Hi there!

I swapped some time ago my LG4 305 Automatic to a L69 305 which was a T5 Manual.

So I used the LG4 Computer as I still had the auto shifting.
It was rather moderate running compared to the previous owners car.

Further I had and still have a very bad mileage (around 8 mpg)
I tried to read out the metrics with a computer, but they were not comming regularly.
So I swapped the O2 Sensor to a heated O2 sensor.
Now I swapped in the 1228079

Here is the strange thing what happens when the 1228079 is connected:
Radio does not work, I can only hear a *clack* in the speakers when turning it on or off
The horn does not work.
Everything else works fine.


When I swap back to the original computer everything works well, but the car is way slower than with this one, also shifting is not as good as with this 1228079.


It seems I have a grounding problem too.
When I press the brake pedal, my dash light turns on. Nothing else.


Any idea ??


PS:
I still have a very bad mileage of ~ 8 mpg !!
No matter what computer I use

 

Start by checking your brake light bulb, it sounds like the filament is shorting from the brake side to the parking light side. Take them all out.

I went through a similar situation with a work S10 truck of similar vintage. We found a bad fuse, but not the one you'd expect based on the symptoms. Check them all no matter how crazy. We also found the dome light to be some odd current path-- turning on the light blew some fuses needed for other things. Removing the bulb was a fix.

I suppose a good test would be to compare ALDL ground to chassis ground and make sure there's no resistance.