found a document on the Temic immobiliser that said if you put in a new ECU or one from another car, or one that has not paired with an immobiliser, that ECU will try to pair itself with the existing immobiliser and if successful will lock itself to this ECU and not allow the original ECU to start the car. OH NO!! REALLY!!
PDF see immobiliser.pdf see page 3

Is this the reason I can't start the car or have I fried the ECU??

I have now sent the ECU and immobiliser to a specialist (see link) to see what my options are for re-establishing communications. ECU Decode

Will keep you updated on the outcome. If anyone wanted to put a functioning ECU from another car (in UK or Europe) Darren from ECU Decode said, he does this as a service because replacement parts are no longer available, and the car is useless without a functioning ECU.

I hope this helps someone!
 

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Discussion Starter #62 (Edited)
Update:

I spoke to Darren at ECU Decode and he told me the immobiliser and the original ECU "no longer liked each other". :frown2: Basically the code in the immobiliser is scrabbled!:help:

A replacement for this "Temic" immobiliser are not available and the company that made them does not exist, second hand ones are not an option. Mazda dealers send ECUs to Darren to work his magic, and "decode" a good working ECU to work on any compatible vehicle.

This means the factory immobiliser will have to be bypassed completely. The alternative is not an option, ie. a non-running car.

He also said the KLK7 (Eunos 800 / Xedos 9 / Millenia) although very similar in its circuit, did not appear to have any immobiliser chip, when the immobiliser tried to talk to it, it probably sent back jibberish and corrupted the coding on the Temic unit, thus rendering the paired ECU & immobiliser useless after that.

I am yet to get the ECUs back but ECU decode appear to do a lot more than decode ECUs.
 

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Hi gwq. I have been following your posts. Very interesting but mostly over my head to be truthful. II have a Eunos Presso with the 2.5L KLZE conversion. I am pondering the MAF swap as an option. Where does the KLY6 18 881R 00 ECU fit into all of the work you have done? Is that an option for a MAF conversion??
 

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Discussion Starter #65 (Edited)
Hi gwq. I have been following your posts. Very interesting but mostly over my head to be truthful. II have a Eunos Presso with the 2.5L KLZE conversion. I am pondering the MAF swap as an option. Where does the KLY6 18 881R 00 ECU fit into all of the work you have done? Is that an option for a MAF conversion??
There are two distinct ECU pinouts ... one for the v6 2.5L OBDI (1992 - 1995) and the other for v6 2.5L OBDII (1996 - 1997) ... what year is the KLY6 ECU?

ie. OBDI or OBDII
 

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Discussion Starter #66
Wow this much appreciated info mustve taken some time to get together thank you unfortunately im a 93 mx-6 owner,
Unfortunately? Please explain?
 

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hope this is in the correct thread, i have a mx6 logbook says its a 1996, however it is a obd1. just wondering if anyone had the eco pinout diagram for this, also its a uk spec, thanks in advance
 

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Discussion Starter #68
hope this is in the correct thread, i have a mx6 logbook says its a 1996, however it is a obd1. just wondering if anyone had the eco pinout diagram for this, also its a uk spec, thanks in advance
If you look at the very first post there is a link to a document that shows all the pinouts for OBDI (91-95) and OBDII (96-98). [plus much more]

It is impossible to have a car manufactured in 1996 and be OBDI. It is more likely that the logbook belongs to a different car. What is the code on the ECU starting with KL-?? ?

Oh... the problem I had with the ECU was not the ECU, it was a faulty fuel pump relay. When I got the ECU back from ECU decode the car still would not start. I later found out that the contacts in the relay were corroded and prevented it from engaging.
 

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Sorry to dig this up from the dead...

But this thread is pure gold!
I have a question though, I have a KLZE engine wich I am rebuilding right now and I plan to put it in my 1999 xedos 6 2.0 v6 KF.
But my stock ecu is a KFA1 and there is no info or pinout on this whatsoever and its very frustrating.
Also I dont recognize the distributor on it, it has only 1 plug on it... all the mx-3's (2 k8's and 1 klze) I've owned had two plugs. I assume one for the coil and on for the cam position sensor.
I'm in contact right now with a guy from the US wich wants to make me a full maf swap kit for this car but we need the pinout for the KFA1 ecu...

The only things I do know from my 1999 2.0 kf xedos 6 are, that it has a 4 plug denso ecu with 3 yellow plugs in there, and that its running the JE50 vaf factory, and that its a new style distributor wich I don't recognize.
Wiring is my biggest nightmare because I simply don't understand it. (I'm more the mechanical guy)
I do have a 1998 K8 mx-3 still for parts. everything on the engine ect is still there except for the fried wiring harness.
I'll add some pics.

The ecu :


Left big plug underside:


Small middle plug underside :


Right plug underside :
 

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Discussion Starter #71
The 1999 xedos 6 2.0 v6 KF should have the OBDII wiring that is very similar to the 1996+ KL. The best thing to do is on each of the connector pins at the ECU do a quick check to see where they are connected in the engine bay wiring loom ... aka a continuity test... check out youtube if you do not know how to do this. Compare the results to the pinouts for the OBDII 1996+ KL ECU.
 

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Thanks, was indeed going to do this, I've ordered 2 Mazda workshop manuals that are period correct to both ecus. Now I can start finding the differences
 

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Discussion Starter #73
The standard workshop manual does not give you ecu pinouts, and the "electrical" workshop manual is almost impossible to find for some KL / KF cars (especially the later ones) and it does give you some insights into ecu pinouts. My work was to show how to adapt a later ODBII ecu with a MAF (mass air flow) sensor capabilities to an earlier OBDI car that had a VAF (volume air flow) sensor, which is very restrictive and inaccurate especially for boost (aka turbo) applications.
 

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I did buy the 2 electric manuals so they are still out there. Both are on their way to my house as we speak. One for the 96+ xedos 6 (Kfa1 is 96 till 99) and one for the 93+ xedos 9 (KL68 is 94 till 95)
They are in German but I can read German so thats fine.
 
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