Ignition light stays on after key removed. Why?

Bought a '79 Spitfire a few days ago, and it was just delivered via transport today. It is a beautiful car. Joy-riding all afternoon today with it. Tonight, when I put it away, I turned everything off, shut down the engine, and removed the key. the IGN light remained lit. Why would that be? Battery is fine. car started right up each time I took her out today, and after leaving the car sit for 3 hours with the IGN light on. Comments or ideas??

Thanks in advance.

Most likely, a bad diode in the alternator; letting battery voltage through to the terminal for the lamp. Probably the alternator is still even working to some extent (it's a 3-phase device so one bad diode only reduces available output), but eventually the light will run the battery down.

And welcome to the BCF! As you saw with Randall's post, lots of help here.


Mickey

Thanks very much for the welcome and the advice. It it best just to replace the whole alternator than try to install new diodes (do they even do that?). Any newer models or manufacturers you would recommend?

thanks again...zoom zoom

Depends on both your abilities and the condition of the old unit. Some good articles:
https://www.oldclassiccar.co.uk/forum/phpbb/phpBB2/viewtopic.php?t=4513
https://www.vtr.org/maintain/alternator-repair.shtml

Lots of folks have swapped in Delco alternators, mostly because they are readily available and cheap (in the USA). Generally it's not too hard, but does take some mechanical ingenuity and some electrical modifications.

If you are looking for pure "plug and play", about the closest I'm aware of is the Bosch alternator from a 1978 Ford Fiesta with air conditioning. (Be sure you ask for the Bosch style, as most Fiestas got a Motorcraft unit that is different.) Delco also makes an equivalent for this alternator, but I don't know how to get it other than asking by application (78 Fiesta with A/C). My Friendly Local Auto Parts Store (aka FLAPS) took two days to get the Bosch, and the price was about $80 (including core charge). But that was a few years ago, it may have gone up and/or be harder to find today.

OK...Things have changed...Not sure why...again.

I took the Lucas alternator out of the car and took it to Advanced Auto, where they did a bench test. No problem with the alternator, though it is only charging at 12v, not 14-15v. The guy said the diodes were fine and that i did not really need to replace the alternator. So I put it back in the car, and now it's a new set of problems. Before, the IGN light stayed on when the car was off, and turned off when I started up the car. NOW...the IGN light goes out when I turn off the car (like it's supposed to, right?), BUT it stays on while the engine is running. It gets brighter as the engine revs, and dims to nothing when I come to an idle stop. Additionally, I notice the blinkers are solid on if I try to put them on (either side) while at a stop, and very slow if I put them on while the engine is turning at speed. Is this still an alternator issue??

Forgot to mention...Before I took the alternator to Advanced to have it bench tested, I took the car there to have them test the alternator while hooked up. Their machine said that there is a low voltage draw of 1.67 amps from the battery when there should not be. This might have been the IGN light when it was on when the car was off...maybe? That reading is what prompted me to remove the alternator for the bench testing

79Spit said:

No problem with the alternator, though it is only charging at 12v, not 14-15v.

Click to expand...

I'd call that a BIG problem, since it takes a minimum of about 13.2 volts to even mostly charge a "12v" car battery! You need to find someone that knows a volt from a Volkswagen!
<div class="ubbcode-block"><div class="ubbcode-header">Quote:] NOW...the IGN light goes out when I turn off the car (like it's supposed to, right?)[/QUOTE]Yup.<div class="ubbcode-block"><div class="ubbcode-header">Quote:], BUT it stays on while the engine is running. It gets brighter as the engine revs, and dims to nothing when I come to an idle stop.[/QUOTE]That could also be a symptom of a bad diode; but might also indicate a bad connection between the alternator and battery; or a bad connection(s) somewhere in the ignition circuit.

I would suggest getting a voltmeter or multimeter (digital multimeters or DMM for short have become so cheap that every Triumph owner should have at least one) and checking some voltages with the engine at fast idle and the headlights on.

First check between the alternator case and the battery ground post. Lucas says 0.25 volts is acceptable here, but I prefer to see under 0.1 volts.

Then check between the alternator output post, and the battery positive terminal. Again, Lucas allows 0.5 volts, but I prefer to see it lower than that.

If either voltage is too high, then work your away along that part of the circuit, to find and fix wherever the voltage drop is. Note that paint and rust do NOT conduct, each connection needs to be clean bright metal to metal. That includes the alternator mounts, since that is how the alternator ground gets connected to the battery.

If that doesn't point out the problem, check between the D+ and B+ terminals on the alternator. (You may have to jam the probes into the connector, or strip off a bit of insulation to connect into these terminals with the plug connected.) If the difference here is more than about a volt, there is a problem inside the alternator. If not, it's time to start going through the ignition circuit wiring to find where it's problem is.

A bit of explanation may be in order: Inside the alternator, there is an extra set of diodes commonly called the "diode trio" that are attached to the same windings as the output diodes; and to the D+ terminal. Thus, if the alternator is working, the D+ terminal gets about the same voltage as the output (B+) terminal.

The D+ terminal is wired to one side of the warning light on the dash. The other side of the warning light is connected to the ignition circuit. So normally, with the engine running, both sides of the lamp are at roughly 12v, and the light is off.

I've uploaded some instructions from Lucas that may help; you should be able to download "Lucas ACR alternator testing.pdf" from https://docs.google.com/leaf?id=0B2H2NJt3...list&num=50
<div class="ubbcode-block"><div class="ubbcode-header">Quote:] Additionally, I notice the blinkers are solid on if I try to put them on (either side) while at a stop, and very slow if I put them on while the engine is turning at speed. Is this still an alternator issue?? [/QUOTE]Hard to say for sure, but it certainly tends to show low voltage in the ignition circuit. That might be because your battery is low (from the alternator not working), or because there is a bad connection(s) in the ignition circuit.

