The 86-89 F and Y bodies were among the first EFI computers used by GM that featured a Mass Air Flow sensor (MAF) for air metering. P4 generation ECM, 160 or 8192 baud ALDL communication (depends on code mask), “memcal” with 27C128 EPROM. Many of these ECMs feature a cold-start injector. They can drive up to 8 injectors and a single coil with distributor. There is no transmission shift control on these ECMs. The 1227165 and 16198259 ECMs can be used interchangeably.
Hardware for Tuning
- G1 Chip adapter and C2 27SF512 chip required to reprogram ECM
- BURN2 Chip Programmer programs 27SF512 chips
- ALDU1 with CABL1 required for datalogging
- Ostrich2 required for real time tuning
- APU1 AutoPROM All-in-one device programs chips, logs data and allows realtime tuning
Software for Tuning
These computers use different masks depending on the application. $32, $32B and $6E are the most common masks.
TunerPro RT + the $32, $32B and $6E definitions works for editing and datalogging. (included with APU1)
TunerCat OBD1 tuner with the $32, $32B and $6E definitions works for editing. (we do not sell, available elsewhere)
TTS Datamaster with the $32, $32B and $6E definitions works for datalogging. (we do not sell, available elsewhere)
Logging a Wideband Without an APU1
One of our customers, Fred, was kind enough to email us with this information. There is a modified bin available to allow logging a wideband with just an ALDU1 instead of requiring the analog inputs on the APU1. This uses the MAT input to the ECM. You can read more on thirdgen.org (and a thread on code patches to log 0-5V inputs)
Recommended Purchase
Platform Notes
While $32, $32B and $6E masks are found on these ECMs, it is highly recommended to start tuning with the $6E mask regardless of which mask the ECM/memcal originally used. Using a chip with the $6E mask will override whatever was present from the factory. The $6E mask does not use the 9th cold start injector and most importantly, speaks at “high speed” 8192 baud for logging, which is a HUGE improvement over the 160 baud logging used by the $32/32B masks. Stock bins for various engines (305, 350, etc.) are available for download at the Gearhead-efi $6E information page.
One of the common things that comes up is the idle change with logging on $6E. It is hard-coded but can be poked with, just like anything. This thread on thirdgen.org explains what you can do.