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TR4/4A Sudden total loss of power

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djwoody

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This afternoon I decided to go for a drive in the TR4A. I turned the key and it fired up as usual. I backed it out of the garage and let it warm up for a while as I folded down the roof and put on the tonneau cover. I got into the car and backed out of the driveway and onto the street at which point the car stalled. I turned the key to restart but nothing. No ignition light, no cranking, totally dead as if the battery was disconnected. I popped the hood but could not see anything unusual. I pressed the button on the back of the solenoid and the engine cranked immediately but would not start. Went back to try the key again and it started up perfectly again.:confused:

I thought this is a bit weird, but maybe it was just a gremlin that can't be explained. Anyway, I took off down the street and at the first stop sign the car stalled again and everything went dead. Same routine - pressed the starter button on the solenoid and then they key started it up again. I decided that I had better head back home instead of getting stuck somewhere too far from home so I turned around and about half way back to my driveway while accelerating it stalled again. This time, after getting it started the same way, I noticed the ignition light stayed on and would not go out.

After eventually making it back home and into my garage I decided to do some further investigation. I am not sure yet what the cause is and am hoping for some insight from some of you but am wondering if a loose connection or a shorting wire at the generator could be the culprit??? I noticed that one of the two wires going to the generator is hanging loose and if I wiggle it I see some small sparks as the connector makes contact with the outer case of the generator. Any other ideas or suggestions would be appreciated.
 
check for a loose low-tension lead from the coil to the distributor.
 
Sounds like the battery itself may have an internal short for such a complete cut out. I would check the age of the battery and see if the posts are loose at all.
 
djwoody said:
...I noticed that one of the two wires going to the generator is hanging loose...
Click to expand...

Both wires should be connected -- they only go on one way (different size connectors). That would account for your red light glowing.

The intermittent no-start could be that white/black wire mentioned above or a loose connection on the ignition switch.
 
Have you tried letting it run in the driveway and spark the loose wire and see if it kills the engine. Might be the problem.
 
Had the exact same problem with my Stag. Bad ignition switch.
 
I had a similar problem twice with the 3A. First time was the ignition wire came loose in back of the dash switch. I suppose vibration over the years loosened it. The second time on a 3 hour trip to the TRF party the main wire to the voltage regulator was loose. Same symptoms and I found it because it was dark outside when I opened the hood. Saw a slight arcking on the terminals. Pinched them together with pliers and never had a problem since. So look for he simple solutions first.
 
If it happens again, try the headlights. If they work, then the problem is the ignition switch or wires/connections in that general vicinity.

If they don't work either, then the problem is closer to the battery. Most common in my experience is a battery clamp that is corroded inside (which can be invisible from outside) or perhaps a bad battery cable (especially if someone has installed those cheesy replacement battery clamps). Could also be a problem at the solenoid, voltage regulator, or ammeter.

I doubt the loose generator lead is the problem, but of course it should be attended to. If it was just losing contact, then the generator would stop charging (and possibly damage itself), but the battery should still run the car for an hour or two. If it was shorting to ground, I think the cutout relay would probably open (so the battery wouldn't be shorted); but if it didn't, you'd see major sparks and/or smoke.
 
had a similar problem on my 4A many years ago, was the battery connection through the solenoid, I would clean all battery connections, at the battery, ground to chassis, through solenoid, easy to do and maybe will solve your problem. My son was having a similar issue with his Subaru just last week, I cleaned the battery cables, and showed him how to clean the battery cables, and it went away.
 
Thanks for all the suggestions. I haven't solved the issue yet but am working on it. On the weekend I removed the ignition switch from the dash panel to check for a loose connection but didn't find one, although the problem seemed to go away once I put the switch back into the panel and I was able to go for a short and uneventful drive.

This evening I wanted to go to my local classic car cruise. Everything started up as normal and I backed the TR out to my driveway. I decided to give Larry K's suggestion a try before heading out (just to be certain). As soon as I touched the generator wire the car cut out and this time I could not get it started again. Instead of going to the cruise I figured I'd better use the time to try and solve the issue. A closer look revealed that the second (larger) wire had totally come off the post on the generator but I could not see where it put it back on again so I decided to remove the generator. Here's what I found...
generator.jpg (click the image to see full size)

To cut a long story short - 4 hours later (after trying to epoxy the small connector back in place) and struggling to get the generator reinstalled and belt to the correct tension, I was very frustrated to find that I still had no power.

