I think I may have the dreaded current leak problem. I have noticed that the truck has been getting progressively slightly harder to start. Went to start it today & it cranked a few times but didn't fire.
I bought quality batteries 4 years ago, $500 worth. I know these trucks pound the batteries during starting. Could it just simply be that 4 years is all I should expect from batteries? Or, should I be looking for something deeper - like BrianB's quest to find leaking current?

Last time I ran the truck was a week ago. I was watching the volt gauge on the way home and it was holding 14.2V with the high beam on running at 90kmh - so I figured that at least the alternator is healthy.

 

Simon,
I still have not been able to track down my drain.
I have taken to leaving it on a trickle charger any
time I have it garaged.
I also bought a small "briefcase" solar panel charger
to keep it charged when I am away from 240 volt outlets.
It solved the problem but it's an ugly solution.
I can give you the Jaycar product number of the solar
charger if you are interested.
I will be very keen to hear about any solution you
come up with.
Best of luck mate.

 

I had a similar problem in our Maverick.

Fortunately it's easy to isolate the positive terminal from the fuse block.

I put a digital ammeter between the positive terminal and the end of the lead to the fuse block. Then started pulling fuses.

The first one I pulled is the one that provides constant power to the clock and radio.

After pulling this it still showed about 0.5 amp drain.

So I just kept pulling fuses until it showed no current drain.

It turned out to be a fault relay in the glow plug circuit.

Hope this helps.

 

Glow plug relay, thats one more thing to try.
Thanks for the tip.

 

Actually I may pull the lead from the Glow Plug Relay, and tape it up, and see how the batteries hold their charge with it disconnected. I have done the AIH delete, so I can just cycle my AIH relay to the GPR if I fing the GPR is the cause of my current drain.

For the moment the truck is on a trickle charger and fired up without hesitation this morning - on full batteries.

 

It might be worth knowing what voltage your batteries have when starting - unplugged. This won't help you understand whether its batteries or if you have a current leak - but if its just a slow start issue, it could be low battery voltage (from either dead batteries or current draw), or another issue entirely - glow plugs, glow plug relay, injectors etc.

It sounds like an electrical issue, but can often be helpful just to eliminate some other causes.

I highly suspect the GPR. Australian climate means the glow plugs aren't really needed, and as a result you don't know when the GPR is dead. It burns a LOT of current, and if the weather is a little cold, can easily give no-start.

 

Thanks Adrian. We're having some sub-zero nights here in 'berra now. I've got the Edge Insight showing volts. I'll have to take the time to let it boot up and note the volts before each start.
I know when I had the battery charger connected, I'm pretty sure the GPR was cycling on and putting a >6 amp load out of the charger which promptly timed out. At that point the volts went to <10 volts on the gauge.

 

Ok, best of luck. I know you can get GPR's for 7.3's stateside for about $25, it may be worth just throwing one at it and see if that fixes the problem - they all die eventually.

 

I'll remove the current GPR and replace it with the AIH relay, which has been sitting there doing nothing since I did the AIH delete (and probably never came on before that either for that matter). I'll let you know how I go. Got some simple wrenching for this w/e!

 

Checked the GPR and AIH relays. 12V unswitched to the +tve pole of the relay. No voltage at the opposite pole when off. When on I have 9V at the opposite pole of the GPR relay - I assume the glow plugs are draining the circuit of 3 volts. As soon as the relay clicks off its back to zero volts on the opposite pole.
So preliminary tests seem to rule out the GPR.
When off, none of the under-dash fuses have any power.

Next I'll have to check the under-bonnet fuses. I take it that they're in the black rectangular box near the brake booster?

In the meantime the truck is on the trickle charger - hovering around 2amps of input after a few cycles of the key and running lights. Done to 1A of input after over-night charging.

 

How much current is draining?
A faulty alternator will consume around the 2.5 to 3amps.

 

Alernator is pushing 14.2 volts when running with the lights on high beam (200w) + 200w of driving lights, and 14.3 volts lights off.

I'm thinking maybe the sealed Century batteries are going south after 4 years. At least they're going south slowly I guess.

Checking out the Optima yellow top spiral cells - there is a local supplier here. $385 a pop advertised price but are supposed to last for 6 to 8 years.

 

Have you used one of those battery testers that measure the
battery voltage across a dummy load?
They are not expensive and most car parts places will have them.
Better than $770 worth of batteries that you don't need.

I have spent many hours researching batteries and have come
across an equal number of both good and bad reports about
Optima batteries so I am still not convinced.

 

Thanks BrianB. I will invest in a battery tester. The Century have an indicator window which is supposed to show green, black, red. They used to be very green. Now they show black with the slightest green tinge. Hence my suspicion regarding the batteries heading south.

 

If you want, you can take your truck to Kmart auto, and they will test your batteries free of charge.

As for batteries, with the exception of my motorbikes, I personally usually just buy the cheapest ones with decent CCA, with some rare (and expensive) exceptions, like Odyssey, I find they all seem to last the same amount.