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2.8 glow plug fault finding

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2.8 glow plug fault finding

Postby magicdeo » Sun Jul 02, 2017 6:19 pm

Gday, i own a 2.8 rodeo. I have been testing my glow plugs lately and they test fine. The only thing is that when i glow it, the voltage starts at 10.3v and slowly climbs up to 11.2 by the time it stops glowing. I have noticed the power at the CSD solenoid does exactly the same thing. Does anyone elses 2.8 do this? When i start it cold, the revs start very low and after a couple of minutes the engine will rev up. Is this normal? Thought maybe the power at the fuel shut solenoid might also be rising slowly and opening the solenoid more??? Not sure. Cheers
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Re: 2.8 glow plug fault finding

Postby geeves » Sun Jul 02, 2017 7:36 pm

Glow plugs sound normal but your battery might be on its way out.
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Re: 2.8 glow plug fault finding

Postby magicdeo » Sun Jul 02, 2017 9:14 pm

Thanks geeves. My battery is a century and is only a couple of months old and seems to be working fine. I understand that the voltage at the glow plugs wont be as high as the battery but I dont understand why the voltage would be low and slowly increase while it is still glowing? I thought the solenoid would have 12v though?
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Re: 2.8 glow plug fault finding

Postby geeves » Mon Jul 03, 2017 5:40 am

what cca is your battery? With the engine running just above idle what voltage do you have at the battery? How clean are your terminals?
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Re: 2.8 glow plug fault finding

Postby magicdeo » Mon Jul 03, 2017 5:34 pm

The CCA are 720. Terminals are clean and the alternator puts out 14.1v
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Re: 2.8 glow plug fault finding

Postby geeves » Tue Jul 04, 2017 5:33 am

glow plugs draw 90 amps
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Re: 2.8 glow plug fault finding

Postby magicdeo » Tue Jul 04, 2017 8:39 pm

So what are you saying? I understand i wont have full voltage at the plugs but what i dont understand is why voltage at the plugs and the CSD solenoid slowly creep up. I thought they would remain the same volts or if anything drop slightly as the glowplugs suck power from the battery?
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Re: 2.8 glow plug fault finding

Postby geeves » Wed Jul 05, 2017 10:28 am

As the plugs heat up the resistance increases so voltage goes up. Try the voltage test at the battery
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Re: 2.8 glow plug fault finding

Postby magicdeo » Fri Jul 07, 2017 12:14 pm

I was recommended by a diesel shop to unplug the wire on the thermostat housing. I thought that by doing that you will always send power to the CSD but they insisted that after a minute or so the power would turn off from there and it would return to normal? Is this true? If that doest work does that mean my timer is faulty?
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Re: 2.8 glow plug fault finding

Postby geeves » Fri Jul 07, 2017 7:07 pm

The timer on the 4jb1 is controled by the coolant temp. Above 5C the glow is 0.5 seconds. Below is is about 30 seconds. Removing this wire tricks the system into believing it is cold. It does also advance the injector timing when cold so it will knock loudly
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Re: 2.8 glow plug fault finding

Postby AndySaraSonia » Thu Aug 24, 2017 5:20 am

Hello to everybody;
I read the post and I have another question about this matter:
My Isuzu, in hot place (summer in Barcelona), always activate the grow plugs during 12 seconds approximately (because I check the relay), I start the motor, but the light in the dashboard never disappear (lighting), and I know that the grow plugs are off (the voltmeter increase again)
Anybody can tell me if some of the thermostats are out of works???
Or is another reason???
Thanks in advance
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Re: 2.8 glow plug fault finding

Postby tonkamu » Fri Sep 15, 2017 3:03 pm

Hi I just would like to know something I've always wondered.
The 2 sensors on the thermostat housing.. the 1 wire coming out sensor is that for the glow plug cold start you're mentioning? and the 2 wire sensor for the idle increase?

I have the 4jb1 engine.
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