Calgary Jeep Association
4x4 Related Groups => Tech Talk => Topic started by: Ostego on April 16, 2010, 10:40:54 PM
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Yesterday my dad hoped in his '94 Jeep YJ and gave my old ford (farm truck) a boost cause the battery was dead..after getting the ford running he got back in the YJ and headed off to Crossfield....about 15 minutes later he calls me and says "come pick me up the Jeep just died as I was driving down the highway!".
Upon getting to him we try to start the Jeep again, but when the key is turned nothing happens, the battery in the Jeep is fully charged and everything (lights, stereo, fuel pump ext.) works...but when the key is turned absolutely nothing happens. We tried to boost the Jeep and nothing...even went as far as driving into town and buying a bran-new battery thinking we may have fried the old one while boosting.
Any ideas? :-\
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Did you check the main wires at the starter? It could be letting enough amps through for the pump, ect... But then not for starting.
Does it even click? Is there power at the solenoid wire?
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strange that it would stop while driving. it is a manual transmission right?
i would be checking fuses and relays then the wiring to the starter. more specifically the ground wire from the battery.
after that i don't know... maybe think of something in my sleep. last night some person had a balloon head.. was like a DK head from goldeneye n64. anyway good luck with it.
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If fuses are fine then you probably cooked a fusable link. check if you have power going into the fuse box.
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Or the ignition switch (tumbler) could be hooped... but it is still in the "Accessory" position, hence the lights, stereo, ect.... seen that before on my old Exploder.
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look at the main bulkhead connector on thefirewsll, likly a broken or weak wire if that is where the problem lies
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Check the battery cables carefully. I've seen a bad cable carry enough load to power the lights but then fall on its face when a heavy load such as the starter is applied.
You could try hooking the booster cables directly to the engine block and starter( or wherever the + battery cable goes to) as a way of bypassing the battery cables.....
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Did you check the main wires at the starter? It could be letting enough amps through for the pump, ect... But then not for starting.
Does it even click? Is there power at the solenoid wire?
No click, yes solenoid has power.
strange that it would stop while driving. it is a manual transmission right?
i would be checking fuses and relays then the wiring to the starter. more specifically the ground wire from the battery.
after that i don't know... maybe think of something in my sleep. last night some person had a balloon head.. was like a DK head from goldeneye n64. anyway good luck with it.
yes its a manual, checked all connections and cleaned them...still nothing.
If fuses are fine then you probably cooked a fusable link. check if you have power going into the fuse box.
YepOr the ignition switch (tumbler) could be hooped... but it is still in the "Accessory" position, hence the lights, stereo, ect.... seen that before on my old Exploder.
still power there.
Have to play with that today.
look at the main bulkhead connector on thefirewsll, likly a broken or weak wire if that is where the problem lies
I'll check that as well.
Check the battery cables carefully. I've seen a bad cable carry enough load to power the lights but then fall on its face when a heavy load such as the starter is applied.
You could try hooking the booster cables directly to the engine block and starter( or wherever the + battery cable goes to) as a way of bypassing the battery cables.....
Battery cables are only a year or so old, the looked fine.
May try a direct engine boost.
Gonna drive out to the Jeep and drag it home today...no sense in letting it sit on the side of the road.
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Since its a manual have you tried roll starting it yet?
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Sounds like a fuseable link to me. Those things just go whenever they want. Sometimes very hard to find. They can look like wire but thicker. Check the wire for the solinoid it should be there. The one in my ma's volks went and it was doing everything that you jeep is doing! It just would not let enough power thru for the starter, but everthing else got power. If it's the link just cut it out and replace it with the same Gage wire as the rest of it, not the link.
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I have had good luck with resoldering a burnt fusible link...just soldering the two ends together and keeping the rest of the link for protection.
I would try either a rolling start or jumping the starter to dtermine whether or not the jeep runs if started and then go from there.
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i recintly had a similer issue with the cherokee, ened up being a fried starter. it wouldnt click or nothing. just zero action when i turned the key.
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I have had good luck with resoldering a burnt fusible link...just soldering the two ends together and keeping the rest of the link for protection.
It's like Pat said in the link above, you're compromising the protection; not a good idea unless it's for the sole purpose of limping your ride home to do a proper fix. Even trying something like this could result in more crispy wires or possibly fire. Fuses are a 1 shot deal if they blow find out why, replace it but not with one that's bigger.
