Fuel Pump/Sending Unit Bulkhead Connector - ZR-1 Net Registry Forums

jss06c6 · 10-06-2020

I've had two failures on two separate C4's associated with the Bulkhead Connector.

This 4 Pin connector rarely sees liquid gasoline; high acceleration/deceleration with a full tank being the exception. It sits in the "vapor space" at the top of the tank.

The first instance was on a supercharged 1995 LT-1. I upgraded to a Walbro 285 in tank pump to handle the fuel demands under boost. The pump became intermittent and finally failed in only 2 months! Cause of failure was corrosion on the bulkhead ground pin. This pump pulls 17 amps at 40 psi. The resistance in the connection resulted in severe overheating at this terminal (inside tank) and ultimately ruined the 285.

I replaced the pump and upgraded the bulkhead and harness to a Racetronix unit. This one has stainless steel pins and in tank wiring. Also added plenty of Dielectric grease to the connection.

I thought this was a one off issue, associated with the high current demand of the 285.. it wasn't.. which is the basis for this post...my personal '91 ZR-1 had a similar failure! This time, it was the primary pump 12 volt terminal. Same issue, corrosion causes high resistance connection and overheated. Continuity finally gave out. At least the pump was still good. Same remedy. Replaced stock bulkhead/harness assy with the Racetronix assembly. The fuel pump / sending unit assembly was one of the last new units available in the market that I found about 3 years ago. It was essentially new..

I don't know if the alloy used in the pins in this 3 year old unit are substandard. I have my original unit and it does not show any issues..

This harness has 14 gauge stainless in tank wiring. If you decide to rewire for a single high flow pump or simply decide to upgrade the wiring in your ZR-1 or LT-1, I'd recommend looking at the Racetronix unit..

The gray wire harness is the 3 year old one in my '91, the other is the '96 LT-1.20200924_120638.jpg 20200924_120627.jpg 20201001_144503.jpg 20200929_090638.jpg Attachment 1

Sent from my SM-G950U using ZR-1 Net Registry mobile app

Meanmyz · 10-07-2020

I posted in another thread about my fuel sending unit repairs, done by Tri Star Radiator.

"we modified your upper wiring harness so that it will not be prone to future issues like many of these units are. "

I am posting here just to get word out on my good experience with a place that refurbishes fuel sending units. It sounds like their fix above in my quoted sentence, is in addressing this issue.

10-06-2020	#1
jss06c6 Join Date: Aug 2015 Location: Magnolia, Texas Posts: 884	Fuel Pump/Sending Unit Bulkhead Connector I've had two failures on two separate C4's associated with the Bulkhead Connector. This 4 Pin connector rarely sees liquid gasoline; high acceleration/deceleration with a full tank being the exception. It sits in the "vapor space" at the top of the tank. The first instance was on a supercharged 1995 LT-1. I upgraded to a Walbro 285 in tank pump to handle the fuel demands under boost. The pump became intermittent and finally failed in only 2 months! Cause of failure was corrosion on the bulkhead ground pin. This pump pulls 17 amps at 40 psi. The resistance in the connection resulted in severe overheating at this terminal (inside tank) and ultimately ruined the 285. I replaced the pump and upgraded the bulkhead and harness to a Racetronix unit. This one has stainless steel pins and in tank wiring. Also added plenty of Dielectric grease to the connection. I thought this was a one off issue, associated with the high current demand of the 285.. it wasn't.. which is the basis for this post...my personal '91 ZR-1 had a similar failure! This time, it was the primary pump 12 volt terminal. Same issue, corrosion causes high resistance connection and overheated. Continuity finally gave out. At least the pump was still good. Same remedy. Replaced stock bulkhead/harness assy with the Racetronix assembly. The fuel pump / sending unit assembly was one of the last new units available in the market that I found about 3 years ago. It was essentially new.. I don't know if the alloy used in the pins in this 3 year old unit are substandard. I have my original unit and it does not show any issues.. This harness has 14 gauge stainless in tank wiring. If you decide to rewire for a single high flow pump or simply decide to upgrade the wiring in your ZR-1 or LT-1, I'd recommend looking at the Racetronix unit.. The gray wire harness is the 3 year old one in my '91, the other is the '96 LT-1.20200924_120638.jpg 20200924_120627.jpg 20201001_144503.jpg 20200929_090638.jpg Attachment 1 Sent from my SM-G950U using ZR-1 Net Registry mobile app Last edited by jss06c6; 10-30-2020 at 09:07 PM.

10-07-2020	#2
Meanmyz Join Date: Feb 2006 Location: Springfield, Minnesota Posts: 444	Re: Fuel Pump/Sending Unit Bulkhead Connector I posted in another thread about my fuel sending unit repairs, done by Tri Star Radiator. "we modified your upper wiring harness so that it will not be prone to future issues like many of these units are. " I am posting here just to get word out on my good experience with a place that refurbishes fuel sending units. It sounds like their fix above in my quoted sentence, is in addressing this issue.