Upgraded fuel sending units

[John z]

So had a slight issue with my car, I burned the inertia switch plug. I currently have an upgraded fuel pump with a 20amp fuse with the tvs1900 supercharger. I wonder if this is too much for the stock wiring. Do they make a unit where I can run a new connector to it? I would want to use the stock fuel pump wiring to activate a relay that has upgraded wire from the junction block to the fuel unit

[agentdr8]

The wiring diagrams show 1mm (~18 awg) wiring for most of the fuel pump and inertia switch circuits, except when it goes to the alarm module. 18awg wiring has a typical max current rating of 9.5A, so if you're actually drawing much higher, you'd want to switch to 14awg or larger and use the existing wiring just to trigger a relay like you've indicated. Did you replace R19 with a 20A fuse? If so, that would make sense why the connector wiring burned out instead of popping the stock 10A fuse. 

 

 

[John z]

Yeah, it was swapped. I'm surprised it lasted as long as it did. Almost 15k miles. 

So the next place that could burn up right now is the connection at the unit or the wire itself. 

[agentdr8]

If the S1s use the same connectors as the 400s, they have an 8-pin connector at the fuel module end. Either Excel or Yazaki. I couldn't find the Excel part #, but the Yazaki shows it's rated for 20A:

https://connectors-catalog.sys.yzk.co.jp/yazaki-web/servlet/SubServlet_e?forward=7283-5574-10&plist=list&select=XX

The fuel pump connector is a 6-pin Tyco/AMP, which can handle between 14awg and 22awg wiring, so it could handle 20A as well if you rewired it:

https://www.te.com/usa-en/product-184060-1.html
https://www.te.com/commerce/DocumentDelivery/DDEController?Action=showdoc&DocId=Specification+Or+Standard114-8004GpdfEnglishENG_SS_114-8004_G.pdf184060-1

The inertia switch connector is a 3-pin Tyco/AMP Econoseal, which can handle wire sizes from .2mm to 2.0mm, so it's 20A capable as well:

https://www.te.com/usa-en/product-1-344273-1.html
https://www.te.com/commerce/DocumentDelivery/DDEController?Action=showdoc&DocId=Catalog+Section1654365_Econoseal0911pdfEnglishENG_CS_1654365_Econoseal_0911.pdf1-344273-1

You should be able to build a relay harness using stock connectors and upgraded wiring. 

[John z]

Unfortunately the S1 uses a different connector. It's more like a triangle 3pin holes(2 used for fuel level) and 2 pin holes for the pump next to it. Wish I got a pic of the connector itself. If I can track down the correct connector.

But that just leaves the unit as the last part of the puzzle. Can it support up to 20 amps or should it be modified.. 

[John z]

Just noticed the Toyota part sticker in that pic. I googled Toyota Camry fuel sender. Looks like it's close. Definitely the same connector

[agentdr8]

I wouldn't think the fuel level sending unit wiring would need to be upgraded. If your goal is to only provide more current to the fuel pump, I'd focus just on its connections.