I just went out to the garage to do the headlight test that Randall suggests and they don't come on. I don't think it's the battery cables or clamps, so next step is to check the solenoid and voltage regulator connections - but that will have to wait for another day. By the way, Randall - you mention the ammeter. Can I assume that if the ammeter is showing a normal reading that it is not the problem?
 
Now take apart the generator and replace the brushes and have the commutator cut and cleaned, should be like new. Replace connector. You can do it or have a electrical shop do it $45-$60. You have had a meltdown in generator. Headlight test is for battery, ammeter is useless at this stage. Epoxy is not going to work.
 
djwoody said:
By the way, Randall - you mention the ammeter. Can I assume that if the ammeter is showing a normal reading that it is not the problem?
Click to expand...
If by "normal", you mean that it shows zero when nothing is working, then no, I wouldn't call that an indication that it (or the wiring to it) isn't the problem. :smile:

My next step would be to get out the DMM or non-powered test lamp and do some checks around the starter solenoid, control box and fuse block. Start right on the end of the hot post on the solenoid. If it doesn't have 12v, then the problem has to be between there and the battery. Next terminal A on the control box. If no juice there, suspect the ammeter or the wires to/from it. Then A1. If no juice there, the control box itself is intermittent (this happened to me, but I was running a 60 amp alternator's output through the control box). Etc.
 
So I tested with my DMM today. The battery shows 12v and I also get a 12v reading at the hot post on the solenoid. I did check the control box terminals (but am not sure if I did it properly - will do it again tomorrow following Randall's steps).

I disconnected, cleaned and reconnected all the connections at the solenoid and at the starter motor. I used a dielectric grease on all these connections to help protect against corrosion. The car started fine at this point but the ignition light stayed on. As soon as I flicked the headlight switch the car cut out again and everything went dead.

Somehow, whatever it takes, I will get to the bottom of this before the weekend is up!
 
If you contact me though the message system I can send you the Lucas Fault Finding Manual.

I suspect you need to service the control-box.
 
Thanks Gentlemen - I have downloaded and will review and report back my findings.
 
djwoody said:
...I disconnected, cleaned and reconnected all the connections at the solenoid and at the starter motor. I used a dielectric grease on all these connections to help protect against corrosion. The car started fine at this point but the ignition light stayed on. As soon as I flicked the headlight switch the car cut out again and everything went dead...
Click to expand...

Did I miss the part where you fixed the generator? Or did you just secure that loose bit with epoxy without opening the unit up (removing the back plate)? As I recall that terminal is normally secured to the body of the housing in an insulated fashion and merely presents thru that rectangular hole with insulation (plastic) around it.

If the generator is at all in doubt I would try starting & running & headlights on, etc with the generator disconnected and see if things change.
 
Hmm, just for clarity, you need to do the tests I outlined while the car is "dead".

Sounds to me like you now have (at least) two separate problems; both the generator not working (red light on) and some problem causing the battery to not supply power to the ignition.

Another point, that generator terminal needs to be able to slide through the plate, so you can remove the plate for service. You probably don't want to epoxy the terminal directly to the plate.
 
Latest update:

I ran the voltage tests on the control box. Contact A and A1 appear to be fine. I cleaned all the contacts as I did with the solenoid connections, so that might help. I tested the battery cables again and they are fine as well. This time when I started the car, turning on the headlights did not kill the engine - and the ammeter clearly shows the change in voltage as I flick the switch. Ignition light is still on steady which, based on the discussion as well as my limited understanding of the Lucas Fault testing guide, indicates that the generator is faulty. Randall's diagnosis so far makes sense (but I still don't know what is causing the power supply problem).

Next, I decided to disconnect & remove the generator again and remove the plate as suggested for a closer look. BTW, the plastic insulator had cracked in half - that was what I was trying to epoxy back together (to keep the connector from shorting against the outer case). My inspection revealed that the generator is totally shot - pieces just crumbled and fell apart (images attached). The brush connection disintegrated and the small connector just separated as soon as I touched it. Inside, things are worse. One of the field coil wires is burnt and crumbling. It's a wonder how this thing actually managed to charge the battery for so long.

So now the question is - do I replace the generator or should I use the opportunity to upgrade to an alternator? If the latter, how easy is the upgrade for a novice like me?

Is it plausible that the power issue I've been experiencing is simply bad/dirty connections at the solenoid or control box and that my tinkering just caused the generator that was about to fail to finally fail?

generator2.jpg generator3.jpg
 
Been following along Dion. Looks like you found the problem. I know that you will get differing opinions but if it were me I would take the oppertunity to upgrade to an alternator.

Cheers
Tush
 
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