need to time delay a relay

I have a relay on my electric fuel pump that also turns on another relay for my Ignition box. The power to the coil on the first relay is from the ignition switch but runs through an oil pressure switch. If oil pressure should drop below 7 psi, I think, it will drop my fuel pump relay which in turn will drop the ignition. What I'd like to do is have a 3-5 second delay in the fuel pump relay.

Does anyone know if I can get a time delay relay for automotive use, 12V?      Or can someone suggest a way to incorporate a resistor and capacitor that would delay the drop of the relay 3-5 seconds.

Thanks

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

Thanks John, I'll give it a try. How durable would you think that circuit be? This wiring is under the rear of the bed on my hot rod S10 ext. cab V8.

Put it in a Plastic Key box if you like.

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

Here is another circuit.

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

Would it matter if the wire coming off "E" terminal of the transistor is about 10' long? Acc power comes from the fuse block, I could implement that circuit under the dash if the long run would not matter??

Thanks.

hotwaterwizard wrote:

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Here is another circuit.

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In the second example, the resistor, which is not specified, is what controls the length of the time delay?? How about the first example, what controls the delay time, only the size of the cap?

Thanks again!

Wouldn't matter.

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

Pardon my ignorance, but what program do you guys use to draw those great looking diagrams?

I use Paint

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

Did you make all the symbols you use or can they be downloaded from somewhere?

Sorry for all the dumb questions.

Thanks for all the help.

I have a Template I use for parts then I connect the lines to the dots where I need them.

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

If you have AIM or Instant Messanger you can talk direct.

Mine is hotwaterwizard on AOL Aim Yahoo MSN

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

I can make you a custom template if you like. tell me what you want on it.

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

Send email direct to hotwaterwizard@aol.com

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

I have added you to contacts in Yahoo messenger. Mine is rodder112002