You're pretty much defeating the purpose of putting in a bigger pump if you don't do a rewire..

 

It's a fair question, but if you draw more current from a system that wasn't designed for it longevity will be affected. You can hook it up to the factory wiring and it will run, but it will not work as well as the flow sheet shows. It can also cause your factory wires to run hotter than what was tested by design engineering at Mitsu. My current setup is relay to battery with the relays coil being excited by old fuel pump +. No issues so far. This makes it so that my fuel pump is full throttle all the time, which may not be everyone's cup of tea.

 

That's kind of my thought on it as well. This pump was already installed when I bought the car but the factory wiring was used. Maybe it was fine on pump gas but with E85 and 30+psi I feel like this issue I'm having with a misfire, is probably due to low voltage and increased amps in the pump. Just getting too hot maybe.. You can make 1 or 2 hits through a few gears and it runs fine but after that, when you try and roll into it the engine just breaks up. When the fuel level is around 1/4 tank to 1/8th tank it not only does it do this after a few pulls, it also has a 2500ish rpm light misfire under little to no load (just cruising).

If you drive it and don't get into it, it doesn't seem to have these problems.

New denso 1-step colder plugs gapped to .023
New spoolin up COP kit
New ID1700's
New Fuelab FPR

 

That very well could be the case. I would run an 8 awg minimum cable from the battery to the supply side of a pump relay to keep things consistent. If you have a sound system installed with at least a 4 gauge wire, then your job just got easier because you can tap off that using a distribution block. Just be sure to upgrade the fuse up front. Current doesn't like to flow through long thin wires at all.

 

Don't forget to upsize the fuel pump ground wire to at least the same size.

 

I ran straight hardwire for a couple years(due to sheer laziness) with no issues and my pump has lasted. I'm sure I was overheating the fuel though. It's certainly a good idea to run a hi/lo but do you think it's necessary? I opted for a PWM setup anyway so I'm mostly just curious, the 450 doesn't seem to mind running full tilt all the time.

 

This is so often overlooked it's crazy. If you have a 8awg 12v and an 18awg factory ground don't even expect to get good current flow.

 

It's not for the pump, it's to have more appropriate fuel pressure for start up, idle, and low load. Which makes it easier to tune.

 

Ah fair enough. I personally never ran into tuning issues but I ran E85 most of the time so that's probably why.

 

Heres a video on youtube that shows how to modify the fuel pump housing.

 

Yeah I will definitely be upgrading the ground as well. General consensus seems to be that the seat-belt bolt would be a good ground location.

 

Good video. A few suggestions I have:

1) Spend 5 minutes to vacuum and dust off the fuel hanger cover surface before unbolting it. You don't want to get dirt in your tank by mistake! 5 minutes up front is worth the risk of fishing for dirt in your tank later!

2) Dont snip wires to solder and extend it instead. Keep it 1 piece from pump to connector for each wire. Try removing the clips from connector and swap on the oem connector. As Pal215 found out, heat shrink will fall apart in fuel tank and if you snipped both wires at same length, you risk shorting and will blow your fuse. In general, when solding wires I always cut at different lengths on each wire so they can't short when heatshrinks fail (because exposed wires are at different locations where one wire will always have the original protective plastic coating).

 

Would be ideal if you could just not have any solder or crimps at all and fully terminated connections. Still don't understand why Walboro doesn't put terminals on their pumps and just permanently wires them.

 

Because they want to sell you a $20 installation kit that connects to their plug and you wire the open end to your connector!

 

Heat shrink can be held in place by just putting a small zip tie at either end. Then it doesn't slide out of the way when fuel causes it to expand.