There's a lot more thought that goes into making them than just running a piece of wire, for instance, do they have to with stand motor start current or resistive load, indoor rated, outdoor rated, fast acting, slow acting, what voltage do they have to interrupt etc.
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On most older vehicles you could test the starter by boosting it directly, place the positive end of the cables to the positive post on the starter and tap the negative end to the starter housing..... A bad starter shouldn't have killed the jeep while driving.
The major components that you should test would be
1) battery.... its new and you have lights and sound so main power connection and ground should be good
2) Starter.... again I don't believe this should have killed the jeep while driving
3) Computer.... It's possible to fry one while boosting another vehicle, but really hard to test, a code scanner may help you here. you could test for power at the distributor cap (not sure what you have under the hood but there should be a main power point coming in to feed the plugs)
4) now it becomes a simple mix of check for fuel, air, spark.... more description of nothing happens would be better
do the lights dim when trying to turn over engine? does it sputter? or does "nothing happens' really mean nothing no sounds, smells or anything else.
The ignition switch could be a possibility, but I would bet good money that you burned out a wire, fuse or computer while boosting the ford (that will teach you, never let your jeep touch a ford)
And as it has been mentioned several times never hard wire or bypass a fuse or link unless you are simply trying to get it home, It will cost you less that $1.00 to replace a link or fuse properly, 1000's more if you burn it to the ground.
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It's like Pat said in the link above, you're compromising the protection; not a good idea unless it's for the sole purpose of limping your ride home to do a proper fix. Even trying something like this could result in more crispy wires or possibly fire. Fuses are a 1 shot deal if they blow find out why, replace it but not with one that's bigger.
There's a lot more thought that goes into making them than just running a piece of wire, for instance, do they have to with stand motor start current or resistive load, indoor rated, outdoor rated, fast acting, slow acting, what voltage do they have to interrupt etc.
the links I soldered were sort of a braided flat copper? material, and about an inch long. if it just burns in one spot (for a known and solved reason) and then is resoldered, leaving 60-70% of the original link length intact I would expect it to still have neccesary protection, no?
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The ignition switch could be a possibility, but I would bet good money that you burned out a wire, fuse or computer while boosting the ford (that will teach you, never let your jeep touch a ford)
Lol. 2 AMC's and a Ford aint THAT bad. :P
Well its defiantly something electrical we got tired of messing with it and swearing at it so were just gonna truck it in to the dealers and let them figure it out.
That's why I'm glad my J20 aint all computerized. ;D
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They break because the melt. They melt because they get hot due to the current running through them. When you look at current carrying tables, the shorter the wire, the more current they say it can carry. The more area, the more current it can carry (larger wire) and soldering, for the part that is soldered, has more area.
Taking all that together, I'd deduce that the shortened, soldered link would fuse at a much higher current. It would still fuse at some point, but so will regular wire eventually.
makes sense but those tables are generally in feet not sixteenths of an inch. I'm unsure how big of a factor length of a conductor is in it's resistance when you are comparing a 3/4 inch piece of a given conductor to a one inch piece of the same material...this I've never seen on the wire gauge charts and I'm not sure if the difference in resistance/load carrying capacity could be measured without some very fasncy tools. Are you saying that a 1 inch and 2 inch piece of the same wire will showa different resistance that is meaningful or measurable? Those tables are more about the ability of a conductor to carry current over longer distaces as far as I understand it.
I accept your deduction that the shorter link could theretically carry a higher current but I'm not sure if it would be "much" higher like you said.
It really wouldn't matter much if you replaced a 10 amp fuse with a 10.5 amp fuse would it?
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I am going through this right now with my MJ, we have now determined that the ECU is poached.
I started it up in the parking lot at work and it ran for a couple min then died. this is at 2am so I got a ride home and came back the next day. tried the basics. fuel - have some, started is roiling over, spark yes. but could not fix it. so on the hook to my buddies shop. put it on the scope and we found the injectors are not getting a signal. I had to go to work so he keep checking wiring and determined the ECU is done for.
So there is another possibility. I don't know how you would determine if the injectors are getting signal without a amp clam or scope. I would not just pull a injector out and check.