In the 1990 thru 1995 Corvette service manuals, the engine computer is referred to as an ECM, which is an acronym for Engine Control Module.
In the Vauxhall Lotus Carlton manuals, the engine computer is referred to as an EMU, which is an acronym for Engine Management Unit.
No, the ZR1's Engine Computer is unique to the LT5 engine. Although the 1990 and 1991 L98 ECM and the 1992 and 1993 LT1 ECM will connect to the four ZR1 ECM connectors, L98 and LT1 ECMs will not function in a ZR1 even with the ZR1 MemCal (PROM) installed.
Yes. The same ECM used in the 1990 thru 1995 ZR1 was utilized in the 1990 thru 1992 Vauxhall Lotus Carlton (aka Lotus Omega and Opel Lotus Omega). The firmware contained in the MemCal (PROM) is significantly different but the engine computer itself is exactly the same.
Typically these part numbers are used for the ZR1 ECM: 01228331, 16163993, 16196394, 88999186. These ECMs were manufactured by Delco Electronics in the USA.
It can be reasonably assumed that at least 7000 ECMs were manufactured for the C4 Corvette ZR1 and another 1000 ECMs for the Vauxhall Lotus/Carlton. This adds up to 8000 units.
It can be speculated that a small inventory of new replacement ECMs was also manufactured. It should be noted that most ECMs that were found to be defective were repaired, refurbished and resold.
The primary cause is Integrated Circuit failure due to the stresses of heat cycling and mechanical vibration over time. These automotive environmental factors lead to the lifting and disconnecting of the wire bonds inside the Integrated Circuits.