It's unfortunately not uncommon to find multiple electrical problems; but I would focus on the alternator/light problem first. Once it's solved, worry about the turn signals.

If money is a problem, this HF multimeter is adequate at a bargain price:
https://www.harborfreight.com/7-function-digital-multimeter-90899.html
But this one has more features, is easier to read, and likely will last longer:
https://www.harborfreight.com/ac-dc-digital-multimeter-37772.html

I agree that there are multiple problems going on here. My experience has been that cleaning connectors to to the various lights and of course the grounds would be very helpful- dirt, corrosion, rust. Has the car been in storage for a while? Start with the simple/ easy stuff, first, T.T.

Thanks for the detailed advice and opinions. They really do help a lot. I was doing further research at

https://www.vtr.org/maintain/alternator-repair.shtml

and came across this test/synopsis:

When your bulb starts glowing or the dashboard gauge shows a no- charge condition, see if charging current is reaching the battery. <span style="font-style: italic">With the engine running at high idle (1500 rpm), measure the voltage at the battery terminals using a volt/ohm meter (VOM) ... On high idle, the voltage at the terminals should be between 13.6 and 14.4 volts. Outside that range indicates bad or dirty connections or defective alternator. </span>

I did this, and the voltage at the battery terminals was 12.4v, the same as it was when the car was off.

I am wondering if it just makes more sense to get one of those Bosch alternators for the '78 Fiesta you were talking about, and replacing the existing alternator simply because it does not seem to be charging the battery sufficiently. It might even cure the IGN light problem, if the existing diodes are actually the problem, right?

Thoughts?

79Spit said:

I did this, and the voltage at the battery terminals was 12.4v, the same as it was when the car was off.

Click to expand...

Which only tells you that the battery is not being charged (and is somewhat run down); doesn't really address why.
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]I am wondering if it just makes more sense to get one of those Bosch alternators [/QUOTE]
I guess it depends on your mindset. Mine runs more towards running a problem to ground, rather than just replacing the parts that might be the problem.

Especially since it still sounds like you have bad connections.

Latest joyride this afternoon made the Oil light come on, and I checked the oil before I left, and it was full. Do all these dashboard indicators come from one circuit or wire cluster? Does the Oil light measure anything else, like differential fluid or anything like that?

Thanks for the answers and the patience!

Sorry, I can't help you there. According to the diagrams I have for a 79 Spit, only the engine oil pressure switch should light the oil light. But I have no idea what the physical wiring looks like under the dash.

Worn out engines and new oil can keep the light off.
Once the oil works a bit and thins out, and the engine gets hot, blink gpes the light.

The light should have power from the ignition switch to one side, the other grounds through the sender.

FIRST thing you do is open the bonnet, engine off, then key on, observe the light on, then unplug the sender wire.
If the light goes out, skip this next bit and move down a line or two.
If the light stays on, you have a short to ground somewhere in the wire from the light to the sender.

Remove the sender, screw in a mechanical gauge, start it and see what oil pressure you do have.

If normal, replace sender with new one.
If not normal, prepare thyself.

The car came with an oil pressure gauge installed under the dash. What pressure ranges are "normal"?

"Normal" should be 40-60 psi at speed in a warm engine. Anything less than 40 at speed might be cause for concern. Note, though, that a very hot idle might be very low, depending on what oil is being used. From my experience, it's pretty much an absolute MUST to use a 20W-50 oil at least in summertime.

I'm not sure offhand about the '79 Spitfire, but starting with the 1969 model year at least, the oil pressure light was somewhat interconnected with the brake failure warning light.

If you are seeing oil pressure over 10psi and the light is lit, I would suspect the sender. Providing it goes out when you disconnect the wire from the sender.
Most autoparts stores can cross referance it . I think mine fits a 79 Chevy Monza.
The connection between the PDWA light and the oil light is to prove that the bulbs are both good when you first start and have no oil pressure. As soon as you develope oil pressure they both should go out.

If you are only getting 12.4 volts from your alternator at the battery with the car running, and it is wired in correctly, get the alternator swapped out. 13.4 - 14.4 is where it should be.

Bosch might be an option if you really know what you are doing.....but that sounds like a little more than what you want to chew right now. There is nothing wrong with the Lucas alternator design.

I would find an electrical rebuild shop and bring the alternator there for a rebuild.

My TR8 A133 alternator cost $65 for a complete redo and looks brand new. I have to believe a Spitfire alternator would be the same or less.

Once that alternator is tested and proven to be fixed, I'd install it and then go onto the next issue (if they even exist anymore).

Lucas electrics act weird when everything is just right. Throw something out of kilter and you can end up chasing all kinds of odd things. One simple step at a time is usually the best method.

My 2 cents anyway.

79Spit said:

No problem with the alternator, though it is only charging at 12v, not 14-15v.

Click to expand...

TR3driver said:

I'd call that a BIG problem, since it takes a minimum of about 13.2 volts to even mostly charge a "12v" car battery! You need to find someone that knows a volt from a Volkswagen!

Click to expand...

No problem with the alternator???? WTF. It only put out 12 volts for goodness sake. That right there would be enough for me to drive, or send, it off for a rebuild.

Did you call these guys?

I would start here:

Joe's Auto Electric
(860) 613-1433
770 Newfield St, #1,
Middletown, CT 06457

A UPS box is probably $10 each way to Green Bay, WI & back.

https://gbrebuilders.com/

Just another option.