What is proper glow plug opperation?

[NapaBavarian]

Well, I think I might have screwed mine up, my truck has a little button under the dash and PO said he would push it and count to 25, worked great for a while, now dosn't do anything and I think I made an expensive mistake

 

[OldiesF250]

when i got my new plugs and tested them, they would get red hot in 5-10 seconds. i also remember reading somewhere that about 5-10 seconds is all you needed.

i would just say that you burned up all the plugs.

 

[The Warden]

What he said...these glow plugsa re actually 6 volt plugs with 12 volts of current going through them (thanks Ford! ). This means that, if they're left on for longer than a certain time, they'll burn themselves out...this is also why they heat up so fast.

Last I checked, the general consensus is that the plugs shouldn't stay on longer than 8 seconds without an 8 second "off-time"...

And, if you've got Autolite or Champion plugs in your engine, BE CAREFUL WHEN REMOVING THEM!!! There's a very real chance that at least one glow plug tip swelled up, and if it breaks off when you're removing the plug, there's a very real chance that you'll have to pull that cylinder head to get the tip out. If you get the piston to TDC before removing the plug, a broken tip will stay in the precombustion chamber, and you still have a prayer of getting it (a common technique is to pull the injector and stick a shop vac suction in there and blow compressed air into the glow plug hole to hopefully dislodge the tip and suck it out).

My condolences, but this is NOT going to be fun... You'll be lucky if all you need to replace are the glow plugs. When you buy new plugs, you're best off with Beru/Motorcraft plugs.

Good luck!!!

 

[Agnem]

The factory controller will hold them for as long as 12 seconds, but then cycle them for only a second or two after that for a minute or so. Using a push button is risky because there is no failsafe against someone doing what you did. A better option is my foolproof glow plug controller which you can build if you have any electrical/electronics experience for just a few dollars. It takes the guess work out of it, and prevents you from turning them back on too soon.

Schematic

 

[Nickbf2504x4]

napa, you must not have motorcraft/berus in there because they should only take 8-10 seconds with good batts in any situation... so be very careful when you take your GP's out

* on a more positive note...i had autolites in my truck that were burned up and they came out distorted but un-broken!*

good luck

 

[deanj]

Factory is around 10 sec's when cold, cycly for a few more sec's. When warm only on for 2-3 sec's. You probably have some burnt out, check using a meter or test lite. When changing clean out around the GP's (air or shop vac) Be carefull that the tips are not swelled, you do not want to break them off. Use anti-sieze on threads. Use BERU.

 

[OldiesF250]

i see some are saying (as deanj did) that you should still use plugs when the engine is warm for 2-3 seconds. after my truck is warm, it will fire right up within a 4 hour period with the GP's not on. is there a reason for using the GP's each time you start the truck?