TR4/4A Basic Wiring Question

[bammons]

I have come to the point in my restoration that it is time to try to get oil pressure before starting for the first time. Upon turning the key after disconnecting the coil and removing spark plugs I only got a click from the solenoid. My starter switch was wired as it was prior to taking everything apart and is shown below. The solenoid is also shown as wired below. When turning the key to the second position (not full start) I get power at terminal #2 and 3 on the starter switch and no power other than the direct from battery on the solenoid. I am committed to try to learn how to use a test light and multimeter but not real good at it now. I will not be able to work on the car after a few more days for a while so I thought I would ask if these items seem to be wired correctly and them go from there. Is there a way to test if the solenoid is good? It is the one that was on the car and the car was running. I cleaned it up but was wondering could I have reversed the battery/starter sides and does it matter if I did? Bruce

 

[Geo Hahn]

It doesn't matter if you reversed the big posts on the solenoid. The fact that you get a click from it when turning the key suggests that your ignition switch is not faulty and is correctly wired.

I'm assuming you don't have a solenoid with a button (may look like a rubber button) that operates it manually. That would have been my next check.

You might hook up your volt meter to the solenoid post with the wire to the starter and see if it is powered when the key is turned. Also worth noting what voltage appears when you do that.

If there is power at that post then I'd be undoing, cleaning and tightening the connections at the solenoid and the starter.

Also worthwhile confirming your ground cable from the driver's side motor mount to the timing cover is in place... without it the starter may not have a good ground and strange things may happen.

 

[Gliderman8]

How’s the charge in the battery?

 

[DrEntropy]

Also worthwhile confirming your ground cable from the driver's side motor mount to the timing cover is in place... without it the starter may not have a good ground and strange things may happen.

Strange things indeed. Like letting the smoke out of the THROTTLE cable and a glowing choke cable... Both easy paths to ground for electrons denied a good chassis-to-engine one.

 

[bammons]

The battery is brand new and show 12.4 volts or so. The starter is a brand new high torque unit. The solenoid does have a button but nothing happens when I press it when the key is in the second position (should have mentioned that). George the test light does not indicate voltage at the starter post with the key in the second position (but maybe I need to try with the key in the third start position?. I can check with a multimeter in the morning. I do have a ground cable attached to the timing cover but I think I attached it with a bolt on the frame rather than the motor mount but I may not have scraped any paint there.

 

[Sarastro]

The numbers on your sketch don't correspond to those on the wiring diagram. I don't know if the switch has numbers on it, or if those are just ones you added for reference.

In any case, if the solenoid is clicking but nothing is happening, something is wrong with the high-current connections between the battery, solenoid, and starter. Or, you have a bad starter or solenoid. Probably not a battery problem; usually you get a loud buzz from the solenoid, when it closes and opens rapidly, if the battery is bad.

Check for voltage at the starter side of the solenoid with the ign switch in start position. If you hear it click and there is no voltage at that point, but you do have voltage at the other terminal of the solenoid, it pretty much has to be a bad solenoid.

Oh, and, yes, per DrE: be SURE you have good ground cables both from the engine to the chassis and battery to chassis.

Don't make this harder than it is. The solenoid is just an electromagnet that closes a big motha switch, just a copper bar that bridges two contacts. It has no polarity, any more than a piece of wire has one. It cannot be connected backwards. Also, if you push the button on the back, it just bridges those contacts manually, so the starter should turn over, whether the ignition switch is on or not. Look at the wiring diagram; the low-current wiring just operates the solenoid; it has nothing to do with the high-current wiring.

 

[bammons]

Steve - I put the multimeter to the solenoid/starter pole while my wife turned the key to start and got 12.8V. The reading doing the same thing at the starter pole read the same. Checked grounds at the battery and engine and they were tight. I used a bolt that attaches the brace in front of the engine to attach the ground. Can I attach a jumper cable to the positive terminal on the battery and touch the starter pole to see if anything happens? So still at the same place all I get is one click and nothing else. The button on the solenoid still does nothing not even a click. The starter switch is what was on the car and the numbers I used correspond to the back of the switch. I wired the switch back the same way I took it off. The PO may have switched it out. Bruce

 

[bobhustead]

12.8 volts means nothing. It is amps that count here. 8 "D" size flashlight batteries in series will read 12 volts, but not have amps to turn your starter. New batteries can be bad right out of the box. New batteries can simply be discharged (low on amps). Your suggested test with a jumper cable could rule out (or in) loose cable connections from battery to solenoid or solenoid to starter. Jumping in a known good and fully charged battery (just like if yours was dead at WalMart) could also give some answers.
Bob

 

[DrEntropy]

Don't make this harder than it is. The solenoid is just an electromagnet that closes a big motha switch, just a copper bar that bridges two contacts. It has no polarity, any more than a piece of wire has one. It cannot be connected backwards. Also, if you push the button on the back, it just bridges those contacts manually, so the starter should turn over, whether the ignition switch is on or not. Look at the wiring diagram; the low-current wiring just operates the solenoid; it has nothing to do with the high-current wiring.

