MuddFoot Posted April 25, 2014 Share Posted April 25, 2014 ok so i pulled all the messed up wiring that the po had rigged up. they had a power wire ran from the fuse panel to the fuel pump to make it come on with the key. so i hooked a new starter relay and it still won't stay running. changed the relay and it does't click at all or anything. has power on 2 polls and thats it. if i ground it it will click like most relays but won't power the fuel pump. i bipassed the ballast res. nothing... never had any jeep do this so kinda lost. any ideas 89 4.0 auto 4x4 Link to comment Share on other sites More sharing options...
Eagle Posted April 25, 2014 Share Posted April 25, 2014 You need a wiring diagram to trace it back. By "bipassed" the ballast resistor, I assume you mean you just hot-wired/jumpered it. That will work if the problem is the ballast resistor itself, but your problem is the circuit. The normal path for power to the fuel pump is a circuit that runs through the ballast resistor. There is a true bypass circuit during starting, that skips the entire ballast resistor circuit and sends a full 12 volts to the fuel pump. If your engine starts but then dies, it sounds like the start bypass circuit is working but the normal RUN circuit has been compromised. When the key is in the RUN position, do you have power at the ballast resistor? Link to comment Share on other sites More sharing options...
HOrnbrod Posted April 25, 2014 Share Posted April 25, 2014 ^^ This. W/o a wiring diagram you're just guessing. If you know how to troubleshoot with the fuel distribution schematic, here it is: https://onedrive.live.com/view.aspx?cid=C40904CFDA278A46&resid=C40904CFDA278A46!140&app=WordPdf&wdo=1 Link to comment Share on other sites More sharing options...
MuddFoot Posted April 25, 2014 Author Share Posted April 25, 2014 no power till i turn the truck over to start it. Link to comment Share on other sites More sharing options...
Eagle Posted April 25, 2014 Share Posted April 25, 2014 no power till i turn the truck over to start it. Okay, then. As I wrote above, "If your engine starts but then dies, it sounds like the start bypass circuit is working but the normal RUN circuit has been compromised." That would explain why the previous owner hot-wired the fuel pump, but to fix it you need to trace that circuit to find out where the break is. Link to comment Share on other sites More sharing options...
MuddFoot Posted April 25, 2014 Author Share Posted April 25, 2014 pulled all wiring apart so i could trace the wires no breaks in the wires and so put the relay back in. key to on no power to anywire followed it around the battery across the front to the ballast from there to in the truck under the carpet to a conector then through the floor to the pump everything looks good. the relay never kicks on. power one 2 polls on relay but nothing leaving on the pump wire. maybe bad ground on relay or ?? ........followed the wiring diagrams all looks to be there. i did find a mess of red wires not hooked up together and they are spose to be. so wired them up no change but my ac works now lol. Link to comment Share on other sites More sharing options...
Eagle Posted April 25, 2014 Share Posted April 25, 2014 key to on no power to anywire followed it around the battery across the front to the ballast from there to in the truck under the carpet to a conector then through the floor to the pump everything looks good. You're going the wrong way. With the key in the RUN position, do you have power to the ballast resistor? It sounds from your description like the answer is "No," so there's no point in checking anything downstream from there. You need to follow the circuit back UPSTREAM (toward the battery and power source) until you find where the flow of power has been interrupted. What relay are you referring to? Where is it located? How did you test it? Link to comment Share on other sites More sharing options...
MuddFoot Posted April 26, 2014 Author Share Posted April 26, 2014 the fuel pump relay near the battery and followed it both ways.. i'm gonna re check. the relay with the key on has power to 2 wires but no power to the wires going to the fuel pump off the relay orange/black wires. i tested the relay in another jeep just to make sure it works. ive followed every wire that comes off the relay and the fuel pump Link to comment Share on other sites More sharing options...
Eagle Posted April 26, 2014 Share Posted April 26, 2014 the fuel pump relay near the battery and followed it both ways.. i'm gonna re check. the relay with the key on has power to 2 wires but no power to the wires going to the fuel pump off the relay orange/black wires. i tested the relay in another jeep just to make sure it works. ive followed every wire that comes off the relay and the fuel pump There is only ONE wire off the relay that goes to the fuel pump. The other heavy wire is power TO the relay. Your first post says you have power to two terminals on the relay, and you say that again here. But you still aren't being clear which two wires have power, and under what conditions, and how you are testing. Link to comment Share on other sites More sharing options...
