ComancheCrusher9800 Posted January 2, 2017 Share Posted January 2, 2017 My 1987 Comanche is having troube starting. Itll turn over and all that and I narrowed it down to the ignition lockout relay circuit. When I took out the relay and used jumpers as the relay it would crank so I went and bought the relay and when I came back and tried it wouldn't start anymorr (though it did still crank) but there wasnt any power going to where the relay plugs in. I don't know what caused it by this point. Is there a fuse that controls that or what? Any suggestions? Help? Link to comment Share on other sites More sharing options...
ComancheCrusher9800 Posted January 2, 2017 Author Share Posted January 2, 2017 It would start when I used jumpers but something happened between the time I used the jumpers and the new relay to cause power to not be there anymore. Does anyone know how to fix this? Link to comment Share on other sites More sharing options...
Eagle Posted January 2, 2017 Share Posted January 2, 2017 I don't even understand the problem. The '87 MJ does not have anything called an "ignition lockout relay circuit." Then, you write that it would turn over (which means "cranl"), but then you wrote that you had to jumper the relay before it would crank (which means "turn over"). Please explain the problem better, and tell us which relay you're talking about. Link to comment Share on other sites More sharing options...
ComancheCrusher9800 Posted January 2, 2017 Author Share Posted January 2, 2017 I would have to use the jumpers before it would start. Okay. So there's two relays attached to the passenger fender well. One is the fuel pump I believe and the other one is the one I'm talking about. So basicly there was no spark. There was power going to the coil but no power leaving the coil until I used the jumper (two pieces of wire) to aCT as a relay. But then the plug in for whatever this relay is doesn't have power to it anymore. So I'm wondering if this relay has some sort of fuse somewhere that I may of burnt Link to comment Share on other sites More sharing options...
ComancheCrusher9800 Posted January 2, 2017 Author Share Posted January 2, 2017 Keep in mind it will turn over like no tomorrow but it wouldn't start unless I used the jumpers but then the plug for the relay lost power somehow but it still does crank Link to comment Share on other sites More sharing options...
Eagle Posted January 2, 2017 Share Posted January 2, 2017 Only two relays? What engine and transmission do you have? And which contact for the relay lost power, the signal contact, or the power contact? Link to comment Share on other sites More sharing options...
ComancheCrusher9800 Posted January 2, 2017 Author Share Posted January 2, 2017 Yeah I only have two relays. I have a 4 cylinder 4 speed. And it doesn't have any type of current going to it Link to comment Share on other sites More sharing options...
ComancheCrusher9800 Posted January 2, 2017 Author Share Posted January 2, 2017 Okay so the red wire going to the plug in has a current going threw it. None of the others do Link to comment Share on other sites More sharing options...
Tex06 Posted January 2, 2017 Share Posted January 2, 2017 Post up some pics man. Your description is still kinda garbled. Sent from my SM-G930T using Tapatalk Link to comment Share on other sites More sharing options...
ComancheCrusher9800 Posted January 2, 2017 Author Share Posted January 2, 2017 I don't even see where I can post pics at Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 2, 2017 Share Posted January 2, 2017 Are you working with a wiring diagram or just randomly sticking jumper wires in a relay socket? It sounds like you might have smoked a fusible link. Link to comment Share on other sites More sharing options...
ComancheCrusher9800 Posted January 2, 2017 Author Share Posted January 2, 2017 I know which wire goes to where on it. But it's running rn. This truck has mood swings. But I'm using the jumpers rn. There is a red wire that goes into the plug it always has a charge to it. When I use the jumpers all four wires end up with a charge and it'll start but if I plug the relay into it, it won't work Link to comment Share on other sites More sharing options...
Eagle Posted January 2, 2017 Share Posted January 2, 2017 I don't have the wiring diagram in front of me, but I believe someone has posted a link to the '88 electrical manual on this forum, and the '87 4-banger should be about the same as the '88. Your two relays are, I think, a fuel pump relay and a starter relay. The relay (and socket) have five terminals, of which only four are used. To help you diagnose this, we need to know which two you're jumping. Also need to know if you have tested the signal side of the relay and socket for power when trying to crank. But the starter relay only affects cranking. I don't think it would prevent firing. Are you sure there's no spark? Maybe the relay you're jumping is the fuel pump relay and the problem is no fuel. Which relay are you jumping -- the forward one, or the rearward one? Link to comment Share on other sites More sharing options...
Eagle Posted January 2, 2017 Share Posted January 2, 2017 Link to the '88 electrical manual: http://comancheclub.com/topic/12083-electrical-manual/ Link to comment Share on other sites More sharing options...
ComancheCrusher9800 Posted January 2, 2017 Author Share Posted January 2, 2017 My fuel pump is hooked to a switch in the cab. There isn't a relay for it anymore. There is no spark when there is nothing in the socket. And I'm connected the two across from each other. The red one to the pink one and the other pink one to the black and white one Link to comment Share on other sites More sharing options...
Eagle Posted January 3, 2017 Share Posted January 3, 2017 The starter relay has nothing to do with spark. How are you testing for spark if it won't crank? Link to comment Share on other sites More sharing options...
gogmorgo Posted January 3, 2017 Share Posted January 3, 2017 Took a quick peak at the wiring diagram Eagle gave you, and the only relay I found on it that is consistent with the wire colours you name is called the "latch" relay, I have no idea what it does. Both the pink wires and the black/white trace back to the ECU and the diagnostic connector. Looks like the pink wires are actually spliced so I suspect there black/white one's the one that really matters. The red wire apparently gets its power from a green fusible link, which also supplies power to the fuel pump relay which you say no longer exists (did you wire that switch yourself and/or do you actually know where the power comes from?) and the TCU which you don't have because manual trans. So you likely wouldn't experience any other symptoms if that fusible link was bad. You could easily have toasted it. I hope you use a test light and/or voltmeter to diagnose electrical issues. Jumping wires at random is a great way to let the magic smoke out. Link to comment Share on other sites More sharing options...
