87 Basket Case

You're not wrong

I'm not a big fan of throwing parts at problem and hoping it fixes it. Fiatslug87 gave me the electrical diag manual for 1987, I found testing instructions incase anyone is interested

Wanted to update the thread... I ended up buying a new tank, pump, filter and sock. I added the extra ground and attached it to the fuel filter bracket. When it was all said and done, I still couldn't get the fuel pump to kick on. I tried applying 12v straight to the pump harness and I could get good pressure at the rail when I did that, but the pump wouldn't kick on when I was Key On. I tested voltage at the pump harness and was getting 0v at key off, 2.8v key on, and 1.8v cranking. I tested the fuel pump relay (I believe it is the middle relay of the 3) and it was good. I moved on to the starter relay. While messing with the rats nest of wires, I could hear the fuel pump kick on! I think the orange wire coming off the B+ terminal on the starter relay runs to the fuel pump and has a bad connection somewhere down the line. I also believe my starter relay is bad because the previous owner bypassed it to put a push button starter in it, but I would like to know the proper way to test the unit. Does anyone know a testing procedure? I have the 4 post relay, the one with out the lead for the ballast resistor.

I'm confused, so this 2x2 should go unused for my 5speed? I went to a junkyard yesterday and pulled a TPS unit connecting harness from an 88 XJ with an auto trans. It fits my truck and both of the harnesses. Also, I've heard you need to calibrate a TPS before it is used, do you know anything about that?

Thanks, I'll.get to eliminating it. Any idea where these harness might go? I feel like the flat connector is unused because it is tucked away pretty good, it runs behind the washer reservoir on the driver's side fender. The square connector seems important though. That one is in the middle of the engine bay, right next to the injectors. All the loom is stripped away here and the harness is zip tied to the TPS monstrosity. I don't see any components nearby that are missing their harness. The picture of the square harness isn't the greatest. It's a 2x2 square 4 pin connector, but only 3 pins are used.

Hello all I've got an 87 4.0 2wd with a BA10/5. I'm in the process of fixing the previous owners "mistakes". The wiring is a nightmare. It seems every time a component went bad, they found a different, terrible way to hack up the wiring and bypass it. The Throttle Position Sensor is missing, and there are wires stuffed into the harness that run under the dash. They run into a (for lack of a better term) block. I'm not sure what this block is, and if it is part of the oem wiring schematic, or just some rigged up BS to trick the computer into "seeing" a TPS. Any light you can shed on the subject is much appreciated.

Thanks Crusier, that's a solid idea. I pulled the tank and bench tested the pump and confirmed it is bad. I've got a new pump, pick up sock, and filter. I also found a handful of pinhole leaks in the tank. I have cleaned the tank up and washed it out, now I'm letting it sit out outside for a few days, trying to let it air out and get the fumes out of it. The plan is to put a couple tac welds over the pin holes. When my tank is sealed up and leak free, I'll install the new pump, add the new ground, and see if I've got good pressure at the rail. Once it's running on its own power, I'll start working my way through the rest of Cruisers mostly renix tips

Ok Ill give that a shot, ive got all day tomorrow to work on in. Ill check my tail light ground and probably drop the tank. I found a pin hole leak that I'm going to try and weld up

Just picked up an 87 with 4.0, BA10/5sp 2wd shortbed and ive got a fuel problem. Previous owner screwed up the wiring real bad, its a mess. When Key is on, I hear the pump running constantly. When I press the brake, I hear the pitch of the fuel pump sound change, like its getting less power. Ive got no pressure at the rail, And I don't have any fuel or even positive pressure coming from the supply hose before the filter. Not sure if I have a bad pump or a wiring issue on my hands. Possibly a fuel pressure regulator? What is the test procedure for the Fuel pump/pressure regulator/ballast resistor?