Just in case anyone does this swap and has knock sensor issues
I converted my 89 chevy astro over to the 16197427 (vehicle was converted to a 350 TBI a few years a go). I was having problems with the knock sensor wiring, originally I connected brown and blue together as desribed in this how to. This does not work on an 89 astro. On this vehicle brown is ground and black is the signal to the ECM (now PCM). This is probably an astro specific thing but there may be other GM TBI vehicles with this discrepency so I suggest going by the pinout of the ESC module which is as follows - pin A is empty, pin B goes to +12 volt, pin C is signal to ECM, pin D is ground and pin E to knock sensor. So connect the wires at pin C and E together. Oh and thanks goes to those who pioneered this conversion and those who have worked to perfect it!
7 Attachment(s)
TH400 Kick Down Relay control TH 400 auto to 16197427 PCM
I think this is a good tread to post a budget update about converting a vehicle with the 1227747 / TH400 combination to a 16197427 PCM which does not have a TH400 Kick Down control.
On vehicles with a 1227747 the TH400 Kick Down Relay is controlled by ECM pin A7 (tan wire with a black stripe), which sends a ground to the Kick Down Relay. The simple budget fix is to install a TH400 Kick Down Switch on the Accelerator Pedal, just like the older non-computer controlled GM Pickups used. The HUGE difference is ECM pin A7 will be switched to ground (black wire with a white stripe) through the Kick Down Switch to make the TH400 Kick Down Relay work. One side of the Accelerator Pedal Mounted Kick Down Switch will be connected to ground and the other terminal of the Accelerator Pedal Mounted Kick Down Switch will be connected to pin A7.
For a long term trouble free service, solder splicing the wiring is HIGHLY RECOMMENDED!
The pictures below are from a 1987 C3500 454 / TH400 that has been updated to a 16197427 PCM that is using an Accelerator Pedal Mounted TH400 Kick Down Switch. The older Accelerator Mounted TH400 Kick Down Switch is a direct bolt in, no modifications required.
dave w