Strange problem with our Traveller

[KeithL]

We were out in the Traveller today with some friends when we had a really weird problem. I noticed the red oil pressure light had come on just as Jayne said she was losing power. Our friend in the back then noticed that the fuel gauge was reading empty. We pulled over at a convenient place to investigate and switched off (the engine hadn't stalled and was still running). When we had set out we had a nearly full tank, reflected by the fuel gauge, so we wondered if someone had syphoned the fuel out of the tank whilst we were at lunch. I looked under the bonnet pretending I knew what I was doing and checked nothing obvious had come loose or fallen off and then got Jayne to try starting it. It fired straight up with no red light and the fuel gauge reading correctly and we drove the rest of the way home without a problem.

Does anyone have any ideas what could have gone wrong that might have caused these symptoms?

It's a standard 1098cc engine with electronic fuel pump and ignition and hasn't given us any problems at all since the Petronix electronic ignition and coil were fitted 10 years ago.

[Andmurph]

Hi KeithL,

Was it a red oil pressure light or amber?

The low oil pressure light is amber

The red light is usually ignition light that indicates when the alternator, or dynamo isn’t charging the battery. Your friend noticed the fuel gauge was reading empty, also a potential sign of a lack of electricity rather than an empty tank.

I’d be inclined to check some electrical connections first. Are the battery lead connections clean and tight? Is the earth lead in good condition with a good connection to the firewall?

Are there any loose connections at the power regulator unit?
Or at the alternator/ dynamo?

I’d also chrck the fan belt isn’t loose as this can also cause intermittent charging issues.

[KeithL]

As you say, it was the red ignition light on the right, not the amber light on the left. My mistake.

Our car has a dynamo but without any additional electrical items such as a radio or USB charging points, and the lights weren't on.

I will run through the checks you suggested. Thank you.

[myoldjalopy]

The fact that the car lost power when the ignition light went out, and the fuel gauge showed empty, suggests it was more an issue of a poor connection somewhere, rather than the dynamo not charging, as there would normally be enough juice in the battery to keep running for a while if the dynamo suddenly failed. The fact that the engine "fired straight up" afterwards indicates the battery was OK.
What were the symptoms of the engine's power loss? Did it just suddenly stop firing, or did it hesitate/splutter?

[geoberni]

Sounds like a dirty connection causing a lack of electrical power rather than poor earth.

With a couple of different symptoms like that, I'd start by looking at the connections at the Voltage Regulator, then move to checking the connections at the fuse box.

[KeithL]

Hi KeithL,

Was it a red oil pressure light or amber?

The low oil pressure light is amber

The red light is usually ignition light that indicates when the alternator, or dynamo isn’t charging the battery. Your friend noticed the fuel gauge was reading empty, also a potential sign of a lack of electricity rather than an empty tank.

I’d be inclined to check some electrical connections first. Are the battery lead connections clean and tight? Is the earth lead in good condition with a good connection to the firewall?

Are there any loose connections at the power regulator unit?
Or at the alternator/ dynamo?

I’d also chrck the fan belt isn’t loose as this can also cause intermittent charging issues.

I've just had a quick look and the fan belt seems to have more play in it than I remember so I'll tighten that up sometime and check all the dynamo, regulator, earth and battery connections as well.

[KeithL]

The fact that the car lost power when the ignition light went out, and the fuel gauge showed empty, suggests it was more an issue of a poor connection somewhere, rather than the dynamo not charging, as there would normally be enough juice in the battery to keep running for a while if the dynamo suddenly failed. The fact that the engine "fired straight up" afterwards indicates the battery was OK.
What were the symptoms of the engine's power loss? Did it just suddenly stop firing, or did it hesitate/splutter?

As a passenger I didn't notice anything wrong with the engine but Jayne said that as she tried to accelerate there was no power. She didn't notice anything otherwise untoward with the engine such as misfiring or spluttering and it kept running until we stopped and switched it off.

[myoldjalopy]

Difficult to be sure about what caused the momentary loss of power - but the fact the ignition light went out and fuel gauge stopped at the same time does suggest a temporary electrical connection fault somewhere. So previous advice to check all connections still holds good for the moment.

[svenedin]

Many years ago when I was a student, I had a failing dynamo. The engine would run for at least an hour or more if the battery had been fully charged with a charger. We would gradually lose power to the point that there wasn't enough power to operate the indicators but the engine would still run.

This sounds like a bad connection.

I am not sure where the fault is though. After checking the battery terminals, remember that all of the power for the car except for the starter motor comes off the solenoid as a brown wire (for a key start). Personally I would start at the battery terminals and check everything. The car is not very electrically complicated so it would not take that long.

Stephen

[mike1864]

As suggested, your wiggling all the terminals may well cure the cause of the (suspected) intermittent high resistance.
But frustratingly, unless you'd performed this during a recurrence, you will probably never know which wiggle worked!

