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A few of the wires were cut including the black/pink ignition wire to the coil. An extension to this wire was added.
A brown and a green wire that go to the transmission were also cut.
I get power at the ignition switch on the steering column as follows:
Key is on...
Green - no power
Orange - power
Brown - power
Red - power
Pink - power
Purple - no power
The engine will fire and run while the starter is engaged, yet dies as soon as the key is released from the start position.
I have power at the coil when the key is is start mode, then nothing in run position.
I get no power at the firewall (Engine & Dash) bulkhead connector in the purple and black/pink wires.
I replaced the Ignition switch on the column, it did not work. Original Ignition switch works.
I have tried jumping the battery to coil and only get small sparks nothing else. Engine does not start, starter does not engage.
Everything is new. Distributor, coil, cap, rotor, plugs, wires, points, condenser, starter, battery positive and negative cables, ground strap, etc.
There is no voltage regulator or ballast resistor.
All fuses work and power is available at both sides of the fuse terminals.
Utilizing the below wiring diagrams....
Thoughts...
It's late in the day I'm ready to retire. The 4-4-2 wiring diagram is generally a B&W diagram (contain in the CSM), there are several departures of the 4-4-2 wiring diagram from other A-Body models, but I don't believe those departures involve the ignition circuit - I might be incorrect.
The reason you don't have a voltage regulator (VR) is why? Sorry, I don't have any time left in the day to evaluate further. Another member might see the issue straight-away but in the mean time, here is a far better more readable 1970 A-Body Wiring diagram with better coloring you'll be able to read much clearer when you zoom (saves your eyes).
The engine will fire and run while the starter is engaged, yet dies as soon as the key is released from the start position.
Sounds like your resistor wire is faulty or not hooked up.
Do you happen to have a high torque starter that does not have the same connections as a standard starter?
I believe the voltage regulator on that car is internal to the alternator. If the plug at the alternator is rectangular vs. square it is internal.
The pink wire must provide voltage when the car is running. Use a test light to see if voltage is disconnected at the pink wire at the same time the car shuts off.
I believe the voltage regulator on that car is internal to the alternator. If the plug at the alternator is rectangular vs. square it is internal.
The pink wire must provide voltage when the car is running. Use a test light to see if voltage is disconnected at the pink wire at the same time the car shuts off.
Jeff - Good point regarding the VR. I think the big difference between the 4-4-2 and other A-Bodys was (as you point out) the 4-4-2 had a very unique ALT w/ an internal VR for 1970.
You have an open wire from ignition switch to coil. With key in run position, it should be hot at plus side of coil. You can use a test light or voltmeter to test this. When in run position it should read less than 12 volts, so coil doesn't overheat and burn out. (Thinking like 8 volts or so) The wire from starter to coil is only hot when key is cranking to send full voltage to the coil for easier starting. The Purple wire is signal for solenoid to activate when key is in start position and cranks the starter and send 12 volts to coil. So that part of wiring is working. You can run a jumper wire from battery to positive on the coil to keep the car running for short time but will be putting full voltage to coil. Hope this makes sense.
Adding to Bill's post, the reduced voltage in the run position at the pink resistance wire will only occur when there is a load on the wire such as the points closed. Without a load it will read full battery voltage.
Sounds like your resistor wire is faulty or not hooked up.
Do you happen to have a high torque starter that does not have the same connections as a standard starter?
There is a partial resistor wire. It was one of the 4 wires that was cut. I've added an 18 guage wire extension to the black/pink wire. This has been my thought, does not having a full length black/pink wire cause improper voltage and therefore no voltage at the coil?
The starter is a new NAPA replacement starter.
Purple wire is connected to S.
Yellow is connected to R.
Last edited by 70-Olds-442-convt; Feb 6, 2025 at 11:55 AM.
I believe that wiring is correct. The purple wire comes from the neutral safety switch and the ignition switch. That is what makes it crank by energizing the solenoid.
You can run a jumper wire from battery to positive on the coil to keep the car running for short time but will be putting full voltage to coil. Hope this makes sense.
When jumping from the battery to the coil, nothing but a small spark occurs.
There will be a small spark because you are energizing the ignition system and bypassing the switch. Have you tried starting the engine with the jumper connected?
In response to all the comments.
I am now able to get the engine running with the lead directly from the battery to the coil.
Once the jumper is removed the engine dies immediately.
Also, this is an internally regulated alternator with no voltage regulator or ballast resistor in the wiring.
Now the question, where to obtain a replacement resistor wire and not have to buy a full harness?
Last edited by 70-Olds-442-convt; Feb 11, 2025 at 01:08 PM.
You are missing the voltage from the ignition switch to the coil+ terminal with the key in the run position. It starts out as the pink wire from the ignition switch to the bulkhead connector and then it's the resistance wire from the bulkhead to the coil+ terminal. Nothing else matters.
Check for voltage on each side of the bulkhead connector at the bulkhead connector, the problem may be dirty connections inside the bulkhead connector.
Load the circuit during the test with something like a small light bulb. If it is tested without a load there won't be a voltage drop.
There is a partial resistor wire. It was one of the 4 wires that was cut. I've added an 18 guage wire extension to the black/pink wire. This has been my thought, does not having a full length black/pink wire cause improper voltage and therefore no voltage at the coil?
Note the (below) narrative regarding a resistance wire.
