caravan wont start.. fuel promblom-AGAIN

1994 dodge caravan 3.3L. what would cause the fuel pump to get intermidiate power only at start up??. when the van starts it will run fine all day. this has happen 4 times within the last 4 months. the van has been
starting and running fine for the last month. my wife got stranded a week ago when the fuel pump would not turn on. i had it towed home and pulled the fuel pump out of the tank for the 5th time. fuel pump tested ok. put it all back together and now the van will start and run fine. i hooked up a test light to the pump wire harness with the wire unplugged. it seems i am getting intermidiate power to the fuel pump plug. when it died last time i was getting the intermidiate 3 seconds of power back to pump, but the pump would still not kick on. thats why i had it towed and pulled the tank again. all symptoms lead to a bad fuel pump. but when it starts i could drive acrosss state without any hesitation. the promblom acures only at start up. in the past i have worked in 3 different service garage's growing up over a 12 year span , and worked with alot of great mechanics that showed me the ropes. i could tear down the van and put it back together with no promblom, but this fuel promblom has me stumped. maybe im just over thinkin here..
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You made no mention, I would start by replacing the fuel pump relay
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If you have power going to the fuel pump and it doesn't work the pump must be bad. It may be the brushes are worn ou t or there may be a bad spot on the commutator. Next time it happens try hitting the bottom of the tank with a rubber mallet while someone cranks it over, if the pump starts working you have a bad pump.
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Exactly what I was going to suggest... Had a similar problem with the wife's '93 caravan. She was stuck and I had to come to the rescue... Had her crack it, and I gave the tank a smack with my fist. Started up immediately.
A little additional information for the OP.
With a problem like you describe, you will only have the problem during start-up. Once the pump is running, it will almost always continue to run, only exhibiting problems again when it must start from a stopped state. It just indicates that the pump is dying (worn out most likely) but not completely dead yet.
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update: i have tryed smacking the tank with a rubber malet. it doesent do anything. i bench test the pump with direst power and it works every time. when i turn the key to the on position you are supposed to hear 2 clicks from the relays. but it only makes one click when it wont start. i tryed changing the relay and it does the same. if i get lucky and keep turning the key on and of untill i hear the 2 clicks then it will start. but for a hole day i tryed it and all i got was the one click from the relays. i would come out the next day turn the key on and i would hear the 2 clicks and the van would start and drive for another week or up to a month. then out of the blue it would act up again with a no start and one click from the relays.
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intermidiate
You don't mention the mileage, you don't say if the fuel pump was replaced in one of the 5 times you removed it!!! And the 3 seconds that you consider intermittent is normal, the shut relay is designed to shut down if the vehicle does not start within 3 seconds of crank until you try it again. Bench testing a fuel pump is not a good idea since one small spark will ignite the pump and possibly you too. This vehicle is 12 years old, its time for a pump anyhow. I would highly recommend installing a MOPAR pump if it has not been done.
Just a thought
Glenn Beasley Chrysler Tech
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it might be some lose problem. my 89 dodge dynasty did the same thing. Later i found, the wires in tank corroded. I put in a new pump anyway to be sure. maxpower wrote:

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