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Topic Review (Newest First)
10-15-2012 07:29 PM
Bruce L. Z28
"R" lead

Hey guys,
Just wanted to say thanks. Just found this site and you answered my question. Changing my 1973 from a standard starter to a high torque and I have the same issue.
This is a great site......
Thanks again.
Bruce L.
10-18-2005 08:25 AM
desavedo I just wanted to say thanks for all of your help everyone. After running a new wire from the ignition switch to the solenoid, and now getting over 11V to the solenoid. It fired up and it appears my issues are resolved. Thanks once again for all your help.
09-21-2005 08:43 AM
desavedo Thanks guys. I'm planning on working on this tonight. I'll see what i come up with.
09-18-2005 05:39 PM

Doc here,

If you are reading 12 volts at the Ignition Input, and only 9 volts out the "S" or start position With nothing else connected<---Read) The switch is No good..A totally dead battery reads 11 volts and below usually around 10.5

If your reading it at the wire "Ends" you may have the wrong wire hooked up to the "S" at the solenoid, the "R" or "I" wire feeding back through an ignition resistor...

If the switch input also is not dropping to 9 volts, but remaining at 12 volts, then you have confirmed the switch is bad...

be sure the "s" and "r" or "I" wires are disconnected while you test (no load).

The system itself is so simple, only a few things can go wrong...

Here is your typical wire diagram..If the wires ar as advertised and go to those specific locations, and the ground is proven good..then it can only be the switch or a mis-wire..

We know the solenoid is good as it runs fine in "Jump" mode..

We do not know the status of the neutral safety switches, reading the thread, no one checked..but for right now lets skip those...because you say you are getting 4 to 9 volts from the start.

Assuming the whole starter functions properly in start mode, "jumped" we can eliminate the starter..

The only other thing it could be is a bad switch..socking the current out across bad contacts...
09-17-2005 07:40 PM
rrmccabe OK, well let me tell you while I ask you that question.

Lets say you have a poor connection before the ignition switch (in the feed). Your true voltage does not show up without any current draw. So if you had 12 volts at the input of the switch without any load and you turned the key to start and it dropped to the same 9 volts you see on the output of the switch, then your bad connection would be in the feed to the switch. You WILL see a small amount of drop but not to 9 volts if everything is as it should be.

Replacing the purple wire based on your previous description sounds like a good idea. But that is not causing the 9 volt problem. You either have a bad switch or you are not getting a good feed to it.

09-17-2005 07:10 PM
desavedo Hello again,
When i tested the voltage at the input of the switch, it was not while it was in the cranking position. I'll be back at it tomorrow and I'll be sure and test that first.

I'm also going to run a new wire from the ignition switch clear down to the solenoid just to clean things up a bit. If it still isn't enough, I'll take your advise and look for a new ign.switch. I'll post results tomorrow. Thanks.
09-17-2005 06:55 PM
rrmccabe Thats too much voltage drop across the switch if the feed is good.

Let me ask you this before I say replace the switch.

Is that 12 volts you measured at the input of the switch while cranking? If not, we still dont know for sure.


As a test, jump the 12v input at the switch to the purple. If it starts then, replace the switch.
09-17-2005 06:09 PM
desavedo Thanks again for all your input.

OK, this is what i found.

1. Jumping the starter worked , and turned the motor over no problem, so I assume my ground is good.

2. Ignition switch ( at the key ), the hot actually has 12Volts to it.

3. The Purple Wire coming out of the ignition switch has about 9 Volts (when turnign the car in cranking position) and is the wire that goes to the Solenoid. . Will that be sufficient ? If 9Volts is not going to work out, I assume i do need to replace the Ignition switch. However, Here is where the bigger problems come into play.

Next, the Purple wire splits into a stock plastic like wire harness or whatever you want to call itat the firewall, and from one side of the firewall to the other, i am losing a few volts. It's reading 6.5 Volts ( not in the car underneath the dash, , but on the other side of the firewall out at the engine compartment). The connectors are old and aged, but not rusted in any way. Then i have 2 other splices that i must be losing a bit of Voltage as well, causing only 4 Volts by the time it reaches the solenoid.
would i be better offto run a entire new wire from my ignition switch all the way to the Solenoid?
09-17-2005 02:07 PM
rrmccabe You will see a slight amount of voltage drop at the solenoid depending on the solenoid coil draw and size of wire that you are feeding it with. 4 volts is way to low.

I think you will find that when you jump the starter its going to crank over fine.

At this point, I would say you have bad wiring, ignition switch or neutral safety (if you have an automatic).

Don't worry about the voltage coming from the old R line. Not sure what mods you have made but you are just getting backfeed from the ignition circuit.

09-17-2005 01:55 PM
desavedo Well, I just got back from checking a few things. While underneath the car, I had someone turn the key to try and start it. The bendix comes out and meshes into the flywheel gears about 1/4 of the way.

I also used a multi meter to test the voltage at the sylenoid ( ignition wire ), during an attempt to start it up, and the voltage on the sylenoid terminal is showing 4.1 volts. Shouldn't this be much higher?

I tested the Main Positive terminal on the starter (+ from battery down to the starter and on the starter end it does read 12.4volts, so I believe that is as it should be.

I also tested the wire that is no longer being used that came from the "r" side of the solenoid when attempting to start it up and it's also showing closer to 3 Volts. When the key is on this wire has continuous power so i'm sure my wires are correct.

I'll head back and drop the car to the ground, and I'll sqweeze in there and cross the starter to see if it will fire. I belive it will having 12Volts opposed to 4. Thanks.

