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Intermittant Electrical....help if you can

Old 03-23-03, 05:42 PM
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Intermittant Electrical....help if you can

car just came back from bret's, who did an engine and LSD rebuild. sometimes the car works fine.

a few nights ago, my dad and i were setting fuel pressure which required the car to be running. so he got in and turned the key to ON (to start the fuel pump), and nothing happened. got out, turned off and on the kill switch, nothing. then we tried again and it worked fine.

now today, we were setting the timing and i was in the car getting ready to start it. turned kill switch on, turned key to ON position (fuel pump started pumping like it should), then when i pulled the choke out, the fuel pump turned off. no power. then tried it again a few seconds later and everything worked fine.

what would possibly cause this? what are some things to check?
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Old 03-23-03, 08:36 PM
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Ok I'll take a stab. Assuming of course that an additional problem hasn't been introduced, I would guess the kill switch. Reason, sometimes the contacts of a large current carrying switch can become burned or pitted (especially if the switch is actually used AT the load it can carry). The additional resistance of the "burned" or "dirty" contacts will NOT allow a "small" load to pass but when you hit it with a LARGE load, the resistance will be broken down and allow the current to flow. Because the connection is a mechanical one it is subject to possible intermittit operation.
If I had the choice of replacing 1 componant, I would replace (or clean) the kill switch.
BTW a simular problem can be noticed with bad battery connections as well. A small load may work (turn on key) but when you try to start (LARGE load) you get a spark at the bad connection and then NOTHING works as the small area that WAS allowing a small current to pass, has now evaporated.
If you cannot disassemble the kill switch for cleaning and inspection, you will have to use a meter or small test light to track where the voltage is lost......battery, kill switch, ignition switch, fuel pump..........Kill switches are often a problem because they may be mounted in an enviromentally adverse area, subject to long periods of non use, used to pass small loads when operated themselves but pass LARGE loads when starter is engaged,,,,,,,,,,,which may be one way to test them. With the problem present (no small load passed-fuel pump) hit the starter. The extra load may bridge the dirty area and presto starter AND fuel pump works.
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Old 03-24-03, 04:48 PM
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you didnt have to reply to BOTH of the threads (1st gen section and race car section) lol but thank you very much for all your help mike. i appreciate it.
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Old 03-25-03, 09:57 AM
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Ahhhh THAT'S what happened! I knew I had (tried to) posted to one,,,,,,but then I saw what I thought was the same thing without my post and since this computer, ISP, etc. does it's ****, I thought it didn't go thru!

But HEY, you asked twice!
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Old 03-25-03, 11:24 AM
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Agreed, i've already gone through one kill switch, night before the event, the car was fine, the morning of, the car was dead. Turned out to be a faulty switch.

PaulC
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Old 03-25-03, 12:42 PM
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it could be the kill, but im thinking its something else, as this just started after the engine uninstall, rebuild, and re-install. nothing changed with the kill switch. hmm

a new, lighter battery was just installed. im just trying to think of what has changed in the recent weeks.
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Old 03-25-03, 02:22 PM
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Just jump across the kill switch and see if the problem goes away.
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Old 03-25-03, 08:35 PM
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I'll second a new kill switch. Just had this happen, and bought a new kill switch. Of course, I found out on Monday before a race that weekend. Ended up buying a Racer Parts Wholesale $14.95 kill switch. Haven't had problems with it since.
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Old 03-26-03, 03:33 PM
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well.... when the key was turned to ON, all the idiot lights went on and the fuel pump turned on as normal, meaning it was getting power. and for all that to happen, the kill switch must have been on. then i pulled the choke, and everything died.
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Old 03-26-03, 05:03 PM
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Well,we could be wrong. But how hard is it to put both main cables on one pole so you cut the switch out of the loop and see if the problem reoccurs?

PaulC
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