1987 Bronco wiring issues

[sonsbronco]

about a week ago, my son went out "wheeling" and once he put it into 4lo, and locking the hubs, apparently the wiring harness got wrapped around the driveshaft by the transfer case, and ripped ALL wires apart. I got under there and connected all the torn wires. Now, the motor turns over, no spark out of the coil, or wires.

Any help, schematics, or links to buy rear harness, would be helpful.

email: [email protected]

Much Appreciated!!!

Dustin

 

[Justshootme84]

It would help to post the year model of your Bronco. You may also find wiring diagrams in the Tech Articles forum. Look for a link to Miesk5's Homepage, too. Welcome to FSB!!! JSM84

 

[sonsbronco]

It would help to post the year model of your Bronco. You may also find wiring diagrams in the Tech Articles forum. Look for a link to Miesk5's Homepage, too. Welcome to FSB!!! JSM84

Sorry.

its a 87 Bronco 4wd, 302 all stock. The wiring that got pulled was the 19 wires that go to the back of the truck. The connectors into the case and all the way back. It did not have any power after it happen, but after connecting the 19 wires up, the motor turns over, but nothing else. I am wondering if one of the wires pulled out somewhere else? Obviously must have. I will look to see what I can find tech articles and all.

Electrical issues can be never ending... I always in the past, got a new one but I can not find anything out there.... <_<

 

[Broncobill78]

I don't have wiring diagrams yet (working on it) but I have an 88" which is the same as your sons. From what you're describing I would hazard a guess that he lost the wiring to his fuel pump, there are actually two on this model, a low pressure pump in the tank & a high pressure booster pump mounted externally, right there on the frame where the harness for the transfer case is. If it's cranking but not firing then I' suspect you don't have any fuel. The engine needs air, fuel & spark to run, figure out which one is missing and you solve your problem. I'll take a quick look at mine & see if I can spot a likely culprit but it's 35* down here in South Florida and I haven't ventured out of the house all day long. I left New England to get AWAY from this stuff.

 

[sonsbronco]

I don't have wiring diagrams yet (working on it) but I have an 88" which is the same as your sons. From what you're describing I would hazard a guess that he lost the wiring to his fuel pump, there are actually two on this model, a low pressure pump in the tank & a high pressure booster pump mounted externally, right there on the frame where the harness for the transfer case is. If it's cranking but not firing then I' suspect you don't have any fuel. The engine needs air, fuel & spark to run, figure out which one is missing and you solve your problem. I'll take a quick look at mine & see if I can spot a likely culprit but it's 35* down here in South Florida and I haven't ventured out of the house all day long. I left New England to get AWAY from this stuff.

I have confirmed there is no spark. I am going to see if there is fuel at the motor as well. Its odd that the motor would not turn over with the wiring in the rear all crapped out. As I said, the motor turns over, checked and no spark at coil/ distributer.

I understand the cold, its abit above 40 but still cold as heck to be laying down on the concrete...

I appreciate the responses!

 

[Seabronc]

The only wires that are in that harness that I can think of that will prevent you from starting the engine are the ones that go to the 2 fuel pumps. The low pressure pump in the tank and the high pressure pump that is just about under the driver seat on the frame rail.

These may help, they are from an 85 but the circuitry is basically the same and the wire color codes are the same.

Good luck,

>-

 

[sonsbronco]

I am at a complete loss.. I have tried to trace wires to the modules, lights, connectors, ect. Talk about a mess. Does anyone know what each of the 19 wires connects to that run directly along the drivers side frame rail. Some go to the transfer case, then some obviously go back to the rear lights.

I have re-connected all wires that got wrapped around the drive shaft. The rear lights do no work, the motor turns over, but will not run. I checked for spark, no go. I am needing to get the truck ont he road as having a teenage son "borrowing" my vehicles, well, is just a pain in the you know what.

I really appreciate ALL of the help and i am hoping some one out there can enlighten me on the wires under the truck. Might a ground keep the truck from running?

Thanks again.... :wacko:

The only wires that are in that harness that I can think of that will prevent you from starting the engine are the ones that go to the 2 fuel pumps. The low pressure pump in the tank and the high pressure pump that is just about under the driver seat on the frame rail.
These may help, they are from an 85 but the circuitry is basically the same and the wire color codes are the same.

Good luck,

>-

 

[sonsbronco]

more to update... I have re-checked spark and nothing. so it turns over but nothing else. fuel pump comes on... any thoughts? I am at a loss.... :blink:

 

[Seabronc]

more to update... I have re-checked spark and nothing. so it turns over but nothing else. fuel pump comes on... any thoughts? I am at a loss.... :blink:

Both fuel pumps or just one?

>-

 

[Broncobill78]

SeaBronc's right. You have 2 fuel pumps, one in the fuel tank (low pressure that pressurizes the line) and a second on the driver's side fuel rail rightn next to the transfer case (high pressure pump that supplies the injectors). I think everyone is still amazed that the loss of a pigtale so far back is effecting the spark. We're all at a loss to explain that one. I hate to say it but you may have to bring it to a shop & let the at least diagnose the problem, we're just not getting anywhere with it. I think we're *all* grabbing at straws on this one.

 

[sonsbronco]

Thanks for all your idea Sea and bill... I have no clue as both pumps are working but I have no spark. I think I am going to make sure all power wires are HOT, and just take it wire by wire. I want my son to work on it, to learn, so this will be a team project. If all else fails, we will replace the complete harness.... I have done that before and I am not afraid of a re-wire....

I appreciate all your help. Anyone have insights as to who sells harnesses?

SeaBronc's right. You have 2 fuel pumps, one in the fuel tank (low pressure that pressurizes the line) and a second on the driver's side fuel rail rightn next to the transfer case (high pressure pump that supplies the injectors). I think everyone is still amazed that the loss of a pigtale so far back is effecting the spark. We're all at a loss to explain that one. I hate to say it but you may have to bring it to a shop & let the at least diagnose the problem, we're just not getting anywhere with it. I think we're *all* grabbing at straws on this one.