1HZ glow plug issue. (1 Viewer)

[Tyson801]

Hey everyone im having dramas with my old hzj80. I've tested volts from negative battery to busbar wires for glow plugs however im not getting anything. I've installed all new NGK glows and tested them with a multimeter and there all good.

My dash light comes on for about 1 second then quickly turns off if I turn the ignition off and then back on it doesnt re appear im unable to double glow the system. Looking at the wiring circuit I noticed a fusible link coming off the pre heat timer. I located the one off the battery and that is fine however I'm not sure where the other FL is (marked in yellow). I suspect this has blown.

Any thoughts or help on what the issue might be would be great

 

[Gerry McGerry]

I don't remember having that fusible link in my HZJ harness, can check tomorrow. Check for continuity between the bus bar and that black/yellow wire from the preheat timer (behind) glove box.

 

[Tyson801]

I don't remember having that fusible link in my HZJ harness, can check tomorrow. Check for continuity between the bus bar and that black/yellow wire from the preheat timer (behind) glove box.

Will do mate. Strange isn't it ? I thought the only one was at the battery.

 

[Gerry McGerry]

The timer box is relatively easy to open up and check for any damaged circuitry. Other than that you can bench test both relays, also if your charge warning light doesn't work you won't get glow.

 

[Tyson801]

Yeah I'll bench them in the morning. Thanks mate I'll check out the battery warning.

 

[Tyson801]

Battery warning light all good . I'll check relays in morning. I was messing about under there about a month ago with AC wiring and I think i accidentally shorted a wire out on the pre heat timer. I could have blown the FL off pre heater.

 

[Tyson801]

Getting reading from BY to glow busbar so that fusible link seems to be fine. Im guessing the relay has gone or the glow plug timer itself. The glow plug relay seems to be behind the fender bit of a dog to get to. How do I bench test the relay ?

 

[Gerry McGerry]

Getting reading from BY to glow busbar so that fusible link seems to be fine. Im guessing the relay has gone or the glow plug timer itself. The glow plug relay seems to be behind the fender bit of a dog to get to. How do I bench test the relay ?

There are two relays. The one in the fender is the glow sub-relay, glow main is on the inner fender arch.

Unplug the connector to the relay that has the smaller wires. Apply 12v+ to the plug and ground the remaining pin, listen/feel for a click.

Easy test is to get someone else to turn the key to ign while you touch the relay, you'll feel it latch.


Just curious, I know you said you're not seeing voltage at the bus bar but is the engine hard to start? The glow light doesn't stay lit very long anyway, and leaving the key on ign for a few seconds longer will still continue to glow the engine regardless of what the light on the dash indicates.

 

[Tyson801]

There are two relays. The one in the fender is the glow sub-relay, glow main is on the inner fender arch.

Unplug the connector to the relay that has the smaller wires. Apply 12v+ to the plug and ground the remaining pin, listen/feel for a click.

Easy test is to get someone else to turn the key to ign while you touch the relay, you'll feel it latch.


Just curious, I know you said you're not seeing voltage at the bus bar but is the engine hard to start? The glow light doesn't stay lit very long anyway, and leaving the key on ign for a few seconds longer will still continue to glow the engine regardless of what the light on the dash indicates.

Yeah engine is very hard to start cold glows dont work at all. Puffs a massive amount of white/black smoke and takes a while to fire up. Once warm and ran it fires up right away. The light indicator goes out super quick like 1 second. Before it used to stay on for a few seconds before disappearing ive also waited 15-20secs with ign on with no change.I've been trying to listen or a relay click but I'm not hearing anything.

I've ordered a new relay that lives behind the fender ill pick it up tomorrow and see if anything changes.

 

[Tyson801]

Relay seem fine. i could feel em click over. Could it be the Resistor ? if so how do i test it ?

im leaning more towards the glow timer not doing its job it seems everything else is and im getting connections between all.

 

[Gerry McGerry]

Could it be the Resistor ? if so how do i test it ?

Good info in these threads:

No after glow - resistor issue? (1HZ 24 volt)

I've had my 24v hzj77 for a year now, and have really enjoyed getting to know it. One of the things I was always impressed with was how quickly it started, even in the cold. In the time I've owned it, I've done a lot of maintenance to get it up to what I consider a baseline. This includes new...

forum.ih8mud.com

Super Glow - explained

I have recently had a problem with my Super Glow system. During my initial diagnosis of the problem I read a great deal about Super Glow - much of it wrong, so I have drawn up a diagram of the workings of the system and done calculations to understand exactly how it works (well as close as I can...

forum.ih8mud.com

Seems like the resistor wouldn't be causing a hard start condition, but worth checking anyway.

Relay seem fine...im leaning more towards the glow timer not doing its job

Timer controls the dash light and the relays, sounds like it's doing it's job so far, or at least some of it's job. Check for voltage at the resister, relay & the bar right where the wire connects to the bar. Could be something silly like a cracked bar, not that I've ever heard of this happening.

 

[Gerry McGerry]

Just a thought, but there's a small round grey single wire plug on the passenger side wheel arch, pretty sure it's from relay to resistor. Mine had come loose and gave me glow issues until I noticed it. Slim chance, but possible.

 

[Tyson801]

Just a thought, but there's a small round grey single wire plug on the passenger side wheel arch, pretty sure it's from relay to resistor. Mine had come loose and gave me glow issues until I noticed it. Slim chance, but possible.

Cheers mate. I will check it all out. I checked
continuity from positive battery to bushbar wire and was algood. Got connection from pre heat to bushbar to. Everything seems OK . I'll pull relays and bench test them properly and test the resistor and check all connectors. Cheers. Mate.

 

[Tyson801]

Have power going to pre heater but no power out via the black and yellow from pre heat to glow busbar. Think the problem is the pre heat timer itself has s*** the bed. I pulled it apart but couldn't really see anything burnt or unusual. Not sure how to test the board but ordered a new one.

Tested relay #1 and relay #2 both seem to be fine. So that tells me all wires connected to relays are fine coming from pre heater. But no power out of the pre heater via BY.

Im at a loss what to do if a new pre heater doesn't fix the issue.

 

[Gerry McGerry]

I think + power goes from the bar to the timer rather than timer to bar. Bar gets it's power from the relays, timer needs to sense what voltage the bar is receving.

Hopefully the timer sorts it out, but if it doesn't here's what I'd look for:

A bad relay can still 'click'. Did you test them for continuity when closed with a multimeter or just by hand?
Double check that fusible link at the battery.
Check continuity across the bar to make sure it's not cracked.
Potentially the glow water temp sensor has bunged up and telling the timer the engine is constantly warm.

 

[Tyson801]

Checked water temp sensor even unplugged it but still doing same thing. All relays have been replaced. Timers been replaced. Check bar for continuity and all other connections are okay.

It's still not glowing.

 

[Tyson801]

Yeah bench tested all relays with both 12v supply and a multimeter.

 

[Tyson801]

Moving on from this issue its costing me alot of money for parts. I just put in a 70A relay (probably abit small) with 10AWG wire from battery with a inline maxi fuse i then ran 10AWG to busbar and then 12v via a momentary switch. Everything's working fine no more rough morning starts .