Glow plugs dont cycle

[blowinsmoke4life]

jus this week my glow plus havent been cycling and it been cold morning lately and i hav to use either and all i hear is a constant clicking noise in the engine bay wen the keys turnrd forward to cycle the glow plugs. any ideas thanx

[DAYTONA392005]

Originally Posted by blowinsmoke4life

jus this week my glow plus havent been cycling and it been cold morning lately and i hav to use either and all i hear is a constant clicking noise in the engine bay wen the keys turnrd forward to cycle the glow plugs. any ideas thanx

I think they are on a timer....it may be bad.

A place I used to work had that prob with one when the timer was replaced prob went away.

[bigcountrysg]

Originally Posted by DAYTONA392005

I think they are on a timer....it may be bad.

A place I used to work had that prob with one when the timer was replaced prob went away.

I have the same problem right now. I replaced the gpr, glow plugs, and then I had to replace an injector. But I am still having cold start issues.

On the IDI engines I believe there is a glow plug controller that is in a water jacket somewhere. Should be somewhere by the thermostat.

[FordGuy100]

On a 7.3 IDI, if the glow plugs fail, that is what it will do. Get your hands on a ohm meter, and test the glow plugs with the engine cold. They should read less than 1 ohm. If its more than 1 ohm, then they are bad and you have to replace them. Only use Beru or motorcraft glow plugs! Others are known to swell in the head and break off, not good.

Your glow plug relay will be at the back of the passenger side valve cover I'm pretty sure. My controller failed so I wired it up to a momentary on switch in the cab (6.9 controller is known to fail in the on position frying the glow plugs, mine didnt though )

[forddieseldoctor]

There is no temp sensor for the glow plug controller. it senses engine heat based on resistance of the glow plugs. this is why when one burns out it doesn't work right. check ur glow plugs and the harness for opens. be careful to make sure you don't accidentally make contact with fuel line and get a good reading on a bad plug.

[SCUFFY828]

ill agree , if the resistance back to the relay is too much then the relay wil just click back and forth as soon as you hit the key

[Clydesdale]

I had the same problem..... I had 2 wires disconnected off the glowplugs but mu glowplug relay controller was also defective; it's ok now.

[PRESTROKER]

Originally Posted by FordGuy100

On a 7.3 IDI, if the glow plugs fail, that is what it will do. Get your hands on a ohm meter, and test the glow plugs with the engine cold. They should read less than 1 ohm. If its more than 1 ohm, then they are bad and you have to replace them. Only use Beru or motorcraft glow plugs! Others are known to swell in the head and break off, not good.

Your glow plug relay will be at the back of the passenger side valve cover I'm pretty sure. My controller failed so I wired it up to a momentary on switch in the cab (6.9 controller is known to fail in the on position frying the glow plugs, mine didnt though )

You have a "how to" on hooking up the momentary switch? I believe mine is the glow plug controller as well. When you light up the glow plugs, the "wait to start" light is only on for 2-3 seconds and then goes off. This is in 35* weather. I use my block heater at home, but when it sits at work for 8-10 hrs. it is hard to start..

[FordGuy100]

Originally Posted by PRESTROKER

You have a "how to" on hooking up the momentary switch? I believe mine is the glow plug controller as well. When you light up the glow plugs, the "wait to start" light is only on for 2-3 seconds and then goes off. This is in 35* weather. I use my block heater at home, but when it sits at work for 8-10 hrs. it is hard to start..

I will try to walk you through it. First off what year is your truck? I dont know if the 87 on up model years are a little different.

You will need a momentary on toggle switch of some sort, mine is off in the middle an on if you push or pull the switch. You will need a in line fuse holder (parts store) and a 10-15amp fuse for it. Look at the passenger side fender well. If your standing at the front of the truck its right past the battery, and will have two fairly big red cables runnng to it on opposite ends of it, it will then have to small (like 12-14gauge) wires running into the other ends of it.


Towards the engine
-----------------------------Small wire-------------------------

----------Red wire------------------------------Red wire-------Front of
truck
----------------------------Small wire----------------------------
Towards the outside of the fender

Its aranged like that.

Take the small wire towards the outside of the truck off, its supposed to be a purple color but mine was faded and brown. To test that its the right one, take some 12gauge wire, and strip both ends. Put one end on the positive side battery terminal, then put the other end on the post that the wire came off of. You should hear a loud click, that is the glow plug relay applying power to the glow plugs. You might wanna hold it there for good 8 seconds, take it off, and try to start the truck. If it starts up easy than you know your glow plugs are still good.

So then you will have to take some 12 gauge wire and attach it to the positive side battery cable. I crimped on an eye style connection so that I could tighten the nut onto it on that post on the battery cable. Run that to the in line fuse holder. After that run that battery cable into the cab and t your switch. The switches are a little different so you will have to test it out. You should have power going to it, but not coming out when in the off position, and obviously power coming out when its on the on position. Now run the power cable (the one that is hot in the "on" position) back into the engine compartment. Crimp on a fitting so that it will attach to the small little post that the purple wire came off of, and find a nut laying around that will go on it (we have a bunch of coffee cans full of misc. nuts and bolts so I just went through them till I found one).

If your glow plugs are all good, then it should start up good. For 50+ degrees outside use a 8 second glow. For around 32* use around a 10 second glow. And as temps approach 10* on down, you might wanna use a 16 second glow (thats what the relay would do at those temps. If your truck doesnt start after that, wait a minute and give it around a 12 second glow, after the initial 16 second glow I wouldnt go more than 12 seconds for risk of burning the glow plugs).

Its alot simpler when you actually jump into it and do it.

[PRESTROKER]

My truck is a '93 IDI 7.3. I'll check it out when I get home..