Having a hard time finding the resistance wire from the firewall block connector my car already has the HEI GM Big Cap. can I just take the resistance wire off of the starter and tape the end and tie out of the way since I can't find the resistance wire in firewall harness block ?or will this cause me problems? do I have to add another power wire to distributor HEI is getting 12 volts at Bat already the car is a 1972 Riviera and sometimes only starts when you let off key. I unwrapped the wiring harness I can't tell what is the resistor wire the only place I haven't unwrapped the wires is about 10 inches at the firewall connector block
Carefully read the 1st post in this thread, http://www.v8buick.com/showthread.p...nd-HEI-System-function-tests-and-modification Sounds like someone already eliminated your resistance wire, otherwise, you would not be getting full time battery voltage to the HEI.
Larry I must not be getting 12 volts full time cause it will only start when it hasn't been started for a while with key in position of not turning starter. but if car runs awhile it starts normally any ideas and cai I just take resistance wire off starter
I don't know who did the conversion to run the HEI, but I've seen all kinds of things. Some people should not be allowed near a car with tools of any sort:grin: If I was you, I'd re wire it completely, the right way. I tell you how to do that in the link I supplied. The GM HEI is really simple to wire. One 14 ga. wire from the firewall to the power side of the HEI. That simple. No other wire is needed. That wire will supply battery voltage in Run, and Crank. Do it right and forget it. It isn't difficult.
In the crank position of the starting circuit GM did NOT supply voltage to the ignition in '72 & prior years. The ignition gets it's voltage from the yellow wire from the starter in the crank position ONLY. So yes, that resistor, more than likely a diode, needs to be hooked up. Tom T.
Tom, That doesn't correlate with my experience. I installed an HEI in my first Buick, a 1972 Skylark 350. I disassembled the firewall connector, removed the resistance wire, and it's extension down to the starter. Replaced it with a single 14 ga. wire directly to the HEI. The car ran for many years like that, and started just fine. In my 70 Buick Chassis manual, the ignition section describes how to test the shorting switch inside the starter solenoid. It states if the shorting switch is not working, it would result in hard cold starting, not a no start condition. Years ago, I had this same problem in my 72 Skylark when it still had points. It would start fine when it was warm, but cold, it was a bear. I knew my choke was working correctly and I had lots of pump shot, but I had to crank it forever to get it to start. When I finally did the ignition system tests with a multimeter, I discovered that the solenoid was not doing it's job and sending full battery voltage through the bypass. I dropped the starter and replaced just the solenoid, and my problem was gone. If the resistance wire did not receive voltage during cranking, my engine would not have run at all with a defective solenoid/shorting switch, yet it did. Below is the wire kit I used from Year One. It has the proper barb to fit into the fire wall connection on one side, and the proper HEI cap connector on the other. That's all I used, and eliminated the yellow wire from the starter.
I don't know exactly what your case was Larry, but I can say with knowledge that if the yellow wire is not hooked up to the starter solenoid the coil will have no power in the start position. This holds true for many GM cars of the era most of us are dealing with.
Me thinks that a wiring schematic might settle this, but that is too easy, we would have to find another thread to argue about.
The ignition 12V feed is hot with the key in the start position, on all GM cars I have ever tested, that goes back to the early 60's. That wire is of course a resistance wire, designed to supply around 5-6 volts to the coil after the engine is fully warmed up, and the wire has reached it's maximum resistance due to current flow thru it. It will get warm, that's why it has the special covering on it. It was required for all vehicles that had points ignition. All cars with points had some type of resistor in the coil feed circuit. The issue is that with this reduction in voltage, it is difficult to get the vehicle re-started warm. This is where the Yellow wire on the starter comes in. It gets voltage only when the plunger in the solenoid is engaged (when starter motor is cranking). That Yellow wire is spliced into the ignition feed circuit just in front of the coil. This provides a clean 12V feed to the points on a hot restart. It is known as the "resistor by-pass wire". It is not designed to supply a large amount of amperage, just clean voltage. Now, in the situation of an HEI being installed in an early car, that system has a much higher amperage requirement. Even the factory used a 10 ga wire from the fuse block to the distributor. Many conversions skip the step to remove the resistance wire from the harness (replace the entire wire, from the fuse block terminal to the Distributor). Or they feed the distributor with another 12V Key-on source, ignoring the fact that that circuit goes dead when the key is in the start position. This is where hooking the yellow wire back up to the new ignition feed comes in.. they now use that wire not to supplement voltage, but to power the entire system, at cranking. Due to voltage drop from poor connections and much too small a wire size for that system, it is not all that uncommon for situations like the original Poster describes.. at times, car won't start until the key is released from the crank position, because the amperage supplied to the distributor, from just that yellow wire, is too low to work the HEI system effectively, and it requires the other feed to create a spark. That other feed is restored when the key is released. To test for this: Remove the Yellow wire from the starter, disconnect the large feed wire from the MSD, and use a test light to determine if that wire stays hot with the ignition switch in the crank position. If it does not, then correct the ignition feed situation, per the instructions in the post that Larry referenced earlier. At that point, then yes, you can eliminate the Yellow wire on the starter. JW
