New Corvette owner needing some advice!
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Joined: Nov 2018
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From: Texas
New Corvette owner needing some advice!
Got my first Corvette recently, a 1989. When I gradually speed up my acceleration is fine, when I floor it, it’s great, but there is this one little area when the pedal is pressed around the halfway point that it will start accelerating then stop completely almost to a stand still, then it will accelerate for another second, then stop completely again. I have to take my foot off the gas then press it around the 3/4 point of it being all the way down to take off again, or gradually speed up. I replaced the spark plugs, fuel pump, fuel filter, ignition coil, PCV Valves and Grommets. I bought a distributer cap/Rotor but have not installed it yet, I know the timing is off though because I’ve had to move the spark plug wires one over counter clockwise on the distributer cap to get it to start. Whatever this is that’s happening to it is worse sometimes more than others. When it’s not so bad I will hold the pedal in that position and make the car do it, after a few times it goes away and the rest of the drive is smooth. Other times it doesn’t happen at all. Any ideas?
Last edited by 89’Vette; Nov 28, 2018 at 11:48 AM. Reason: Forgot to add something.
Racer
Joined: Jul 2017
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From: PA
Thread Starter
Advanced
Joined: Nov 2018
Posts: 71
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From: Texas
What???? First thing you need to do is make sure the firing order is set up correctly. Once that's done, you'll need to get a timing light and check the base timing, I believe it's supposed to be 6 degrees BTDC? Then test drive again. Did you actually check fuel pressure? Pump and filter may be new but regulator could be bad.
No I have not checked fuel pressure. Just checked the MAF sensor, and TPS. Both are working properly. Could it be faulty injectors or a vacuum leak?
Safety Car
Joined: May 2001
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From: Fairfax Virginia
First: Welcome to the Corvette Forum!
Sounds like a fuel volume issue there. It might be starving for fuel when you are accelerating which is probably the pressure regulator since you changed the fuel pump and filter. Try taping a fuel pressure tester to the windshield so you can see it while you try to drive and go for a test ride. Let us know what kinds of pressures you have when the car cuts out. Does it happen when the tank is full or when?
Check the EGR on the car to be sure it is not just another vacuum leak. Try listening for a vacuum leak, frequently people with normal hearing can find them.
The only reason I am familiar with this was my own 1988 C4 had rust in the fuel supply pipe that eventually plugged the line so the car could not run without hesitating and doing similar to what you tried to describe. I tried running air pressure through the line and got a fraction of the other end. In the end I replaced the fuel supply line on my car. My return line is fine, just the supply line. I have also seen Corvettes that had their fuel lines bent or crushed by a car lift. It is worth looking at.
Good Luck and be sure to tell us what you find when you check the fuel pressure!
Sounds like a fuel volume issue there. It might be starving for fuel when you are accelerating which is probably the pressure regulator since you changed the fuel pump and filter. Try taping a fuel pressure tester to the windshield so you can see it while you try to drive and go for a test ride. Let us know what kinds of pressures you have when the car cuts out. Does it happen when the tank is full or when?
Check the EGR on the car to be sure it is not just another vacuum leak. Try listening for a vacuum leak, frequently people with normal hearing can find them.
The only reason I am familiar with this was my own 1988 C4 had rust in the fuel supply pipe that eventually plugged the line so the car could not run without hesitating and doing similar to what you tried to describe. I tried running air pressure through the line and got a fraction of the other end. In the end I replaced the fuel supply line on my car. My return line is fine, just the supply line. I have also seen Corvettes that had their fuel lines bent or crushed by a car lift. It is worth looking at.
Good Luck and be sure to tell us what you find when you check the fuel pressure!
