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Posted By Discussion Topic: Engine test stand wiring questions -- page: 1 2     Flatbob 07-06-2012 @ 3:09 PM reply profile send p.m. Member Posts: 437 Joined: Oct 2009 I have an 8BA on a test stand and have a few questions. I have run a wire from one of the two small terminals (hot side) on my starter solenoid to hot side of my on/ off switch, from the other side of my on/off switch (cold side) I ran a wire to the other small post on the starter solenoid (cold post), from the other side of the starter button I ran a wire back to the hot side of my on/off switch. Am unable to get starter to crank. There is a small post next to the large post on the starter that the cable from starter solenoid attaches to; what is this small post for; could that be why my starter won't crank because I don't have a wire running to this small post? The starter is an after market high torque starter. I have a two wire alternator that I ran one of the wires (yellow) to the hot side of my on/off switch, the directions say to attach the coil wire (red) to the on/off switch as well; would it attach to the same terminal as the yellow wire (hot side of on/off switch) making the coil hot all the time which doesn't seem right to me or would it go to cold side of the on/off switch? Also, nothing at this point has an inline fuse. This message was edited by Flatbob on 7-6-12 @ 3:17 PM juergen 07-07-2012 @ 5:40 AM reply profile send p.m. Member Posts: 259 Joined: Jan 2010 Where is the solenoid? On a GM type starter it is on the starter. Ford used an external starter and since you talk of two terminals, I assume it is the later type external solenoid. In either case, I don't understand why one small terminal is hot. In my experience, both are cold' Applying a hot source to one terminal will energize the solenoid and if the starter is engaged, the other terminal becomes a hot source which can be used to feed 12 volts directly to the coil. This would bypass any external resistor to the coil but only when the starter is engaged. This also assumes that the ground is good to both the starter and solenoid (if external). Both the coil and the alternator sense/control should be to the cold side of an on/off switch or they will drain your battery. I don't know of your alternator type but some require a separate on/off feed for both the coil and the alternator in order not to power the coil when the engine is running and the two wires are connected even when the on/off switch is turned off. supereal 07-07-2012 @ 7:46 AM reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 If you have two small terminals on the solenoid, it is a universal replacement type. To use it with a Ford grounding type button, you need to connect a jumper wire from one small terminal to the battery side of the solenoid, and the other to the starter button, the body of which has to be grounded. Another configuration is to put a ground jumper to one of the small terminals, run battery voltage to the button, and a return connection to the other small terminal. That is the way our test stand is set up. With any test stand, be very careful to see that it is strong enough to hold the engine when the throttle is worked. The flywheel and other rotating parts can cause the stand to tip over from the counter rotating force under rapid acceleration. As to the alternator wiring, the alternator on/off lead goes to the switched side of the ignition switch, as does the feed to the coil. When the ignition switch is off, the coil is disconnected. The other side of the alternator goes to the hot side of the battery. This message was edited by supereal on 7-7-12 @ 7:48 AM Flatbob 07-07-2012 @ 9:05 AM reply profile send p.m. Member Posts: 437 Joined: Oct 2009 Super, as you describe I have a jumper wire running from the battery side of the solenoid to one of the small terminals on the solenoid; I also took a wire from that same terminal to make my on/off switch hot. When you say "and the other to the starter button" do you mean another wire from the other unused small terminal on the solenoid to the starter button. That's the way I have it now with the other side of the starter button going to the cold side (switch side) of the on/off switch. When I push starter button I hear a click from the starter button but starter won't crank. On my aftermarket starter I have two posts one for the starter cable and another very small post; could this small post be a ground for the starter, could this be why starter won't crank because it's not grounded? This message was edited by Flatbob on 7-7-12 @ 9:10 AM supereal 07-07-2012 @ 10:25 AM reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 If you have only one small terminal on the solenoid, the battery connection is internal. To operate the solenoid, you need to furnish ground to the solenoid via the starter button. That means running a wire from the solenoid small terminal to the button, and another from the body of the button back to the ground side of the battery. The button shouldn't be making a click. What you are probably hearing is an arc when the button tries to ground the battery. Flatbob 07-07-2012 @ 12:22 PM reply profile send p.m. Member Posts: 437 Joined: Oct 2009 Super, I have two small terminals on my solenoid, one side is connected to the battery side of the solenoid with a jumper wire. What wire runs from the second unused terminal on the solenoid? The starter button I have has two posts on the back; don't know if that makes it a Ford type or not. This message was edited by Flatbob on 7-7-12 @ 12:24 PM supereal 07-07-2012 @ 12:29 PM reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 I'll give it another try. Your solenoid with two small terminals should have one connected to the large battery terminal of the solenoid (not the starter motor side), and the other to one side of your two terminal button. The remaining terminal on the button should be connected to a good ground, such as the mounting screws holding the solenoid. Pushing the starter button will then cause the solenoid to work, running the starter motor. Flatbob 07-07-2012 @ 1:35 PM reply profile send p.m. Member Posts: 437 Joined: Oct 2009 Super, have done as you described and starter button no longer arcs internally but starter motor doesn't crank. Is there a way to wire the starter motor direct (battery cable to starter cable?)to see if it's good? supereal 07-07-2012 @ 1:51 PM reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 Yes. You can jump across the big terminals on the soleniod with a heavy connection, such as the kind of cables used to jump start cars. Or you can remove one of the battery cables at the battery, then connect both battery and starter on the same solenoid terminal. Then place the battery cable back on the battery. Be careful, as a starter draws 500 amps or more, so wear heavy gloves to prevent burns. I suspect that the starter button may have burned its contacts. Before you try to run the starter with a direct connection, touch the terminal on the solenoid that goes to the button to ground. That should pull the solenoid if the battery isn't run down. At least, your should hear the solenoid click. This message was edited by supereal on 7-7-12 @ 1:53 PM Flatbob 07-07-2012 @ 3:03 PM reply profile send p.m. Member Posts: 437 Joined: Oct 2009 Super, got the solenoid to click when I shorted the two small terminals on the solenoid. I'll find some gloves and run a battery jumper cable across the cable posts on the solenoid and see what happens. I think your right, I probably fried the starter button as I recall I had a wire get extremely hot when I first had the button wired. Thanks for the help, Bob

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