You will NOT hear a "click" while pushing the solenoid button. The click is heard only when the iggy is in the start position. But one or the other of the solenoid large terminals should have 12V at all times, pushing the button should show 12V on the other terminal (to the starter). Not there, bad solenoid.

I put the multimeter to the solenoid/starter pole while my wife turned the key to start and got 12.8V. The reading doing the same thing at the starter pole read the same. Checked grounds at the battery and engine and they were tight.

If that voltage is present, it sounds more and more as if you may have a starter "defective outta th' box" to me.

 

[bobhustead]

Doc-
I think he could read 12 volts where you suggest and still not have the needed amps in the battery. Agreed, of course, that no voltage at the "out" pole of the solenoid when you have volts going in would likely be a bad solenoid.
Bob

 

[bammons]

Put a jumper cable on the starter post and attached to positive terminal on the battery. It seemed to have a delayed reaction but it did spark but no turning of the starter/engine. I have a load tester I can dig out of the shed tomorrow and test the battery. I have read the instructions on my HF multimeter and can't figure out how to get amps on it. Bruce

 

[bobhustead]

Trying to test amps where we are talking about (on an active load were the battery fully charged) would peg the needle and probably fry the HF meter. Your meter would need to be in the circuit, not parallel to it and a starter at work would pull 250 or 300 amps.
Bob

BTW If your battery is fully charged the spark you mentioned in post 11 should appear fairly vigorous.

 

[bammons]

I just load tested the battery and it held up. Bruce

 

[bobhustead]

Begins to look like the starter. I would pull it and test it on the bench with jumper cables, one to the bolt flange and pos to the power stud.
Bob

 

[Geo Hahn]

If I understand correctly, you have a high torque starter (which typically contains a solenoid) but have also retained the original solenoid.

There is a way to do this which some choose to use either for a more original look and/or to retain the use of the solenoid button... but you need to think it through.

In particular I got the impression that you still had two big cables on the original solenoid and that doesn't sound right to me.

 

[bobhustead]

If, as George thinks, the starter has a separate solenoid this could change the calculus.
Bob

 

[DrEntropy]

Must admit never thinking about the new starter having an integral solenoid. Should be some sort of diagram with it to explain the 'new' connections though.

...and I even put one of the WOSP high-torque ones on our personal MG here. GAH!

 

[Geo Hahn]

Use with care as I am unsure if this is a match for what you have, but it shows how to retain the original solenoid... the key being an added bypass wire to trigger the solenoid in the hi torque starter:

Without that bypass wire you would get a click but no engagement.

 

[bammons]

Yes as stated above I do have a new high torque starter from BPNW and yes I did install the bypass wire so as to use the original solenoid. My wiring corresponds to the first drawing in Geo's post above. You guys know alot more than me but it does seem like the issue is with my new starter. I think that putting the jumper cable from the battery directly to the starter post without any turning points to that. That would eliminate any ground question as well as far as being the cause of the starter not turning (seems to me). I have a order to put in before I leave for a while and was hoping it was as simple as a new solenoid that I could easily replace but as I said I think it may be the starter now. I have had the starter for about a year (but still unused) so I probably have no warranty recourse. I will bench test it as Bob says. I may not be able to do that before I leave and if that is the case it will be early Oct. before that happens. Rats! After all this time I was ready to hear the motor spin. This car may hate me, I seem to have to fight with everything. When I test the starter will it have to be in a vise? Is there any way that in installing the starter that the teeth would not have aligned and causing it to lock up? The starter has Bosch internals as I understand it - can it be repaired or are new starters no longer repairable? I wonder if it would be worthwhile to wire it as shown above without the bypass and use the internal solenoid. Bruce

 

[bobhustead]

It will try to rotate a little on the bench, but nothing you can't handle. You will need to position a bypass wire as in the diagram, but leave one end unconnected and manually connect and remove it to effect the test. If the bypass wire is fastened in position, the starter will spin forever. Try to turn the armature by hand to see if one of the bushings in the starter might be frozen to the armature. If so, you can probably free it up with a little leverage or pliers (whatever fits best).
Bob