93 Fbody computer differences

[BARNESGN]

Can anyone teach me the differences/problems with the 93 computers. I am looking to buy a 93 Formula. I ve researched that they have EPROMs like chips but thats it.

[1QUICKZ28]

http://lt1swap.com/all_lt1.htm


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[Injuneer]

The 93 ECM (Engine Control Module) was a carryover from the third Gens. It uses a replaceable “chip” called the MEM-CAL, which consists of a PROM memory and CAL-PAC, which contains the back-up “limp home” system. That is completely different than the 94 and up PCM (Powertrain Control Module), which has a non-replaceable, flash programmed EEPROM. The 94 and newer PCM also includes a replaceable knock module (filter) that is not present in the 93 ECM.

93 has four almost square harness connectors with unique pin outs, while 94+ has 4 flat rectangular connectors, which have the same basic pinouts 94-97.

Some differences in mode of operation:

- 93 controls only the engine, 94+ also controls the M6 (skip shift, reverse lockout) and the operation of the 4L60E auto trans.

- 93 operates only in speed-density. 94+ uses a mass air flow sensor, with default to speed-density on MAF failure.

- 93 runs batch-fire injectors (2 banks of 4 injectors). 94+ fires each injector individually, timed to TDC.

- 93 will flash DTC codes on the SES light, by shorting DLCpins. 94/95 require an OBD-1 scanner, 96/97 an OBD-2 scanner.

- 93/94 use a 12-pin DLC. 95-97 use a 16-pin DLC.

- 93 uses 1-wire O2 sensors, 94+ uses 4-wire, heated O2 sensors

[BARNESGN]

Thanks guys.
Seems to be similar to the TPI engines.
Speed density wow!

[Fastbird]

Fred hit it (though I will add that the Skip Shift Solenoid in the 93's is routed through the PCM, I know from personally repinning a harness to make it function in a 93 M6 swap I did for a guy).

Depending on what you want to do with the car, you could get away easy if staying mild, or be prepared to swap it out and throw some bills at it doing an LS or aftermarket PCM swap. Finding someone who tunes the chips anymore is going to be a task.

[Injuneer]

We’re you wiring a 92/93 Corvette? The ZF 6-speed used in the Corvettes had the CAGS feature, and the solenoid is driven off pin B9. But the Borg-Warner T56 (both M28 and M29 versions) used on the 93 F-Body does not have a Skip-Shift feature, and pin B9 is unused. Or, installing a 94+ T56 would allow you to activate the solenoid by adding the wire.

Or possibly you meant the reverse lockout solenoid on a 93 F-Body? That is activated off pin B1 on the factory PCM.

[Fastbird]

We’re you wiring a 92/93 Corvette? The ZF 6-speed used in the Corvettes had the CAGS feature, and the solenoid is driven off pin B9. But the Borg-Warner T56 (both M28 and M29 versions) used on the 93 F-Body does not have a Skip-Shift feature, and pin B9 is unused. Or, installing a 94+ T56 would allow you to activate the solenoid by adding the wire.

Or possibly you meant the reverse lockout solenoid on a 93 F-Body? That is activated off pin B1 on the factory PCM.

Bingo. Man it's been too long. Reverse lockout is what I pinned in on the 93 I swapped. Right up by the shifter. Dang I'm getting rusty!