Service number 1227747 was used in GM light duty trucks between 1987 and 1991 with engines 4.3L V6, 5L V8, 5.7L V8 and 7.4L V8 with automatic or manual transmissions. Note that some of the 89-90 heavy duty trucks could use a 1228747 computer and so those guys need to physically look at that white label on the computer and get that info.
Service number 1228746 was used in Camaro, Firebirds, Caprice and pretty much all TBI cars from 1989-1990. The Camaro and Firebird continued to use this ECM through 1992. The Camaro and Firebird had the L03 5L TBI engine and the rest had either the L03 5L or the L05 5.7L TBI V8 with automatic or 5 spd. No factory 5.7L 5 speeds were produced in the car line. The Camaro and Firebird also got the VATS Pass key security system which after 10 years may give you some starting difficulties as the steering column begins to wear. This VATS system can be disabled through the chip if requested at time of purchase for no extra charge. This ECM also has the 108 mph speed limiter which on a modified engine can be somewhat of a nuisance. This too can be programmed out of the chip for no additional cost f requested at time of purchase.
Service number 1228063 was used in Camaro and Firebird for only one year 1988. This makes chips very hard to find and an extra expense for me since this was only used the one year. Pretty much all the 1228746 info applies to this ECM.
Service number 1228747 was used in the GM heavy duty trucks from 1990 with all the engine combinations in the heavy duty trucks. GM wasn't real consistent on its use.
Service number 1228062 was used by GM in 1989-1990 S10's with 4.3L V6 It was also used in 1988 but GM threw another one in there occasionally.
Service number 16144288 was used by GM in 1991-1992 S10's with 4.3L V6 and the 92 fullsize 4.3L trucks.
Service number 16147060 was used by GM only in 1991-93 in the heavy duty trucks
Service number 16146299 was used by GM only in 1992 in the light duty V8 trucks and some of the heavy duties. Another case of needing to actually check that service number on the computer itself.
Service number 16156480 was used by GM only in 1993 in the heavy duty trucks
Service number 16168625 was used by GM only in 1993 in the light duty trucks.
Service number 16196395 and 16197427 were used by GM in 1994-1995 in the light duty trucks and heavy duty.
Service number 16156930 was used by GM only in 1995 in the heavy duty trucks.
Service number 16136965 was used by GM in 1991-93 Caprices.
Service number 16196395 and 16197427 are interchangeable and used in 1994-95, S10 and full size trucks, vans and motorhomes with 4.3L clear to 454 engines and manual, 4L60E and 4L80E transmissions.
Although not TBI I am including information on V6 Fieros since my wife has one. I program chips for it too. Service number 1227170 used by Pontiac in the 1986-1988 Fiero's. The 1985 V6 Fiero used service number 1226869 and have recently released my performance chip for this ECM. The 1227170 ECM has the ability to set a rev limiter to help prevent over revving the engine as in a missed shift much like the newer cars. It also has speed limiter capabilties if you want to govern the max speed at which your kids can run their car. By default both the rev limiter and the speed limiter are not used by GM on the Fieros.
I am adding another non TBI since my brother bought himself a TPI Vette.
Service number 1226870 was used by GM in 1985 only in the Corvette and TPI equipped Camaros and Firebirds/Trans Ams.
Service tag and prom id are both found on a white label on the vehicles ECM (computer), as seen in the photo below.