'98 Vortec PCM Options

[Brickyenne]

Hi,

I understand this might be a very old topic, however info seems not conclusive, or there are a lot of options to the point of being confusing.

So, hope someone in this place can help. Swapped a '98 Vortec 5.7 out of a Suburban complete with transmission that looks like a 4L70E or something like that, it is a 3 piece transmission, very different from 4L60E, and it is not a 4L80E. PCM is a blackbox 16258835. No BCM is present/used on the donor Suburban.

Problem is, engine starts and shuts off after 3 seconds. The well known Passlock problem is present.

Questions are:

1. Does HP Tuners supports this PCM to remove the Passlock? Info on HP Tuners site is inconclusive. Some say these PCMs aren't supported, however HP Tuners site list the vehicle as supported. Some say a swap to '411 PCM is required some others don't. A local tuner says it can be done, however noticed he's not well aware of the blackbox type pcm issue....so what?

2. Will a '97 non passlock PCM will work with this transmission? Yes? What PCM # should I be looking for?

3. Found some small bypass circuits that claim to provide the adequate signal to the PCM and make it fire the injectors. However there are apparently two versions: a train of pulses for which this circuits work, or a serial class 2 communication scheme for which will not work. The bypass manufacturer list the vehicle as supported, but on the other hand found wiring diagram for '98 Suburbans specifying a serial class 2 comm. So will this circuits work or not? In which cases will work?

Really appreciate if someone can clarify this.

Thanks in advance,

Alfredo.