Will not accelerate🤦‍♂️ I some help

[Frank DuVal]

I wonder if under throttle I am not getting enough volts to the coil. Hard to check that but anything is possible at this point.

Have you measured this at idle? Why would it change at higher rpm? Real easy to measure, just get a long wire, attach to coil + terminal, run to inside car, close engine lid, attach wire to + lead of meter and ground the - lead of the meter, set to 20 volt scale or so, start engine and check idle voltage then go for a drive. Only when safe to do, look at meter reading.

[bbodie52]

In a voltage divider circuit, the effect of the ignition coil primary resistance in series with the ballast resistor wire in the circuit can only be read accurately with a multimeter when the negative side of the coil is grounded (as with the points closed) and electrical current is being conducted through the coil primary winding. When the points are opened (or the negative terminal on the ignition coil is not grounded, you will simply read battery voltage.

With the engine running, you would get the high and low voltage readings fluctuating back and forth — switching each time the points (or electronic ignition) is triggered by the rotating distributor cam lobes. This cannot be read accurately by a multimeter, since the multimeter display wants to show a steady-state voltage. The rate of change will be affected by the pulse rate as the engine RPM increases or decreases, plus the base voltage will rise above the nominal 12.5VDC produced by the battery, because of the impact of the alternator/generator charging system (normally somewhere around 14.5 VDC as the charging system voltage rises above battery voltage).

To measure the voltage fed at the coil positive terminal, the ignition key must be ON and the negative coil terminal must be grounded. If there is a ballast resistor wire in the circuit, its impact on the voltage provided to the coil can be measured with the multimeter between the positive coil terminal and chassis ground when the coil negative terminal has been grounded and the coil primary winding is conducting electrical current.

[RangersCorvair]

Just checked the exhaust and all looks open. I cracked it at the muffler to header. Tried to start it and I noticed that when I first start it and the “gen” light is lite it runs rough until I nurse the throttle and gen light off, then it runs good at idle. I tried it again and unplugged the 1,3,5 wire and it started and ran the same as before with the gen light lite. How is half, or every other plug, getting power when the gen light is on then all plugs once the engine hits an rpm to turn off the gen light? The previous owner put a small fuse block in the engine by the battery. It has a lead from the + and - sides of the battery. Those measure the same as the battery when off. There is a wire running to a plug that goes to the front firewall it’s black and red. A wire running off a fuse to the coil. And a + and - going to the fuel pump. When I start it the alternator is pushing 15.5 volts, the hot sides of the fuse block is not a steady 15.5 but jumps on the volt meter. Seems like I have an inconsistent voltage issue. Perhaps when I give it throttle under load there isn’t enough or too much voltage and it falls flat. Maybe the fuse block shuts off the fuel pump and that why I am not able to go above 1/4 throttle.

[Frank DuVal]

Oh, someone rewired stuff. You have your work cut out for you!

How is half, or every other plug, getting power when the gen light is on then all plugs once the engine hits an rpm to turn off the gen light?

I do not understand the question. A Corvair engine will run just fine on three cylinders/one head. It just lacks horsepower. Generator light just indicates something amiss in the charging circuit, not the ignition circuit. Did you try running on just the other head?

The previous owner put a small fuse block in the engine by the battery. It has a lead from the + and - sides of the battery. Those measure the same as the battery when off.

So far so good....

There is a wire running to a plug that goes to the front firewall it’s black and red. A wire running off a fuse to the coil. And a + and - going to the fuel pump. When I start it the alternator is pushing 15.5 volts, the hot sides of the fuse block is not a steady 15.5 but jumps on the volt meter.

And now we are off the rails. If this fuse block gets it's power from the battery, and the coil is connected to this fuse block, then it would be on all the time, so one could not shut off the car. Not your issue, so is there a relay on this fuse block? Also you mean a wire is black with a red tracer (going to a plug), or you do you mean two wires, a red and a black?

15.5 volts is high, could be 1. meter is not calibrated, so it reads 15.5 when then voltage is actually 14.5 or so. 2. the battery is low on charge so the alternator is playing catch-up (normal). If the battery is a steady reading on the voltmeter but the added fuse block is not, something is very bad. Is there a relay? Is it chattering?

If fuel delivery was the issue, you would still have an initial burst of power leaving a stoplight with it floored and then fall on its face when the float bowls went dry, then recover somewhat as the fuel continued to dribble in and you returned to idle. Have you done the fuel delivery test? Disconnect one carburetor's fuel line, place fuel line into clear FUEL SAFE bottle, run fuel pump for 30 seconds. Is the amount in the bottle at least as much as the shop manual calls for? Might have to do only 15 seconds if bottle too small.

You should also get a battery voltage reading from the cigarette lighter aka power port and see if it varies while driving down the road.

Is there a relay? Look for it. Replace it or substitute a known good one. Maybe from your daily driver if a common one.