ComancheCrusher9800 Posted January 3, 2017 Author Share Posted January 3, 2017 I'm using a light test and my dad wired the fuel pump back when he had it bc he was tired of the fuel injector and just put a carb on it. And yeah the b+ latch relay is what I believe it is. And the red wire has power to it tho. That's the only one with powe but a relay still won't work in the socket. And it will crank but it wouldn't turn over. But rn my problem is something with the actual relay. I've bought 3 different ones and none of them work with it. I have to use 2 wires that take the power from the red one to the pink one and that pink one brings the powe to the other pink one (bc it's two wires spliced together) and then that pink one brings the power to the black and white one. I got the truck to run when I did this but if I don't then it won't Link to comment Share on other sites More sharing options...
87MJTIM Posted January 3, 2017 Share Posted January 3, 2017 Took a quick peak at the wiring diagram Eagle gave you, and the only relay I found on it that is consistent with the wire colours you name is called the "latch" relay, I have no idea what it does. Both the pink wires and the black/white trace back to the ECU and the diagnostic connector. Looks like the pink wires are actually spliced so I suspect there black/white one's the one that really matters. The red wire apparently gets its power from a green fusible link, which also supplies power to the fuel pump relay which you say no longer exists (did you wire that switch yourself and/or do you actually know where the power comes from?) and the TCU which you don't have because manual trans. So you likely wouldn't experience any other symptoms if that fusible link was bad. You could easily have toasted it. I hope you use a test light and/or voltmeter to diagnose electrical issues. Jumping wires at random is a great way to let the magic smoke out. There is a link in the DIY section that takes you to pdf of the Renix fuel injector system. http://comancheclub.com/topic/36875-get-your-copy-of-the-renix-fi-fuel-injection-manual-here/ If you follow the links (p. 53 of the manual, p. 57 of the pdf), you can see the power latch relay maintains power after the engine shuts off to allow sensors to reset themselves for the next re-start. Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 3, 2017 Share Posted January 3, 2017 In order for an automotive relay to work one side of the operating coil must be grounded. If you know how to use an ohmmeter, check for continuity to ground on pin 85 (normal) or pin 86. Link to comment Share on other sites More sharing options...
MJCARENA Posted January 3, 2017 Share Posted January 3, 2017 Did you apply power to the black with white tracer? I think that it is the ground for the relay coil. If you did you might of damage the ECU. Link to comment Share on other sites More sharing options...
gogmorgo Posted January 3, 2017 Share Posted January 3, 2017 If what Tim says is true, then I expect this won't have a huge amount of bearing on the engine running. Unless the fuel pump switch is still getting power from the original fuel pump circuit in which case the fuel pump isn't running when there's no power to that red wire. And your post about no power at the socket is what I'm going off, sounds like an intermittent problem? You may need to consult your dad on this. If you really do have no spark (how do you know), it's unrelated to the latch relay, and considering with a carb on there we have no idea what other changes could have been made or what your ignition system looks like, or if it has anything at all to do with the ECU. If the fuel injection parts still exist I would strongly suggest putting them back in. I realize the 2.5L is only TBI but it's still a major step backwards to go to a carb, and anyone who says otherwise is either lying or not very bright. No offence to your Dad. But it did run like this and you should probably solve why it's not running before you switch things back just to prevent having multiple not-running problems happen at once. Link to comment Share on other sites More sharing options...
mikekaz1 Posted January 3, 2017 Share Posted January 3, 2017 Holy electrical nightmare. Now this is why I bought an HO. Link to comment Share on other sites More sharing options...
Eagle Posted January 3, 2017 Share Posted January 3, 2017 I'm using a light test and my dad wired the fuel pump back when he had it bc he was tired of the fuel injector and just put a carb on it. And yeah the b+ latch relay is what I believe it is. And the red wire has power to it tho. That's the only one with powe but a relay still won't work in the socket. And it will crank but it wouldn't turn over. But rn my problem is something with the actual relay. I've bought 3 different ones and none of them work with it. I have to use 2 wires that take the power from the red one to the pink one and that pink one brings the powe to the other pink one (bc it's two wires spliced together) and then that pink one brings the power to the black and white one. I got the truck to run when I did this but if I don't then it won't 1. For a relay to work, it needs power to two terminals -- the main power input terminal, and the "signal" input terminal. The main power input is hot at all times *(or should be). The relay is an electronic switch -- the input side of the "signal" circuit is only powered when you activate the switch or whatever it is that's supposed to operate the relay. So if you're just standing next to the fender and probing the relay socket -- you won't have power to the signal side of the relay unless someone (or something, in the case of the latch relay) activates the circuit. 2. Here's an explanation of what the latch relay does, and I don't think it would cause a no-start: http://www.justanswer.com/jeep/7l0xs-function-power-lacth-relay-88-jeep.html 3. You are still using confusing terminology. "Crank" and "turn over" mean the same thing -- the starter motor is engaged and turning the crankshaft. If it cranks, it turns over. If you mean it won't start, that's "won't start" or "doesn't fire." 4. Assuming Gogmorgo is correct and that relay socket you're probing is fed by a fusible link -- you may have burned out the fusible link. Link to comment Share on other sites More sharing options...
ComancheCrusher9800 Posted January 4, 2017 Author Share Posted January 4, 2017 I got it working by just putting two online fuses in as the relay Link to comment Share on other sites More sharing options...
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