Fuel pump/ in tank wire failure?
Thread Starter
Race Director
Joined: Sep 2001
Posts: 14,682
Likes: 753
From: NEwhere Ohio
Fuel pump/ in tank wire failure?
Installed a new 450 l/hr walbro in tankfuel
pump this summer in my supercharged 93 vert.
ive always used the racetronix relay harness, but that said I do use the stock 16 ga bulkhead wiring into the fuel tank sender.
anyways, car broke down in my driveway with zero fuel pressure. Despite 0 fuel pressure , I would see a 2 second burst of power at the wiring to the fuel tank sender, when key first turned on. So I know the racetronix relay and stuff was still working.
sometimes the car would start and run for a few minutes only to break down with 0 fuel pressure .
so I pulled out the fuel tank sender expecting to see some kind of wiring issue. Nada. Nothing.
the fuel resistant shrink wrap tubing around my in tank soldered pump wires looks perfect...
ground (to the sending unit) looks fine,
im wondering about that goofy 90 degree bulkhead connector (where wires pass into the tank) if something in there didnt ‘melt’.
lastly, the walbro 450 l/hr pump itself will be my next investigation
this is frustrating bc i dont want my car to be unreliable. Thats not how my c4 rolls.
id love to hear any ideas...
pump this summer in my supercharged 93 vert.
ive always used the racetronix relay harness, but that said I do use the stock 16 ga bulkhead wiring into the fuel tank sender.
anyways, car broke down in my driveway with zero fuel pressure. Despite 0 fuel pressure , I would see a 2 second burst of power at the wiring to the fuel tank sender, when key first turned on. So I know the racetronix relay and stuff was still working.
sometimes the car would start and run for a few minutes only to break down with 0 fuel pressure .
so I pulled out the fuel tank sender expecting to see some kind of wiring issue. Nada. Nothing.
the fuel resistant shrink wrap tubing around my in tank soldered pump wires looks perfect...
ground (to the sending unit) looks fine,
im wondering about that goofy 90 degree bulkhead connector (where wires pass into the tank) if something in there didnt ‘melt’.
lastly, the walbro 450 l/hr pump itself will be my next investigation
this is frustrating bc i dont want my car to be unreliable. Thats not how my c4 rolls.
id love to hear any ideas...
Last edited by dizwiz24; Jan 25, 2020 at 03:32 PM.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Yea the expensive Walbro pump I installed in my camaro didn't last 2 years. Kind'a surprised and disappointed. Not gonna waste money on expensive pumps again but I don't have a supercharger either.
My assumption is the larger pumps get uncovered more often since they don't have (fit in a) "bucket". Just my assumption though - take it or leave it. A better supply system may need it's own sump but again I'm not where I need one.
My assumption is the larger pumps get uncovered more often since they don't have (fit in a) "bucket". Just my assumption though - take it or leave it. A better supply system may need it's own sump but again I'm not where I need one.
Drifting
Joined: Jan 2005
Posts: 1,354
Likes: 325
From: San Antonio Tx
Mine failed in the tank bulkhead connector with no visible sign. It was causing an intermittent problem. I replaced it with the racetrinix in tank harness and never had any more trouble with the pump.
Le Mans Master
Joined: Aug 2017
Posts: 6,943
Likes: 1,490
From: New Jersey
I don't think the wires melted. If they did you should have blown a fuse, this assuming the relay harness feed for the pump is fused. I personally would probe the pump and see if there is power at key on and if not I would check the relay itself. Pumps generally don't work then quit then work again. My experience is they quit and that's it. Relays I have seen do what you describe. If you want to check the bulkhead connector, check for continuity between the wires and between the tank and each wire. Mess with the plug too in case they've moved apart too.
Hope this helps.
Hope this helps.
Drifting
Joined: Jun 2018
Posts: 1,402
Likes: 287
From: Brisbane Australia
C4 of Year Finalist (performance mods) 2019
I don't think the wires melted. If they did you should have blown a fuse, this assuming the relay harness feed for the pump is fused. I personally would probe the pump and see if there is power at key on and if not I would check the relay itself. Pumps generally don't work then quit then work again. My experience is they quit and that's it. Relays I have seen do what you describe. If you want to check the bulkhead connector, check for continuity between the wires and between the tank and each wire. Mess with the plug too in case they've moved apart too.
Hope this helps.
Hope this helps.
my guess is relay or the crappy connector where the wires enter the tank.
Thread Starter
Race Director
Joined: Sep 2001
Posts: 14,682
Likes: 753
From: NEwhere Ohio
im already using their hotwire relay kit (as mentioned).
Thread Starter
Race Director
Joined: Sep 2001
Posts: 14,682
Likes: 753
From: NEwhere Ohio
Relays have a couple of ways of failing. The contacts can overheat and become aneled which affects the contact surface and the springs tension of the contact, this will cause intermittent faults. Sometimes the heat in the contacts cause the plastic push rod to melt and although you can hear the relay click the contacts don’t move. That mode is generally not intermittent. And lastly the coil can fail also not intermittent.
my guess is relay or the crappy connector where the wires enter the tank.
my guess is relay or the crappy connector where the wires enter the tank.
The racetronix relay seems fine (so that leads me to the bulkhead connector)
Drifting
Joined: Jun 2018
Posts: 1,402
Likes: 287
From: Brisbane Australia
C4 of Year Finalist (performance mods) 2019
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Drifting
Joined: Nov 1999
Posts: 1,324
Likes: 18
From: St. Peters MO
I had similar issue, it ended up being a broken wire between the bulkhead at the top, and the fuel pump. The insulation was intact "visually", but as gasoline would slosh around it would bend the wire and lose contact. Crack in the insulation (wire coating) was very, very difficult to spot. I pushed it onto a trailer one time, towed it home, only to have it fire right up on the trailer when I got home with it.
Had to replace the wire harness inside the tank.
Had to replace the wire harness inside the tank.
Le Mans Master
Joined: Feb 2005
Posts: 6,485
Likes: 566
From: Clearwater Florida
….. I had the same issue with my car … The top pic shows the 90* bulkhead wiring connector … if you look closely at the pin on the left you can see that it is black … I couldn't find a suitable bulkhead connector anywhere so I made one out of a nylon toilet seat screw … its the same diameter as the OEM bulkhead fitting … I cut the nose off the end and drilled 2 holes all the way through the screw top to bottom just large enough to pass a 12ga wire through it … I used some tight fitting flat washers on both sides with a pair of brown fuel system o-rings to seal it to the factory sending unit/fuel pump plate …..
Drifting
Joined: Jan 2005
Posts: 1,354
Likes: 325
From: San Antonio Tx
Le Mans Master
Joined: Feb 2005
Posts: 6,485
Likes: 566
From: Clearwater Florida