# Fuel pump relay 101



## painter (Nov 24, 2003)

Hello all, again 
This should be my last question for a little bit,
As some of you know I've got an 83 GTI I'm working on putting 40mm dual side drafts on 
everything is hooked up now (aside from the brakes) and it runs 
started up after a bit of cranking but it runs and that's cool 
I have just the bare bones wires hooked up to make it run 
starter, alt, battery, msd box, coil and dist, plus some of the fuse panel 
The problem is I'm trying to get the fuel pump to run off of the stock fuel pump relay, 
When plug in the relay, hook up the battery and turn the key or crank the car the pump doesn't work 
If I jumper the relay the pump works no matter what position the key is in 
all the circuits are connected to what seems to be the proper wires in the bay 
1 to the neg side of the coil 
30 power all the time 
31 ground 
15 switched power 
87 to the pump 
is there something I'm missing 
I've tried 3 different relays all with the same results 

I would like it to work with the stock relay if at all possible 
any help would be great


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## need_a_VR6 (May 19, 1999)

*Re: Fuel pump relay 101 (painter)*

Check continuity from 1 to the neg side of the coil. You try a NEW relay? Those ones are notorious for going bad.


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## painter (Nov 24, 2003)

*Re: Fuel pump relay 101 (need_a_VR6)*

I'll double check from 1 to the coil 
I've tried 3 different relays at the very least I know one of them is out of a running car
but all 3 had the same result


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## painter (Nov 24, 2003)

*Re: Fuel pump relay 101 (need_a_VR6)*

It has continuity from at the 1 on the relay to the neg. side of the coil
I'm quite stumped on this one I've connected and tested and checked quite a bit and still nothing


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## painter (Nov 24, 2003)

*Re: Fuel pump relay 101 (painter)*

So I think after fooking with the wiring and a lot of head scratching i have this figured out I think
Let me know if i got something wrong
I installed an MSD 6 box and if I'm thinking correctly that is what's been causing the problems 
so MSD has a ground and a hot for power these are standard battery + and a body ground

it also has 2 leads to the coil a red and black
These are pretty standard again 
Pos to the coil and Neg to the coil
then there's the other 2, a red and a white 
red is technically the 15 
and white the 1 

the 15 should be switched power 
and the 1 goes to the distributor
the 1 also goes to the fuel pump relay and gives it a pulsed signal
now in theory and the way VW did it you would hook up the the pump relay 1 directly to the coil 1 and that should be the pulsing ground that the relay needs to properly close
but with the MSD6 box in the mix the 1 terminal at the coil doesn't pulse
I had to pull a wire right off of the white distributor wire and go to the 1 terminal at the relay 

and if I'm correct 
(I burned out my 4 relays testing with the 1 wire pulled direct from the coil so I'm waiting on some e-bay specials to see that this works)
I should have a pulsed 1 connection coming right off the dist.
It all works with a test light like it should and hopefully the new relay will prove it too




_Modified by painter at 7:05 AM 11-21-2009_


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## Salsa GTI (Aug 29, 2000)

*Re: Fuel pump relay 101 (painter)*

get rif of that mk1 relay....it needs the pulsing ground from th efactory coil...the msd is feeding the coil all kinds of wacky things..like multiple pulsesand things it does not like....swap in a regular relay and trigger it of key on power and be done with it...those relays are problematic at best for your setup


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## need_a_VR6 (May 19, 1999)

*Re: Fuel pump relay 101 (Salsa GTI)*

If your MSD has a tach out wire, just hook that up to the wire that used to go to the coil to the tach/relay.


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## painter (Nov 24, 2003)

*Re: Fuel pump relay 101 (need_a_VR6)*


_Quote, originally posted by *need_a_VR6* »_If your MSD has a tach out wire, just hook that up to the wire that used to go to the coil to the tach/relay.

Tried that all ready, it didn't work either
I asked this question in the mk1 forums as well since I didn't really get an answer in this one 
see here -> http://forums.vwvortex.com/zerothread?id=4657298


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## need_a_VR6 (May 19, 1999)

*Re: Fuel pump relay 101 (painter)*

Interesting solution, at least you know that induction works.


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## Space9888 (Mar 18, 2002)

*Re: Fuel pump relay 101 (painter)*

you say you jumped the relay and the pump works. this indicates that you have power on the load (switched) side of the relay. this does not indicate that you have power on the switching side of the relay, what switches the switching side of the relay the ignition wire.


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## Space9888 (Mar 18, 2002)

*Re: Fuel pump relay 101 (Space9888)*

the easy answer is if you run a secondary wire from the ignition switch, coil, or the msd box that is switched on with the key, and you wire that into the switching wire on the relay pigtail you will have solved your problem. 




_Modified by Space9888 at 2:20 PM 11-24-2009_


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## painter (Nov 24, 2003)

*Re: Fuel pump relay 101 (Space9888)*


_Quote, originally posted by *Space9888* »_you say you jumped the relay and the pump works. this indicates that you have power on the load (switched) side of the relay. this does not indicate that you have power on the switching side of the relay, what switches the switching side of the relay the ignition wire. 

power on the switched side or the 15 circuit comes from the original 15 circuit 
it's the 1 wire I was having trouble with 
the 1 wire to the relay is a pulsed signal that originally came off of the neg side of the coil 
when I spoke with an MSD tech on the phone (something I should have thought of sooner) he said anything that use to come off of the neg side of the coil should now be attached to the MSD white wire. Not the neg side of the coil 
But I tried that and it didn't work either 
what did work was wrapping the 1 wire around the main coil output wire 
and as I said earlier it's not the best solution but it's working


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## Space9888 (Mar 18, 2002)

*Re: Fuel pump relay 101 (painter)*

http://****************.com/smile/emthup.gif


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## lunkers (Feb 26, 2004)

*Re: Fuel pump relay 101 (painter)*

i had a similar problem when i installed a mallory ign on my 80 scir, car would fire but not run. i had to buy a tach adapter, i think the msd set ups are the same. all the adapter does is let the signal go in one direction. had me going nuts at the time all for a little five dollar adapter wire. when you crank it see if the tach goes crazy, thats what mine did


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## VenaGTi (Mar 19, 2006)

*Re: Fuel pump relay 101 (lunkers)*

does this help?


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## Alfonso T. (Aug 29, 2001)

*Re: Fuel pump relay 101 (VenaGTi)*

Well: The power (15) is getting ok to one side of the relay coil, thats Ok, but the other side of the fuel pump relay coil has to get a ground connection in order to close the circuit AND that's part of the original ECU job (at least on Digifant), so it can turn on/off the fuel pump relay as needed.
If your MSD ignition system has a cable that provides a ground path when you turn on the ignition, that cable should be connected to the "ground" side of the fuel pump relay coil.
Hope it helps.


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