1HZ glow system problems.

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lshobie

lshobie

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Hi Guys, I have a 2004 HZJ79, it is fricking cold here now and it is starting very badly now.

I tested the glow plugs, they are new and fine (edit, tested them wrong so I need to redo that part), I disconnected the water temp sensor and checked voltage to the glow plugs, I got 11.09 volts at start and it climbed over 12 volts and then shut off all votage after 9 seconds, then instantly the volts come back up to 12V for about 3 seconds then shuts off - then no more voltage to the glow plugs.

So, I bought a new glow plug relay and preheat timer and installed them - still no difference. I see in the engine manual that there is a glow resistor to check - but mine doesnt have a resistor that I can find anywhere - looks like there is a place in the intake man. where it can screw in but never looks like there was one in this.

Fuseable link is new, complete main wire harness is new.

It used to start great on the coldest days of minus 30, now it is just bad.

What am I missing? There is nothing else new to buy that I know of.

Can someone please check their 2004 HZJ79 and see if you have a glow resistor in the intake manifold.

Any help would be greatly appreciated.

It is to the point that it is even hard to start after it is plugged in. If one glow plug were bad would it cause the timer to mess up? The glow plugs are new last year and I dont suspect there is a problem with them.

And no I don't want to install a wilson switch on my truck - the preheat system is a good system and works very well - when it works:)

Thanks

Louis
 
works well when it works... yep
but
it isn't so go wilson and quite dropping good money after bad...

another classic remark:
plugs are new so there can't be a problem... buddy... recheck to confirm.

yes, i have to agree completely, when the glow system on a HZ works, they are one of the easiest diesels to start at any temp...
 
Hmm,

You have a 24v. set up, so your preheating cycle, at -30c. temps, should be on the order of a bit more than 30 seconds.

While you have replaced the timer, have you checked that the water temp sensor is functioning properly? At -20c., the resistance should be between 15~20Ω.

Which relay did you replace, the main or sub-relay?
 
lshobie said:
Can someone please check their 2004 HZJ79 and see if you have a glow resistor in the intake manifold.

Any help would be greatly appreciated.


Thanks

Louis
Click to expand...

Do 75s have it?
Have tried temporarily disconnecting the relay and warming the plugs direclty from the battery? It would isolate the problem.

I know how you feel about the 1HZ glow system ,mine does the job in 3 seconds regardless of the temp.
 
This is a 12V system on my 79 series. The water temp sensor doesnt seem to be the problem as I eliminated it from the circut by unplugging it - the plugs only glow for 9 seconds with it unplugged.

I can try direct power from the battery but the relay is new as well.

I saw somewhere that the alternator has something in it that tells the timer when the engine is running so it shuts the full voltage off - no idea if that is true.

If the timer is new and the relay is new, and there is no resisitor, and the wire harness is new there should be a simple explanation. All the grounds seems to be good.
 
the glow is tied in with the charging system, if the charging system goes down then the glow is shut off...
 
Go from the battery
 
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