I made a diy hot wire setup. Might have an issue. Any ideas?
05-26-2011, 12:19 AM
#1
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I made a diy hot wire setup. Might have an issue. Any ideas? Okay today I did a diy hot wire setup for my intake walbro 255 pump.Just to see if I can get a few psi back. From the 10psi that I have been losing.
Before I started I took a voltage reading on the purple wire."power wire for the fp." while the car was running. It was at 13.7 volts idling.
I ran 10 gauge wire straight from the pos. side of the battery with a inline 30amp fuse. to the new relay. wired it up like this.
Relay:
30- wire from battery
85- ground
86-purple wire coming in from wiring harness.
87- purple wire going into fp.
87a- not used.
Now I took a reading while idling and now it reads 12.95volts at the output wire from the relay to the fp. and the incoming power wire from the battery to the relay reads 13.9 volts. Straight on the battery terminal when idling Im getting 14.2 volts.
So I went from 13.7 volts from the stock wire going to the fp. down to 12.9volts from the relay output wire going to the fp. Shouln't it have been higher?
Did I wire up the relay right?
Im kinda at a loss. I haven't driven it yet until tomorrow, because we had some crazy tornado action here. But I will take it out, Im just afraid I will lose even more fp pressure when going wot. Im losing 10psi. from 62-52 when just running na. I was hoping this would help me regain a few psi. Any ideas?
Before I started I took a voltage reading on the purple wire."power wire for the fp." while the car was running. It was at 13.7 volts idling.
I ran 10 gauge wire straight from the pos. side of the battery with a inline 30amp fuse. to the new relay. wired it up like this.
Relay:
30- wire from battery
85- ground
86-purple wire coming in from wiring harness.
87- purple wire going into fp.
87a- not used.
Now I took a reading while idling and now it reads 12.95volts at the output wire from the relay to the fp. and the incoming power wire from the battery to the relay reads 13.9 volts. Straight on the battery terminal when idling Im getting 14.2 volts.
So I went from 13.7 volts from the stock wire going to the fp. down to 12.9volts from the relay output wire going to the fp. Shouln't it have been higher?
Did I wire up the relay right?
Im kinda at a loss. I haven't driven it yet until tomorrow, because we had some crazy tornado action here. But I will take it out, Im just afraid I will lose even more fp pressure when going wot. Im losing 10psi. from 62-52 when just running na. I was hoping this would help me regain a few psi. Any ideas?
05-26-2011, 07:52 AM
#2
"Now I took a reading while idling and now it reads 12.95volts at the output wire from the relay to the fp. and the incoming power wire from the battery to the relay reads 13.9 volts. Straight on the battery terminal when idling Im getting 14.2 volts."
Sounds to me as tho you have excessive volt drop across the relay. [1vdc]
Are you checking with the dvm at the neg post, or to the engine?
How are the wires terminated? Crimped w/ correct tools, etc?
Sounds to me as tho you have excessive volt drop across the relay. [1vdc]
Are you checking with the dvm at the neg post, or to the engine?
How are the wires terminated? Crimped w/ correct tools, etc?
05-26-2011, 08:15 AM
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I just made my own "hot wire" also. Ran mine from the alternator. 10awg from alt to 30amp fuse. ran 10awg from fuse to 40amp 4 terminal relay. 10 awg from the relay to my aeromotive 340 in tank.
Relay:
30- 10awg from alt
85- 10awg ground
86-purple wire coming in from wiring harness.
87- 10 awg to fp
also ran 10awg from neg terminal on fp to ground in trunk.
Did you crimp or solder your connections?
will check to see what I'm getting for volts.
Relay:
30- 10awg from alt
85- 10awg ground
86-purple wire coming in from wiring harness.
87- 10 awg to fp
also ran 10awg from neg terminal on fp to ground in trunk.
Did you crimp or solder your connections?
will check to see what I'm getting for volts.
Last edited by bridges; 05-26-2011 at 08:23 AM.
05-26-2011, 11:57 AM
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"Now I took a reading while idling and now it reads 12.95volts at the output wire from the relay to the fp. and the incoming power wire from the battery to the relay reads 13.9 volts. Straight on the battery terminal when idling Im getting 14.2 volts."
Sounds to me as tho you have excessive volt drop across the relay. [1vdc]
Are you checking with the dvm at the neg post, or to the engine?
How are the wires terminated? Crimped w/ correct tools, etc?
Sounds to me as tho you have excessive volt drop across the relay. [1vdc]
Are you checking with the dvm at the neg post, or to the engine?
How are the wires terminated? Crimped w/ correct tools, etc?
05-30-2011, 09:11 AM
#5
I just made my own "hot wire" also. Ran mine from the alternator. 10awg from alt to 30amp fuse. ran 10awg from fuse to 40amp 4 terminal relay. 10 awg from the relay to my aeromotive 340 in tank.
Relay:
30- 10awg from alt
85- 10awg ground
86-purple wire coming in from wiring harness.
87- 10 awg to fp
also ran 10awg from neg terminal on fp to ground in trunk.
Did you crimp or solder your connections?
will check to see what I'm getting for volts.
Relay:
30- 10awg from alt
85- 10awg ground
86-purple wire coming in from wiring harness.
87- 10 awg to fp
also ran 10awg from neg terminal on fp to ground in trunk.
Did you crimp or solder your connections?
will check to see what I'm getting for volts.
Soldered connections are much better than crimped, but it should be easy to find a bad connection. Use a meter set to resistance. A low-tech method is to simply let the circuit run for a few minutes and grab the connections with your hand. Resistance generates heat so a bad joint will be warmer than the rest of the wires