If you're not inclined to install a ballast resistor (1.30 Ohms - 1.40 Ohms) as suggested by Tim, your best bet (IMO) is to find a resistance wire at a salvage yard while browsing/cruising the salvage yard. The challenge isn't difficult to understand, but once you understand this, you'll gain appreciation for the resistance wire. You want to introduce the appropriate/correct resistance. Historically, a resistance wire replaced the need for a ballast resistor. Sorta long-winded...
The resistance wire is quite different than other wiring on your car. Copper wire (in general) has the least amount of resistance & provides (in general) the best conductor for electrical wiring - e.g. no/none/limited/least resistance - a very high conductor with essentially no resistance. The resistance wire you'll note in the wiring diagram has a unique coloring pattern & there's a reason for this. The resistance wire is not copper, but instead is made from Nichrome wire (primarily nickel + chromium; either Nichrome A or Nichrome C) - it is an alloy. The biggest challenge in finding new Nichrome resistance wire to make your own is finding "insulated" Nichrome wire. It's definitely available (and cheap), but it needs to be an insulated Nichrome wire for your application. Like all wire applications, as the length of the wire increases, the resistance increases. If you were to begin w/ a Nichrome wire of size 14 Gauge AWG @ 1.6mm (diameter) w/ a known resistance of 0.171 Ohms/ft you'd need 7.89 ft. (0.171 x 7.89 = 1.35 Ohms) of this wire. The wire length needs to be continuous end-to-end. Since the resistance is proportional to length of the wire, you simply use a single piece of Nichrome wire of the appropriate size & length. If you increase/decrease the Nichrome wire AWG gauge, you increase/decrease wire length to accommodate a resistance of 1.35 Ohms. Be mindful to check total resistance of the Nichrome wire end-to-end before you install the Nichrome wire since in this application the purpose is to introduce the appropriate amount of resistance (1.35 Ohms). When you introduced an 18 gauge wire (of unknown length) into your evidently "partial resistor wire" you introduced a highly likely departure from the appropriate/correct resistance (1.35 Ohms) required for this resistance wire. HTH
Last week I pulled a complete engine harness out of a 1971 Cutlass, it does not have the resistor wire.
I cannot find an insulated Nichrome wire anywhere online.
Last edited by 70-Olds-442-convt; Feb 14, 2025 at 10:04 AM.
As I said...I'd be more inclined to rip/cut one out of an existing engine bay in a salvage yard. So, you understood the resistance needs to be 1.35 Ohms - good. Again, you can use a ballast resistor as Tim suggested or find some insulated Nichrome to meet the length resistance you need (1.35 Ohms). I understand you can find non-insulated Nichrome everywhere...because Nichrome is generally wound tight & enclosed in a small (generally) cylindrical container (functioning as a resistor - hard to believe, eh?).
Dupont sells a product called Kapton film (cheap) you might consider using. I haven't done it for a vehicle resistance wire, but there's no reason it shouldn't work. I've used it and have a couple rolls of the stuff because historically I've worked on my own guitar amplifier circuit boards, some appliances, friends circuit boards, etc. It has exceptional physical & chemical properties over a very large range of high heat applications and it's an electrical insulator. You can buy it in various widths for obvious various applications. These suggestions are in case you want to do it yourself. Buy a roll of non-insulated Nichrome of a specific resistance/ft., cut to length to equal 1.35 Ohms, wrap it in Kapton. The only other notion/idea is you might find longer lengths of heat-shrink insulation. You could slide several long heat-shrink insulation tubes together, heat-shrink them to the Nichrome wire. Ideas anyways if you don't want to go salvage yard hunting or using a ballast resistor.
Last edited by Vintage Chief; Feb 14, 2025 at 10:12 AM.
I thought I'd seen some long lengths of heat-shrink tubing somewhere...I guess they do sell it in rolls. I've only ever used the pre-cut lengths. Anyways, I saw some here at Home Depot, and HF. Not sure exactly what sizes (diameters) they make it in 1/4" might work by the time it shrinks down - not sure, you're on your own. I know they make much smaller diameter heat-shrink in pre-cut form, but you'll be using a fair number of them but it can be done.
I may have been incorrect on the Nichrome A &/or Nichrome C, it may in fact be called Nichrome 80. At any rate, attempting to help you out here ensure you find a length w/ the appropriate Ohms/ft to get a piece of the appropriate length. You're around the Nichrome 14 GA AWG 1.6mm range w/ a known resistance of 0.171 Ohms/ft. That will get you a piece of ~7.89 ft. (0.171 x 7.89 = 1.35 Ohms).
The "F" word resistor wire "might" work but it's a chance - reason>>NOTE: There is no description in the details identifying the resistance of this wire (e.g. 1.35 Ohms or otherwise). If they can't list the meaningful/informative details they don't know what they're talking about or too lazy to mention it. Stay away.
The NAPA wire "at least" lists it @ 1.35 Ohms (for the entire length of wire).
A big thank you for everyone that provided advice and feedback.
I was able to acquire an original resistance wire with original connectors on each end. The cut wire was removed and the "new" replacement was installed.
The engine fired up and ran immediately.
A big thank you for everyone that provided advice and feedback.
I was able to acquire an original resistance wire with original connectors on each end. The cut wire was removed and the "new" replacement was installed.
The engine fired up and ran immediately.
I'm having similar issues, but I’m suspecting my culprit is weak voltage at idle from a 53 year-old alternator. If you’re willing to spend two minutes with a volt meter, maybe you might be able to help with my troubleshooting.
Does your “new” resistance wire still get hot when the car is running, and what voltage do you see at the coil at an idle?
