I am in the process of installing my walbro and I was wondering why everyone was doing the relay mod. It looks like the factory wiring may be 14 awg and the walbro is 16 awg. Someone convince me why to run the 10 awg wire. I read somewhere about the walbro would pull 6 amps. I have read the threads about the upgrade but why would you have voltage drop from about 15 foot of wire. Someone who has already been threw this, let me know.
fuel pump relay mod
- Thread starter 89supracrazy
- Start date
Its because the stock pump does not run on 12v all the time and the wiring is 20 years old so when you start stressing it it could catch on fire.
Its a safety type of thing.
Its a safety type of thing.
i asked the same question, but was told it still might not be necessary? unless there is a dif between the relay mod and 12v mod?
I understand about the 12 volt mod. That has to do with the resistor pack. I have it jumpered over. Hvyman, the efi fuse which is 15 amp is supposed to protect the wire. That is its overcurrent protection. The wire could get brittle like you said. It does go threw two relay tips before it reaches the fuel pump. They are circuit opening relay and the fuel pump relay. I don't care much for that set up. If I use my factory wiring is it going to be hard on my fuel pump. If anybody has any input let me know.
Its not a matter of wiring going to be hard on the fuel pump, its the other way around. Yes there is a fuse but that does not mean its always going to pop before something catches on fire.
Do it any way you want but if your car happens to catch on fire because of old wiring then what?
It takes more currant(amps) to push volts through resistance. The longer the wire the more resistance. The more resistance, the more amps you need to push the voltage through.
Do it any way you want but if your car happens to catch on fire because of old wiring then what?
It takes more currant(amps) to push volts through resistance. The longer the wire the more resistance. The more resistance, the more amps you need to push the voltage through.
One thing you guys need to be very careful of if changing the intank wiring is that not all wire insulation will cope in fuel... 
I upgraded my wire to 3mm intank then when I swapped out the pumps a couple of months back I found the 12 month old wire at the point of massive failure, The insulation was brittle and cracked if bent at all, black was worst.
Since then I've replaced it all with 16g Tefzal which has Teflon insulation.
I upgraded my wire to 3mm intank then when I swapped out the pumps a couple of months back I found the 12 month old wire at the point of massive failure, The insulation was brittle and cracked if bent at all, black was worst.
Since then I've replaced it all with 16g Tefzal which has Teflon insulation.
I was shocked/horrified!
Total disaster waiting to happen once the tank got down to almost empty....
Bending the wire was like bending uncooked spaghetti.
Total disaster waiting to happen once the tank got down to almost empty....
Bending the wire was like bending uncooked spaghetti.
Shit yeah esp considering I'd played around with the Tsunami's at 200+psi base pressures
(couple of the terminals were a little toasty looking inside the tank)
(couple of the terminals were a little toasty looking inside the tank)
IJ.;1561695 said:
My bud is a mechanic, and he finds stuff like this often- but many times it's pure negligence and stupidity. For example: Some kid brought in his Civic for a basic tune up, and said that the car wasn't running properly. He had just bought it, and genuinely wanted to get it running well for a daily driver to and from college. Turns out the fuel pump was failing. My friend dropped the tank, only to find the wires for the fuel pump BARE, AND TWISTED together. No insulation, literally stripped and twisted together. That's it!
Yikes!
Quick question being that you mentioned the intank wiring IJ, i just installed a walbro, is it safe to use the supplied connector and wires mated securely to oe wires? I have it assembled but not in tank yet. what i did was use 3/4 of oe wires, being that they looked to have a good coating on them, and just enough of the supplied connector wires, soldered and wrapped with heat shrink, that i believe is resistent to fuel. will i be ok with that?
Don't call me stupidshaeff;1561836 said:
<jk>Would prefer a good crimp connector but of you're sure the heat shrink is fuel rated it'll be fine.89supra7mgte;1561871 said:
so is crimping in this case more suitable, than solder unless properly covered? And if the heast shrink will not withstand fuel what kinda danger or issues am i looking at? I might just crimp instead and save the hassle.
89supra7mgte;1562055 said:
Solder Joints can be prone to failure if not done perfectly, Crimp connectors on the other hand are simple, easy and pretty well fool proof, have a look how connections are done on most aircraft.
If the heatshrink isn't fuel proof you run the risk of a tank explosion if the power wire arcs when the tank is almost empty.
(NOT a risk I'd take anytime and why the brittle insulation freaked me out so badly as it'd only been in there for a year)
89supra7mgte;1562055 said:
What I did was drill the rivets out of the fuel pump bracket and used stainless steel 8/32 bolts,washers,lock washers, and nuts. It took a 3/16 drill bit for the rivets. Then I crimped on a blue round connector. I did not won't to make any splice in the tank. Just make sure the bolts don't stick threw the nut far.
I read about the upgrade for the fuel pump mod and I know the wiring may be old but if you measure the voltage at the diagnostic block you get 12 volts. That is with the resistor pack jumpered. If you run a 10 awg from the battery back using a relay of course the fuel pump is going be louder and maybe pump more. You are putting around 14 volts to the fuel pump. That is what your alternator is putting out. It looks like to me that it is overkill and would shortin the life of the pump. I am going to back probe my fuel pump at the connector and I will post what my voltage is. If it is low then I will consider doing the upgrade.
ok crimping it is. the in tank wires look good i bent and tugged them no cracks and still flexible with good connections