Hey there. I'm new to this area but not to the forums. I have a '71 Camper Special with a 7.3 IDI and C6 that I stuffed into it a few weeks ago (I love the way it runs!). And of course, I'm having glow plug issues. To make things simple I wired up a starter button to the glow plug controller so I could activate the glow plugs manually. Now, I know there has been alot of discussion about glow plug voltage but nobody seemed to clarify this. Problem is, my plugs ALL burned out within a week. I was using bosch plugs. Yea, I know, beru.... but bosch has always made a good plug in my experience. When I check the harness, I get 12.8 volts at all terminals. Basically, it gets power straight from the battery with an inline fuse when the button is depressed and I never used it for longer than ten seconds.
When they were all working, I would ten volts when activated. Does this seem off to anyone? Also, does the controller have a built in voltage regulator? What kind of voltage do you all have when plugs are activated? When I check plugs online, they all say 6V, even the 6.9 plugs. Is there such thing as a twelve volt plug? I know, alot of questions here....

Thanks, Sam

 

The plugs are 12 Volt plugs. Maybe you got 6 Volt Bosch Plugs by mistake.

About the only thing you can do wrong is to leave the power on too long. That is why factory system have the glow plug controller which basically measure resistance and shuts the power to the plugs. As each plug heats up the resistance to electrical current flow thru the plug increases which is measured by the GP controller and trips the solenoid in the controller that shuts the power to the plugs. If your cylinder is hot, the plugs won't even come on.

I now have over 100k on the Bosch plugs (Made in Germany) I put in my 93 F250 a few years back. They work fine. I got a replacement set of Beru plugs ready to go if the Bosch Plugs ever were to go on me.

Note, I had a really bad experience with Bosch Plugs that were made in Japan a few years back. They kept burning out one a week and by the time I got to replacing the 5th one I just replaced them all with ones that were "Made in Germany" and never had a problem since. I guess this reflects the common problem of vendors lending out their brand name to different manufacturers. I lost a lot of respect for Bosch products after that fiasco.

Seb...

 

The plugs are indeed 6V plugs. However, Ford ran 12V to them to make them heat faster. This makes them easy to burn out.

I had troubles with Bosch plugs burning out quickly on me as well. The Beru's are much better.

I use a push button system and get just under 13V measured coming out of the GP relay. However, unless it is very cold I do not fire them for more than 7 seconds.

Hope this helps.

 

Do you have a relay wired into the system?

Glow plugs draw about 200 amps on a cold engine.

 

Ok. Yea, the glow plugs are the Japanese ones. I just ordered a set of Motorcraft/Beru ones so I'll try those. Yes, I'm still using the original relay, but have wired up a switch to control it manually and disconnected the controller.

-Sam

 

Use a momentary switch, spring loaded to off.

To easy to bump a switch to the on position and cook glow plugs.

10 seconds is my standard glow time in the winter.

Summer with warmer engine temps 6 or 7 seconds is plenty.

Below -10, well now I usually increase the glow time to 12 or 13 seconds.

 

all of these glow plugs are 6 volt plugs
they heat quickly at 12 volts thats why the controller cycles them
too long of an on time and they burn out

 

Minimum voltage to the plug should be 9 volts........if you have the solid state controller and it worked before use it........ The solid state system can't be beaten if it is serviceable/works.