Thanks. I'll give that a try here today as that's about the only thing i haven't tried yet.
09-17-2005 07:08 AM
rrmccabe I still would try jumping the battery post term on the solenoid to the start terminal just to check and see before you pull it out and shim it. Such an easy thing to do.

At the point your video shows the starter should be spinning. Normally the bendix drives out much harder than that. Remember that its not allows going to hit the flywheel aligned every time. It could be a half tooth off and needs to have enough torque to drive in and mesh.

Give the jump test a try. A starter gear extending out is a pretty violent movement. Not like what yours is showing.

09-16-2005 09:05 PM
desavedo Well i went ahead and had the starter tested and it works fine. It's making a clicking noise, and i took a video if what it's actually doing. If you have high speed internet it's here: . I'm almost convinced that i need to shim the starter as when the starter gear trie's to engage, i think it may be hitting the flywheel. I'll test the voltage at the solenoid tomrrow when in cranking position and shim it if needed and see what i come up with. Thanks all for the help. I'll post results this weekend sometime and hopefully it's good news

wow! I just realized my vid is 42mb., so probably scratch that idea. anyways, I'll definatley be on the forums again this weekend. Thanks Again.
09-15-2005 09:15 PM
rrmccabe I misread the part about you testing the voltage with a light to the coil. I thought you meant at the solenoid. My mistake.

Regardless, the lack of voltage at the coil (normal or not) has nothing to do with the starter not making noise. You can leave the coil completely out of it at this point as it has nothing to do with step ONE which is the starter turning over. Votlage to the coil is Step #2 and comes after the motor turns over.

So if your Motor and Starter is well grounded, has a good 12 volts to the starter via the battery cable and is still NOT clicking over and making noise, you need to find out why the starter is not engaging. Either a starter/solenoid issue or the wire coming from the ignition is not applying enough power.

When you say slight noise... Is this like a solenoid click and nothing else?

If you can, try jumping the Big battery terminal on the started to the "s" terminal and see if it turns over.

09-15-2005 08:29 PM

Doc here,

Originally Posted by desavedo
Hello again Doc:

First of all thanks for the reply. I only had a few minutes to look things over, but i tried firing up the car today without the "R" wire in place. Basically, it will ever so slightly make a noise down in the starter area. I don't believe i have enough voltage.

================================================== ==
OK, First Check all your battery terminal connections...clean, inspect and confirm tightness..

Then Check your ground system ..(the major offender in this type of problem) The negative wire From the Battery, to a bolt, at OR near the STARTER.

From that bolt run a battery cable with 3/8 ring terminals on BOTH ends, from there to the frame (cable can be had at auto parts stores or wally mart about 6 bucks)

From the very same block bolt, run 2 #10 gauge wires, one to the firewall, and one to the Alternator ground lug, or mount bolt..

If you have any electrolysis (powered white coating) on the alternator or it's mount (those are made from aluminum .. what were they thinking?) pull it all off with hardware, and sand or water blast it until it's semi shiny..when you go to remount it..get some aluminum wire bonding paste, and coat all the hardware ANY where it comes into contact with the block (steel)

Get some braided cable (rat by the roll) and bond the front fenders to the frame..the doors to the door posts .. the hood to the firewall..the trunk to the body, and the gas flap to the body..

Burnish ALL grease and paint off of the areas you are grounding wires, use proper Star washers (inner or outer stars) , Screws, bolts and Tech Screws along with locks..

Do this and your will have the best system for your car, that will be trouble-free for many years, AND provide RFI shielding for Audio and communication products..

While you are doing this, Charge your battery for 10 hours at a 6 to 10 amp may only be retaining a surface charge.

================================================== ==

I didn't have a volt meter, but had a test light. when the key is turned over " in the start position" the + terminal on the coil barely has enough juice to power the test light.
Is that normal or do i have a problem somewhere? Also, are you suggesting I run that "r" wire that i am currently not using from the " S" terminal that the ignition is also using, then route that to the + side of the coil?
================================================== ====

If you were going through a resistor, and the points were closed or the lamp filament were high enough in resistance.. the weak light would be normal..If not , then it's a problem to track down..

If you HAVE not been using it..and it ran fine .. don't even bother with it..

However, If it won't start while cranking, then yes .. get a relay, ground one side of the relay coil, run the other to, and parallel into the "S" wire..this will fire the relay when you hit "start" ...

The contacts on the relay Cw and NO will hook up to the battery or main terminal on the solenoid, and the "R" wire..In this manner, when the car is in "Start" ,( you will notice everything normally cuts off electrically during start..)The Relay will fire when you hit start, and close a set of contacts and complete a circuit between the battery, and the ignition insure it will start in Crank mode. and subside when you let off the key..

09-15-2005 08:11 PM
rrmccabe desavedo,

First of all the "R" wire has nothing to do with the ability to crank.

The S wire is the "trigger wire" that fires the solenoid. Doc, is 100% correct as usual but let me put it in other words.

The OEM starter is HOT all the time. This is the large battery cable in the center. The "s" terminal is just a solenoid wire that engages the starter. The "R" wire is a "hot shot" wire that provides a FULL 12 volts back to the coil during cranking and in reality bypasses the voltage drop resistor that powers the coil in the normal run position.

So if you are lacking power to that wire during cranking and you are POSITIVE that its the correct wire that should be on the S terminal, you need to backtrack the wire and find out where it is losing power. It goes back to the ignition switch via a Neutral safety (in the case of an automatic trans).

This wire should have a full 12 volts and your test light should be as bright as if it was connected direct to the battery.

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