Eagle Posted April 26, 2014 Share Posted April 26, 2014 Look at the link Hornbrod provided. On page 16, it shows that power TO the fuel pump relay comes from a fusible link. Check that fusible link -- if it's blown, you won't have any power to the fuel pump relay. Link to comment Share on other sites More sharing options...
MuddFoot Posted April 26, 2014 Author Share Posted April 26, 2014 fuse link has been bypassed it was gone before i got the truck Link to comment Share on other sites More sharing options...
Eagle Posted April 26, 2014 Share Posted April 26, 2014 fuse link has been bypassed it was gone before i got the truck There are four wires (or there should be four wires) coming off the fuel pump relay: 14 gauge Yellow -- This comes from the ignition switch and should be hot when the switch is in the RUN position. Terminal #86 14 gauge Red -- This is the one from the fusible link. It should be hot at all times. Terminal #30. 16 gauge Green w/ trace -- this one is the relay ground for the control or "trigger" side of the relay. It grounds into the ECU. It should show hot when the ignition is in the RUN position. Since it goes to ground, you should also be able to test the ground independently. Terminal #85 14 gauge Orange -- this leads to a junction, and then to the fuel pump. This should be hot when the control side is closed. Terminal #87. Keep in mind that the ECU cycles the fuel pump depending on the pressure in the fuel rail. I believe that opens or closes the ground in the ECU. Link to comment Share on other sites More sharing options...
MuddFoot Posted April 26, 2014 Author Share Posted April 26, 2014 thanks I'm check it out as soon as i get home Link to comment Share on other sites More sharing options...
Eagle Posted April 26, 2014 Share Posted April 26, 2014 Looks like there's a diagnostic port to test the relay function. Terminal #6 in diagnostic connector #1. And the fuel pump relay is controlled by ground. With the ignition switch in the RUN position, there should always be power to the input leg of the control side (terminal #86). If you're not getting 12 volts there, the problem is between the relay and the ignition switch. If you ARE getting power there, you should be able to override the relay function by jumpering terminal #85 to a known good ground. Then you can probe the diagnostic connector to see if connecting and disconnecting the ground switches the relay on and off. Link to comment Share on other sites More sharing options...
MuddFoot Posted April 27, 2014 Author Share Posted April 27, 2014 thanks I'm try it in the morning i got home lil late. Link to comment Share on other sites More sharing options...
MuddFoot Posted April 27, 2014 Author Share Posted April 27, 2014 ok works perfect now thank you. but in that main harness under what use to be the overflow bottle there are 4 red wires are they just hooked up the same as all the orange and yellow wires in clusters or ?? this guy really @#$%ed my wiring ... Link to comment Share on other sites More sharing options...
Eagle Posted April 27, 2014 Share Posted April 27, 2014 So give us a hint -- what was the problem? Link to comment Share on other sites More sharing options...
MuddFoot Posted April 27, 2014 Author Share Posted April 27, 2014 red wire coming off fuel pump relay like you said. was cut where all the other red wires under the coolant bottle location. so now do they all get hooked together like the yellow and orange wires Link to comment Share on other sites More sharing options...
Eagle Posted April 27, 2014 Share Posted April 27, 2014 Hornbrod gave you the link to the electrical shop manual. The diagram you need is on Page 16. Link to comment Share on other sites More sharing options...
MuddFoot Posted April 27, 2014 Author Share Posted April 27, 2014 yeah i downloaded it. I'm checking now Link to comment Share on other sites More sharing options...
MuddFoot Posted April 27, 2014 Author Share Posted April 27, 2014 yep looks like all of them are linked together. looks like alot of fun. thank you guys. also shows one of those red wires goes to the transmission controls so maybe that fix that issue too. ill brb an an hr or 2 Link to comment Share on other sites More sharing options...
MuddFoot Posted April 28, 2014 Author Share Posted April 28, 2014 sorry got a little side tracked. runs great now. when i put my dash back together ill let you guys know about the shifting issue...thanks eagle and Hornbrod Link to comment Share on other sites More sharing options...
MuddFoot Posted May 2, 2014 Author Share Posted May 2, 2014 well now truck runs good but now my gauges don't work Link to comment Share on other sites More sharing options...
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