Reworking harness for high volume Fuel Pump

[Matthew Jeschke]

I have a separate post on fuel pump pressure. Finally bit the bullet and bought a high volume fuel pump for my build. Hopefully helps with fuel issues. Long story short...

I need to figure out what terminal pins are used in the fuel pump connector.

I have the pins for the under hood junction block but need the pins for the fuel pump connector. I have a couple of those connectors with butt joints they give you in pump packages but I want to do it right and re-pin the connector. The new pump calls for 12 gauge wire.

Here's additional notes on my fuel pump upgrade:

NBS 2nd gen Tahoe Fuel Pump Upgrade - Matthew Jeschke

Have you been chasing fuel problems? Bad gas mileage on your Chevy Truck? Then you are in the right place. I built up a 2001 Tahoe with a LQ9 (6.0L LS). Initially Fuel mileage was BETTER than the smaller 5.3L LM7 I replaced. However, somewhere along the line my gas mileage dropped by nearly...

matthewjeschke.com

 

[Matthew Jeschke]

This project is turning into a nightmare. There's SO little information online about various Delphi connectors and their corresponding current load at 14 volts. I think the fuel pump circuit will handle 15 amps. I'm going up to 13.5V... But I'm not for sure what gauge wire the factory already has. I purchased 12 gauge to get me from the junction box to the pump housing. There's a harness from the pump housing to the pump itself too. I think that's 14 gauge, but I don't know number of strands in wire to calculate their aggregate cross sectional area. Sigh, anybody have experience with automotive wiring, enough to know what factory did? I seem to have gotten deeper than FSM details.

 

[Fless]

Someone who can look up the specific connector should be able to provide a part number and the pinout. From there you can figure out which terminals fit the connector.

 

[Matthew Jeschke]

Junction Block Underhood Connector F1 I believe. The FSM doesn't seem to have the connector number for the sending unit.

There's a second connector inside the pump. I need to crimp the new connector that came with the pump inside the sending unit as well.

 

[mattbta]

HTH,

 

[Matthew Jeschke]

Sweet @mattbta I've seen this in the FSM for my corvette but not sure where it was at for my Tahoe. I now see the connector specifies Metri-Pack 150. Oddly the shape in the diagram is different than the actual connector though but it's something. I was thinking they maybe Metri Pack 150 terminals.

Here's another question I cannot quite figure out. There's different sizes of Metri Pack 150? I noticed the pin inside the sending unit is same shape but looks to be thicker metal / connection than the pin on the external harness. But both appear to have that Metri Pack 150 shape.

Thanks!

 

[mattbta]

Sweet @mattbta I've seen this in the FSM for my corvette but not sure where it was at for my Tahoe. I now see the connector specifies Metri-Pack 150. Oddly the shape in the diagram is different than the actual connector though but it's something. I was thinking they maybe Metri Pack 150 terminals.

Here's another question I cannot quite figure out. There's different sizes of Metri Pack 150? I noticed the pin inside the sending unit is same shape but looks to be thicker metal / connection than the pin on the external harness. But both appear to have that Metri Pack 150 shape.

Thanks!

I grabbed it for a 2001 based on your site. Maybe it changed over the years? Was that the correct MY for your rig?

 

[Fless]

Grab the Aptiv catalog from this site: https://www.aptiv.com/en/solutions/connection-systems/catalog

Search for your connector and they should also list the terminals that go with it.

 

[Matthew Jeschke]

@mattbta yes was correct MY, 2001 Tahoe. Either way, VERY helpful. It actually looked like the connector inside the sending unit as apposed to the one on the outside of the sending unit. Pins and their colors were correct. And was good to know is a Metri Pack 150 which I'd suspected.

@Fless dang dude awesome! I didn't think to search Mouser. I buy stuff from them for work. Silly me, I guess they carry all the Delphi stuff too. Really cool. Very helpful, something I never knew.

BINGO, exactly what I needed. Dimentions!

https://www.mouser.com/datasheet/2/105/delphi_02062018_12047884_cus01_s02-tif-1360573.pdf

I'm kind of dreaming. If I had the resources would be great to make an aftermarket sending unit that had an inter changeable and or shim able pump sleeve. Then have fittings that would accommodate AN6 and or quick disconnect as well as upgraded wiring. The factory sending unit leaves a LOT to be desired but I guess it works for the little 140 LPH pump the trucks come with. Unfortunately, you can buy an aftermarket dual pump sending unit, but not one for upgrading just a single pump system. You have to cut the factory one all up and modify it.

 

[Matthew Jeschke]

Ah hell. I put in new pump and the pressure is maybe the same if not a bit lower. A friend kept saying to check the voltage drops. I have done that but I did the drop across the wire to the pump and pump to ground. Not the junction box.

This time I hooked up my power probe to the battery. Then I connected the probe to the power pin of the relay with truck off. It of course turned on the pump when I pressed the pull up button.

However, I noticed probe showed only 10.8 volts of the 12.65 volts the battery had. I pulled the junction box apart thinking maybe a fault in that. I took the connector out and powered ONLY that pin for the pump. Same voltage 10.8v. It's roughly 2v lower than the battery. Assuming rouge load isn't in the junction box. I've been through everything between the relay and the ground. It's rewired with 12 gauge wire.

For record, it's drawing 10.5 Amps at around 45 PSI / truck off.

I have metri-pack connectors on order. Hard to believe but maybe my soldered connections to get it running put a several ohm load on the line?

NEVERMIND UPDATE: I need to be VERY careful of power probes. I redid the test with a Handheld DMM and voltages agreed. There was a 200mV drop from the battery to the junction box and like 20mV from the ground return path. Nothing worth noting.