Hi there,
I am new to the forum, however I have read tons of various forums for quite a few weeks now. I recently got a 95 Toyota T-100 3.4L V6 4x4 Auto. It was a little rough and needed some attention. With the help of some write ups I have replaced the timing belt, tensioners, water pump, and cam seals. Also I have cleaned my MAF, IAC and TB. Replaced ECU coolant temp sensor. I also replaced my rear wheel bearings and changed the seals. Changed both differentials oil and replaced the brake master cylinder and rear shoes and wheel cylinders. I also welded a pretty cool tailgate up that I can post pictures of later, only cost $50! Tightened all loose bolts and have been trying to get everything that rattles, to not. Anyways so it evident I am trying to get this thing running well.

Here is where the story gets TERRIBLE! I decided to install an aftermarket stereo into the thing. I noticed there was a factory amp in there, so I yanked it out, and cut off the plugs and soldered on all the proper connections. I had the battery disconnected the entire time. When I hooked the battery back up, the stereo would cut out and didn't sound all that great, the accessory wire only has about 4 volts? It was a used head unit so maybe it was already messed up. But here is the worst part. I started my truck up and a bunch of stuff wasn't working. It fired up and ran, but the tachometer didn't work, the heat shot up through the roof, the gear selector didn't show which gear it was in. And I could get it to go into gear and drive but it wouldn't shift out of first.
I am half decent with mechanical stuff, is something rattles or squeaks or doesn't feel right I will hunt it down and fix it.
Electrical is NOT MY FORTE. So I am at a complete loss at what I could have done. I have checked all the fuses and none where blown. Could I have fried my ecu? Would the car even run with a messed up ecu? Or does the factory amp act a link between two power sources as there are about 3 or 4 wires I didn't use when hooking up the head unit. Anyways if any of you have any guess at all where to start or an attempt to diagnose it would be very helpful! I went out and bought an OBD2 reader, and I am going to hook it up tomorrow and see what is says. Oh and I did disconnect the battery again for a couple hours to try and reset the ecu but it still had the same problem. Any help will be appreciated, thanks!
-Andrew

 

Post some piccies of what yer wiring setup looks like.