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hi, I have no spark issue on my 350 V8 engine. hei distributor parts all new. only can start the engine with 2,5 mm battery cable mounted on the + of battery and batt terminal connector on the coil. any helps? cheers
I already have 12 volts on the tach and batt terminal connector of the coil by key on Position. I think I lose voltage by turning the key to crank position.
That is very possible. You can confirm this condition using a test light (or voltage meter). The fault could be with ignition switch itself or the wiring. For example, if your vehicle was originally equipped with breaker point ignition there are two wires, "run" or ballasted power and "start" or ballast bypass power. When an aftermarket system like HEI is installed these two wires need to be joined.
thanks for answer, will test today everything in Detail with test light with voltage numbers printed on. what Do you mean with aftermarket parts? the car fired up with these cheap parts setup man years. with ignition switch you mean the part where the ignition key sits in? (lockable key) cheers
My experience with GM products is limited, but I believe the actually ignition switch itself is usually mounted down low on the topside of the column and is actuated by a metal rode. However, without more information about the vehicle I can not be certain.
tested today the pink terminal batt connector on the coil. it has 12 volts showing on ignition key during on position. when I crank the engine it Shows only 6 volts on the multimeter. the same with the battery itself. 12 volts by on Position and 6 volts by cranking the engine. it seems I loose 6 volts during cranking the engine.
12 volts I have on the battery if I dont crank the engine. the battery was deep unloaded a few times and I reloaded it with a battery recharger more than once. the question is how much voltage power loss is normal by cranking the engine
I would have a problem with the battery voltage dropping below 9 ½ volts while cranking.
A good rule to follow when troubleshooting any electrical issue is to start with a good power source. It’s so simple it can be easy to overlook. In this case a healthy fully charged battery.
If your reading 12.0 volts across your battery terminals with the everything off your battery needs to be charged and possibly load tested.
The chart I posted earlier kind of sucks because it leads you to believe a battery voltage of 12.0V is still useful… maybe for other applications but, not in the automotive world.
This is the mental note I keep in mind for 12V batteries SOC (State of Charge %)
Sounds like weak cells in the battery... Not able to hold the CCA..... I would say the battery is not good.....
HEI will not work if the voltage drops below 10.5 Volts....
Try a different battery that will hold a high voltage... Min. 10.5 volt cranking....
I would have a problem with the battery voltage dropping below 9 ½ volts while cranking.
A good rule to follow when troubleshooting any electrical issue is to start with a good power source. It’s so simple it can be easy to overlook. In this case a healthy fully charged battery.
If your reading 12.0 volts across your battery terminals with the everything off your battery needs to be charged and possibly load tested.
The chart I posted earlier kind of sucks because it leads you to believe a battery voltage of 12.0V is still useful… maybe for other applications but, not in the automotive world.
This is the mental note I keep in mind for 12V batteries SOC (State of Charge %)
tested today and the engine runs only with a 12,5 mm wire from the battery + to the distribitor batt connection. is there any other trick or wiring that I can change to get the car running and shutting off with the key?
I also have to say that the hot 12 volt wire from the distributor on the other end is not connected to the fuse box. I think its connected with the lockable key ignition.
Have you tried charging or replacing the battery? The cranking and open circuit voltages you previously reported at the battery suggest it's not in good condition.
Of coarse that doesn’t mean there aren’t other electrical issues but, it’s best to address the power source first.
Battery aside, If running power directly to the distributor allows the engine to fire, that suggest there is a voltage drop somewhere… For example, It could be the wires/connectors between the distributor and ignition switch, across the ignition switch contacts or somewhere between the ignition switch and battery.
Using your multimeter you can perform whats called a voltage drop test to help pin point the issue.
You will need to add a load (For example a test light with a good ground) while checking the circuit for voltage drop, that is the important part.. current must be flowing during the test. The easiest place to check for an issue is with one lead at the distributor and the other at the battery positive terminal, this should show the total voltage drop on the + side of the circuit. If the number is high. Then, start moving that lead down the line. Using a wiring diagram for you vehicle application would be ideal. Once you know where the issue is you can correct it.
Below I posted videos about voltage drop and how to back-probe a connector without damaging it. Please don’t pierce wires.
The rule I use for voltage drop is not exceeding 0.5V on older stuff and I usually use T-pins for back probing.
I posted this video just because I like it, it’s for breaker point ignition but, a lot of the information is still solid. Just remember you don’t have to worry about a ballast resistor or amp gauge and instead of points you have an ignition module and magnetic pickup.
found that the pink 12 gauge igniton cable from the coil runs to a thick cable tree covered with a plastic sleeve. this cable was cutted before to and added the cable for the e choke to it. I removed now the e choke from this pink cable again and turned the copper parts of the pink wire together again and isolated. no success. battery fully loaded 12.8 Volts. I gave the battery extra voltage with jumper cables with my second car helping. 13,6 volts and still not firing. cables under the dash looking good. no ignition switch to see.
1. Does that wire have 12 volts with the key in the on position?
2. Does that wire have 12 Volts when you turn and hold the ignition key in the cranking position?
It sounds like you found a poor splice connection that was previously made for adding an electric choke coil. This should be corrected by cutting and striping to clean fresh copper with no broken strands. Then crimping and/or soldering the wires back together. Simply twisting the wires back together is no good. Either use an insulated butt connector or solder and heat-shrink.
After you've made the above repair see if that works. If the no-spark condition still persist continue looking for your voltage drop elsewhere in the circuit.
Something else to consider.. when cranking an engine for a prolonged amount of time where you have fuel but, no spark can result in a flooded engine. Sometimes even when the initial issue is corrected the engine will not fire because the spark plugs are wet with fuel. It may be necessary to do a "clear flood" by cranking the engine with the throttle wide open. This assumes the choke unloader works on your carburetor, in other words with a cold engine at WOT the choke should also open.
I have 12 volts on this cable with key on postion but not at crank the engine. I found another error on the starter solenoid relay wiring I think. my main battery cable goes on top of the solenoid with 2 other wires on this place (one is red and the other orange color) and there is another thicker pink color cable that goes to the right side of the starter solenoid position. on the left side there is no wire.
Looking at a wiring diagram it looks like your pink ignition wire passes thru a firewall bulkhead connector goes directly to your ignition switch. It sounds like you have a faulty ignition switch that is cutting power to ignition while in the crank position...
You'll have to lower your steering column in order to get to the switch on top.
Here is an example of your switch. It's will vary depending on if the vehicle has an automatic or manual transmission, column vs floor shifter and tilt vs non-tilt wheel.
its an 84 trans am. the wire from the IGN fuse box to the coil also doesn t work. I have 12 volts Power there bit no spark. think I loose voltage in the key cranking Position or a voltage Transfer problem. on the starter solenoid there is no wire on the r terminal.
05-07-2023, 04:35 AM
