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fuel pump issue

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Old Jun 4, 2012 | 01:02 AM
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Default fuel pump issue

So, I'm not sure if I'm getting power to my fuel pump in my 96 laredo or not. Is there an easy way to check if I have power or if its just completely dead?
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Old Jun 4, 2012 | 09:56 AM
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You should hear the pump come on for a few seconds when you first turn the key to the run position, if not, check the fuse and the relay. If those check out the chances are good the pump is bad.
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Old Jun 4, 2012 | 12:58 PM
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Yeah I've gone through the whole check list and I didn't hear the pump and all fuses and relays are good. I do know that the jeep was in a wreck before I started working on it... Could the pcm cause the jeep to turn over but not fire and the fuel pump not work?
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Old Jun 4, 2012 | 03:37 PM
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The cam and crank sensor could, but you should still have the two second prime when you first turn the key on. The PCM should be the last resort, they don't fail very often, but they do fail.
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Old Jun 4, 2012 | 03:45 PM
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Originally Posted by moose27
Yeah I've gone through the whole check list and I didn't hear the pump and all fuses and relays are good. I do know that the jeep was in a wreck before I started working on it... Could the pcm cause the jeep to turn over but not fire and the fuel pump not work?
Disconnect the fuel pump connector at the pump and place a volt meter on the ground (negative lead) and B+ (positive lead) terminals of the connector. The ground and B+ connections are at opposing corners of the six pin plug. B+ is the upper right corner when viewing the connector straight on with the connector locking clip at the top. Ground is the opposit diagonal corner (lower left). When cranking the engine you should be reading battery voltage.
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Old Jun 4, 2012 | 07:55 PM
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What should the voltage read?
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Old Jun 4, 2012 | 07:55 PM
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I'm also thinking it could be a crankshaft position sensor gone bad?
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Old Jun 4, 2012 | 08:56 PM
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The tank would still prime check for power At the pump.
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Old Jun 4, 2012 | 09:14 PM
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Originally Posted by moose27
What should the voltage read?
The voltage should be whatever the battery voltage is (i.e. ~12v).
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Old Jun 4, 2012 | 09:15 PM
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Originally Posted by moose27
I'm also thinking it could be a crankshaft position sensor gone bad?
What is the problem you're attempting to troubleshoot?
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Old Jun 12, 2012 | 01:42 PM
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I'm trying to get my jeep running again, it was in a wreck and sat for 2 years. It will turn over just no spark. I've listened for the fuel pump, but nothing. I've banged on the fuel tank to try and jump start the pump but nothing as well.
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Old Jun 12, 2012 | 06:00 PM
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Originally Posted by moose27
I'm trying to get my jeep running again, it was in a wreck and sat for 2 years. It will turn over just no spark. I've listened for the fuel pump, but nothing. I've banged on the fuel tank to try and jump start the pump but nothing as well.
If it was involved in an accident it's possible the accident caused a short which blew fuses or fusible links. I would also recommend you test the fuel pump relay (should be located in the "relay box" found in the engine compartment on the passenger side).

Finally I've heard some Jeep models include some type of cut off which is activated in the event of an accident. You may want to investigate if this cut off exists (after a quick review I can't find reference to it in my service manual) and, if it does, that it hasn't been activated due to the accident.
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Old Jun 13, 2012 | 01:17 AM
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That's the other thing I did, I switched the horn and fuel pump relay since there the same and still nothing. I knew the horn worked before I switched the relays and jt worked fine after. I've actually never heard of the cut off thing, something I'll have to search for tomorrow
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Old Jun 13, 2012 | 01:21 AM
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How serious was the accident? They did start putting fuel cutoffs in vehicles but i dont know when. If it was a good bump it probably didnt trip but if you banged something decently then it probably did. The whole idea of the thing is to keep a fire from happening, so id hunt it down and see if you get any luck
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Old Jun 13, 2012 | 02:26 AM
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It was t boned in the front driver side at the wheel, it was hit hard enough to bend the rim
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