Bosch Jetronic ECU P/N 0 280 000 564. I'm fairly sure these are specific to 89' 900(S), and apparently are known to be flaky. If anyone knows of an alternative P/N that is compatible please let me know. If you have a decent used one you can get rid of PM me with price and shipping to 14301 (or N0B 1SO if your in Canada). Thanks!