Ok, I'll try to make it brief, but oh well. 89 Laredo body, 96 wiring harness, 97 4.0l engine. If I crank it without the fuel pump relay in, or the fuel pump disconnected, it doesn't blow the fuse.

Fuel pump appears to go out. Replace fuel pump and gas tank while I'm at it. So on the fuel pump, harness connector didn't match, so hooked up power, ground, and fuel guage. The other two are for pcm sensors.

Blew the fuse.

Checked all my wires for rubbing. Replaced the CPS. Still blowing the fuse.

Pcm was cracked, replaced it. Blew the fuse.

Voltages and ohms all look good. I went and got a replacement fuel pump. Hooked it up out of the tank and it seems fine. Put it in the tank, you guessed it, blew the fuse.

I'm at wits end. In the attached, I'm using wires 1, 3, and 5. The other two are taped off. Should they be used?

Any other suggestions??


Ran new line from the fuel pump relay to the fuel pump and hooked it up to a chassis ground. Blew the fuse.

 

I'm dying here

 

Hooked it up out of the tank and it seems fine.

Did you actually activate the pump and it ran without blowing the fuse?

 

However, I didn't crank the engine which is when it blows. It was the first time i had i actually run though. Might be a stupid question, but in the image i posted, should i ground the second wire?

 

Try it and see?

 

Those are the actual colors of the wires you have? I'm not seeing that pattern on the schematics. Maybe I'm looking at the wrong schematic. Are ALL your wires 1996? Is the ECU, fuse box and PDC 1996? What Fuse# is blowing? Were all your fuel pumps new and for a 1996?

 

IIWY I wouldn't be experimenting with wires that go to the PCM until I knew they were supposed to go there.

 

Also, did it ever work correctly? When did it stop?

 

Those ate the actual colors at the fuel pump. All wires are 96, but it's weird, some things match schematics, some things don't. Yes, yes, and yes for those. Fuse 6, a 30a maxi in the pdc. All fuel pumps were new. The fuel passmore are for an 89. I wired up the positive, ground, and fuel indicator.

 

It had been sitting fit several years before I got it. It was working with that configuration, but I don't know the last time.

 

In the 97 FSM fuse 6 in the PDC looks to be a 40A going to the blower relay. I think it's time to examine the wires from Fuse 6 out.

Sure you have the right relay?

 

Fuse 6 on this PDC is the pcm/tcm 30a. See attached.

 

Or interestingly, a 30A Fuse 6 in 97 went to a diesel Fuel Heater.

Where'd that harness come from?

 

I honestly don't know. Closest I can figure is a 96 Cherokee country? It was done before my time.

 

Your attachment didn't come through.