HJ60 Starting voltage issue (1 Viewer)

[FatlessLemon]

Hello all, I have an 86 HJ60 with the 24V battery system.

When I start the truck up in the morning it feels like it has a bit of a weak start. When I turn the key to warm up the glow plugs the voltage reading reads about 18V and then I hear an audible click and it jumps up to around 20-22 volts. It starts a little weak and then it's fine.

After it's been running and I drive it around when I shut it off and go to start it back up it starts at around 18V again but this time I hear one audible click and the voltage reads 20-22 but then I hear another click and the voltage reads 24V and it starts very strong.

Any reason why this is? I also notice until I start driving or I give it a blip of throttle the filter light and lights on the dash are all on, and the alternator doesn't seem to be charging, it only reads 18V. Once I give it a blip all lights go out and the voltage reads 26V.

Thanks all.

 

[duncanrm]

Hello all, I have an 86 HJ60 with the 24V battery system.

When I start the truck up in the morning it feels like it has a bit of a weak start. When I turn the key to warm up the glow plugs the voltage reading reads about 18V and then I hear an audible click and it jumps up to around 20-22 volts. It starts a little weak and then it's fine.

After it's been running and I drive it around when I shut it off and go to start it back up it starts at around 18V again but this time I hear one audible click and the voltage reads 20-22 but then I hear another click and the voltage reads 24V and it starts very strong.

Any reason why this is? I also notice until I start driving or I give it a blip of throttle the filter light and lights on the dash are all on, and the alternator doesn't seem to be charging, it only reads 18V. Once I give it a blip all lights go out and the voltage reads 26V.

Thanks all.

The click is likely your Superglow system doing its thing. Superglow will stay on the lower voltage for a short while in the mornings - this may account for your slower cranking speed in the morning. Superglow starts a higher voltage glow for a few seconds then drops to a lower voltage glow - even through the cranking process.

 

[FatlessLemon]

The click is likely your Superglow system doing its thing. Superglow will stay on the lower voltage for a short while in the mornings - this may account for your slower cranking speed in the morning. Superglow starts a higher voltage glow for a few seconds then drops to a lower voltage glow - even through the cranking process.

Hey thanks for the response!
Good to know, I've been reading into the superglow system and im still trying to wrap my head around it.

The lights staying on until throttle is given, is that normal operation?

 

[duncanrm]

It really shouldn't need a blip on the throttle .. but the vehicle is getting on in years and odd charging faults creep in.. if you could source a replacement alternator it'd be worth starting that process before you have to do it urgently. Your current one is probably externally regulated - most available replacements are going to be internally regulated - keep this in mind, the wiring changes are not difficult but just so you're not ambushed by the problem..

 

[FatlessLemon]

It really shouldn't need a blip on the throttle .. but the vehicle is getting on in years and odd charging faults creep in.. if you could source a replacement alternator it'd be worth starting that process before you have to do it urgently. Your current one is probably externally regulated - most available replacements are going to be internally regulated - keep this in mind, the wiring changes are not difficult but just so you're not ambushed by the problem..

Okay noted, I'll start looking into sourcing one. I appreciate all the help thank you!

 

[sved]

Can be a ground issue.
Check ground cable on left motor mount and the one close to the starter that connects to the frame.
Quick test, connect starter / jumper cable between left battery minus and the engine block. See if that makes a difference.

 

[FatlessLemon]

Can be a ground issue.
Check ground cable on left motor mount and the one close to the starter that connects to the frame.
Quick test, connect starter / jumper cable between left battery minus and the engine block. See if that makes a difference.

Thanks for the advice I'll try looking into that aswell, there was definitely some wiring voodoo going on from the previous owners so it's worth looking into I think

 

[kouglof]

Hello, I made quite a significant dive into the superglow system, having it retro engineered (see this post)...
But as far as you describe it yours seems to be operating fine.

If you indeed have an alternator issue check your car battery voltage while powered off. In case of a low battery voltage the effectiveness of the preheat is reduced and that could lead to rough starts when the temperature is low...

Good luck !

 

[FatlessLemon]

Hello, I made quite a significant dive into the superglow system, having it retro engineered (see this post)...
But as far as you describe it yours seems to be operating fine.

If you indeed have an alternator issue check your car battery voltage while powered off. In case of a low battery voltage the effectiveness of the preheat is reduced and that could lead to rough starts when the temperature is low...

Good luck !

Ya I was scratching my head for awhile trying to figure it all out, I redid all my grounds and was still having issues. Turns out it was just a roach battery. I was confused because they were just replaced by the previous owner so they were relatively new but turns out it wasn't good. Replaced them both and it starts strong now, even stronger now since I've replaced all the grounds lol.

Thanks!

 

[45Dougal]

Might be worth checking your charging voltage again now you have a new battery.
If you have the external regulator, then it is adjustable. 26v sounds a bit low and could risk draining your new batteries too.

 

[Squash]

You should allow you glow system to power down before hitting the starter.
If you pay attention you can hear and feel the difference between a proper glow cycle and a start cycle while glowing.
Drives me insane!

 

[ceylonfj40nut]

I have had a hell of a time maintaining battery voltage on 24v HJ60. Even with new batteries. What helped some was getting a pair of batteries with the same manufacture month. I have a good used 24v alternator with vac pump if you need. Also have other 2H parts should you need.

 

[kouglof]

You should allow you glow system to power down before hitting the starter.
If you pay attention you can hear and feel the difference between a proper glow cycle and a start cycle while glowing.
Drives me insane!

For the sake of clarity and good understanding of the superglow system I would like to correct that
Superglow has 2 phases: preheat and postheat.
You should wait for the preheat to end (which is materialized by the dashboard light extinction) before starting but the superglow will not be off, it will just be in postheat mode using less current.