3780R Resto - Engine Restart

[jbcollier]

It would fry your alternator diodes, virtually instantly.

[BDA]

Would that affect your ignition, though? You should be able to start the motor without an alternator. Maybe you have to disconnect the alternator first. If that doesn't work, it sounds like you're going to have to start following wires. Are you getting juice to the starter? Ammeter? Ignition switch? Coil? Study the proper wiring diagram (there are links to nice colorized diagrams on the main page of the forum. Follow the wires from the + side of the battery until you find were you stop getting current.

After you figure this out, you'll need to take your alternator to a shop to fix your diodes.

[DManglano]

No power to the ignition or starter.

[EuropaTC]

I don't have an alternator wiring diagram to hand but from what you've said I would think John is on the money with the alternator diodes, that's where I'd start looking.  Unfortunately these cars aren't like moderns with fuse protected circuits, there's nothing to protect you from accidentally reversing polarity and alternators don't like that or running without any load.

I've posted the top part of the federal diagram. You should be getting power to the starter motor solenoid which then follows to the alternator, ammeter and from this your ignition switch is powered. If nothing is happening at the ammeter then it sounds like the alternator is the problem. 

I'd be looking to swap the alternator myself, or at least get it checked by an electrician. You can replace diode packs on the Lucas alternators, I'm not sure about the model you have there but I'd bet an electrician could sort it for you.

As an aside, I'd guess with the alternator out of the circuit & it's drive belt disconnected you should be able to hot wire the ignition and start the car, but I'm not sure that's worth the trouble until the state of the alternator is known.

Brian

[jbcollier]

Might also burn out the ground strap and the ammeter.

Power to the starter is directly from the battery.  Start at the battery and follow the large positive and negative cables as laid out in the wiring diagram.

[DManglano]

I'd also like to check the fuse but can't seem to find the fuse box.  I looked under the dash (driver and passenger side) but couldn't find a box with the 4 fuses.  Does someone have a picture of where it should be located?  Thanks,

[BDA]

The ignition and starter aren't fused so that's not your problem. In any case, the fuse box houses 4 fuses and it's on the passenger side just below and behind the dash. You'll probably have to push the tunnel cover a bit out of the way.

[4129R]

The ignition and starter aren't fused so that's not your problem. In any case, the fuse box houses 4 fuses and it's on the passenger side just below and behind the dash. You'll probably have to push the tunnel cover a bit out of the way.

Where the passenger's left knee would be on a LHD car.

[LotusJoe]

Panel is mounted on the tunnel on the passenger side just under the dash

[DManglano]

Battery charged to 13.85 volts
Charge at ground - 13.85 volts
Charge at engine block - 13.85 volts
Charge at starter solenoid - 13.85 volts

Checked ignition coil.
3.5 ohm at primary
9.6 ohm at secondary (a little low but should still be able to turn over the car)

Fuses are all good

Taking alternator to be tested.

[Roger]

You can take the plugs out of the alternator, it has no part to play in getting battery power to the ignition switch, which is fed by the plain brown wire coming from the starter solenoid.
The brown wire with  yellow trace is the supply from the alternator when it's charging. It doesn't supply battery power at startup.

[DManglano]

The manual has 3 electrical drawing.  One for UK, Federal, and non-Federal.  I believe the non-Federal applies to my car as it is the only one that shows a color for the wire from the starter solenoid to the ignition (WR).  I have power at the start solenoid.  How do I test if power is getting to the ignition switch?  Could it now just be a bad ignition switch that I need to swap out?  Here are pics of the starter solenoid and the ignition switch wires.

[BDA]

I think you should choose the wiring diagram based on your VIN. Check this out: http://www.lotuseuropa.org/LotusForum/index.php?topic=752.0

But at this point, it probably doesn't matter which one you choose as the part you're interested in will be the same for any TC.

I think you might confused with starter and solenoid. If, with the ignition switch at the start position (second click), you get voltage between the white/red wire at the solenoid and ground, there is nothing wrong with your ignition switch. If the starter doesn't turn, there is something wrong with your solenoid or starter.

It's always good advice to go with John. If your ammeter is fried, you won't get juice to your ignition switch. If you are getting voltage between the + terminal of the battery and the engine, then your ground strap is ok (but should check it anyway.

To follow the current from the battery to the ignition switch:
Check the voltage between ground and the starter post (the one with the big brown wire). If you're getting battery voltage, check the voltage between ground and the large brown wire at the ammeter. If you get battery voltage there, turn on the ignition and check the voltage between ground and the brown/white wire at the ignition switch.

If your ammeter is gone, I'd advise you to replace it with a volt meter. You connect all the wires going to and from the ammeter and then run a new hot wire from the fuse box to the new volt meter and a ground wire from the other post to a good ground. You will not need a volt meter to run your car after you've connected the ammeter wires.

Let us know what happens.

[jbcollier]

It sounds like you are using a digital multimeter to check for power.  I would use a test light.  A digital multimeter will show a voltage reading through the rattiest of connections.  A test light applies a small load to the circuit and can be much more useful when diagnosing an issue.

Now, let’s get back to basics.

You hooked up the battery backwards, not unusual BTW.  So, first, disconnect the large wire on the alternator.  Now hook up the battery properly, cleaning the connections at the same time — clean, bare metal on metal covered with petroleum grease (vasoline).  Follow the ground large ground wire to the chassis or engine.  Clean its connections.  Find the ground strap that runs from the engine to the chassis and clean its connections.  Now follow the large positive wire (usually to the starter solenoid) and clean its connections.

Now briefly touch the large wire to the alternator back onto its terminal.  Any sparks? (Probably not, just good to make sure).  All good?  Hook it back up.  Sparks?  Alt fried, leave it disconnected for now — it will need to be repaired or replaced.

Get your test light and hook it across the battery.  Note how bright it is. Head to the ignition switch and hook the lead from the test light to chassis ground.  Use the test light’s probe to test for power at the brown or brown/white wire at the switch.  If there is no power, then there is a problem between the switch and the connections at the starter solenoid.  Use the wiring diagram to find and test each connection until you isolate the problem.

Do all that first and report back as I’m typing all this on a particularly small phone...

[jbcollier]

PS: The reason I’m asking you to clean connections is that they tend to “fry” when a very large current flows through them.