possible starter motor problem

[Beau]

Here's the trouble...

On some mornings on first start up the engine turns over slow (half the usual speed) but fires up within couple seconds like normal. I thought the batteries were on there way out so got them checked. One was good but not 100% so was replaced under warranty. A few days later I had the same problem again.

I'm not sure on this, but I do believe it has occurred on cooler days rather than the hot days. By cool I mean around 15 degrees. I've not had a problem with it starting back up during the day. It's happened about three time now within the past month and it's only in the morning. What I'm going to try next when the slow start occurs is to switch it off back instantly, and crank it again and see what happens.

Is there a possibility the starter itself is on it's way out? It's the original starter so is a good 20 years old. I've only ever replaced the solenoid contacts on it.

 

[StarCruiser]

Worth taking it out Beau, open it up, check the brushes are free to move, in fact remove them from their holders and inspect them. There should be enough length on them so the springs sit on them not the brush boxes (tubes). Give the whole thing a clean up in brake cleaner. Inspect the commutator (copper bars in a cylinder shape) for any signs of burning or grooving and test between each segment and its neighbour on Ohms, should be the same reading give or take. If grooved, have it skimmed in a lathe gently until cylindrical. Check for and wire brush off any significant corrosion that would be a problem (careful around the windings not to wire brush them). Drop a little oil in the bearings and reassemble and all should be good.

 

[Beau]

Update - So this morning I had the same slow crank, as though the batteries were dead. But they weren't.
As soon as it started I let it run for maybe 5-10 seconds and then switched her back off. Turned the key to start back and it fired up like normal. So I'm pretty convinced it's the starter playing up and when warm the starter function as it should, compared to when it's cold.

Starcruiser, I haven't looked specifically but other than what you're saying is there anything that may need replacing? I'm yet to open up a starer so have no idea what they should look like in good/bad condition. Are there rebuild kits for them? Thanks for the advice, I'll probably end up doing that

 

[StarCruiser]

Brushes would be the most replaceable item but even at the age of your truck they shouldn't be overly worn. It is far more likely that it needs a good clean. If I were you I'd get it on the bench and inspect it before buying anything. If it does need brushes you'll soon see but it's unlikely.

 

[Beau]

So last weekend I had the starter out! I didn't get any pics as hands were a mess!
Contacts all good, as should be as a year ago I replaced/upgraded them.

Brushes worn over the years but still plenty of life left on them. I'm actually surprised at how little they've worn considering 21 years of starting... A bit dusty but it was the first ever time opening up that side. I used a cloth and soft tooth brush and cleaned out the commutator bar of dust. Inspected it and no visible wear or damage.
The armature winding all looked good. Nothing burnt or out of place. Overall I was impressed by how well these things are made.

Anyway, yesterday was a cold day so I got to test the starter out and it's still doing the same thing. Slow cranking, around 100RPM. The colder it is - the slower the crank. It'll fire up after 3-4 seconds but shouldn't be like this. It would sometimes be slow for the first 2 seconds like a dead battery and then would be normal speed and fire up. After initial start up I could switch off and turn the engine back on like normal

Whatever the issue, it's temperature related. And that points at the batteries. But it's not them! I've cleaned out all connections and all are tight/well connected. Once temps stay above about 15 Celsius it doesn't seem to have an affect.

Thoughts anyone? It's a bit puzzling. It's easy for me to live with it, but when I head up north and we get to freezing temps I have a feeling the problem may be even worse.

 

[StarCruiser]

Have you checked your Earth straps are
tight and in good condition? Also try testing voltages at different points when poor starting and when good. Across the batteries, across the starter at the starter itself and on the motor side of the solenoid. It sounds like a loose connection to me. Test from battery + to starter terminal and to the motor sid of the solenoid. Do the same on the negative. You should get small voltage drops, you're looking for something bigger.

 

[Steve H]

Hi Beau. Might be a daft question but what oil are you using? My neighbour has a Toyota Carina and last winter had slow starting problems. He was using a 10w40 oil in the car, Toyota spec was 5w30. He had it changed at next service and all seems good again. Had no problems in the frosty mornings and his was a petrol engine. Also oil light went out earlier. Worth a look at perhaps

 

[Beau]

Starcruiser, I've checked all earth straps, as well as cleaned them out. I'll check the voltage at the starter. We've just past a cold spell so I'm gonna have to wait a while for another cold day to come about. I might check it warm anyway to get a base line reading.

Steve, I've considered the oil but am not using anything that shouldn't cope with the weather. I'm also using 10w-40, which is more on the thicker side during these colder days but not out of range for the oil viscosity.

Funny enough, today was about 15 degrees in the morning, I was expecting it to be a bit slow but she started right up like normal. It never seems 100% consistent. I'll double check earths. Thanks for everyone input!

 

[StarCruiser]

Sounds like time to check voltage across every switch and every connection as well as the battery voltage. A base line is good. Note your readings down in a table and see if a pattern emerges if nothing becomes obvious straight away. Ideally measure the current as well but you will need a DC reading clamp meter and that's a bit specialised. If you can borrow one perhaps? Post your table on here if you like when you've got baseline and poor crank readings and I'll take a look.

 

[Beau]

Just thought I'd post that I believe it's a battery problem, or at least something possibly draining the battery. I swapped ONE of the batteries out (the older of the two) with one in my other car. And to my surprise it fired right up like normal and the starter spun the engine over quick, but what should be normal I guess. This worked fine for a day and then it returned back to it's usual self of cranking slower for 2-3 seconds before starting.

