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1hz wont glow

Posted: Thu Feb 10, 2011 5:53 pm
by wagone
Hi all i have a 1hz in a 75 series and it uesd to glow and start fine. eg glow for a few seconds, crank then start strait away. Now when i turn the key on the glow light just flashes on for a split second then stops, so its not glowing long enough. It will still start because its a fairly healthy engine but it is harder than usual. I have replaced glow plug timer relay and it is still the same :(

Re: 1hz wont glow

Posted: Fri Feb 11, 2011 9:02 am
by keencdk
[b]Fusible Link[/b]
On a HZJ80 there is a fusible link from the battery, and I assume the same on a 70 series with 1HZ. Check that as this can blow when glow plugs short out. Mine had actually been replaced with standard wire and it showed 12V at both sides (continuity), however it was feked and could not carry the current required to glow the plugs. When I removed it, the strands were so brittle they fell apart when I removed it.

[b]Relay[/b]
When you (or a helper) turn the key to glow you should hear the relay clunk in. If there is something amiss it will probably only clunk in then clunk out a second later. Hold a multimeter on the buzz bar and get someone to turn the key to glow. You should get the glow plug voltage, which I think is 12V for a 1HZ. If this is the case the relay is working OK

[b]Glow Plugs[/b]
Take out all the glow plugs and inspect for burnt ends. If you have a multimeter check for continuity as well. If the glow plug voltage is 12V, you can apply 12V for maybe 0.5 to 1 second to the glow plug. It should get hot at the tip if it is working correctly.


The glow plug timer circuit etc is a pita to be honest, 2 relays, a resistor, a timer circuit and a fusible link. I replaced mine in my 80 series with

Battery - fusible link - glow plug relay - glow plug buzz bar

Activation on the relay was via a simple push button on the dash. Give it 5-7 seconds and she would start first time every time, and troubleshooting was simple as.

Re: 1hz wont glow

Posted: Fri Feb 11, 2011 7:12 pm
by cambo-84
going through the same thing with mine, glow plug relay ended up being the problem. Toyota want $215 for a relay :bad-words:

on the hunt for a 2nd hand one

Re: 1hz wont glow

Posted: Sat Feb 12, 2011 7:59 am
by wagone
thanks heaps guys i have a set of glow plugs on order. Ill fit them monday night and post back as to how its going.

Re: 1hz wont glow

Posted: Sat Feb 12, 2011 5:41 pm
by mrfras
Hi All,
I had a simmular problem with my HJ75 years ago & it turned out to be the relay as said Toyota wanted heaps a new relay so went to Repco & brought a remote starter soleniod & replaced it with that got to be carefull as Toyota relay has 2 thin wires 1 is from switch other 1 is earth, remote doesn't need the earth connected as they earth thru body

Thanks
Fras