I thought a few representative pics would be nice for future reference.
XJ220 ECM Markings.
XJRS Markings:
Note this one is SPD1002. and is labeled Zytek Type R1-0-12
(Oddly I can’t find an reference to SPD1122 or Zytek: 20/007/0006) Dr. Solly, can you say more about that PN?
Edit. Nevermind I see it on this Facelift XJRS ECM’s label:
I can’t make out the SPD part for 100% certain though.
I haven’t found the SPD1122 PN in the XJRS parts list either making me think the image is just too blurry to properly read it.
R1-0-12 is apparently the same thing as part SPD1162 identified as existing in a 1992 XJRS. (Looking a the board markings -on another forum - it’s clear the board numbers inside are the same between these two units regardless if there are PROM updates or not. The SPD1162 ECM is listed as a component of the JS1 Equipment Kit that included all the diag stuff.
<10/13/19 Edit:>
Jaguar EPC list these XJRS ECM PNs.
Under Client Code 24 (whatever that means)
SPD1161 for all countries (USA not listed)
For another variant, this time some shipping to the USA:
SPD1162 (USA)
SPD1140 (Europe)
SPD1132 (Europe from VIN 179737)
This unit uses a Hitachi Motorola Clone CPU. AN HD6303X - pretty common processor that’s well documented and still available for projects these days. I should note that the totally hackable re-programmable Lucas 14CUX (software available) uses a variant of this same chip.
Now interestingly, we know that some DB7’s that used Zytek can use the same diagnostic box, but it’s quite possible? Maybe? that Rolls Royce/Bentley could use it too? (Given the Zytek part number similarity).
1997 Bentley Turbo part:
Zytek PN 20/021/0007A
Aston Martin DB7 i6 ECM:
Zytek ECM SPD5333 (various issued versions?) Maybe SPD5489
Zytek PN 20/020/0003E / XYRATEX PN 06H 2995
MAF based so no MAP port.
Also, Janspeed 6cyl Turbo XJR’s used a modified XJRS V12 ECM (part number unknown)
For further interest, the guts of the XJRS ECM look like this:
Note the 12 obvious MOSFETS for the Injectors, and the 13’th & 14’th odd man out for some other purpose.
I like Megasquirt as much as the next guy, and although it’s easier than this ECM for sure, I think this ECM STILL has it beat for sophistication given the number of VE & advance tables it has + diag code output. Plus it has enough MOSFETS for the Sequential EFI if that’s considered important.
A Closer Look:
And one brave XJRS owner got creative, de-soldered his PROMS and ECM and did a data dump to file for analysis (he didn’t get far, but he discovered some tables. If you speak Japanese, that blog is here:
It suggest that with the right BIN files & format files, the data from the ECM could be read live in a standard Tuner program built for talking to different ECMs like Tuner Pro RT or other software package (free).
One Last Look:
Eventually maybe enough documentation will come together so that owners of cars w Zytek’s made in the late 80s to late 90’s can actually do diagnostics on their cars. It’s a tall wish but maybe eventually.
BTW, does ANYONE know what else a PM4 connector is called or who made it? What catalog it might be in? I’d like to find the pinout (what position is pin 1-9 by drawing). That would help w/ replicating the data connector cable at least. Interestingly the PM4 connector wasn’t JUST used as the diagnostic connector on the XJRS, it was used on the XJS from at least 1992, and the XJ40 as the diagnostic connector. One would think it would be available.
Dr. Solly, you uploaded these on another forum that I haven’t had a chance to reply to yet:
Diag Box Side:
Car Side:
Edit: I answered my own question.
What a friggin PITA! I had to work this backwards from a similar 3 pin connector, figure out it’s product group, and then it’s alternative name. Eventually found it on TE connectors, and I found out that this OBSOLETE series of connectors is called: “Positive Mate Mark Iv Connectors And Contacts”
I got lucky with an RFP place that listed a green 9 pin assembly and it’s PN. Well that PN didn’t show up at TE’s website NOR did it show up when doing a PN search, but that 5Pin connector of the same series did. Looking at THAT connector’s URL for the datasheet PDF I figured I’d try to hack it by changing the PN in the URL. I got damned lucky
Note car black connector mating PN is 343066 (no pdf for that one)
And THERE IT IS. The pinout we need:
Still a little unsure about orientation. I presume the black connector above is for the 220, not the XJRS, so maybe a little different pinout than given in the XJRS S80 datasheet.
So from the green connector we know that #5 is used. Connector 5 in XJRS datasheet leads to an ECM pin described as a 5V input (despite the fact that the illustration shows it connecting to the grounded shield wires on 7 & 9.
That means the pinout (which should be confirmable by wire colors going in should be:
So
1 = +12V (Red/White line on an XJRS black connector)
5 = 5V Signal/Ground (confused on this one - but on a red wire - XJRS)
7 = Ground (black wire XJRS)
9 = TX/RX 0.670V (green wire XJRS)
That leaves the only other direct to ECM possible communication wire #6 (5V input also but unshielded) left with nothing talking to it. But that’s probably ok. It may be used w/ a different connector for reprogramming or ? Don’t know…
So really (as expected) only pin 9 and maybe pin 5 would need to be watched by oscilloscope during communication to reverse engineer the protocol and box.
(Borrowing your pic from the JEC forums: Zytek ECU Tuning/Diagnostics - www.jec.org.uk)
240° 5 pin din connectors on side of box:
Next it would be nice to know for sure what the pin to pin layout looks like for the 240° 5 pin din put to 9 pin RS232 port looks like (and if there are any resistors or crossovers in that). As well as the 240° 5 pin din to PM4 plug pinout
Din plug numbering convention assuming Zytek used it:
Serial port pinout
~Paul Kobres