TR4/4A TR4 no start

[KJP]

I am having a similar issue that a few others have had. Car ('65 TR4) ran fine earlier in the day, then turn key and nothing. Engine turns over fine when hitting solenoid button. Swapped out red/white wire from ignition switch to solenoid, still no go. Had a new spare solenoid, put that in, still nothing. Swapped out ignition switch with a new one, still nothing. Previous owner had converted over to negative ground and pertronix ignition (in Lucas distributor) during the car's restoration. Any ideas? Read on here that the ammeter may be an issue, but tracing wiring diagram not sure. No lights, no horn, fuses look OK.

 

[bobhustead]

Make sure the battery terminals are clean and tight. Then look at the grounds, making sure that the engine, body, and frame have electrical (ground) continuity to the battery earth terminal.

Bob

 

[KJP]

Thanks for the reply Bob. Terminals and grounds are all good, tight, and not corroded. Engine turns well when I press solenoid button just nothing else.

 

[bobhustead]

Check each fuse for power. Put a test light clip on the battery ground. Put the probe on each fuse, both at each clip and both metal ends on each fuse cartridge (4 touches per fuse). My primitive Haynes manual diagram shows two fuses. One of these should probably show power at all 4 test spots at all times and the other only when the ignition switch is on. If you don't find power with this test, let us know.
Bob

 

[KJP]

Negative batt terminal is grounded. Black clip to negative terminal and red clip across fuses, nothing with ign switch on or off. Now if I swap it to
Red clip to positive batt terminal and black clip across both fuses' connections shows +12.41 volts with ign switch on and off. Yes, only two fuses, I believe the lower one should protect a few items when ign is on.

 

[Sarastro]

By "then turn key and nothing..." you mean it's not cranking, right? If so, it seems clear that you are not getting power to the start terminal on the solenoid. You can confirm this by checking it with a voltmeter. The solution is to work back from the solenoid through the electrical system and see where you are losing it. I think you will find it quickly that way.

The solenoid and its associated circuit are not fused, so checking fuses won't help.

Randomly replacing components is probably the worst way to troubleshoot electrical problems. Tracing through the circuit methodically, to home in on the problem, is the best way.

 

[KJP]

correct, turn key, no cranking. No lights, no horn, etc.. with ign switch in any position. Yes, this car should run without either of the fuses I believe. I am using a Fluke digital multimeter in volt mode. Red clip to + batt, black to red/white term on solenoid shows 12.41V with ign switch on. Also tested by running a known good wire to replace red/white wire from ign switch to solenoid, same result - nothing. Dumb question, for a car that was supposedly converted to neg ground by prev owner, is this normal?

 

[bobhustead]

Sorry, I didn't look fully enough at the diagram. Looks like a brown/blue comes out of the control box at pole A1 and supplies power to pole 1 of the ignition switch and continues to the light switch. A white/red comes out of ignition switch pole 3 to activate the solenoid when the key is turned. A brown comes off the battery post of the solenoid, thru the ammeter, coming out of the ammeter as a brown/white to pole A of the control box. Can you find power at any connections on any of the described wires? Ii is of interest that the horn works on a circuit powered by a brown wire that also comes off the solenoid battery post. The fact that both the horn and the other circuit powered from the battery terminal on the solenoid points to no power getting out of the solenoid battery pole into both the brown wires. Or some ground fault common to both brown wire circuits.
Bob

 

[KJP]

Showing 12.41V with red clip on + batt and black going to the control box terminals A and A1 with ign switch on and off. Actually 12.41 V on all control box terminals.

 

[bobhustead]

If you jump directly from the battery to the solenoid pole connected to the white/red wire, does the starter turn? It is not uncommon that a circuit will show full voltage but not be able to function under designed load. I still suspect the brown wires coming off the battery pole of the solenoid. I am thinking bad contact at the crimp on the terminal that connects the brown wires to the battery pole of the solenoid. Maybe try a direct jump from battery positive (you are negative ground) to pole A of the control box ? And another direct jump from battery positive to the purple wire the diagram shows coming out of the horn fuse to test the horns.
Bob

 

[Sarastro]

correct, turn key, no cranking. No lights, no horn, etc.. with ign switch in any position. Yes, this car should run without either of the fuses I believe. I am using a Fluke digital multimeter in volt mode. Red clip to + batt, black to red/white term on solenoid shows 12.41V with ign switch on. Also tested by running a known good wire to replace red/white wire from ign switch to solenoid, same result - nothing. Dumb question, for a car that was supposedly converted to neg ground by prev owner, is this normal?

