...any suggestions on what I should try next? I really need to sell this to pay for summer class tuition for me and my kids' summer sports camps. Thanks!
Fuel Pump Fuse Issues
Thread Starter
7th Gear
Joined: May 2012
Posts: 7
Likes: 0
From: Fort Scott Kansas
Fuel Pump Fuse Issues
I have a 1979 Corvette I'm trying to sell but I have to get it running first. It has the motor and transmission out of a 1989 Corvette (350 w/TPI) and ran great. Unfortunately, it died on the highway and wouldn't start again. It sounded like it wasn't getting any fuel so I started doing some investigating. Turns out the fuel pump fuse, located near the alternator, was blown and if I replaced that it would start, but blow the fuse if I drove it more than a few blocks. It has an external or inline fuel pump, so I traced the wiring from the pump all the way and found a bad ground, so I fixed that, crossed my fingers, and started it again. Fuse blew again (25amp). When it's warm, it'll blow them almost immediately, but if it hadn't been driven for a day or so, it'll start up and idle just fine but I don't dare drive it anywhere. Would the fuel pump itself be the problem or could it possibly be the relay? I don't have access to any diagnostic equipment but I am open to suggestions. Also, I am on a VERY limited income. I really need to sell the car but very few people want to buy one that they'd have to pull home. Any advice would be MUCH appreciated!
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
I'm just guessing because I don't know much about the TPI but I wonder if those pumps were able to run dead head. Here is what I'm thinking. Depending on how the whole thing was put together maybe the fuel filter is blocked and the pump is overheating. I seem to remember most of the systems are setup with a return so the pump doesn't dead head,maybe yours was bypassed ?
I think I would try to get the fuel line opened just past the pump and see if it will run unrestricted.
Do you know if it has the sock in the tank ?
I think I would try to get the fuel line opened just past the pump and see if it will run unrestricted.
Do you know if it has the sock in the tank ?
Thread Starter
7th Gear
Joined: May 2012
Posts: 7
Likes: 0
From: Fort Scott Kansas
There is no regulator but I'm not sure about the sock. Would a relay display the same symptoms? I only ask because it is cheaper to replace but whatever I can do to get this thing going. Thank you for your help. I just went through a major wiring project after I found out the aftermarket alarm they'd installed was shutting the entire car down and they'd installed neon tubes all throughout the undercarriage which of course no longer worked. It was a MAJOR mess, but now I am actually confident in the wiring. I will see what I can figure out and try your suggestions. I'm sure I'll be posting again soon.
Thread Starter
7th Gear
Joined: May 2012
Posts: 7
Likes: 0
From: Fort Scott Kansas
Ok, it has been a couple weeks but no solution. Unfortunately it seems I am working backwards. I replaced the pump and filter with brand new ones. The pump is a Summit brand putting out 45psi and at first it acted like it was trying to start. I checked where the Schrader valve was supposed to be (someone put NOS line there and a couple other places) and there was strong fuel pressure, although I do not have a gauge to check it. I tried some more and it sounded like it wasn't getting fuel. I took the plug where the Schrader valve used to be and it had air coming out instead of fuel this time. Took off the filter and it was dry. No fuel to the filter (or pump). I tried plugging in the NOS lines again since that was the only other thing I'd touched but no change. It was running and driving with the old pump, but now nothing! Sounds like an issue in the tank itself, but I am FAR from a mechanic (although I did have one come by and make sure everything was connected correctly). I have to do this myself due to losing my job and feeding my kids is a bigger priority but my backup driver also went down yesterday. Any ideas?
Thread Starter
7th Gear
Joined: May 2012
Posts: 7
Likes: 0
From: Fort Scott Kansas
No, but it didn't blow the fuse previously until I drove it a mile or 2 down the road. Also, I found the positive wire melted to the muffler so I replaced that as well. Hopefully, the fuse issue is behind me. I can hear the pump kick on when I turn the key too. My hair is turning grayer every time I look at the car.
Last edited by FS94Tiger; Jun 28, 2012 at 01:23 PM.
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Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
Could all of this effort be the result of having a defunct accelerator pump in your carb? With today's ethanol-laced fuel, the accel pump seal might just swell and fall of the pump piston, if it isn't alcohol-capable. You can check the accel pump action by removing the air cleaner (engine OFF) and, while looking down into the primary venturi (open choke plate manually, if you need), give the throttle linkage on the carb a quick WOT shove. You should a full squirt of raw fuel going into each of the primaries. If you do not, the accel pump in your carb is inoperative and it is no wonder it won't start....it isn't getting ANY fuel!!
Fixing that would be a lot easier than doing the electric fuel pump 'thing'. Not to mention that your engine still won't start with no fuel getting to the intake.
In any event, wish you luck on your project.
Fixing that would be a lot easier than doing the electric fuel pump 'thing'. Not to mention that your engine still won't start with no fuel getting to the intake.
In any event, wish you luck on your project.
Last edited by 7T1vette; Jan 27, 2019 at 11:56 PM.