2002 100 series Landcruiser charging delay

Submitted: Sunday, Aug 09, 2020 at 16:57
ThreadID: 140349 Views:8143 Replies:4 FollowUps:6
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Hi my grandsons 100 series dash lights are staying on after start up and do not go of for a minute or so.
Testing with a multi meter there is no charging until lights go of then charging commences as per normal .
Vehicle ticked over 600k as this problem commenced is this a coincidence ?
Has a duel battery set up ,both crank together.
Any ideas much appreciated ,I am leaning to alternator or regulator .
Regards Garny

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Reply By: RMD - Sunday, Aug 09, 2020 at 18:16

Sunday, Aug 09, 2020 at 18:16
Two things I can think of.
1. If it does it after a cold start it may be the intake heater current drain keeping the charging from happening until it switches off. That can be verified by having a multimeter reading the heater solenoid output terminal, and if it shows it switches off at the time charging begins, then that area needs looking at.
2. The alternator may have blown a diode which will reduce it's output by 2/3rds which will greatly slow it's ability to bring up the voltage of the battery, particularly if the intake heater is ON . Therefore the regulator won't be getting much rotor field current if its a exciter diodes are also compromised. If you switch on most appliances when charging is happening the alternator should hold a good healthy voltage, ie, 12.6v . If not , then the diodes are not good and healthy.

PS. Are the batteries fighting each other. ie. Duelling? OR does it have DUAL batteries as in 2?
AnswerID: 632881

Reply By: Athol W1 - Sunday, Aug 09, 2020 at 20:43

Sunday, Aug 09, 2020 at 20:43

You are describing exactly what happens when the Alternator brushes get sticky or are nearing the end of their life. Time to get an alternator overhaul or replacement.

What you are describing as a duel battery setup is nothing more than both batteries operating as one, and was just a matter of Toyota using cheaper batteries. It is easy to fit a better battery to the left side for starting purposes only, then fit a VSR to the right side battery which can be fitted with a deep cycle battery.

AnswerID: 632885

Follow Up By: RMD - Monday, Aug 10, 2020 at 08:30

Monday, Aug 10, 2020 at 08:30
I agree the brushes may be worn , but if it regularly starts charging after a similar time after each start, maybe not brushes. It apparently charges normally when started. If brushes are stuffed it isn't going to keep doing that is it? If the charging was intermittent then suspect brushes.
FollowupID: 909799

Follow Up By: Athol W1 - Monday, Aug 10, 2020 at 08:45

Monday, Aug 10, 2020 at 08:45
Experience tells me that what is being described often shows in the early stages of worn or sticky brushes, often just a short sharp increase in engine revs can get things going again until next cold start. This condition can slowly worsen, or can result in a catastrophic and sudden failure requiring all internal components to be replaced.

Still time to get some expert attention.

FollowupID: 909800

Follow Up By: RMD - Monday, Aug 10, 2020 at 09:25

Monday, Aug 10, 2020 at 09:25
Do you mean when brushes don't contact it causes catastrophic failure? Just the brushes not touching can mean no charge of course, but catastrophic failure is pretty strong. Yes replacement of brushed at minimum but hardly all internal components. I have rebuilt hundreds of alternators from small to large and the brushes worn out/not touching has never caused any failure of anything else in the alternator. It simply ceases to charge.

Brushes replace, slip rings cleaned or machined and new bearings is more than 95% of most failures, sometimes diodes if charge current output is low and alt can't maintain sufficient voltage.

Therefore the test of voltage and current output will confirm internal condition of major items, still worth checking brushes at 600K though if last replacement isn't known.
FollowupID: 909802

Follow Up By: Garny - Monday, Aug 10, 2020 at 20:38

Monday, Aug 10, 2020 at 20:38
Thanks for the responses I feel we are on the right track.
Will post a correct result next week as have booked the culprit into the experts for diagnosis .
FollowupID: 909821

Reply By: Member - DOZER - Wednesday, Aug 12, 2020 at 09:55

Wednesday, Aug 12, 2020 at 09:55
If its diesel, check the plug into the alternator, which are known to become loose in the connections
AnswerID: 632920

Follow Up By: RMD - Wednesday, Aug 12, 2020 at 11:47

Wednesday, Aug 12, 2020 at 11:47
Yes , can happen, my HJ61 was loose after about 17 years and simply stopped charging. Spade terminals became slightly corroded.
FollowupID: 909828

Reply By: JohnnyC - Monday, Aug 17, 2020 at 20:29

Monday, Aug 17, 2020 at 20:29
Hi Garny,
RMD is on the money, after a cold start the alternator is disconnected from the rest of the system and all of its output goes to the intake pre heater, to help reduce emissions,about 60-80 amps at idle and over 100 with a few revs.
Meanwhile the battery supplies everything else and sits between 11 and 12 volts, after up to a minute the alternator transfers over to its normal duties and the system voltage then increases to around 14 volts.
The fact that the warning lights stay on during this preheat period appears to be a separate issue.
AnswerID: 633013

Follow Up By: Garny - Tuesday, Aug 18, 2020 at 22:17

Tuesday, Aug 18, 2020 at 22:17
The problem has been solved I had the alternator replaced and the dash lights have returned to normal .
Charging is as per normal as well.
FollowupID: 909929

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