This makes a BIG difference! If you are not getting power to other parts of the car as well, then that's an important clue.

The test you made isn't meaningful. You need to check voltages between the various points in the circuit and ground, not to the battery.

That said, and assuming you have a stock electrical system, the horns and the lead to the control box are both connected to the battery at the solenoid. If the horns are not working, and you are not getting power to the rest of the electrical system, the problem has to be right there. I don't see how it can be anywhere else. If there was a problem at the ammeter, say, the horns would still work.

 

[KJP]

This makes a BIG difference! If you are not getting power to other parts of the car as well, then that's an important clue.

The test you made isn't meaningful. You need to check voltages between the various points in the circuit and ground, not to the battery.

That said, and assuming you have a stock electrical system, the horns and the lead to the control box are both connected to the battery at the solenoid. If the horns are not working, and you are not getting power to the rest of the electrical system, the problem has to be right there. I don't see how it can be anywhere else. If there was a problem at the ammeter, say, the horns would still work.

Yes, stock electrical system, new harness during restoration about five years ago, negative grounded. If i test from ground either at negative batt terminal, body, or where ground cable attaches to body to any of the before mentioned points I get no voltage. Push button on solenoid turns motor, so I assume solenoid is getting power, and from ground to + side of solenoid shows 12.41 V.

Are you suggesting control box? Car ran fine up until last Friday when she died...

 

[bobhustead]

I read Steve's last paragraph as saying the same thing I said in post #10. The problem is most likely where the two brown wires (that power 2 separate circuits, which are both dead) are supposed to electrically connect to the battery pole of the solenoid.
Bob

 

[bobhustead]

Checking our hypothesis is quick. You do not have to remove any of the wires, just run parallel jumpers from the solenoid battery cable to the A pole of the control box and the outlet pole of the horn fuse.
Bob

 

[KJP]

I am going to look and test, and recrimp the brown wires on the solenoid, on my car they share the terminal on solenoid with the solenoid to starter connection. Which is opposite what the factory pos ground manual shows. Diagram shows starter cable on opp side of solenoid and neg batt connection sharing solenoid connection with brown wires. Shouldnt this solenoid terminal with the brown wires be to + battery, the hot side if car polarity reversed to neg?

 

[bobhustead]

The two brown wires need to be powered at all times. They need to be connected to the large pole that takes battery power directly from the (+) battery terminal via the big cable. This big cable is always energized. If the brown wires are connected to the large solenoid pole that joins, via another big cable, to the starter, they would be energized only when the ignition switch is in start position and sending power to the small white/red wire that attaches to the solenoid. If they are connected to the starter cable pole of the solenoid, that transmission of power will never happen because the source of power to the ignition switch is the very brown wire that goes to the ammeter and thence continues as a brown/white into pole A of the control box, and then from control box pole A1 as a brown/blue connected to pole 1 of the ignition switch. A photo might help if you have the tech. You don't need to think about positive and negative ground.
Bob

 

[KJP]

Well guys, progress... swapped cables on solenoid to how a neg ground car should have a starter connection. With hot side (+) to where brown cables connect. And, the car started with ign switch. Once. Then nothing. Control box/generator was polarized. Car has new solenoid in that I tossed in last evening. Could something be blowing a connection somewhere?

 

[bobhustead]

While the solenoid is just a switch activated by an electromagnet, (so where the big cables go probably doesn't matter) the convention is that the cable off the battery goes on the top solenoid pole and the brown wires connect to that pole so they are always hot. The cable off the solenoid to the starter goes on the bottom solenoid pole. Please use a test light with a sharp probe, with the alligator clip attached to good ground (battery neg if possible) to probe each connection from the eye terminal on the solenoid to the power pole on the ig switch and to the purple wire going to the horn. It should light at each connection. positive and negative ground are no longer material.
Bob

 

[KJP]

I will have to dig up my light probe, if I cant find it I think my voltmeter should work. But I do have a horn now. No lights or starter from ign switch, but I do have a horn.

 

[bobhustead]

From your last post (#19), I point out that the brown/blue that supplies power to the ignition switch at Pole 1 continues from pole 1 as a brown/blue to power the light switch at pole 4. No power at the light switch means no power is making it through the brown coming from the solenoid into the ammeter-control box-ig switch circuit I have previously described.
Bob