Thanks for taking the time to do this. I've wanted to do this to see what difference it made, it's obvious it does. I rewired mine last night on my new project. Basically i'm running two pumps, one it tank and one inline. I wired to relays that share one trigger, the 12v from battery and the ground. From there each relay goes to each pump. Should work nice.

 

Honestly, I have never been a fan of those rewires on some other cars. But seeing this has turned me into a believer! Definitely a cheap,easy, and worthwhile mod.

 

When I relocated my Battery to the trunk and did the rewire...I was seeing the same voltage at both places..

 

Where would the gains from this be shown? I'm guessing high throttle/high rpm where the demand for fuel is highest? Do you feel a difference since the mod?

 

The idea is to get more consistent and possibly more volume from the fuel pump. Biggest benefit would be additional margin of safety against running too lean. Personally, I didn't feel any difference in power, but I did notice less knock after I did the mod. My current setup is very mild, so others with heavier mods may really notice an improvement, particularly when it comes to getting a good tune.

 

Awesome post. Thanks for taking the time to post the results of the rewire and including before and after information. I will add this thread to the "Rules & FAQ" page at the top.

 

The idea is to supply the fuel pump with the highest possible voltage you can get to it. More voltage available at the pump means more potential fuel volume from the pump, all other factors remaining constant.

Ceteris paribus

Great writeup!

Although this would greatly benefit the stock fuel pump, how much do you guys think it will help with a 255 in there?

 

The same exact way. Without it, it's not going to flow what it is rated as.

It's like saying if you were running 3 cylinders and expecting your turbo to output its maximum amount of boost.

 

Guess I got another thing to do this winter yay!

 

Look at that loss of voltage.

 

Would you need different fuses/wires going from a stock to walbro 255? ie: bigger, more volts?

 

Would you need different fuses/wires going from a stock to walbro 255? ie: bigger, more volts?

Bigger pumps require more amperage to run at full potential (versus the stock pump). I chose to run 12 awg wire for my setup (Walbro 190), and review the results. Based on what I came up with, I felt the 12 AWG wire is sufficient.

Remember, the more amperage an electrical device draws, the greater the voltage drop would be on the same circuit.

To give a hypothetical example; voltage drop on the fuel pump circuit may be .2V with a stock pump, but may increase to 1.6 V with a big pump that pulls a lot more amperage.

^^^The diagram in the post above me is exactly how I did mine. I chose to solder and heat shrink all connections to eliminate any possible sources of voltage drop (small as they may be).

 

Great write up!

 

1. Relay

2. 10awg wire (enough to go from you battery to your trunk

3. 12awg wire (one foot should do)

4. 10awg wire (enough to ground somewhere in your trunk)

5. Inline fuse holder

Plus all the ring holders and solder-less crimps, radioshack carries everything you need and will cost less than $20.00.

Here are the instuctions

http://www.plymouthlaser.com/rewire.htm

Here is a diagram that I was kind enough to draw in paint.

There is no increase in performance but helps your pump maintain a constant voltage and keeps knock at bay, I was a sceptic my self and let me tell you, I am so glad I decided to do it. It took me about three hours but I did it and it wasn't as hard as I thought it would be, the hardest part is routing the wire through the car and the trunk.

Also while your back in your trunk buy a on/off switch and mount it where ever you want it, T it in to your ground wire, this will require some extra 10awg wire but it is worth it if you don't want your car easily stolen.

 

Nice writeup consolidating information. OP, why did you opt for 12 awg wire instead of the bigger 10 awg?

 

To be honest, it was the largest gauge wire we had on a spool at work (meaning: free). I figure I would try it, and measure the difference. Going to larger 10 AWG may have been more fitting if I was running something bigger (255 lph+), but for my setup, I think the 12 AWG seems good enough (for now).

Definitely wouldn't hurt to run 10 AWG, and I probably would have if I had some readily available at the time. I did this at work between jobs when we where slow at the dealer I used to work at.

Basically; bigger gauge wire could only help. If you have it, may as well use it. And remember, just as important are the connections along the way. I'd recommend soldering everything you can, and make the most of connector surface areas.

 

this is a great tool the map you posted thanks agian i am looking into this problem my self

 

Thanks for sharing your results with us. With every DSM I've owned, the fuel pump rewire has always been the first mod' that gets done.

 

Thanks for this. I have been "lurking" around learning about different mods and have heard of this one but it is nice to see the difference.

 

I noticed a greater performance gain from rewiring my fuel pump than putting in a big 16g, it is that important, up top it just pulls and never runs out of fuel.

IMO it is mandatory, going with a walboro 255 and using the stock wire would be a waste, the power that a more powerful pump would require would be to much for the stock wire to handle.

 

I noticed a greater performance gain from rewiring my fuel pump than putting in a big 16g, it is that important, up top it just pulls and never runs out of fuel.

A fuel pump rewire doesn't add HP ... So I call this sentence BS.

 

So let's say that I was running out of fuel with my stock fuel pump and stock wiring. Would I get a little more fuel out of the same pump if I did the rewire with 10ga wire? This is all hypothetical.

 

Sorry, I will not be giving advise anymore to anyone, I am new to this so I don't see why I was even giving advise when I am obviously not qualified to.

DSM4LIFE, there is no need to be rude, I am not here to disrespect anyone or any mods, there is a reason why I haven't been banned, I always apologize when I do something wrong.

 

It's bad advice which causes newbs to blow their cars up, or make poor modification decisions with their cars.

 

Glad this thread was done. It def. seems to show the difference in rewired vs stock. Damn, now I have yet ANOTHER thing to add to my list of stuff to fix/do on my car.

 

+1 good thread

 

Has anyone ran there rewire directly to the alternator? I have a alt. relocation kit and it seems that you would be getting more direct power flow and there would be less wires out in the bay (a.k.a cleaner).

 

Well the alternator is in the bay too ... One thing you can do to have less wire right on the + battery is use a fused distribution block. So you use something like a 4ga wire with an inline 60amp fuse and hide the distribution block in the car, than run the fuel pump rewire and other accessories like gauge or switch from the block.

Like this:

 

About how much extra psi would a fuel pump rewire allow you to run?