Wont crank, under dash wire identification

[tommi3520]

Hi

I have a 1986 m1028, i was adding some gauges and also doing a bit of clean up (removing alpine radio with large wire bundle and other old sins) but now it wont crank over, sometimes it does nothing when i try to start (only dash light dampens out like usually) and sometimes there is some bad sounds coming from the hood but no cranking. All the dash lights and everything else look like normal, only when i try to crank there is a problem. Luckily there were not to many wires i was messing with so hopefully ive not done to much butchery, see photos below:

I made these grey wires longer with a blue wire just so it was easier for me to check their voltage and such. The picture of the wires on the floor i cut out of the truck to shorten the grey wires, those got connected to the black hole that was the radio and a switch to turn the radio on and such.

Ive looked over the wire diagrams but im not able to read out what i need.

 

[tommi3520]

okay so those blue connectors are what somebody has installed to steal current from existing factory wire it seems, wrong way of doing it, so i dont think i need to worry about deleting those thief wires. Although both batteries are fully charged im going to have them checked for load, and take it from there.

 

[tommi3520]

The wires under the dash seem to have nothing to do with it. I had the batteries load tested and they are really good. The truck actually started but it is very unhappy so i need to resolve this before it causes more damage.
Im getting 26volts at the positive busbar, also AT the starter
Engine is getting good ground.
Look at pictures and video and let me know if you have any ideas before i dive deeper into this.

 

[tommi3520]

Problem is solved, i replaced the worn out flex plate but that was not the issue which i kind of knew (but it was missing teeth so it was due)
.
What i did was to connect the battery cable first to the 24v bus bar and then the starter cable ontop of the battery cable in the busbar, i had them reversed from when i was building new battery cable (thought it didnt matter and maybe it doesnt) and then i replaced the battery terminals because they did not look that good and aslo the cable itself near the terminals. After i did those two it fires up normally. here is a video that shows what was happening.

fast forward to 1.13

It was power starvation to the starter from the thick cable.