[RangersCorvair]

Frank, for some reason I cannot seem to post a picture or thing would be easier for me to show. It must have a relay of some sort in it. It does not have power until I turn the key thus not running with key off once started. The battery is 12.4 key off not running so don’t know why the alt is pushing that much. There is a solid red wire off the fuse block spliced into a black with red stripe wire that goes to the firewall. I tried running the fuel pump straight to the battery, by passing the fuse block, and got the same results. I also tried running a + wire from the battery straight to the coil and the same results. I have not tried your recommendation of running a long wire into the cabin and driving. I will do that when I can. The car runs so rough until the gen light goes out and the other side comes to life but it falls when given throttle. Not sure if they are connected but I assume they are. Thanks again for the help.

[Dennis66]

Ryan, with no picture, can you describe exactly what wires you have going to the coil? I'll kind of go over what someone described earlier: There should be two positive wires coming from the car harness. One is yellow and goes straight back to the starter solenoid (mine has a plug with two wires - purple for the crank signal, and yellow going to the coil). the purpose of the yellow wire is to supply full voltage to the coil when cranking - ONLY WHEN CRANKING. The second positive wire coming from the car to the coil is the ballast resistor wire (or it's supposed to be). It has a white or whitish woven covering. This gives the reduced voltage when running. That's the OEM design. Don't know exactly what your HEI / breakerless system is, but mine has a yellow and a red wire going to the coil (IIRC red is to positive, yellow is to negative). Mine also has a 3 wire plug that runs from the box to the distributor (where the pickup is located).
It is possible to have "spark blowout" at higher RPMs. One thing that hasn't been asked yet: What color spark do you have?
Pull a plug, place it on a good ground, and crank while watching spark ( I jumper a alligator clip to the purple wire mentioned above and can touch this to the positive battery terminal to start from the engine compartment. Hope this helps some. Dennis

[RangersCorvair]

Dennis I have a pink wire coming from the fuse block, added by previous owner, going to the + coil terminal add a red wire coming from the distributor. On the - side I have a yellow wire going to the distributor. The distributor has a red to + on coil, a yellow to - side n coil and a black to a ground I put on the body.

[Dennis66]

Other than the fuse block wire, the rest sounds okay. Really need to see some pictures to figure out what is going on. If you can't post pictures here, would you want me to give you my number and you can send them to me? I can DM you my number. Dennis

[bbodie52]

» Sun Dec 17, 2023 12:17 pm

Just checked the exhaust and all looks open. I cracked it at the muffler to header. Tried to start it and I noticed that when I first start it and the “gen” light is lite it runs rough until I nurse the throttle and gen light off, then it runs good at idle. I tried it again and unplugged the 1,3,5 wire and it started and ran the same as before with the gen light lite. How is half, or every other plug, getting power when the gen light is on then all plugs once the engine hits an rpm to turn off the gen light? The previous owner put a small fuse block in the engine by the battery. It has a lead from the + and - sides of the battery. Those measure the same as the battery when off. There is a wire running to a plug that goes to the front firewall it’s black and red. A wire running off a fuse to the coil. And a + and - going to the fuel pump. When I start it the alternator is pushing 15.5 volts, the hot sides of the fuse block is not a steady 15.5 but jumps on the volt meter. Seems like I have an inconsistent voltage issue. Perhaps when I give it throttle under load there isn’t enough or too much voltage and it falls flat. Maybe the fuse block shuts off the fuel pump and that why I am not able to go above 1/4 throttle.

Each spark plug receives whatever the coil secondary output is when the rotor gets to that distributor cap tower. The coil output would not change from plug wire to plug wire, unless there is corrosion and damage inside the distributor cap that is disrupting the high voltage that is routing to each spark plug in sequence. But a low voltage from the battery could weaken the coil spark plug output or disrupt the electronic ignition module until the alternator output engages. (Does your alternator have an internal voltage regulator? Is it a "single wire" alternator, or does the alternator have multiple wires connected to the vehicle wiring harness)? Some alternators may develop a problem where the charging output to the battery fails to appear until the alternator reaches a higher RPM range.

With any additional wiring that is not original factory wiring or illustrated in the schematic wiring diagram, you must visualize, or sketch the wiring source and targeted connection, plus any connection points, such as a relay or switch, that is in-between. Editing a copy of the original wiring schematic to reflect physical changes may be helpful in making it easier to trace the circuit and then "seeing" what has been modified or added.

Wire color does not matter, but the wire gauge, or thickness, and the length of the metal conductor may impact the circuit — depending on the circuit load and amount of electrical current that must be conducted to a given electrical device. A good electrical ground return path to the battery negative terminal is equally important. For example, the thick cable to the starter motor/solenoid from the battery positive connector is essential to provide adequate current flow when the starter motor is engaged. But a ground return path to the battery negative terminal that is equal to the current-carrying capacity of the positive cable is also essential for the starter motor to function properly.

The transaxle and engine are physically (and electrically) isolated from the car chassis by three rubber mounts. For the starter. charging system. and ignition system that are mounted on the engine and transaxle to function properly, a ground-return path to the battery negative terminal that is equivalent in wire gauge and current-carrying capacity to the positive cabling but provides a ground to the powertrain that is equal to the power sources supporting the starter, charging system, and ignition system must be present. In other words, the battery negative cable MUST be bolted to the engine, and not just to the car chassis. A secondary battery ground connection from the car chassis is also needed to ground the electrical components that look to the chassis for a ground return path to the battery.



