hello all. I have an issue with a dodge dakota 1997 4x4 5.2l automatic.

story is it is my brother in laws truck and he destroyed his transmission. He got a used one and I agreed to put it in (horrible job). I got the new transmission in and started it up. it ran fine and went through the gears so I put the exhaust back on. I went to start it again afterwards and it was cranking to slow to fire. I hooked up the charger and let it charge for a minute or two. I went to start it again and it wouldn't start only crank.

So the truck can crank for days but won't start. the gauges don't seem to work either. the voltage gauge goes up a little to 8v but no more. The other guages move up a little but don't respond. the fuel gauge doesn't move at all even though there is fuel in the truck.

what I have done,
checked all the fuses and relays. there all good.
my shops program (alldata) told me to test voltage at the coil. it came up as 8v not the battery voltage it should be at. this leads me to the ecu being bad.
This sounds like the problem to me but before I spend the money on an ecu I was wondering what you guys think it might be.
thanks