Messed up my C2 again, Driveability)
Thread Starter
Drifting
Joined: Feb 2010
Posts: 1,732
Likes: 267
From: Richmond Texas
Messed up my C2 again, Driveability)
Screwed up my car again.
Parked the car and somehow left the key on. Went back a couple of days later..Battery completely dead, put a fresh battery in the car, fires right up, Idles really well but bucks on take off, almost like the accelerator squirter isn't working (it is) runs rough going down the road. Figured I toasted the points leaving the key on so I got a new set of points and condenser , all they had was a uni set (AC Delco D1007), set the dwell to 30*, set the timing to 12 initial, 32 total, hooked up the vacuum advance,( it works, hooked to manifold vacuum port on carb), Car still bucks on take off and runs bad going down the road, tried a used coil off my Plymouth, didn't help. Voltage at coil with engine running is 10.5.
I am at a loss, what else could I have messed up? Anyway I could have messed up the cap or rotor leaving the key on?
Parked the car and somehow left the key on. Went back a couple of days later..Battery completely dead, put a fresh battery in the car, fires right up, Idles really well but bucks on take off, almost like the accelerator squirter isn't working (it is) runs rough going down the road. Figured I toasted the points leaving the key on so I got a new set of points and condenser , all they had was a uni set (AC Delco D1007), set the dwell to 30*, set the timing to 12 initial, 32 total, hooked up the vacuum advance,( it works, hooked to manifold vacuum port on carb), Car still bucks on take off and runs bad going down the road, tried a used coil off my Plymouth, didn't help. Voltage at coil with engine running is 10.5.
I am at a loss, what else could I have messed up? Anyway I could have messed up the cap or rotor leaving the key on?
Instructor
Joined: Dec 2025
Posts: 169
Likes: 54
From: Pachuta, MS
This is a tough one but I can't see anything like this damaging the cap or rotor. What I can see is something like ignition switch contacts being overheated (though not likely) or the resistor being overheated or possibly the voltage regulator barely working now or the coil wire getting so hot (from the coil) that it barely conducts spark now because the carbon conductors have broken down or a poor connection between the switch and the coil. I suggest that you eliminate all the primary ignition causes at one whack (since you have replaced the points and condenser) by jumpering from +12v to the '+' terminal of the coil. If the problem persists, I would then rig a temporary wire from the points to the '-' terminal of the coil. You could probably run it through the window in the cap. If that fails then replace the coil wire or at least test it with an ohmmeter. That ought to be a good start. Final thought: Does this thing have an electric choke? You could have burned him up. If there is a radio suppression capacitor connected to the '+' side of the coil, you might try disconnecting him(just the lead) because he could have been damaged by the coil's heat.
Last edited by acstephenson; May 9, 2026 at 06:34 PM.
Le Mans Master
Joined: Aug 2005
Posts: 6,510
Likes: 1,945
From: Temple Terrace Florida
You can for testing purposes, connect a wire from the positive side of the coil to the positive side of the battery, That will bypass the ignition switch and give full battery power to the ignition system. Jerry
Thread Starter
Drifting
Joined: Feb 2010
Posts: 1,732
Likes: 267
From: Richmond Texas
It has 10.5 volts running to the + side of the coil. I can hot hire it and see if that helps but I thought it was supposed to have around 6 volts running
Instructor
Joined: Dec 2025
Posts: 169
Likes: 54
From: Pachuta, MS
Somewhere between 7 & ~ 9 is typical but it varies. The important point is that it has nearly 12 VDC while cranking. The only reason that 12 volts isn't supplied all the time is that it will burn the points fairly quickly but for testing purposes that's fine. Your 10.5 volts is a bit high and suggests that the coil isn't pulling quite enough current. Get the jumper test out of the way and go from there. One thing that could cause the somewhat abnormal voltage is a broken wire between the distributor ground and the breaker plate. It might have burned up.
