Hey guys I've been having some issues and can't seem to figure it out. This is on a 1990 Hilux Surf. I changed the fuel filter yesterday and when I went to go start it up it was slow cranking and then nothing. It has been getting harder to start the vehicle for about the past week (lots of cranking before start) and I guess it finally decided not to start. I went to go check my batteries (dual set up for diesel), and both read at 11.9 V. So I jumped the truck and tested the voltage after letting it run a bit and both batteries are at 12.5ish. Tested the alternator and that was also reading at 12.5ish. It starts at the moment but the batteries both read under 12 when the engine is off and I'm not sure how long this will last. I need it to run and will not always have access to another vehicle to jump and I have no idea what to look at. Anyone have any ideas?

Thanks,

 

First off, your alternator should be putting out 13.5+ volts at idle. Maybe double check that? It may not be charging.

 

It's definitely not reading above 13. Would that mean that I need to replace the brushes on the alternator as is it not charging?

 

T'were it so simple! Start by doing the standard tests: http://web.archive.org/web/201102051.../2onvehicl.pdf While a really bad brush can reduce output, there are a lot of places I would look first.

Is your "alt" light on? If it is, well, why did you ignore it? If it isn't, I would suspect a bad wire from the Alternator B terminal (the big heavy one). (The alternator is putting out some voltage to turn off the alt light, but it's not getting to your battery.) How did you "test the alternator"?

 

The only light that I have had on was the water in fuel filter light which was why I changed it in the first place. I tested it by using a voltmeter and putting the positive lead to the alternator and the negative one to the neg battery post. It read the same as if I were just testing one of the batteries. I will have to check this other wire to see if the connection is good.

 

Also just tried to start it again and all it did was slow crank until nothing. Now it won't start at all (unless I jump it again). At first I thought it was my starter but my batteries are essentially dead which means that they weren't charging when the engine was running. Is this even an alternator problem or are one of the batteries just not holding charge which causes it to leech from the other battery therefore killing both?

 

If you read 12.5 volts AT the alternator while the engine is running, then the alternator is not putting out any "juice." (even 13.5 is pretty low, at the bottom end of the spec for a hot alternator) I have no idea if your batteries are no good, but I know that they are not being charged.

Since you have a HiLux, I'm guessing you're not in the US. Where ever you are, do they test alternators at the auto parts store? If not, the link I gave you shows how to test the regulator; if not the regulator, then you need to repair or replace the alternator.

At a minimum, make sure that the three wire connector (three smaller wires, not the heavy "B" terminal) does not appear to be damaged. If the alternator is not receiving the "IG" line (red), it can't produce power (though, in that case, you should have the ALT light).

 

I will check the wiring first and see if that may be the case. I have some replacement brushes on the way from my local Toyota dealer but those don't come until Tuesday so it will give me some time to play around with the wiring. It could be the wiring and it's my dash lights that are broken (the turbo light likes to come and go as it pleases, yet I know the turbo works), so maybe that is the problem. If not then I'll pull the alternator and replace the brushes.

Also I'm up in Northern/central Alberta and the Surf was imported around a decade ago from Japan.

 

Load test the batteries. If you can't an auto parts store can. I'm leaning towards the alternator isn't doing its job. Jump it again and retest the alternator. Anywhere from 13.5 to 14.1 at the battery terminals shows a functioning alternator.

If your not getting any charge to your batteries check your grounds and all alternator wiring.

 

Just curious on this engine how do you prime the fuel system after the filter change ??

First you need to get your discharged batteries charged the only way is with a battery charger .

A alternator is not meant to charge discharged batteries .

This has a normal dual battery set up with a positive cable joining the two batteries .one cable to the starter the other to the fuse block

Then the two negative cables ground to the engine block and inner fenders .

All the terminals clean and tight .

Disconnect the batteries one bad one can pull the other one down .

This could be as simple as just drawing the batteries down and not recharging

Poor connection someplace

Cooked wire coming off the Alternator B terminal

One or both batteries bad

Shorted diode in the rectifier draining the batteries

Over lubricated the alternator from fluid leaks and spills