1975 will not fire up
Thread Starter
5th Gear
Joined: Jan 2022
Posts: 5
Likes: 0
1975 will not fire up
The issue: My car will turn over, but it will not fire up.
Scenario that lead up to this. My car is garage kept, but one day I had to park it in the driveway, but there was a bad rain storm. I normally don’t shut my hood, but it is almost closed all the way. (Just not latched all the way down).
After the rain storm (5-7 days), I was able to drive my car, but it was running a little rough. When I approach a stop sign it would stall, so I had to rev up the engine just a tad to keep it from stalling. I tried a week later to start the car, and it would not fire up. It would turn over as if it wanted to start, but it didn’t. Any thoughts about what could be the issue.
Scenario that lead up to this. My car is garage kept, but one day I had to park it in the driveway, but there was a bad rain storm. I normally don’t shut my hood, but it is almost closed all the way. (Just not latched all the way down).
After the rain storm (5-7 days), I was able to drive my car, but it was running a little rough. When I approach a stop sign it would stall, so I had to rev up the engine just a tad to keep it from stalling. I tried a week later to start the car, and it would not fire up. It would turn over as if it wanted to start, but it didn’t. Any thoughts about what could be the issue.
Advanced
Joined: Aug 2021
Posts: 58
Likes: 24
From: Knoxville TN
1st thing I'd do is to isolate to either a spark or fuel problem.
For spark, a cheap FLAPS spark tester is very helpful when troubleshooting spark issues. If no spark at the plugs the HEI may have gotten wet or blown a fuse.Pull the distributor cap and make sure it's high & dry in there.
For fuel remove the air cleaner so you can peer down the primary side of your carb (with a screwdriver, clothes pin or something similar to hold the choke wide open) then work the throttle linkage to wide open throttle and observe is you see a squirt of fuel down in the carbs throat. If no fuel squirt you could be out of gas, clogged fuel filter, bad fuel pump etc... Course these problems would be the result of coincidence than the rain. Altho rain may have gotten down into the carb & intake so pulling the plugs and drying them out may be necessary.
Good luck.
For spark, a cheap FLAPS spark tester is very helpful when troubleshooting spark issues. If no spark at the plugs the HEI may have gotten wet or blown a fuse.Pull the distributor cap and make sure it's high & dry in there.
For fuel remove the air cleaner so you can peer down the primary side of your carb (with a screwdriver, clothes pin or something similar to hold the choke wide open) then work the throttle linkage to wide open throttle and observe is you see a squirt of fuel down in the carbs throat. If no fuel squirt you could be out of gas, clogged fuel filter, bad fuel pump etc... Course these problems would be the result of coincidence than the rain. Altho rain may have gotten down into the carb & intake so pulling the plugs and drying them out may be necessary.
Good luck.
Race Director
Joined: Nov 2006
Posts: 13,225
Likes: 7,823
From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
2022 C3 of the Year Finalist - Modified
Cruise-In VIII Veteran
Well, he drove it after the rain. It ran less than great and didn't wish to idle.
I would run through a standard tune up first. Plugs, cap, rotor and ign. timing first. Then if it starts carb adjustment. And go from there.
On changing the plugs observe the color and condition of the plugs. These can tell you heaps!
I would run through a standard tune up first. Plugs, cap, rotor and ign. timing first. Then if it starts carb adjustment. And go from there.
On changing the plugs observe the color and condition of the plugs. These can tell you heaps!
Thread Starter
5th Gear
Joined: Jan 2022
Posts: 5
Likes: 0
I didn’t see coming through, so I poured a little gas in the carburetor and it started right up, but it quickly stalled when the gas was used.
About 500-1000 miles ago, I replaced the fuel tank and fuel sending unit because the tank leaked and the fuel sending unit wasn’t registering the amount of gas. Both are new. I can replace it again, but before I do, is there a fuse that runs the pump? I will definitely look for the filter and see about changing it.
About 500-1000 miles ago, I replaced the fuel tank and fuel sending unit because the tank leaked and the fuel sending unit wasn’t registering the amount of gas. Both are new. I can replace it again, but before I do, is there a fuse that runs the pump? I will definitely look for the filter and see about changing it.
Burning Brakes
Joined: Dec 2017
Posts: 1,043
Likes: 414
2023 C3 of the Year Finalist - Modified
I didn’t see coming through, so I poured a little gas in the carburetor and it started right up, but it quickly stalled when the gas was used.
