Zytek ecu model number?

XJ220
20

I don’t know yet. The Facelift JagSport cars’s ECM had at least 3 types of memory:

  1. There’s processor memory on the Hitachi HD6303X CPU (datasheet available) , - where the core program resides - and presumptively where the “DTC” codes get written given the Japanese XJRS owner/ECU hacker did not see them written to prom.

  2. At lest 2 PROMS (I haven’t IDed yet) EPROMS or - as described on the Japanese Blog, EEPROMS which probably contain data tables / ve tables / spark correction tables / temp value lookup tables etc.
    The markings on those chips are: DE2864-350 9026 - with a white sticker noting their positions as IC13, and IC 14 but possibly obscuring other information. )

  3. And a Hitachi HM62256 CMOS SRAM (static ram - closely related datasheet available-) chip for low power storage fo rewritable memory. --also possibly where codes are written.

I have written to the Japanese XJRS’s owner via that blog interface asking if it’s possible he still has the dump files from the PROM and ECM and if he’d be willing to share. Don’t’ know if I’ll ever hear anything as it looks like the blog was abandoned in 2016.

One thing that has become clear is that the TWR XJRS cars 88-89 during their last years experimenting w/ using the Zytek ECU used a different computer than the JagSport cars did. A wiring diagram for that has just been published on the Jaguar XJRS owners Facebook Forums and there are some clear differences including the diagnostic connector (which might just need a different dongle to work). But pin 7 is ground on one and signal on another:

88-89%20TWR%20Zytek%20Diagnostic%20Port
88-89%20TWR%20Zytek%20Diagnostic%20Port1390×569 139 KB

I don’t’ know if they’ll get around to it, but I’ve asked a couple of the XJRS owners if the need to send their CPUs off to Zytek for a fix involving the fuel pump, if they’d mind getting some high resolution shots of the guts so that the chips inside can be identified.

Getting a dead interface box with which to play 19th’ century doctor would be great!

EDIT: Just found this.
Some time back Peter Fritz “MauiHoss” noted he was able to ACQUIRE/PAY FOR the diagnostic equip from Zytek directly, along with getting his ECM checked & gives contact info:

End Edit

Just so it’s here, this is the best I’ve got At The Moment, for the older TWR Zytek wiring:

XJRS%20Wiring%20Diagram
XJRS%20Wiring%20Diagram960×720 180 KB

EDIT:
The chips marked DE2864-350 9026 are Timer E2 64K Electrically Erasable PROMs
I found the closely related PDFs here for the series: DE2864 datasheet & application notes - Datasheet Archive

DE2864_EEPROM_Datasheet_FirstPage
DE2864_EEPROM_Datasheet_FirstPage883×1117 65.1 KB

The base number is “DE2864” “350” represents the minimal nanoseconds for “read cycle time,” I.e these weren’t the most expensive chips in the series. I’m not the same board slot could accommodate the DE28C256 larger memory chips even though their both 28pin DIPs. The pinout is close but… might not work.

This was a hard to find datasheet. I’m not sure how hard it would be to obtain a supply of these chips… OR… maybe… a way to slap a modern EEPROM in such that the pinout still works.

To get an idea of possible variations of the chip these are series part numbers:
DE2817A150
DE2817A200
DE2817A250
DE2817A300 Timer E2 16K Electrically Erasable PROMs
DE2817A350
DE2818C1072AS1R0N

DE2864-200
DE2864-250
DE2864300 Timer E2 64K Electrically Erasable PROMs
DE2864450
DE2864450
DE2864A150
DE2864A250
DE2864H250

DE28C256200
DE28C256250 Timer E2 256K Electrically Erasable PROM
DE28C25625D
DE28C256300
DE28C256350
DE28C256A200
DE28C256A250
DE28C256A350

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