Thread Starter
Drifting
Joined: Feb 2010
Posts: 1,732
Likes: 267
From: Richmond Texas
Somewhere between 7 & ~ 9 is typical but it varies. The important point is that it has nearly 12 VDC while cranking. The only reason that 12 volts isn't supplied all the time is that it will burn the points fairly quickly but for testing purposes that's fine. Your 10.5 volts is a bit high and suggests that the coil isn't pulling quite enough current. Get the jumper test out of the way and go from there. One thing that could cause the somewhat abnormal voltage is a broken wire between the distributor ground and the breaker plate. It might have burned up.
One thing I did notice is that when I hooked the positive side of the coil wire to the coil it arcs pretty good. Never noticed that before. Is that normal? That was with the points closed, when they are open, it doesn't do that. I attached the video hopefully
Last edited by SledgeHammer 2.0; Yesterday at 06:43 PM. Reason: Grammer, added content
Drifting
Joined: Sep 2024
Posts: 1,516
Likes: 989
From: Florida
Years ago a mechanic at the shop struggled with the same symptons as you are.. It turned out to be a bad condenser. I read where you put in a set of unipoints and I have no idea how to " check " a condenser but thought I would toss it in the ring here...
Instructor
Joined: Dec 2025
Posts: 169
Likes: 54
From: Pachuta, MS
That spark looks a little strong indicating the coil may be pulling too much current. Are you sure that Plymouth used coil is good? (It could also have introduced some fatal virus that GM cars have no antibodies for.) Something I do note in your image are what appear to be little bubbles in the coil wire insulation. I would be really interested in knowing the resistance of your coil wire; it might have been cooked by the coil's heat, This whole time I've had the feeling that we've been drawn down the ignition path but that it may be something else such as electric choke, electric fuel pump, or some other component that was damaged. At least you have eliminated a bunch of things that it ain't like bulkhead connectors, resistors, points and condenser. This thing still is screaming bad coil because these are the classic symptoms but it could be the coil wire.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
Thread Starter
Drifting
Joined: Feb 2010
Posts: 1,732
Likes: 267
From: Richmond Texas
That spark looks a little strong indicating the coil may be pulling too much current. Are you sure that Plymouth used coil is good? (It could also have introduced some fatal virus that GM cars have no antibodies for.) Something I do note in your image are what appear to be little bubbles in the coil wire insulation. I would be really interested in knowing the resistance of your coil wire; it might have been cooked by the coil's heat, This whole time I've had the feeling that we've been drawn down the ignition path but that it may be something else such as electric choke, electric fuel pump, or some other component that was damaged. At least you have eliminated a bunch of things that it ain't like bulkhead connectors, resistors, points and condenser. This thing still is screaming bad coil because these are the classic symptoms but it could be the coil wire.
A couple of years ago my bulkhead connector fried out and I put an engine and under dash wiring harness in it, so I think the wiring is good. I haven't replaced the tail light wiring harness. I don't have an electric choke nor a electric fuel pump. I will measure the resistance and get back, This car is wearing me out. I have owned it since 1988 and it's been a great car up till 4-5 years ago.
Drifting
Joined: Apr 2011
Posts: 1,589
Likes: 382
From: Australia
I don’t think it’s the root of the problem, but can’t be helping.
Last edited by anyChevy; Yesterday at 10:13 PM.
Instructor
Joined: Dec 2025
Posts: 169
Likes: 54
From: Pachuta, MS
I've had one other thought (and it fits with my psychic tingling that we've been looking at the wrong stuff): All of this could be nothing more than a poor/broken battery or ground connection around the battery itself --- especially the smaller cables. These batteries (especially the non-AC cars) can be a pain to get in and out and it would be very easy to damage or fail to tighten a cable in the process. Measuring voltage across the battery while it's running might also provide a clue.
Drifting
Joined: Dec 2014
Posts: 1,750
Likes: 137
From: Chantilly Virginia
I would look very closely at the path from the points to the coil. The breaker plate is moving frequently during startup and driving (especially if you are having misfires) If you tested with a jumper from the points to the coil, did you disconnect the existing coil wire at the points or just parallel it with the jumper?