About 500-1000 miles ago, I replaced the fuel tank and fuel sending unit because the tank leaked and the fuel sending unit wasn’t registering the amount of gas. Both are new. I can replace it again, but before I do, is there a fuse that runs the pump? I will definitely look for the filter and see about changing it.
About 500-1000 miles ago, I replaced the fuel tank and fuel sending unit because the tank leaked and the fuel sending unit wasn’t registering the amount of gas. Both are new. I can replace it again, but before I do, is there a fuse that runs the pump? I will definitely look for the filter and see about changing it.
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
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
No fuse. No electric pump on a '75.
You have already answered your own question.
You poured gas in the carb, it started. So, the IGN is fine.
I assume an air cleaner was in place during the rain storm?
You have already answered your own question.
You poured gas in the carb, it started. So, the IGN is fine.
I assume an air cleaner was in place during the rain storm?
Thread Starter
5th Gear
Joined: Jan 2022
Posts: 5
Likes: 0
Yes the air cleaner was on. The previous owner replaced the carburetor, so I am not sure if the fuel filter was replaced, but I would have assumed so. It just seemed so coincidental that this is occurring right after the storm. I put gas in the tank not too long ago, so it has gas and the tank registers 1/2 a tank. With a new tank, I don’t see how water could have got inside the tank. I am baffled.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
That brings up another question. The area surrounding the gas tank fill has a drain. It assures that rain or car wash water does not enter the tank via under the gas cap.
The drain for that fill port is a rubber hose coming off to the side then down towards the ground. Make sure its not plugged with crap.
Lift the gas tank door and pour a glass of water around the gas cap. The water should drain as fast as you pour. Does yours?
The drain for that fill port is a rubber hose coming off to the side then down towards the ground. Make sure its not plugged with crap.
Lift the gas tank door and pour a glass of water around the gas cap. The water should drain as fast as you pour. Does yours?
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 9,135
Likes: 4,244
From: US-PNW
Intermediate
Joined: Apr 2019
Posts: 26
Likes: 6
From: Jacksonville
Update
So I believe I may have isolated the problem. I pulled the gas line away from the carburetor and disconnected the positive lead to the distributor. The fuel pump pushes out fuel into a container, so it appears to be working just fine. The first time I did this, the fuel was yellow, and had some sort of floaters in it. I assume this may have clogged the filter or caused fuel from flowing into the carburetor.
I bought a new filter and I cleaned out about a gallon of gas from the line in the tank.
I put everything back with a new filter and fuel does not flow into the carburetor. I can pour gas directly into it, and it will start up.
I assume I may have clogged something in the carburetor. Is there an easy way to clean it out with it being on the car? Can I use a carburetor cleaner or try to blow air through the system?
I bought a new filter and I cleaned out about a gallon of gas from the line in the tank.
I put everything back with a new filter and fuel does not flow into the carburetor. I can pour gas directly into it, and it will start up.
I assume I may have clogged something in the carburetor. Is there an easy way to clean it out with it being on the car? Can I use a carburetor cleaner or try to blow air through the system?
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 9,135
Likes: 4,244
From: US-PNW
... the fuel was yellow, and had some sort of floaters in it. I assume this may have clogged the filter or caused fuel from flowing into the carburetor.
I assume I may have clogged something in the carburetor. Is there an easy way to clean it out with it being on the car? Can I use a carburetor cleaner or try to blow air through the system?
I assume I may have clogged something in the carburetor. Is there an easy way to clean it out with it being on the car? Can I use a carburetor cleaner or try to blow air through the system?
What brand/model carb do you have? (Stock was Rochester Quadra-jet.) The carb's design will tend to dictate best ways to flush it.
Intermediate
Joined: Apr 2019
Posts: 26
Likes: 6
From: Jacksonville
Update
It was the old Rochester but previous owner changed it to a QuadrJet?
I am not sure if it was the right thing to do but I think it’s beginning to work.
After changing the filter in the carburetor and trying to clean it out with a carburetor cleaner, my car did not work.
I took my air compressor and shot air through the line with the filter still in place. It’s not a very high psi compressor. I felt the air go through the carburetor. After this ran rough for 30 to 45 seconds, and now it is purring like a kitten.
I hope this is not temporary, and I dislodged whatever was clogging the system.
I am not sure if it was the right thing to do but I think it’s beginning to work.
After changing the filter in the carburetor and trying to clean it out with a carburetor cleaner, my car did not work.
I took my air compressor and shot air through the line with the filter still in place. It’s not a very high psi compressor. I felt the air go through the carburetor. After this ran rough for 30 to 45 seconds, and now it is purring like a kitten.
I hope this is not temporary, and I dislodged whatever was clogging the system.