what causes early glow plug failures? (1 Viewer)

[coldtaco]

Ok, what part of the glow plug system causes early death to glow plugs? I'm assuming over voltage? I replaced my glow plugs a year ago with 11V plugs. I checked them today and two have failed. Need to find new ones again :-(

 

[roscoFJ73]

What brand were they? Do you have the stock glow system?
Mine are 22 years old and have done 265000klms. My last 75 series also had the original plugs, so they don't die easy if everything is working properly.

 

[GTSSportCoupe]

Glowing too long or too many times will burn them out faster. Break apart an old one and you'll see it's just a tiny little filament coiled up in there.

 

[coldtaco]

Don't know what brand. It also has the wilson switch mod done, but I think the stock system was left in tact. The first time I started noticing something going weird was that the glow plug light stopped coming on. If you look at the light before you turn the key to Run you can see the light come on for just a fraction of a time (blink of the eye). When using the wilson switch I usually only have it on for 5 seconds, then after it runs hold another 5 seconds.

 

[vwluv10338]

I have a Wilson switch on my 2H and two large batteries wired together. Had the cheap relay stick and leave them on which killed my batteries flat. Still never had a plug go bad on that one

 

[coldtaco]

So, I took some voltage readings. The relay on the fender would stay on for about 22 seconds before going off. Taking voltage from those relays mounted to the intake manifold they both read about 10.5V with some fluctuations upward but never above 11V. But I did not find any half voltage from either of these relays.
I checked the bulb for the glow plug light and it is good. When you turn the key to on the light bulb just starts to come on when goes off.
Which of the two relays is suppose to read half voltage? or Both? What relay switches from full voltage to half voltage?
Still need to find new glow plugs.

 

[bj40green]

It also has the wilson switch mod done, but I think the stock system was left in tact.

Wilson switch is a mod to manual glow. If properly installed it can overrule the existing glow system.

So, I took some voltage readings. The relay on the fender would stay on for about 22 seconds before going off. Taking voltage from those relays mounted to the intake manifold they both read about 10.5V with some fluctuations upward but never above 11V. But I did not find any half voltage from either of these relays.
I checked the bulb for the glow plug light and it is good. When you turn the key to on the light bulb just starts to come on when goes off.
Which of the two relays is suppose to read half voltage? or Both? What relay switches from full voltage to half voltage?

This indicates that you have a "Super glow" system.

Dead glow plugs are not caused by over voltage. Your plugs are 11V, which is correct for a 12V system.
Dead glow plugs can happen if one of the relays is stuck in the "on" position, but if that's the case, it will also drain your batteries overnight.

All the info about glow plugs and glow systems is here; -► Which plugs should I be running - B, 2B, 3B, H and 2H diesels

Rudi

 

[gerg]

Long ago, when I bought my first cruiser, I had glow plug failure from too much advance. Like lots and lots of advance. It disintegrated the tips. Needless to say, it was a very bad idea.

 

[coldtaco]

so, what part of the glow plug system regulates glow time and does the switch over from full (11V) to half (6.5V)?

 

[coldtaco]

After some testing it appears the timer has failed, or at least part of it. Wonder if still available?

 

[roscoFJ73]

It shows it as being available but with different part numbers.
28521-68042 (08/1986 - 07/1987)1$572.65
28521-68080 (08/1987 - 07/1988)1$601.24
28521-68090 (08/1988 - 12/1989)1$601.24

HJ60 12v are using the same part number

But there are aftermarket types with adjustable timers that are probably a lot cheaper.

 

[bj40green]

This is the Super Glow for a HJ75

NOTE: The glow plugs are 6V
No. 1 Glow Relay = Pre Heat
No. 2 Glow Relay = After Glow
The Glow Plug Resistor takes care of the voltage drop

Copy from Which plugs should I be running - B, 2B, 3B, H and 2H diesels
Super glow 6V
Toyota 19850-68050 (or 68051), Denso DG220, Bosch GPT214, Champion CH125, HKT PT146
Here the Toyota engineers sped-up the pre-heating procedure by using faster heating plugs (lower voltage plugs). They also installed two stages of pre-heat, and automated both these pre-heating durations according to coolant/block temperature and other factors. The first stage connects the busbar directly to the battery (12V) and the second stage (after-glow) drops this voltage to somewhere close to the plugs nominal voltage (6V).
Like the "Fixed Delay system" there is again a glow light (pre-heat light) that is extinguished to tell you when to crank. However here it illuminates for a much shorter time. (Typically just 2 or 3 seconds.)

This is a Wilson Switch set up

NOTE: The glow plugs are 11V
Momentary switch, relay, 4 or 6 glow plugs.

Some people do this

NOTE: Doing this, you're frying your 6V plugs with 12V
If you have 11V plugs in this set up..... the timer won't work.

Rudi

 

[coldtaco]

Gonna have to try and figure out how the Wilson switch is wired. Thanks.

 

[gerg]

First, tell wife your re-engineering the glow system on your truck and your not exactly sure how long it will take. A fair statement actually with a non quantifiable time frame. That is the key....non quantifiable time frame....remember that one.....Next take a 10Ga wire from battery positive to heavy momentary switch at a place of your choosing, 10Ga wire from momentary switch to glow plug bar......Its that easy. Next lay the template for your snorkel onto your fender and plan how to cut it out. Choose the appropriate hole saw. Double check your measurements and start drilling. Lay the snorkel onto the fender and mark the pillar mounts.......once snorkel is done, inform your wife the glow system was a complete success and you got way more done that your had originally expected. .

 

[coldtaco]

First, tell wife your re-engineering the glow system on your truck and your not exactly sure how long it will take. A fair statement actually with a non quantifiable time frame. That is the key....non quantifiable time frame....remember that one.....Next take a 10Ga wire from battery positive to heavy momentary switch at a place of your choosing, 10Ga wire from momentary switch to glow plug bar......Its that easy. Next lay the template for your snorkel onto your fender and plan how to cut it out. Choose the appropriate hole saw. Double check your measurements and start drilling. Lay the snorkel onto the fender and mark the pillar mounts.......once snorkel is done, inform your wife the glow system was a complete success and you got way more done that your had originally expected. .

She knows better

 

[gerg]

Doh!

 

[brownbear]

So I have the 10.5 volt plugs. left the resister in place, and control my plugs with a push button. No light on the dash. I can tell when they are drawing by watching the volt meter.

I am going on 13 years with the same plugs. I live in Canada, so they get used on every start. I don't use my cruiser in the winter though,...

I feel it's okay to keep the resister as it's just a voltage drop, and could keep the plugs lasting longer, down fall is you use up a bit more amperage off the battery and could have cooler plugs. Advantage is I feel I can hold the plug button much longer. I even use it for afterglow once started to keep smoke to a min.

I'd remove the timer and simply go fully manual. With a push button on the dash. Something that cannot be left on like a switch. Has to be a momentary switch not a maintained switch.

 

[coldtaco]

Tested unplugging the timer, no more power to the glow plugs using normal system. Then pushed the "Wilson" switch and I got power to the plugs for as long I hold the button in. So, looks like this will work Got new glow plugs on order, 10.5V I believe.