If the electrical components in the ignition system are not properly grounded, the positive source voltage may be irrelevant if a good ground return is not available.

Your trouble descriptions may suggest a marginal voltage powering the coil and Pertronix Ignitor components. If the voltage from the battery is low (as might occur if you have a bad cell inside the battery, the ignition system behavior may be weak or erratic when it is running on battery only, and the voltage regulator in the charging system may not engage the generator output immediately when the engine starts and is idling slowly. Increasing the engine speed may ultimately produce an output from the generator that will bring the system voltage up enough so that the electronic ignition, coil, and charging systems all begin to perform as expected. But the fault may reappear once the engine is shut down and restarted, if the battery voltage is low and if the charging system is still offline at engine idle speeds.

Your description of the problems and symptoms would seem to suggest that this scenario is a possibility. The only way to know is to measure the battery voltage with a voltmeter to see what is going on at the beginning, after the engine starts, and what happens when you see a voltage rise once the charging system kicks in. If the battery voltage turns out to be weak and inadequate until the generator output begins, substituting a different battery may help to clear your problems. If the voltage regulator is not performing properly, you may discover that much of the time you are driving with a low system voltage, and that the battery is not being charged at all times with the engine running. The faults may disappear wen the charging system output reappears and supplements the weakened battery.

[RangersCorvair]

Brad I have a “3 wire” alternator but no external voltage regulator. There is a heavy gauge wire going from the alt to the battery + side. A wire that goes to a brown wire in the factory wire harness and that’s all. The regulator that is usually mounted on the firewall is completely gone.

[Frank DuVal]

There should be two positive wires coming from the car harness.

FYI, not all Corvairs have two wires on the positive terminal of the ignition coil. Yes, the wiring is the same, just the junction between the resistance wire and the "yellow" wire is in the harness, not on the coil.

The car runs so rough until the gen light goes out and the other side comes to life

Hmm, how do you know one side is not running? I know you removed the spark plugs wires on one head and said it ran the same. I asked you to do the same with the other head, as until you have all the information of tests, you are just guessing as if you did no tests. Why do I ask this? Because if the engine runs the same with the other three plugs disconnected, then spark is the issue, but if the other three plugs disconnected make it not run, then fuel is more likely. Have you done the simple hand over carburetor test yet?

An internal regulator is not adjustable, so if it keeps outputting 15.5 after the battery has charged (and 12.4 is not charged, BTW, 12.6 is design voltage of lead acid cells, surface charge will be slightly higher when charging is finished), replacing the regulator is only repair. Quick test for meter accuracy, measure the voltage of the battery in another properly working car, both with engine off and engine running.

[Frank DuVal]

To post a picture, or any file, click on Attachments below the posting box you type into. Follow directions there. Test:

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[RangersCorvair]

Frank, I pulled wires and I used my IR temp gauge and the header on the passenger side was still 56 degrees. The drivers side was well into the 100s.

Tried the attachment button, still no picture. It asks for the file but is not there when I post.

[bbodie52]

To add a photograph file, you must select a photograph file from your list of image files (typically a .jpg file). Maximum file size per attachment: 20 MiB.

Why does my alternator not start charging until revved?

The trouble you describe is likely due to the brushes or a bad wire connection inside the alternator. You need to get the shop to replace that alternator to make sure of the issue. There are some simple voltage checks that could be done to prove that the trouble is with the alternator.

You may have a faulty internally regulated alternator. The red wire in the picture should help the alternator to properly initialize at idle so that it begins to produce voltages that are higher than just battery voltage. If there is no charging voltage output, you could be driving on battery voltage only, and if that voltage is low the coil and electronic ignition module may malfunction and produce a weak or erratic spark to the spark plugs. The GEN light you are seeing is abnormal, and may indicate a faulty alternator. A misfire caused by faulty operation of the Pertronix Ignitor, or a weak coil output caused by inadequate voltage in the Primary coil winding may cause a poorly performing engine. HOWEVER if one bank of cylinders is misbehaving, as indicated by a cold exhaust on one side only, a carburetor fault is likely. Both problems may exist at the same time, which may confuse your troubleshooting efforts.

[Dennis66]

So far, we don't know whether he still has the generator, or an alternator conversion. We have exchanged phone numbers so he can send pics straight to me and hopefully figure out exactly what he has.
Regarding "not all Corvairs have two wires going to the positive side of the coil". Can anyone confirm if the 1964 does? I know my 1962 does. Dennis

[Frank DuVal]

According to page 8-26 of the 64 Supplement, there is only one wire to the + terminal of the coil.

The junction between the copper wire to the coil and the resistance wire is at the two terminal connector going to the starter, you know, where the purple wires are.

The copper wire from the two terminal connector to the ignition coil is Black with a Yellow stripe.

https://www.corvair.org/chapters/corvan ... Sys-64.pdf