Howdy all,
I'd like to bring another issue here. A friend of mine is still having problem with his Chevy.
To keep it clear what he initially had:
- ABS indicator turned on
- no more gears shifting
- lack of power (probably due to a transmission limp mode)
We pointed out the VSS sensor. Got a replacement one (no AC Delco available on our market) and:
- transmission shifts but needs a higher rpms than usual to shift the gears (have had busted speed gauge so cannot compare to speed)
- lack of power for over 2k5 rpms
We assumed on BF, that either the sensor is inaccurate or there is some crap at the gearbox, so it does not detect gaps accurately (skips some of them). BUT they gave me an info today, that the problem with engine exists also on idle, when VSS should not be processed. On the other hand, as far as I know, all these problems came at once.

He lives 100miles from me, so it is somewhat difficult for me to get there and hook up with my dongle. Since AC Delco genuine sensors would cost almost $200 with shipping and handling to Poland (and the replacements does not seem worth dealing with), I thought we better make sure of ECU parameters. Especially, the problem exists also on idle. So, my first thought was to open the process loop and see how the ECU controls the engine on the default map. Easiest way would be to disconnect the MAF sensor plug, except there is no MAF. I was quite surprised with that, but found a topic here:

https://blazerforum.com/forum/2nd-ge...-blazer-19257/
where Svartlkk says there were none till '96.

Kindly asking if someone could post a brief info how the process is controlled then?
They told me there is an IAT sensor and that's all for intake. I assume that O2 sensor is a feedback signal that adjusts the injection timing on a spider (1) If so, then there are no fuel trims between air and fuel, right? So, would disconnecting the O2 open the process loop then?

Cheers, Mike
(1) engine runs apart of spider device anyway as it is the 1st gen LPG with a mixer on the air intake