Electric fuel pump wiring

smokey503 · Posted: Tue Jul 22, 2014 4:34 pm Post subject: Electric fuel pump wiring

I am installing a electric fuel pump with a relay from a dasher/rabbit with fuel injection.

The relay I bought has the fuse in the top.

This is how I plan to wire it
Terminal 30 gets constant +12V from the battery (a fuse is a good idea).
Terminal 15 gets +12V when the ignition is switched on.
Terminal 31 gets chassis ground.
Terminal 1 (sometimes labeled 31b) is Tach input; terminal 1 if the ignition coil.
Terminal 87 goes to the positive lead of the fuel pump; the other pump lead goes to chassis ground.

For terminal 30 do I have to run it all the way to the battery, or can I run it from constant 12v from the fuse box?
Since the relay has the fuse built in, do I need a fuse between the battery and relay or where I get constant 12 volts? I'm guessing I don't need one.
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Danwvw · Posted: Tue Jul 22, 2014 4:49 pm Post subject:

I ran my 30 contact (fused) to the 12Volts on the coil and the 86 the relay coil to the D+ of the alternator (well thru a 40ohm resistor). That way if the engine stops but the key is still on the fuel pump stops. I use a radio shack relay but the Rabbit Relay would be nice! Some Starters have a terminal to run to your relay coil to latch it. (I added the prime switch later, it;s in the engine compartment)

Image may have been reduced in size. Click image to view fullscreen.

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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

smokey503 · Posted: Tue Jul 22, 2014 6:03 pm Post subject:

I appreciate the help on the diagram. But that diagram just confused the hell out of me.
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If a car travels the speed of light, would the headlights work?

Glenn · Posted: Tue Jul 22, 2014 6:08 pm Post subject:

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smokey503 · Posted: Tue Jul 22, 2014 6:19 pm Post subject:

Thank you Glenn.

Does the constant power have to be ran directly to the battery? I really don't want to run extra wire if I can avoid it. I have just enough wire if I can get the constant 12 volts from the fuse box.
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If a car travels the speed of light, would the headlights work?

smokey503 · Posted: Tue Jul 22, 2014 6:30 pm Post subject:

This is the diagram I am going off of.
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If a car travels the speed of light, would the headlights work?

Joel · Posted: Tue Jul 22, 2014 7:00 pm Post subject:

I ran mine straight to the battery through a 25amp fuse with the same setup, although my relay also has terminal 50 for start signal as well.
you lose a bit if voltage by the time it gets ignition power from the fusebox.

Danwvw · Posted: Tue Jul 22, 2014 8:58 pm Post subject:

Yes if the alternator stops the fuel pump stops and that's it you want it to shutdown that way, that's why it's wired that way. My little Type 1 fuel pump only draws about an amp so it runs fine off of the coil 15 wire. It works quite well, the shutdown circuit already saved my engine once.
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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

smokey503 · Posted: Thu Jul 24, 2014 1:54 pm Post subject:

While cleaning up some of the wiring. I found a switch ran to a relay that was used to turn on and off some fog lamps.

How do I wire the switch to turn the fuel pump power off for security reasons?

Is this possible with using the Rabbit/Dasher electric fuel pump relay?

Anyone have a good place to hide the switch so it's not easily found but still in reach of driver?
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If a car travels the speed of light, would the headlights work?

smokey503 · Posted: Fri Jul 25, 2014 11:30 am Post subject:

I got the electric fuel pump wired. It sure is allot quit in the engine bay without the fuel pump push rod making a racket.
The push rod was mangled at the end causing me to stall out on the freeway.

Now iI really want to figure out how to install a switch to cut power to the fuel pump fire security.
Would I just need to put a switch in the fuel pump power wire?
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If a car travels the speed of light, would the headlights work?

Danwvw · Posted: Fri Jul 25, 2014 11:39 am Post subject:

You could put it on the 30 wire but the 15 wire just after the coil before both relay wires would be more correct! But yeah, even at the fuel pump is fine. Perhaps better if the relay shorted out to make it run then you would have a way to shut it down. If your old mechanical fuel pump is causing problems just remove the rod. Get one of these fuel pump block-offs.
http://www.cbperformance.com/ProductDetails.asp?ProductCode=3179

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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

smokey503 · Posted: Fri Jul 25, 2014 12:11 pm Post subject:

With the mechanical fuel pump, I didn't realize how loud it was until I removed it and I put the block of plate on. So far very happy.
Cut up my kids foam mat to insulate the noise and seriously can't hear the facet pump at all except when I turn the car off. I can hear the pump for a split second then it shuts of like it's supposed to.
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If a car travels the speed of light, would the headlights work?

ToughBug

New guy question. But I did read this thread and searched the older ones....

My 73 Super Beetle was converted to a carb system by PO. They installed facet fuel pump on rear firewall in front of the fan shroud. It's failed and needs to be replaced. Getting to it almost requires dropping the engine.

While I'm at it I thought I'd move it up front to lessen the chance of a leak causing a fire. Figure I'll put it where the fuel injection type pump was originally, near right front wheel housing.

Is there a correct circuit up front to tap into for power?

Is this what ya'll were discussing re: pulling power from the fuse box?

Danwvw · Posted: Fri Jul 25, 2014 6:53 pm Post subject:

Good Idea! I don't think the 1973 Super Beetle had an electric fuel pump, I think 1976 was the first year for the fuel injection on the beetle. But yeah, you could install that Rabbit relay or any proper sized relay up front and use it to operate the fuel pump. I would use the generator light wire to trigger it.
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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

johnnypan · Posted: Fri Jul 25, 2014 7:03 pm Post subject:

safety circuit with pushbutton override I mount the pump on the "napoleons hat" and the relay behind the dash...facets are ok,rotary pumps are better

smokey503 · Posted: Fri Jul 25, 2014 7:18 pm Post subject:

It's all installed and working awesome. Went on a hour drive up some hills. No more starving the engine of fuel.

My mechanical push rod was mangled at the end. See why I wasn't getting the fuel at higher speeds. I knew it couldn't of been vapor lock. The mechanical pump was not really hot either. Oh well. Don't have to deal with that anymore.
Although I will carry a spare mech fuel pump in case the electric pump shits the bed.
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If a car travels the speed of light, would the headlights work?

ToughBug · Posted: Fri Jul 25, 2014 9:05 pm Post subject: thanks!

Sorry to divert thread. Thanks for the advice. In the wiring diagram the push button would run the pump even without the key at 'start', right? but only as long as the button is depressed? Or does the button activate the relay to switch the pump on or off with each push? I'm learning how relays function.

Joel · Posted: Fri Jul 25, 2014 9:17 pm Post subject:

Tough bug your engine is out of a fuel injected bug (thats why it has no fuel pump spot) but your bug wasnt fuel injected.

the prime button is only neeeded when the car sits for a few weeks and the carb dries out.
another reason the tachometric relays are better, they self prime before starting.
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1974 Germanlook 1303 2.5 Suba-Beetle

Danwvw · Posted: Fri Jul 25, 2014 9:23 pm Post subject:

ToughBug · Posted: Fri Jul 25, 2014 9:27 pm Post subject:

Thanks Joel. Appreciate the help from Oz. Lived in Brisbane for a while and visited NSW. Loved it. We all want to go back.

I'll need to relearn some of this. All of a sudden I can't see the point of the relay at all. Simply running wire off of this alt light circuit seems like it would run the pump with the car was starting/running, right? I'm missing something, I know. Assuming the voltage of the alt light circuit is 12V, the amperage can be handled, and that the voltage is a match for the pump.

I'm making some dumb mistake here, aren't I?


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