low voltage to fuel relay

[Masscrawler]

Sup all, I'm having a hell of a time with my MJ.

 

This afternoon when I went to go fire it up I didnt hear that fimiliar buzzing from my fuel pump.

 

The MJ had been sitting for a few months so I assumed that it was my fuel pump and proceeded to remove it for a replacement. I went and bench tested and what do you know... fine. Thats what I get for assuming..... anyway I tested the relay and ballast all ok.

I turned the key on and get about 2v from slot 87 from the relay. I thought atleast one of the slots would provide a constant 12v but none show.

 

My question is does slot 87 provide the 12v needed when keyed or is it a switch to activate relay. I'm also wondering if the ignintion switch would have something to do with it also.

 

Can anyone shed some light on this for me.

 

 

Thanks Jeep Peeps

[HOrnbrod]

Pull your left tail lamp off and check the ground connection behind it for rust/corrosion. Your pump grounds there, as well as the relay. It's a sheet metal screw ground. Pull it apart, clean the rust off, and put it back together tightly shiny metal on shiny metal. Then use a little dielectric grease over the connection.

[Masscrawler]

Pull your left tail lamp off and check the ground connection behind it for rust/corrosion. Your pump grounds there, as well as the relay. It's a sheet metal screw ground. Pull it apart, clean the rust off, and put it back together tightly shiny metal on shiny metal. Then use a little dielectric grease over the connection.

 

I will go check that out right now

[jimoshel]

As long as the ign sw is on, there should be +12V at terminal 30 and 86 on the fuel pump relay socket. If there is no voltage on 30, check your fuseable link. There should be nothing on slot 87. It's empty.

[Masscrawler]

Pull your left tail lamp off and check the ground connection behind it for rust/corrosion. Your pump grounds there, as well as the relay. It's a sheet metal screw ground. Pull it apart, clean the rust off, and put it back together tightly shiny metal on shiny metal. Then use a little dielectric grease over the connection.

 

I will go check that out right now

 

Ok, checked the ground.. I have brighter tail lights now but still low voltage on the pump side. :D

 

jimoshel, When the key is on: terminal 86 has about 2 to 4v not 12v for some reason. It kicks it over to 30 at same voltage. Possibly a bad ECU? I'm guessing the ecu feeds the relay its power?

 

I will go check the power on both sides on the fusable link