[myoldjalopy]

As suggested, your wiggling all the terminals may well cure the cause of the (suspected) intermittent high resistance.
But frustratingly, unless you'd performed this during a recurrence, you will probably never know which wiggle worked!

I think its more about checking whether the connections are firm and secure/not corroded, rather than just wiggling them and hoping for the best...

[geoberni]

As suggested, your wiggling all the terminals may well cure the cause of the (suspected) intermittent high resistance.
But frustratingly, unless you'd performed this during a recurrence, you will probably never know which wiggle worked!

I think its more about checking whether the connections are firm and secure/not corroded, rather than just wiggling them and hoping for the best...

I agree. Actual inspection and cleaning is required, maybe even replacement, if found lacking.
Just wiggling and then carrying on if it appears fixed, is like keeping an SU Pump working by banging it when it stops, instead of actually taking the top off and cleaning the contacts.

There's a Classic Car website, I think it was for one of the MG Models, where a page about SU Pumps reminds owners that they spend hours regularly and lovingly tinkering with their engines and many other aspects of their cars like lubrication, yet they moan about their SU Pump; having not touched it for decades.
Proper maintenance applies to all aspects of Classic Car Ownership because they are many decades beyond their design lifespan.

[mike1864]

As suggested, your wiggling all the terminals may well cure the cause of the (suspected) intermittent high resistance.
But frustratingly, unless you'd performed this during a recurrence, you will probably never know which wiggle worked!

I think its more about checking whether the connections are firm and secure/not corroded, rather than just wiggling them and hoping for the best...

And what is the first thing that anyone does to "check the connections are firm and secure/not corroded"?
They wiggle them!
This might even provoke a wire to fall out of its connector; fault found (probably!)
But I never claimed (or suggested hoping) that "just wiggling" would resolve the issue. I was just pointing out that wiggling several connections (like any later cleaning/re-terminating) might cure the intermittent fault without ever revealing the exact culprit with the corrosion/high resistance.
PS I agree about SU pumps; I clean my points and filter every year.

[Andmurph]

We took the Midget out for a run on Tuesday after fitting new leaf springs from Jones Spring Engineering.
A 256 mile round day trip from Wimborne, Dorset to Valley of the Rocks, Lynton, Devon via the A396 from Bampton to Dunster and Porlock Hill. A highly recommended route for a shakedown run.

It was fantastic! A little cold but clear and dry. On approaching Taunton on the return journey the indicator flash rate decreased, by the time we stopped for petrol they had stopped flashing and a turn of the ignition key gave just a quiet click. I push started it on the petrol forecourt and drove back to Wimborne with hand signals only. The engine pulling like a train.

On arrival back at Wimborne still just a click when turning the key so it was pushed into the garage until today. A cursory glance looked like battery connections and fan belt were slightly loose.

Today I found the full extent of the damage and the real reason we lacked electricity! Not even enough for the LED indicators!

The picture shows the damaged dynamo commutator, it had shredded the brushes and pulled out their wires.

Beyond repair I think. A new alternator on its way!

I find it remarkable that the engine ran for 75 mile or more without any dynamo. I’m so pleased that it did though. Much easier to fix in a warm coffee fuelled garage.

[KeithL]

Apologies to everyone for the delay updating this post. We've been away and this morning was the first chance I have had to look at the Morris again. I had previously spotted that the fan belt seemed looser than I remembered and sure enough it had more than the recommended amount of movement in it. The bolts on the Dynamo and the adjustment slider were all tight so there could have been some slight movement but I suspect the belt has stretched over time. Once I had worked out the sizes of the bolts concerned (1/2" AF for the two at the top of the dynamo and 9/16" AF for the adjustment slider bolt if anyone's interested) it didn't take too long to take the extra slack out of the belt. When I started it up the ignition light went out instantly and only flickered on when I pushed the choke right in whilst still cold and it was on the verge of stalling.

I suspect this was the problem so I'm going to leave it as that for the moment and see what happens.

Thanks to everyone for their input.

[Edward1949]

On arrival back at Wimborne still just a click when turning the key so it was pushed into the garage until today. A cursory glance looked like battery connections and fan belt were slightly loose.

Today I found the full extent of the damage and the real reason we lacked electricity! Not even enough for the LED indicators!

The picture shows the damaged dynamo commutator, it had shredded the brushes and pulled out their wires.

Beyond repair I think. A new alternator on its way!

I find it remarkable that the engine ran for 75 mile or more without any dynamo. I’m so pleased that it did though. Much easier to fix in a warm coffee fuelled garage.

I've had similar experiences in "the olden days" where, after a dynamo failure, the last thing to give up is the ignition - everything else electric is closing down , even the interior light giving a feeble orange glow! I assume that the old-fashioned coil ignition system is designed to overperform in order to facilitate cold starting . Thus when the engine is actually running it can accommodate a huge voltage drop and still provide an adequate spark.

[PhilEKH]

It's a guess, I but sometimes the little voltage regulator (attached to the back of the speedo) goes rogue and send dodgy fuel gauge signals.