How many relays can I put on the fuel pump output?

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Subaru_EA82_4EAT_AWD
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How many relays can I put on the fuel pump output?

Post by Subaru_EA82_4EAT_AWD »

I'm just wondering if I can put more than one relay on the fuel pump out put or would it be too much load for the Megasquirt (V3.0 board, MS3 & MS3X)?

Thanks.
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DaveEFI
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Re: How many relays can I put on the fuel pump output?

Post by DaveEFI »

There are all sorts of relays. If you mean the fairly standard 20 or 30 amp auto type, you should be OK with two of those. The output can sink 1 amp. Auto relays usually take about 0.2 amp.
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whittlebeast
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Re: How many relays can I put on the fuel pump output?

Post by whittlebeast »

Here is my wiring diagram that I use. I have three relays in my fuel pump signal from the Squirt.

http://www.nbs-stl.com/CRX/Civic%20CRX%20Wiring.jpg

Andy
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Re: How many relays can I put on the fuel pump output?

Post by dontz125 »

Andy - you seem to have a lot of wire and components downstream of your main relay; lots of places for things to go worng. Do you have a fuse protecting the 'brown' circuit?
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whittlebeast
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Re: How many relays can I put on the fuel pump output?

Post by whittlebeast »

Here is a pic of the relay center I use.

http://www.nbs-stl.com/CRX/MRC_1%20Relay.jpg

There is a fuse on each relay that is behind the relay that you can't see in this pic. The only place that is not fused goes from the battery to the relay block. You can see the fuses in this pic.

http://www.nbs-stl.com/CRX/CRX%20Interior%20Wiring.jpg

Andy
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Re: How many relays can I put on the fuel pump output?

Post by jeffmarsh750 »

Andy, Like that diagram. What program do you use to make that ??? Also why are 4 relays required to run 2 shift buzzers ? just curious.
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whittlebeast
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Re: How many relays can I put on the fuel pump output?

Post by whittlebeast »

jeffmarsh750 wrote:Andy, Like that diagram. What program do you use to make that ??? Also why are 4 relays required to run 2 shift buzzers ? just curious.
I drew it in windows paint. I started with the standard one in one of the manuals.

The buzzers are two different tones.... beeeeep BEEEEEP WAAAAA as you come up thru the power band

The two relays makes it so I can kill the buzzer as the revs fall thru the same RPM.

See the tune in

http://www.nbs-stl.com/CRX/CRX%20ITB%20Last%20Day.zip

Andy
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