So I'll be checking any potential drains in the system. The only obvious problem is that my rear two bumper lights (side and break) don't work due to being rusted out pretty badly. I'm wondering if this could cause any drain problems?

 

[Shayne]

Battery leads can corrode inside the sheath for no reason at all , a proper random mystery for all and any vehicle i suppose , something to check anyway ?

 

[Trevor]

There is one earth that can fail or give problems which is the little double earth from the drivers battery. One short lead goes to the inner wing and the other down to the bottom of the engine block on the drivers side. Might not make a difference but I'd consider chucking the existing and beefing both those leads up.

 

[Beau]

I've not checked the leads under the sheath, but I have checked the connections on both ends. I know the exact one you're referring to Trevor and have replaced the lead going to the body from the battery. I've also added another earth cable on the starter side battery going battery to body, and then body to engine. Having inspected all cables I think they're fine.

I've just done a draw test and the car is using 300 milliamps (0.3amps?) with all doors closed, except the bonnet. This I believe is normal and wouldn't drain the battery quick at all. I've left both batteries disconnected and will see what voltage they read in the morning, One is at 12.70, the other 12.68.

Another question - Is testing the voltage at the battery whilst the engine running the only way of testing a good/working alternator? I'm reading about 14.2 when running which would indicate it's doing it job. Is this a reliable way? The alternator is as old as the truck with 200k on it...

 

[Trevor]

Yes I reckon the voltage when running is healthy enough so that old alternator is doing its stuff.

300 milliamperes is probably the clock and again small enough not to worry about.

Cables can look fine and terminals cleaned but it's whether the resistive performance has broken down in the cable which is the bit you can't see, in the old days cranking up a Mega might have helped, my view still is to replace a known weakness.

The cable I referred to has a fairly thin cable to body earth and it's not super beefy to the block, if it's not brilliant and I'm assuming you have the twin battery setup then it might just be enough to reduce the earth return back to the battery when starting.

Given you are having temp related symptoms, this could/possibly/maybe be down to a cable breaking down but as usual with these things it could just be a red herring.

Change out the cheapest and easiest first to try and elimate.

 

[Beau]

Lets say it was the cables at fault or a bad ground? Why when charging the batteries separately and sticking them in would the cruiser fire right up without a problem. Give it a day and the starter now turns over 3/4 the speed it should and is consistent. If I shut her off and start back up it'll start back up instantly, but as time goes by the batteries seem to drain. But like you said, maybe the hot engine bay hides possible ground faults, electricity seems to be a bit odd at times.

 

[StarCruiser]

It's beginning to sound to me like a battery problem Beau. Is yours 12v start with two parallel batteries or 24v with a change over relay liking the 80s? If so you may have an internal fault in one battery or even in the connections between the two.

Very difficult to say for sure without voltage readings across every connection under starting load. I would say it's worth getting your batteries checked. Also are they a matched pair?

If nothing more than process of elimination, it looks like batteries are the one thing left.
As a guess, I would say it sounds like you have a 12v start setup with two batteries solidly connected in parallel. Under the heaviest load (1st start in the cold) one battery isn't connected either by a poor connection in cabling or something in the battery itself. If this is the case you could try just using one battery to start, then repeat for another first start with the other and see what speed it turns over at. If my theory is correct you should with one battery get the same slow start and with the other it should not turn over at all. Then you could if terminal configurations allow, swap that battery to the other position and see if there is any improvement. If not it's the battery, if there is it's in the cabling or connections.

 

[Beau]

Yup, 12v setup with two batteries in parallel. No, the batteries are not the same, I know for longevity and reliability they should be but to be honest, for the last 15 odd years I've never had the same kind of battery and never had a problem...

I checked back the voltage on the batteries today and one was 12.68, the other 12.64 so I would say they're both fine? Your idea on starting it with one battery sound like a fair test. I might just have to bite the bullet and remove all cabling and check/replace them if I don't see anything obvious with the batteries.

 

[Shayne]

Tomorrow morning when you expect a slow crank why not take a reading from the starter , if power is getting there then there's no wiring problems .

 

[Steve Wright]

Yup, 12v setup with two batteries in parallel. No, the batteries are not the same, I know for longevity and reliability they should be but to be honest, for the last 15 odd years I've never had the same kind of battery and never had a problem...

I checked back the voltage on the batteries today and one was 12.68, the other 12.64 so I would say they're both fine? Your idea on starting it with one battery sound like a fair test. I might just have to bite the bullet and remove all cabling and check/replace them if I don't see anything obvious with the batteries.

Hi Beau
I think using batteries that are not a match pair you have been lucky, as a ex service engineer working with batteries we were told to fit as a pair of a set if more, as when you put a new one in it pulls down the older one.
The other thing you say about the voltages I assume you have measured them off load, what you need to do is measure when starting, but when there is two involved you would have to disconnected one and measure the voltage as you start it and then do the same with the other and I would say you will find one dropping down to say 7/8 volts where should be higher that about 10 volts.
The thing to try is a "drop test" on each battery.

My two peneth is as you put a new battery on and when its cold it pulls the older of the two down too much but when it warm it turns it ok to start .

 

[tim falce]

I have the same problem when it's getting down to near zero degrees, the only time it's OK is if the battery has been on charge, I even replaced a battery under warranty a year ago, it was again fine until this year when the problem started again. One thing that helped was changing the oil from 10/40 to 5/30. I think there is a common problem with the electrical system draining the battery on these when not in use but no one seems to know what it is. Mine only has one battery btw